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TABLES OF CONTENTS
CHAPTER

TITLE

1

INTRODUCTION

2

REVIEW OF LITERATURE

3

MATERIAL AND METHODS

4

RESULTS AND DISCUSSION

5

SUMMARY
LITERATURE CITED

PAGE

List of Tables
Sr
...
1

Physical and Chemical Properties of Soils

4
...
2

Cd adsorption parameters of the Freundlich adsorption equation
for Ca-10
...
3

Calculation of Freundlich Model for Ca-10

4
...
5

Cd adsorption parameters of the Langmuir adsorption equation
for Ca-10

4
...
7

Amount of Cd adsorption and adsorption percentage at Ca-20

4
...
9

Calculation of Freundlich Model for Ca-20

4
...
11

Cd adsorption parameters of the Langmuir adsorption equation
for Ca-20

4
...
13

Amount of Cd adsorption and adsorption percentage at Ca-30

Page No
...
14

Cd adsorption parameters of the Freundlich adsorption equation
at Ca30

4
...
16

Parameters for the Linear Form of Langmuir model

4
...
18

Calculation of Langmuir Model for Ca-30

4
...
20

Cd desorption parameters of the Langmuir desorption equation
at Ca10

4
...
22

Calculation of Desorption of Freundlich Model for Ca-20

4
...
24

Cd adsorption parameters of the Freundlich adsorption
equation at Ca30

4
...
26

Calculation of Desorption of Langmuir Model for Ca-30

4
...
28

Comparison of adsorption and Desorption at Ca-20

4
...
30

Completely Randomized AOV For Adsorption Study At Ca-10

4
...
32

Completely Randomized AOV For Adsorption Study At Ca-30

4
...
34

Completely Randomized AOV For Desorption Study At Ca-20

4
...
No
4
...


Relationship between ECdC and Cd adsorbed per unit of soil
(x/m) at Ca10

4
...
3

Relationship between ECdC and Cd adsorbed per unit of soil
(x/m) at Ca20

4
...
5

Relationship between ECdC and Cd adsorbed per unit of soil
(x/m) at Ca30

4
...
7

Logarithmic

relationship

(desorption

isotherm)

between

equilibrium solution Cd concentration (ECdC) and Cd adsorbed
per unit weight of soil (x/m)
...
8

Logarithmic

relationship

(desorption

isotherm)

between

equilibrium solution Cd concentration (ECdC) and Cd desorbed
per unit concentration of Cadmium (x/m) at Ca20
4
...


4
...
11

Comparison of Adsorbed Cd

4
...
Adsorption and desorption of Cd in soil
control the availability and accumulation of Cd in plants
...
This experiment was conducted to study the adsorption-desorption behavior of Cd
in the presence of Ca in soil
...
Soil (3g) was taken in 50 ml centrifuge falcon tubes spiked with
the combination of 0, 10, 20, 40, 60, 80 and 100 mg/kg Cd with 20 and/or 30 mg/kg Ca
...
After equilibrium is attained, solution was filtrated and the residual soil was
kept for desorption study
...
01 M sodium nitrate solution (30 ml) was
prepared and added to the falcon tubes containing residual soil from adsorption study
...
Suspension was filtered using Whatman 42 filter paper
...
Adsorption parameters
of Cd in soil was studied using Freundlich model and Langmuir equation
...
At Ca-10 mg kg-1 maximum adsorption was observed (6-90 mg kg-1) and at Ca-20 adsorption
was (5-86 mg kg-1) while minimum adsorption was observed at Ca-30 (3-82 mg kg-1)
...
It was concluded that maximum adsorption was observed at Ca-10
mg kg-1 while maximum adsorption was observed at Ca-30 mg kg-1
...
, 2016)
...
, 2018) have led to their
wide distribution in the environment, raising concerns over their potential effects on human health
and the environment
...

Because of their high degree of toxicity, arsenic (As), cadmium (Cd), lead (Pb) and mercury (Hg)
rank among priority metals
...
, 2016)
...
Most of the heavy metals are metabolically non-essential and thus they are toxic
for living organisms though at small concentration
...
, 2019)
...

The natural contribution of heavy metals is small but human activities have main role in
contribution of heavy metals
...
, 2017), Ni-Cd
batteries, plating, pigments, pesticides

(Sterckeman et al
...
, 2017)
...
Due to this situation farmers use waste water to irrigate the crops (Yang
et al
...
In Pakistan, untreated water irrigates almost 32,500 ha (Murtaza et al
...
In
Pakistan, now a days irrigation of agricultural land with canal water is limited as well as its
increasing population leads to the shortage of surface water which makes more use of un-treated
water to irrigate the crops, which ultimately pollute the soil with heavy metals
...
Transformation and immobilization of heavy metals by sorption is a very effective
method at low cost, and easily controllable (Safari et al
...

Concentration of cadmium (Cd) > 0
...
, 2011) Cd
concentration will be reach upto the level of 0
...
00 mg kg-1 if these soils irrigated
with raw sewage for longer period of time
...

Disposal of sewage sludge onto agricultural land leads to the accumulation of Cd in root
zone (Yingchao et al
...
Agricultural soil are greatly affected by Cd concentration at high
level, which also cause environmental problems (Kasemodel
...
The adsorption and
desorption of Cd in soil is controlled by different factors like type and amount of clay minerals,
net negative surface charge density of soil and organic matter
...
Major factors affecting the mobility
and phyto-availability of Cd include soil pH, total amount of Cd in soils, source of Cd, organic
matter and soil type (Ali et al
...

Metals availability in soils is controlled by different chemical reactions including
adsorption/desorption, precipitation/dissolution, ion exchange, soil texture and soil pH (Mohamed
et al
...
Soil pH also decreases Cd bioavailability (Egene et al
...
Heavy metal
adsorption-desorption is a very significant phenomena to study the metals behavior in soils
...
, 2019)
...
2018)
...
Cd ranked at seven number as an inorganic toxic contaminants and carcinogenic
element
...
003 mgL-1 in
fresh water (Dhir, 2014)
...
, 2014)
...
By ion exchange mechanism, many metals are adsorbed on
exchange sites and these metals remain in competition with naturally occurring cations (Ca2+,
Mg2+, Na+, and K+) for adsorption sites
...
, 2016)
...
By increasing specific amount of Ca chloride in soil
solution, Cd adsorption on exchange site can be decreased
...

Research shows that, Ca2+ has antagonistic effect with Cd for exchange site in soil (Youness et al
...

Keeping in view the effect of Ca on adsorption and desorption of Cd, this study was
conducted to study the effect of Ca on the adsorption and desorption of Cd in soils using Freundlich
and Langmuir models
...
Some of them are toxic even if their concentration is
very low and their toxicity increases with accumulation in water and soils
...
The most important interfaces involved in
heavy metal adsorption in soils are predominantly inorganic colloids such as clays (Bradl, 2002)
metal oxides and hydroxides (Demirata et al
...

Therefore, the study of adsorption processes is of utmost importance for the understanding of how
heavy metals are transferred from a liquid mobile phase to the surface of a solid phase
...
(2015) studied the adsorption of four different metals such as Pb, Cd, Cu and Zn
collected from four different places using batch experiment
...
By using regression equation, data of
adsorption were correlated with adsorption isotherm
...
It was concluded that adsorption data better
correlate to Langmuir than Freundlich isotherm and all parameters in these isotherms were
deliberated
...
In these three functions all parameters
were discussed
...

Sulaiman (2015) studied the effect of different factors affecting bio-sorption of Cu ion from
aqueous solution
...
In waste water copper exist in form of Cu (II) while copper carbonate exists in
form of organic complexes
...
12g which reduced the water quality and it is nontoxic element
...
From results it was concluded that all factors have effect on removal of Cu from
industrial waste water
...
(2016) an experiment was conducted to study the synthesis by co-condensation of
mesostructured cellular foam (MCF) functionalized with propyl polyethylenimine (pPEI) was
performed and the capability of this material to extract cadmium cations from aqueous solutions
was investigated
...
Adsorption isotherm fitted perfectly Langmuir and Freundlich models
...
The
regeneration of the adsorbent was achieved by an acid-base treatment
...

Atanassova (2016) evaluated the effect of competing Cu, Zn, Cd and Ni ions in0
...
The objective of this study was to
investigate the adsorption/desorption behavior of Cu, Zn, Cd and Ni in soil clay fractions differing
in physico-chemical properties as influenced by increasing Cu initial concentrations
...
Sorption of Cu conformed to a Freundlich equation
...
01 M Ca(NO 3 ) 2 were considered
‘specifically adsorbed’
...
More than 70% of the Cu was specifically sorbed
...
At surface
coverage, higher than 200 mg Cu per kg of soil clay, Zn sorption in the Planosol and Gleyic Acrisol
clays took place at low affinity sites
...
Ni was not retained by the Planosol and Gleyic Acrisol clays and was ion
exchangeable adsorbed by the Vertisol clay
...

Chen et al
...

The adsorption kinetics and influencing factors were investigated to discuss the competitive
adsorption effect of Ni and Pb
...
It was concluded that with increase the amount of zeolite level adsorption
efficiency of Pb and Ni increased while the decrease in saturation adsorption capacity took place

gradually
...
If environment is acidic, then Ni adsorption was inhibited by Pb adsorption in mixed
heavy metals
...
If different temperature were given to both Ni and Pb than adsorption
efficiency of Pb was higher than of Ni
...

Jalali (2017) conducted sorption and desorption studies of Cd, Cu, Ni and Zn were carried out at
the pH range of 2 to 9 ina soil amended with three sorbents including bentonite, calcite and zeolite
...
A geochemical computer model was used to simulate the sorption of metals by control
and amended soils as influenced by pH
...
Furthermore, metals sorption on
soil amended by sorbents was greater than control, indicating the increase of soil sorption capacity
by adding sorbents, while desorption decreased
...

In general, the maximum sorption of metals was observed by bentonite-amended soil and calciteamended soil, whereas the maximum desorption of all metals obtained in zeolite-amended soil,
suggesting that the sorption of metals on zeolite was based on the reversible mechanism
...
In addition, this sequence was observed mostly for metals activity and desorption
(occasionally an exchange in the positions of Cd and Ni) but with an inverse trend
...

Mishra et al
...
The kinetics, thermodynamics,

sorption/desorption mechanism of different metal ions on different adsorbents under different
experimental conditions were observed
...
All the metal ions were desorbed by using acids like HCl, HNO 3 and H 2 SO 4 in
most of the cases, except Cr (VI)
...

Since Cr (VI) is present in anionic form; it was eliminated from the loaded adsorbents using bases
like NaOH, Na 2 CO 3 or NaHCO 3
...
(2017) studied the effect of pH, ionic strength and incubation time on adsorption and
desorption of Ni in acric soils
...
0 to 8
...
It was analyzed during 0, 4 and 12
weeks when concentration of Ni increased from 5 to 100 mg L-1 than adsorption capacity of Ni
was maximum in subsoil after 12 week
...
In top soil samples due to higher organic matter content and low PZSE
(Point of low zero salt effect) adsorption was higher
...
When the samples were incubated for 4 to 12 week than Ni desorption were less because of
increasing Ni interaction with colloidal particles over period of time
...
(2018) studied the retention of five heavy metals (Cd, Cu, Ni, Pb, and Zn) by ten soils
from nine soil series using kinetic sorption batch methods over a wide range of input
concentrations for each heavy metal
...
Soils with high organic
matter and soils with high pH, due to the presence of carbonates, exhibited strong sorption for all
heavy metals
...


For

soils

with

high

pH,

adsorption

followed

the

order

Pb > Cu > Zn > Cd > Ni where Zn exhibited more affinity than Cd
...

This is indicative of increased sorption which varied among soils and heavy metals
...
(2018) studied the influence of natural free iron oxide coatings on adsorption and
desorption of Cd and Cu in aqueous media
...
Allophane sample used for this study consisted of natural
allophane (NA) with iron oxide and natural allophane (NA) without iron oxide coating
...
Characterization of material showed that

natural allophane with iron oxide coating comprised of ferihydrate like mineral while natural
allophane without iron oxide coating comprise of aggregate which are organized by allophane
...
It was concluded that natural
allophane without iron oxide coating has greater Cu and Cd adsorption capacity as compared to
allophane with iron oxide coating (NA-FeO)
...
(2018) studied to quantified and investigate the mechanisms for Cd2+ adsorption on
biochars produced from plant residual and animal waste at various temperatures
...
The Cd2+ adsorption isotherms, adsorption kinetics, and desorption characteristics
were studied via a series of batch experiments, and Cd2+ loaded biochars were analyzed by SEM–
EDS and XRD
...
4
mg g−1, of all studied biochars
...
Both the pyrolysis temperature and feedstock affected
the quantitative contributions of the various adsorption mechanisms
...
9– 72
...
0–72
...
7–50
...
4–43
...
2 –14
...
4–18
...
4–3
...
0–
5
...
For biochars produced at higher pyrolysis temperatures, the
contributions of Qcp and Qcπ to adsorption increased, while the contributions of Qci and Qco
decreased
...
3–50
...
Results suggested that biochar
derived from rice straw is a promising adsorbent for the Cd2+ removal from wastewater and that
the low-temperature biochars may outperform the high-temperature biochars for Cd2+
immobilization in acidic water or soils
...
Heavy metals retention ability by ten soils
was quantified using batch equilibration techniques
...
In centrifuge tubes 3 g soil was taken and
different heavy metals solution of 30 ml was added in this
...
Results
indicated that data obtained from sorption follow the Freundlich model for all ten soils
...

Burakov et al
...
For the removal of metals from solution phase
adsorption is important phenomenon
...
In this review adsorption capacity of metals
in tabular form is also discussed
...
From this study it was analyzed that
as compared to conventional, non-structured absorbent are more effective for removal of heavy
metals from waste water
...
(2018) studied the adsorption and desorption of Cu in silty clay soil
...
They observed that after 4 hours of experiment, adsorption
process reached equilibrium and data fitted well to Elovich model for kinetic sorption process
...
When the concentration of H+ ions decreased,
adsorption capacity of Cu increased while desorption capacity decreased
...
In addition when adsorption capacity of native soil and soil without organic matter were
compared than it was concluded that native soil have higher adsorption capacity as compared to
soil with removal of organic matter
...
During this study maximum adsorption of Cu occurred at 350C
...

Haryanto et al
...
The aims of this investigation were to apply the pseudo order
1st and order 2nd equations to identify the type of adsorption interaction of Cd on two type sand

surface bases on correlation coefficient (r2)
...
The binary metal ions in solution was mixed with the sand then shaken in 100 rpm
...
The result found that the Cd with r2 =0
...
9989
for first and second order respectively, for black sand and r2 =0
...
999 for first and
second order respectively, for white sand
...

Bostani et al
...
The Freundlich isotherm best defined the heavy metal adsorption signifying multilayer
adsorption
...
, Pb > Cu > Ni for all
treatments under both adsorption conditions which was linked with the ionic radius, hydrolysis
constant, and electronegativity of particular metals
...
The biochar of corn straw (BCS) had the maximum adsorption capacity (Freundlich
Kf (mg g−1) for Cu = 1
...
23 and Pb = 2
...
00, Ni = 59
...
00), indicating the BCS is the best
effective treatment for heavy metals stabilization in the soil
...

Yumi et al
...
The objective of this research was to obtain natural
allophane with (NA-FeOx) and without (NA) iron oxides from a Southern Chilean Andisol and
determine the influence of the natural free iron oxide coatings on the adsorption of cationic
pollutants Cd (II) and Cu (II) in aqueous media
...
Among
the kinetic models evaluated, the pseudo-second order model presented a better correlation with
the experimental data
...
Langmuir and Freundlich adsorption models fitted
the experimental data well, suggesting that the adsorption process is a combination of physical and

chemical phenomena
...
Desorption
studies demonstrated that most adsorbed cations were retained by the adsorbent, indicating
irreversible chemical adsorption on specific active sites of the adsorbents
...
(2018) an experiment was conducted in which Magnetic biochar (MBC) was produced
by magnetite (Fe 3 O 4 ) precipitation onto Douglas fir biochar (NBC) that had been generated by
wet fast pyrolysis
...
The NBC and the resulting MBC were used to remove Pb2+ and Cd2+ from
water
...
Batch sorption studies were carried out from pH 2–7 with adsorbate
concentrations from 10 to 250 mg/L at 25, 35 and 45 °C
...
Then MBC was magnetically removed, while
NBC required filtration
...
The amounts of
lead and cadmium adsorbed onto both NBC and MBC were lower at low pH values and increased
with increasing pH
...
The maximum Langmuir adsorption capacities at pH 5 and 45 °C for
Pb2+ and Cd2+ uptake were ∼40 and ∼16 mg/g for NBC and ∼27 and ∼11 mg/g for MBC,
respectively
...
1 M HCl

and water
...
Adsorption equilibria of
Pb2+ and Cd2+ onto both NBC and MBC were reached within 2 min while the other biochars
required from 2 to 20 h
...

Haryanto et al
...

Two types of sand such as white and black sand were used for this study
...
All sand was washed with
distilled water until washing water has constant pH to conform that sand has already same
condition before use as natural adsorbent
...
After that flask was shaken for 6 hours at 150 rpm and reading was obtained
using Atomic Absorption Spectrophotometer
...
From results it was concluded that
both type of physical and chemical interaction occurred on surface of sand
...
(2019) Cd and Ni chemical reactivities in soils are highly dependent on various soil
properties
...
Results revealed that several soil
characteristics control Cd and Ni sorption-desorption where, the mutual effects of pH, CEC, soil
carbon, clay, silt, and CaCO 3 contents govern their behavior in soils
...
The studied soils exhibited higher Ni sorption capacities than
Cd (Ni-Smax > Cd-Smax)
...
Simulations of Cd and Ni kinetic reactions
were performed using a multi reaction model (MRM)
...
The highest
reversible reaction rate and low hysteresis for Cd and Ni were associated with the low soil sorption
capacities
...

Jingjie et al
...
Our results showed that, under the experimental conditions, the kinetic adsorption
approached equilibrium within 5 min, and the Sips isotherm model was most suitable for data
fitting
...
Furthermore, desorption experiments showed that Ca2+ and Mg2+ in the diatomite
caused an ion exchange interaction, and this was primarily responsible for Cd(II) adsorption
...

Additionally, our data indicated that the adsorption mechanism did not change significantly after
regeneration
...


Reinhart et al
...
Most biochars caused an
increase in pH of approximately 1 unit which is often the main driver of the metal immobilization
...
For the other amendments, however, the results were higher due to the
nutrients leached from the applied products
...
However, the amount of metals
immobilized was lower than expected
...
(2005) describes that retention mechanism of metal icons at soil surface is often
unknown so we prefer the term sorption
...
Hizal et al
...
surface precipitation (SP) and Fixation of
metal ions
...
Actually adsorption (Ad) is two dimensional accumulation of matter at solid or
water interface
...
(3) Hydrophobic interaction: they contain highly non polar organic solutes
...


Precipitation
Sposito (1984) describe the surface precipitation as three dimensional mechanism which forms 3D network and it is categorized by growth of new solid phase
...

It is a function of pH and quantity of anions and metals present in surface precipitation (SP)
...
(1993) described that precipitation of hydroxide (OH-) in pure Freundlich
isotherm models are used but if concentration is lower than Langmuir isotherm model are used
...


Fixation / Absorption
It is also a principle mechanism of Sposito (1986) said that absorption/fixation involves diffusion
of metal species into solid phase
...
Diffusion into lattic structure of mineral take place for heavy metals adsorbed on the
surface of clay mineral (CM) and metal oxides (MO)
...
Total dissolution of particles in which they are
assimilated is required in order to remove heavy metal
...


Specific Adsorption
This is less reversible and more selective form of adsorption in this inner sphere complexes are
formed described by McBride (1994)
...
Schindler et al
...

These functional groups may be inorganic groups
...
At a result properties of metal
constituting the adsorption (Ad) site impact the adsorption (Ad) tendency
...
It is electrostatic phenomenon in which cation which are near surface are exchanged by
cation from pore water (H 2 O)
...
As compare to specific

adsorption (SA) nonspecific adsorption (NSA) is a reversible or quick mechanism
...
(1994)
...


Empirical Model
In empirical models involve empirical description of adsorption data it is described by Papini and
Majone
...
For observation of adsorption data posteriori form of empirical model is used
...
No of parameter
should be kept limited and should be adjusted according to number of variables such as metal
concentration in liquid phase
...
These models are based on relationship between solid and liquid phase of metal
concentration at constant temperature
...
(2000) define the equilibrium is form
of chemical potential o two phases and these relationship are called isotherm
...
Volmer (1925) derived new
isotherm for homogenous surfaces
...
For empirical description of heavy metals
adsorption isotherm used are called general purpose isotherm (GPI)
...
(1996) give the semi empirical model approach (SEM) for description of basic
mechanisms
...
Before setting up a equilibrium reaction
mathematical form is chosen that is linked with mass balances (MB) of different components
...
Higher number of variables are required as variety of components taken into
consideration due to this reason semi empirical model (SEM) as more valid as compare to
empirical model (EM)
...

Basic difference between two approaches is that empirical model have no electrostatic term while
mechanistic model (MM) have this electrostatic term
...
For determination of this interaction two important molecule are used such as Freundlich
(1906) and Langmuir (1918) isotherm model
...
(2019) and kanan et al
...

Equation of Langmuir isotherm model is shown in equ (1)
qe

= q m K L Ce/1+K L C e (equ
...
Langmuir isotherm is
mostly expressed in form of dimensionless constant that is called RL or separation factor
...
II)

KL is Langmuir adsorption energy constant
RL is shape of isotherm that may be either favorable or unfavorable or may be linear
...
If RL value is less than 1 than
shape of isotherm will be favorable
...

If
RL > 1 than shape of isotherm will be unfavorable
RL < 1 than shape of isotherm will be favorable
RL = 1 than shape of isotherm will be linear
RL = 0 than shape of isotherm will be irreversible

Freundlich Isotherm Model
This is oldest model driven by Russell and Prescott
...
This model is based on hypothesis that
adsorption (As) enthalpy is free amount adsorbed and sorption is mostly based on heterogeneous
surface
...
Freundlich isotherm equation is given below:
X/m

=

K f (ECdC)1/n

Here
C

= Equilibrium concentration

X/m

= Amount adsorbed in mgkg-1

1/n

= Rate of Adsorption

Kf

= Freundlich proportionality constant

Hannan et al
...
Linear form of Freundlich equation is given by
(Freundlich 1906)
...
(2005) it is heterogeneous system that have 1/n value approaching to zero while
homogenous system have 1/n value approaches to unity
...
(2005) also observed that value of 1/n < 1
...

X/m / ECdC
Higher K f value indicates higher adsorption (Ad) capacity while lower K f value indicates that
soil having lower adsorption capacity
...
Gomes et al
...
The pH of REQ soil decreased more than the RAR soil at the same Cd2+ loading
...
, 2002)
reported that heavy metal contamination potentially causes soil acidification, and the more the
heavy metal input, the more acute the acidification may be
...
In equilibrium solution pH generally increased with desorption and was lower when
Cd2+ concentration in the equilibrium solution increased
...
(2000) stated that carbonate dissolution increases when the pH of soil decreases as
ionic exchange is the principle retention mechanism of heavy metals
...
Heavy metals are retained by soil
mainly as carbonate salt when the calcium carbonate (CaCO 3 ) contents in soils are high
...
It includes clays, metal oxides and hydroxides, carbonate contents as well as organic
matter (Zhao et al
...
Sorption of heavy metal increase is due to several mechanism such as
physical, chemical sorption and precipitation (Xiong et al
...
Calcium carbonate content in
the soil increases soil pH by following hydrolysis reaction
...


Effect of Complex Formation
Metal cations form complexes with inorganic and organic ligands resulting has a lower positive
(+ve) charge than the free metal ion and carry a net negative (-ve) charge
...
These properties includes the
type and amount of ligands present, soil surface properties, soil solution composition, pH and
redox condition which have effect on sorption, Metal adsorption and mobility is mostly affected
by complex formation between metals and organic ligand
...
The ectent of complexation between a metal and soluble organic
matter depends on the competition between the metal-binding surface sites the soluble organic
ligand for the metal
...
Order of metal organic complex is reported by Overcash and Pal (1979)
...

While the order of metal mobility is reported by khan et al
...

Copper (Cu) and Nickel (Ni) has high mobility because they have higher ability to form complex
with soluble soil organic matter (SOM)
...

(1992)
...
When contact time increase adsorption
capacity of Cd also increases
...
(2000)
...
If we look toward desorption capacity this
will first increases than decreases with increasing the desorption time so for desorption
experiments time of 30 minute is considered mostly reported by Lalhruait luanga et al
...
All the basic analysis of soil, and experiment was
conducted in soil and water chemistry Laboratory, Institute of Soil and Environmental Sciences,
University of Agriculture, Faisalabad
...
1
...
Soil samples was air dried, grinded and sieved using 2 mm
sieve
...
2
...
1)

3
...
1
...
Weighted 40 gram
of air-dried soil added into 600 ml of beaker then added 60 ml of dispersing solution covered the
beaker and left for overnight
...
Then the suspension was stirred at high speed for
3 minutes
...

After hydrometer was removed and materials of graduated cylinder was shaken with the help of
metal plunger
...
Removed the hydrometer form cylinder, shook the
material with plunger then after 2 hours second hydrometer reading was recorded
...
If temperature was above then 20 Co for each degree added a factor of 0
...
4 to the readings and get CHRI
and CHR2, respectively
...
2
...
Soil Saturated Paste
Distilled water was added into soil and left for overnight
...


3
...
3
...
Oven dried the
sample till constant weight
...
2
...
pH of Saturated Soil Paste (pH s )

Before taking reading, pH meter was calibrated with buffer solutions of 4
...
00 and 9
...
The pH was measured by placing the electrodes of pH meter into the soil paste and reading
was recorded
...
2
...
Soil Saturated Extract
Extract of saturated paste was taken by applying positive pressure on paste with the help
of filter press after getting extract of soil, 0
...
Only 1 drop of sodium hexametaphosphate solution
for 25 ml extract was sufficient
...
2
...
Electrical Conductivity (EC e )
Electrical Conductivity was measured using ECmeter
...
01
N Potassium Chloride solution (KCl)
...


3
...
7
...
4118 𝑑𝑑𝑑𝑑𝑚𝑚−1
𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸 0
...

One to two drops of EBT indicator was added to saturated extract then added NH 4 OH+NH 4 Cl
solution as a buffer, then titrated against 0
...
Soluble
Ca2+ + Mg2+ was measured by using the formula (followed by U
...
Salinity Lab Staff, 1954)
...
2
...
Soluble CO 3 2-

(𝑅𝑅2 − 𝑅𝑅1) × 0
...
01 N H 2 SO 4 soluion
...
01 N H 2 SO 4 solution till colorless end point
...
S
...


3
...
9
...
01 × 1000
𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚

Soluble HCO 3 - was determined using 0
...
One to two drops of methyl
orange as an indicator were to the extract after soluble CO 3 2- determination and then titrated against
0
...
Soluble HCO 3 -was measured using the
formula (followed by U
...
Salinity Lab Staff, 1954)
...
01 × 1000
𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆

R 1 = mL of H 2 SO 4 used for HCO 3 -

3
...
10
...
01 N AgNO 3 solution
...
01 N AgNO 3 solution till brick red endpoint
...
S
...

𝐶𝐶𝑙𝑙 − =

𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑂𝑂3 𝑢𝑢𝑢𝑢𝑢𝑢𝑢𝑢 × 0
...
2
...
Sodium Adsorption Ratio (SAR)

Sodium adsorption ratio (SAR) was calculated usingformula (Salinity Lab Staff, 1954)
...
1 Physical and Chemical Properties of Soils
Soil
Characteristics

Units

Value

pH

---------

8
...
2

CO 3

mmol c L-1

1
...
7

Cl-

mmol c L-1

7
...
74

Soluble Na

mmol c L-1

8
...
22

Textural class

----

Clay loam

3
...
Treatment Plan
3
...
1
...
3
...
For Calcium
T 1 = Control (Normal soil)
T 2 = 10mgkg-1 of CaSO 4
T 3 = 30 mgkg-1 of CaSO 4

3
...
Adsorption of Cd
Three replication of each treatment was used
...
In order to achieve equilibrium,
the suspension was kept for seven days and shaken for 30 minutes period twice daily
...
Filtrate was analysed using Atomic Absorption Spectrophotometer (AAS)
...
Its corresponding adsorption
isotherm equation was formulated and explained
...
5
...
01 M Sodium Nitrate solution was prepared
...
Taken three gram of soil which

was left in tubes, and 30 ml of 0
...

Thesetubes were kept overnight and next day centrifuged and filtrate was obtained
...


Freundlich adsorption and desorption isotherm equation used in this study is given below:
K f (ECdC)1/n

X/m

=

C

= Equilibrium concentration

X/m

= Amount adsorbed in mg/kg-1

1/n

= Rate of Adsorption

Kf

= Freundlich proportionality constant

Here

Statistical Analysis
General linear model was used for comparison of experimental result
...


CHAPTER 4
RESULTS AND DISCUSSION
This study was conducted to study the adsorption-desorption behaviour of Cd in soil
...
1 Adsorption study
Adsorption data of cadmium was analyzed according to Freundlich and Langmuir Isotherm
...
The amount of Cd adsorbed per unit soil (x/m) increased
progressively with an increase in added Cd and this increase was linear
...
41 mg kg-1 with Cd 20 , the amount of Cd
adsorbed was 14
...
28 mg kg-1 Cd adsorbed with Cd 40 , similarly with Cd 60 and
Cd 80 , Cd adsorption was 54
...
62 mg kg-1, respectively and 90
...
When compared the control with other treatments, it was concluded that the
minimum adsorption took place in control and adsorption was maximum with Cd 100
...
When soil was equilibrated with Cd 10 , Cd
adsorption % was (64
...
56%) and (80
...
18%) while (92
...
23%) of Cd adsorbed with Cd 80
and Cd 100 respectively
...

Similarly, when we compared the % of Cd solution concentration with respect to the added Cd, it
was observed that with increasing the level of added Cd, % of Cd solution concentration was
increased
...
11%) and (70
...
79%) and (91
...
03%) and (90
...
When we
compared all the treatments, it was concluded that with Cd 10 % Cd solution concentration was the

minimum and with Cd 100 , % Cd solution concentration was the maximum with respect to the added
cadmium
...
4
...
91

69
...
11

70
...
28

80
...
71

91
...
62

92
...
215

90
...
0094x - 0
...
969

80

x/m

60
40
20
0
0
-20

1

2

3

4
ECdC

5

6

7

8

Figure
...
1 Relationship between ECdC and Cd adsorbed per unit of soil (x/m) at Ca10

4
...
1 Freundlich adsorption Isotherm
The conducted isotherm (Figure 4
...
Lo ECdC] which gave a linear fit
...
7944
...
344 and
0
...
The value of exponent (1/n= 0
...
2) which relates
to the characteristics of the absorbent
...
, 2006)
...
They
also found that Freundlich equation gives the straight line
...
, 2000, Arshad et al
...
, 2003)
...

Y = a + bx
Y = 0
...
2959
Here
a = Intercept
b = Slope

2
...
2399x - 0
...
7944

Log (X/m)

2
1
...
5
0
0

1

2

3

4
Log (C)

5

6

7

8

Figure
...
2 Logarithmic relationship (adsorption isotherm) between equilibrium solution Cd
concentration (ECdC) and Cd adsorbed per unit concentration of Cadmium (x/m)
...
4
...

Description

Proportionality

Exponent (1/n)

Correlation
coefficient (R2)

constant (K f )

Units

Mgkg-1

mgL-1

Value

1
...
2399

0
...
033a

Log x/m

Log ECdC

1/n

Kf

x/m=K f (ECdC)1/n %ad

0

0
...
432

0
...
344

0
...
077b

6
...
185

--1
...
239

1
...
025

69
...
124c

14
...
607

-0
...
239

1
...
039

70
...
242d

32
...
652

0
...
239

1
...
078

80
...
389e

54
...
740

0
...
239

1
...
125

91
...
512f

73
...
819

0
...
239

1
...
164

92
...
6197f

1
...
320

0
...
344

0
...
23

90
...
4
...
1
...
Langmuir in 1918 is generally suitable for describing the chemisorption process
when ionic or covalent chemical bonds are formed between the adsorbent and the adsorbate
...
(2019)
...
, (2020) explain adsorption capacity which affects
the mobility and toxicity of lead and cadmium onto three magnetites having nanometric (M1-30
nm and M2-60 nm)
...
99) and Langmuir
(R2 = 0
...
R value less than 1 which shows Langmuir model is suitable for data which show
linear relationship
...
Ignoring the
surface heterogeneity and the van der Waals interactions between adsorbates and adsorbents
(Sreńscek-Nazzal et al
...
For Langmuir Isotherm model, the simple linear
equation is
Ce/Qe =Ce/Qm + 1/(Qm*KL)
Where Ce represents the equilibrium concentration (mg/g), qe is the quantity adsorbed at
equilibrium (mg/g), Qmax and KL are constants which represent the adsorption capacity and

energy of adsorption respectively
...
Zakariyya
...


Table
...
4 Parameters for the Linear Form of Langmuir model
Amount of Cd
added (mg L-1)

ECdC (mg L-1)

x/m (mg Cd kg-1
Soil)

C/x/m=
ECdC/x/m

0

0
...
077

6
...
013

20

0
...
11

0
...
242

32
...
056

60

0
...
71

0
...
512

73
...
023

100

0
...
215

0
...
Langmuir Equation which was used in this study is given below
x/m = K L b (ECdC)/ [1+ K L b(ECdC)]

Regression coefficient (R2 = 0
...
(2019) reported that value of R < 1 shows a linear relationship
Y = a + bx

Y = 0
...
006

a = Intercept

b = Slope
K L is the bonding energy constant which is always equal to (L mg-1), here the bonding energy is
(0
...
5)
...
2019)
...
4
...
457

Value

0
...
66

y = 0
...
008
R² = 0
...
035
0
...
025
0
...
015
0
...
005
0
0

1

2

3

4
ECdC

5

6

7

8

Figure
...
3 Logarithmic relationship (adsorption isotherm) between equilibrium solution
Cd concentration (ECdC) and Cd adsorbed per unit concentration of Cadmium (x/m)
...
033a

0

0

166
...
435

2
...
077b

6
...
011

166
...
435

5
...
11

20

0
...
11

0
...
66

0
...
627

70
...
242d

32
...
012

166
...
435

15
...
70

60

0
...
71

0
...
66

0
...
124

91
...
512f

73
...
0075

166
...
435

30
...
03

100

0
...
215

0
...
66

0
...
403

90
...
4
...
2 Adsorption study at Ca-20 mg kg-1
Adsorption data of cadmium was analyzed according to Freundlich and Langmuir Isotherm
...
The amount of Cd adsorbed per unit soil (x/m) increased
progressively with an increase in added Cd and this increase was linear
...
16 mg kg-1 with Cd 20 , the amount of Cd
adsorbed was 11
...
29 mg kg-1 Cd adsorbed with Cd 40 , similarly with Cd 60 and
Cd 80 , Cd adsorption was 46
...
49 mg kg-1, respectively and 86
...
When compared the control with other treatments, it was concluded that the
minimum adsorption took place in control and adsorption was maximum with Cd 100
...
When soil was equilibrated with Cd 10 , Cd
adsorption % was (51
...
85%) and (63
...
95%) while (81
...
92%) of Cd adsorbed with Cd 80
and Cd 100 respectively
...

Similarly, when we compared the % of Cd solution concentration with respect to the added Cd, it
was observed that with increasing the level of added Cd, % of Cd solution concentration was
increased
...
60%) and (55
...
23%) and (%), after (76
...
86%) and (86
...
When we
compared all the treatments, it was concluded that with Cd 10 % Cd solution concentration was the
minimum and with Cd 100 , % Cd solution concentration was the maximum with respect to the added
cadmium
...
4
...
16

51
...
17

55
...
29

63
...
17

76
...
49

81
...
92

86
...
651x- 0
...
949

80

x/m

60
40
20
0
0
-20

1

2

3

4

5

6

7

8

ECdC

Figure
...
4 Relationship between ECdC and Cd adsorbed per unit of soil (x/m) at Ca20

4
...
1 Freundlich adsorption Isotherm
Adsorption data of cadmium was analyzed according to linear form of Freundlich equation which
gives a linear fit
...
7099) (Figure 4
...
The 1/n which is rate of adsorption in soil
was (0
...
Similar values is reported by several researcher (Zhou and Li,
2001; Hussain et al
...
Due et al
...
If we compared the adsorption data of
Ca20 with Ca10, it was analysed that Ca10 have higher adsorption as compared to Ca20
...
0256x – 0
...


Table
...
8 Cd adsorption parameters of the Freundlich adsorption equation at
Ca-20
Description

Proportionality

Exponent (1/n)

Correlation
coefficient (R2)

constant (K f )
Units

Mgkg-1

mgL-1

Value

1
...
256

0
...
256 while extent of
adsorption was 1
...

y = 0
...
0116
R² = 0
...
5

Log (x/m)

2
1
...
5
0
0

1

2

3

4
Log C

5

6

7

8

Figure
...
5 Logarithmic relationship (adsorption isotherm) between equilibrium solution Cd
concentration (ECdC) and Cd adsorbed per unit concentration of Cadmium (x/m) at Ca20
...
214a

0

0

0

-0
...
256

1
...
006

0

10

0
...
16

51
...
71265

-0
...
256

1
...
106

51
...
615b

11
...
7

1
...
211

0
...
012

0
...
85

40

1
...
29

259
...
402949

0
...
256

1
...
266

63
...
436d

46
...
7

1
...
157

0
...
012

0
...
95

80

1
...
49

654
...
816175

0
...
256

1
...
479

81
...
258f

86
...
2

1
...
354

0
...
012

0
...
92

Table
...
9 Calculation of Freundlich Model for Ca-20

4
...
2 Langmuir Model
...
4
...
012

0

0

10

0
...
16

0
...
297

11
...
044

40

0
...
29

0
...
194

46
...
026

80

1
...
49

0
...
237

86
...
025

Adsorption data was analyzed according to linear form of Langmuir equation which gives a
linear pit
...
4570) which indicated a relationship of adsorption data with the
Langmuir equation Zakariyya
...
0138x – 0
...
377) (Tablr 4
...
When the RL value is less than unity (< 1) the adsorption is said to be
favorable (Zakariyya
...

Table
...
11 Cd adsorption parameters of the Langmuir adsorption equation for Ca-20

Description

Bonding Energy

Langmuir

Correlation

constant (K L )

adsorption

coefficient (R2)

maximum (b)
Units

Lmg-1

mg Cd kg-1 soil

Value

0
...
33

0
...
33 while
bonding energy was 0
...


y = 0
...
008
R² = 0
...
035
0
...
025
0
...
015
0
...
005
0
0

1

2

3

4
ECdC

5

6

7

8

Figure
...
6 Logarithmic relationship (adsorption isotherm) between equilibrium solution Cd
concentration (ECdC) and Cd adsorbed per unit concentration of Cadmium (x/m) at Ca-20

Concentrations ECdC x/m

C/x/m=ECdC/x/m b

KL

x/m=K L *b(ECdC)/[1+(K L )(ECdC) %ad

0

0
...
33

0
...
409b

5
...
0289

134
...
377

17
...
60

20

0
...
17

0
...
33

0
...
280

55
...
025c

25
...
0260

134
...
377

37
...
23

60

1
...
17

0
...
33

0
...
230

76
...
847e

65
...
0256

134
...
377

55
...
86

100

2
...
92

0
...
33

0
...
778

86
...
4
...
3 Adsorption study at Calcium 30 mg kg-1
Adsorption data of cadmium was analyzed according to Freundlich and Langmuir Isotherm
...
The amount of Cd adsorbed per unit soil (x/m) increased
progressively with an increase in added Cd and this increase was linear
...
41 mg kg-1 with Cd 20 , the amount of Cd
adsorbed was 14
...
28 mg kg-1 Cd adsorbed with Cd 40 , similarly with Cd 60 and
Cd 80 , Cd adsorption was 54
...
62 mg kg-1, respectively and 90
...
When compared the control with other treatments, it was concluded that the
minimum adsorption took place in control and adsorption was maximum with Cd 100
...
When soil was equilibrated with Cd 10 , Cd
adsorption % was (64
...
56%) and (80
...
18%) while (92
...
23%) of Cd adsorbed with Cd 80
and Cd 100 respectively
...

Similarly, when we compared the % of Cd solution concentration with respect to the added Cd, it
was observed that with increasing the level of added Cd, % of Cd solution concentration was
increased
...
11%) and (70
...
70%) and (91
...
03%) and (90
...
When we
compared all the treatments, it was concluded that with Cd 10 % Cd solution concentration was the
minimum and with Cd 100 , % Cd solution concentration was the maximum with respect to the added
cadmium
...
4
...
23

32
...
09

45
...
63

51
...
26

65
...
71

74
...
71

82
...
3
R² = 0
...
4
...
3
...
1) was examined according to the linear form of Freundlich
equation [Log x/m vs
...
8)
...
753
...
28 and 0
...
The value of exponent (1/n= 0
...
14) which relates to the
characteristics of the absorbent
...
, 2006)
...
They also
found that Freundlich equation gives the straight line
...
, 2000, Arshad et al
...
, 2003)
...
232x – 0
...
4
...
28

0
...
766

y = 0
...
246
R² = 0
...
5

Log x/m

2
1
...
5
0
0

1

2

3

4
Log ECdC

5

6

7

8

Figure
...
8 Logarithmic relationship (adsorption isotherm) between equilibrium solution Cd
concentration (ECdC) and Cd adsorbed per unit concentration of Cadmium (x/m) at Ca30
...
303a

0

0

-0
...
232

1
...
089

0

10

0
...
23

0
...
292

0
...
28

0
...
3

20

0
...
09

0
...
146

0
...
28

0
...
45

40

1
...
63

1
...
051

0
...
28

0
...
57

60

1
...
26

1
...
186

0
...
28

0
...
43

80

1
...
71

1
...
289

0
...
28

0
...
63

100

2
...
71

1
...
372

0
...
28

0
...
71

Table
...
15 Calculation of Freundlich Model for Ca-30

4
...
2 Langmuir Model
The Langmuir adsorption isotherm is used to describe the equilibrium between adsorbate and
adsorbent system
...
4
...
303

0

0

10

0
...
23

0
...
714

9
...
079

40

1
...
63

0
...
535

39
...
039

80

1
...
71

0
...
357

82
...
028

0
...
039x + 0
...
467

0
...
035
0
...
025
0
...
015
0
...
005
0
0

1

2

3

4
ECdC

5

6

7

8

Figure
...
9 Logarithmic relationship (adsorption isotherm) between equilibrium solution Cd
concentration (ECdC) and Cd adsorbed per unit concentration of Cadmium (x/m) at Ca-30

Table
...
17 Cd adsorption parameters of the Langmuir adsorption equation at
Ca30
Description

Bonding Energy
constant (K L )

Langmuir
adsorption
maximum (b)

Units

Lmg-1

mg Cd kg-1 soil

Value

0
...
34

Correlation
coefficient (R2)

0
...
316)
...
2019)
...
303a

0

0

83
...
316

7
...
510b

3
...
158

83
...
316

11
...
3

20

0
...
09

0
...
34

0
...
29

45
...
124d

20
...
054

83
...
316

21
...
57

60

1
...
26

0
...
34

0
...
22

65
...
946f

59
...
033

83
...
316

31
...
63

100

2
...
71

0
...
34

0
...
57

82
...
4
...
4 Desorption study at Calcium 10 mg kg-1
Adsorption data of cadmium was analyzed according to Freundlich and Langmuir Isotherm
...
The amount of Cd adsorbed per unit soil (x/m) decreased
progressively with an increase in added Cd and this increase was linear
...
024 mgkg-1 with Cd 20 , the amount of Cd adsorbed was 3
...
013 mg kg-1 Cd adsorbed with Cd 40 , similarly with Cd 60 and Cd 80 , Cd adsorption
was 4
...
528 mgkg-1, respectively and 6
...
When
compared the control with other treatments, it was concluded that the minimum desorption took
place with a Cd 100 and desorption was maximum with control
...
When soil was equilibrated with Cd 10 , Cd adsorption % was
(20
...
085%) and (10
...
328%)while (6
...
663%) of Cd adsorbed with Cd 80 and Cd 100
respectively
...

Similarly, when we compared the % of Cd solution concentration with respect to the added Cd, it
was observed that with increasing the level of added Cd, % of Cd solution concentration was
increased
...
24%) and (15
...
033%) and (8
...
91%) and (6
...
When we
compared all the treatments, it was concluded that with Cd 10 % Cd solution concentration was the
maximum and with Cd 100 , % Cd solution concentration was the minimum with respect to the added
cadmium
...
4
...
Lo ECdC] which gave a linear fit (Figure 4
...
The empirically derived Freundlich
adsorption equation (Pant and Reddy, 2001) used in this study is given below;
x/m = K f (ECdC)1/n
Regression cofecient( R 2 =0
...
127) which is less than 1( Tabel 4
...
(2005) it is heterogenous system that have
1/n value approaching to zero while homogenous system have 1/n value approaching to unity
...
(1974)
...
(2003) and Rahman et al
...
Kf which is proportionality constant is the ratio of two things
(Amount absorbed in solid phase/ amount absorbed in solution)
...
127x + 0
...
909

1
0
...
8
0
...
6
0
...
4
0
...
2
0
...
4
...


Concentrations ECdC x/m
0

0
...
077d

2
...
124c

40

Log x/m

Log ECdC 1/n

Kf

x/m=Kf(ECdC) %ad

-1
...
127

1
...
004

0

0
...
1135

0
...
013

0
...
24

3
...
479

-0
...
127

1
...
016

15
...
242bc

4
...
603

-0
...
127

1
...
031

10
...
389b

4
...
699

0
...
127

1
...
050

8
...
512ab

5
...
743

-0
...
127

1
...
066

6
...
6197a

6
...
824

-0
...
127

1
...
079

6
...
4
...
4
...
4
...
78

7
...
12

0
...
139x + 0
...
873

ECdC/x/m

0
...
08
0
...
04
0
...
1

0
...
3

0
...
5

0
...
7

ECdC
Figure
...
12 Logarithmic relationship (desorption isotherm) between equilibrium solution Cd
concentration (ECdC) and Cd desorbed per unit concentration of Cadmium (x/m) at Ca10

Concentrations ECdC x/m

ECdC/x/m b

KL

x/m=K L *b(ECdC)/[1+(K L )(ECdC) %ad

0

0
...
19

0
...
180

0

10

0
...
024

0
...
19

0
...
407

20
...
124c

3
...
0411

7
...
78

0
...
085

40

0
...
013

0
...
19

0
...
142

10
...
389b

4
...
0778

7
...
78

1
...
328

80

0
...
528

0
...
19

0
...
052

6
...
6197a

6
...
0930

7
...
78

2
...
663

Table
...
21 Calculation of Desorption of Langmuir Model for Ca-10

4
...
In
Freundlich model, the parameters like log (x/m) and log (c) was plotted against each other to
calculate the desorption parameters
...
With Cd 10 was added into
soil, amount of Cd 10 desorbed was 3
...
17
mgkg-1 and 5
...
61 and 9
...
21 mgkg-1 desorption took place at Cd1 00
...
When compared the desorption %
of Cd with respect to the added Cd, it was observed that, Cd desorption % decreased with
increasing the level of the added Cd
...
1%), with Cd 20 and Cd 40 , Cd adsorption % was (20
...
75%) and Cd adsorbed with
Cd 60 was (12
...
31%) and (10
...
When we compared all the treatments, it was concluded that the maximum Cd
desorption % took place with Cd 10 while the minimum Cd desorption % took place with Cd 100
...
When soil was equilibrated with Cd 10 and Cd 20 , % of Cd solution concentration was the
maximum (32
...
85%), after % of Cd solution concentration was going to increase, with
Cd 40 and Cd 60, % Cd solution concentrations was (14
...
68%), after with Cd 80 and
Cd 100 , % Cd solution concentration was (11
...
21%) respectively
...


4
...
1 Freundlich adsorption Isotherm
Adsorption data of cadmium was analyzed according to linear form of Freundlich equation which
gives a linear fit
...
836) which indicated a relationship of
desorption data which equation
...
149) which is
less than 1
...

Y = a + bx
Y = 0
...
076
y = 0
...
0761
R² = 0
...
2

Log (x/m)

1
0
...
6
0
...
2
0
0

1

2

3

4

5

6

7

8

Log (ECdC)
Figure
...
14 Logarithmic relationship (desorption isotherm) between equilibrium solution Cd
concentration (ECdC) and Cd desorbed per unit concentration of Cadmium (x/m) at Ca20
...
214d

0

10

0
...
21

20

0
...
669

0
...
079

0
...
507

-0
...
149

1
...
066

32
...
17

0
...
211

0
...
079

0
...
85

1
...
59

0
...
011

0
...
079

0
...
75

60

1
...
61

0
...
157

0
...
079

0
...
68

80

1
...
05

0
...
266

0
...
079

0
...
31

100

2
...
21

1
...
354

0
...
079

0
...
21

0

10
...
4
...
5
...

x/m = K L b (ECdC) / [1+K L b (ECdC)]
x/m = Amount of Cd adsorbed (mg Cd Kg-1 Soil)
b
KL

= Langmuir adsorption maximum (mg Cd Kg-1 Soil)
= Bonding energy constant (L mg-1)

ECdC = Equilibrium Cd concentration (mgL-1)
R2

= Coefficient of determination

K L is thebonding energy constant which is always equal to (L mg-1), here the bonding energy is
(0
...
When the RL value is less than unity (< 1) the adsorption is said to be favorable (Zakariyya
...

Hence it is concluded from desorption data of Ca20 maximum desorption was 9
...
058
...
859x + 0
...
994

12

Log (x/m)

10
8
6
4
2
0

0

0
...
5

2

2
...
4
...
214d

0

0

9
...
058

1
...
409cd

3
...
127

9
...
058

1
...
1

20

0
...
17

0
...
76

0
...
433

20
...
025b

5
...
183

9
...
058

3
...
75

60

1
...
61

0
...
76

0
...
263

12
...
847a

9
...
204

9
...
058

4
...
31

100

2
...
21

0
...
76

0
...
362

10
...
4
...
6 Desorption study at Calcium 30 mg kg-1
Adsorption data of cadmium was analyzed according to Freundlich and Langmuir Isotherm
...
The amount of Cd adsorbed per unit soil (x/m) decreased
progressively with an increase in added Cd and this increase was linear
...
02 mgkg-1 with Cd 20 , the amount of Cd adsorbed was 5
...
07 mg kg-1 Cd adsorbed with Cd 40 , similarly with Cd 60 and Cd 80 , Cd adsorption was
8
...
98 mgkg-1, respectively and 13
...
When
compared the control with other treatments, it was concluded that the minimum desorption took
place with a Cd 100 and desorption was maximum with control
...
When soil was equilibrated with Cd 10 , Cd adsorption % was
(40
...
1%) and (15
...
55%) while (14
...
16%) of Cd adsorbed with Cd 80 and Cd 100
respectively
...

Similarly, when we compared the % of Cd solution concentration with respect to the added Cd, it
was observed that with increasing the level of added Cd, % of Cd solution concentration was
increased
...
2%) and (28
...
18%) and (13
...
98%) and (13
...
When we compared
all the treatments, it was concluded that with Cd 10 % Cd solution concentration was the maximum
and with Cd 100 , % Cd solution concentration was the minimum with respect to the added cadmium
...
6
...
4
...
17

0
...
833

y = 0
...
111
R² = 0
...
4

Log (x/m)

1
...
8
0
...
4
0
...
4
...


Concentrations ECdC x/m

Log x/m

Log ECdC

1/n

Kf

x/m=Kf(ECdC)1/n %ad

0

0
...
519

0
...
17

0
...
510cd

3
...
604

-0
...
159

1
...
095

32
...
714c

9
...
749

-0
...
159

1
...
133

45
...
124b

20
...
783

0
...
159

1
...
209

51
...
535ab

39
...
910

0
...
159

1
...
286

65
...
946a

59
...
078

0
...
159

1
...
362

74
...
357a

82
...
119

0
...
159

1
...
438

82
...
4
...
6
...
0575x + 1
...
833

1
...
2

ECdC/x/m

1
0
...
6
0
...
2
0
0

1

2

3

4
ECdC

5

6

7

8

Figure
...
18 Logarithmic relationship (desorption isotherm) between equilibrium solution Cd
concentration (ECdC) and Cd desorbed per unit concentration of Cadmium (x/m) at Ca30

Concentrations ECdC x/m

C/x/m=ECdC/x/m b

KL

x/m=K L *b(ECdC)/[1+(K L )(ECdC) %ad

0

0
...
39

0
...
057

0

10

0
...
02

0
...
39

0
...
097

32
...
714c

5
...
127

17
...
011

0
...
45

40

1
...
07

0
...
39

0
...
213

51
...
535ab

8
...
189

17
...
011

0
...
43

80

1
...
98

0
...
39

0
...
364

74
...
357a

13
...
179

17
...
011

0
...
71

13
...
4
...
7 Adsorption Comparison
Adsorption data of all treatments was analyzed according to linear form of Freundlich and
Langmuir equations
...
In all types of the treatments amount of adsorbed Cd per
treatment decreased progressively with increase in amount of added calcium and this increase was
linear
...
91 mg kg-1 while in Ca-20 was 5
...
23 mg kg -1 at Ca-30
...
11 to
11
...
09 mg kg -1 at Ca-30
...
28 to 25
...
63 mg kg -1 at Ca-30
...
71 mg kg-1 at Ca-10 mg kg -1 while at Ca-20 adsorption was
46
...
26 at Ca-30 mg kg -1
...
62 mg kg-1 at Ca-10 while in Ca-20 it was 65
...
71 mg kg

-1

at Ca-30
...
215 to 86
...
71 mg kg

-1

-1

at Ca-10 mg kg

-1

and Ca-20 mg kg

-1

at Ca-30 mg kg -1
...

If we compared the amount of Cd added with adsorbtion of Cd it was observed that with the
increasing level of Cd, fraction of Cd adsorbtion decreases in all type of treatments however this
decrease in Cd adsorption was linear
...
When treatments are equilibrated with 40 ppm
Cd then maximum adsorption of 80% at Ca-10 mg kg -1 and 63% and 51% of added Cd adsorbed
at Ca-20 and Ca-30 mg kg -1 respectively
...
When treatments are equilibrated with 80 ppm Cd then 92% Cd adsorption at Ca-10 mg kg -1 and

81% and 74% of added Cd adsorbed at Ca-20 and Ca-30 mg kg

-1

respectively
...

If we compare the control samples with different Ca treatments it was recorded that maximum
adsorption took place in control as compared to the other treatments while minimum adsorption
took place at Ca-30 mg kg -1
...
239 while extent of
adsorption was 1
...
435, and at Ca-20 mg kg -1 rate of adsorption was
(0
...
012) and bonding energy was (0
...
When compare
the adsorption with Ca-30 mg kg -1 rate of adsorption was (0
...
28) and bonding energy was (0
...

14
12
10
8

ads
...
Ca-20

6

ads
...
4
...
Comparison of Adsorbed Cd

4
...
The parameters like log (x/m) and log (c) was plotted against each other to
calculate the adsorption parameters
...
When 10 mg L -1 Cd was added to soil which was treated with Ca-10 then the amount of
Cd desorbed was 2
...
21 mg kg -1 and 4
...
With
increasing the level of Cd 20 mg kg -1 the amount of Cd desorption was increased from 3
...
17 mg kg -1 at Ca-10 and Ca-20 respectively and 5
...
Further increasing the
level of Cd 40 mg kg -1 the amount of Cd desorption was increased from 4
...
59 mg kg -1 at
Ca-10 and Ca-20 respectively and 6
...
However when 60 mg kg

-1

Cd was

added, amount of Cd desorbed was 4
...
61 mg kg -1 and 8
...
When increase in cadmium concentration at 80 mg kg 1

the amount of Cd desorbed was 5
...
05 mg kg -1 and

11
...
With increasing the level of Cd 100 mg kg1 the amount of Cd desorption
was increased from 6
...
21 mg kg -1 at Ca-10 mg kg -1 and Ca-20 mg kg -1 respectively and
13
...
It was concluded that the amount of Cd desorption was minimum
in control while maximum adsorption took place when different levels of Cd were treated with Ca30 mg kg -1
...
When Ca-10 mg kg

-1

treatment was equilibrated with 10

ppm Cd, 69% of added Cd was adsorbed, while at Ca-20 mg kg -1, 51 % of the applied Cd was
adsorbed and 32% Cd adsorbed at Ca-30 mg kg -1
...
After 40 mg L-1 when 60 mg L -1 Cd was added the Cd
adsorption decreased to 91% at Ca-10 mg kg -1 76% at Ca-20 mg kg -1 while 65% at Ca-30 mg kg 1


...

The minimum adsorption of 90% was observed at Ca-10 mg kg -1 adsorption of when 100 ppm Cd
was added again adsorption percentage deceased to 86% at Ca-20 mg kg -1 while at Ca-30 mg kg 1

82% desorption of Cd was observed
...
At Ca-10 mg kg -1, rate of

desorption was 0
...
013 and bonding energy was 0
...
149) while extent of desorption was (1
...
58)
...
159) while extent of adsorption was (1
...
114)
...
Ca-10
des
...
Ca-30
4
2
0
normal

cd10

cd20

cd4o

cd60

cd80

cd100

Figure
...
20
...
9 Comparison of adsorbed and desorbed amount of Cd at Ca-10
When 10 mg L

-1

Ni was added to soil which was treated with Ca-10 then the amount of Cd

adsorbed was 6
...
024 mg kg-1
...
11 mg kg-1 and amount of Cd

desorption was 3
...
Further increasing the level of Cd 40 mg kg

-1

the amount of Cd

adsorption was 32
...
013 mg kg-1
...
71 mg kg-1 , amount of Cd desorbed was 4
...
When increase in cadmium concentration at 80 mg kg -1 the amount of Cd adsorbed was 73
...
53 mg kg-1
...
215 mg kg-1 and desorption was 6
...
4
...
91

2
...
11

3
...
28

4
...
71

4
...
62

5
...
22

6
...
10

4

des
...
4
...
Comparison of Adsorbed and Desorbed Cd

4
...
16 mg kg-1 the amount of Cd desorbed was 3
...
With increasing the
level of Cd 20 mg kg

-1

the amount of Cd adsorption was 11
...
17 mg kg-1
...
29 mg kg-1and Cd desorption was 5
...
However when 60 mg kg -1 Cd
was added, amount of Cd adsorbed was 46
...
61 mg kg-1
...
49 mg
kg-1 the amount of Cd desorbed was 9
...
With increasing the level of Cd 100 mg kg1 and
amount of Cd adsorption was 86
...
26 mg kg-1

Table
...
28 Comparison of adsorption and Desorption
Cd Level

Cd Adsorbed (x/m)

Cd Desorbed (x/m)

mgKg-1

mgKg-1

0

0

0

10

5
...
21

20

11
...
17

40

25
...
59

60

46
...
61

80

65
...
65

100

86
...
26

12
10
8
6
ads
...
20
2
0

Figure
...
22
...
11 Comparison of adsorbed and desorbed amount of Cd at Ca-30
When 10 mg L -1 Ni was added to soil which was treated with Ca-30 then the amount of
Cd adsorbed was 3
...
02 mg kg-1
...
09 mg kg-1 and amount of Cd desorption
was 5
...
Further increasing the level of Cd 40 mg kg -1 the amount of Cd adsorption was
20
...
67 mg kg-1
...
26 mg kg-1 , amount of Cd desorbed was 8
...
When
increase in cadmium concentration at 80 mg kg -1 the amount of Cd adsorbed was 59
...
48 mg kg-1
...
42 mg kg-1 and desorption was 13
...
4
...
23

4
...
09

5
...
63

6
...
26

8
...
71

11
...
42

13
...
30

4

des
...
4
...
Comparison of Adsorbed and Desorbed Cd

Table
...
30 Completely Randomized AOV For Adsorption Study At Ca-10
Source

DF

SS

MS

F

P

Treatment

6

1
...
18622

68
...
0000

Error

14

0
...
00271

Total

20

1
...
3259

CV 15
...
0301

Std Error (Diff of 2 Means) 0
...
4
...
25011

0
...
0000

Error

14

0
...
00083

Total

20

Grand Mean 0
...
26166

CV 6
...
0166

Std Error (Diff of 2 Means) 0
...
4
...
28711

0
...
0000

Error

14

0
...
00307

Total

20

Grand Mean 0
...
33006

CV 8
...
0320

Std Error (Diff of 2 Means) 0
...
4
...
87144

0
...
9

0
...
05098

0
...
92242

Grand Mean 1
...
60

Standard Error of a Mean

0
...
0493

Table
...
34 Completely Randomized AOV For Desorption Study At Ca-20
Source

DF

SS

MS

F

P

Treatment

6

2
...
37502

454

0
...
02255

0
...
4597

CV 6
...
0166

Std Error (Diff of 2 Means) 0
...
4
...
35620

0
...
6

0
...
02210

0
...
37830

Grand Mean 1
...
18

Standard Error of a Mean

0
...
0324

SUMMARY
Heavy metals are defined as the metals with density more than 5 g cm-3 Heavy metals
accumulate in soil and plant with different amounts
...
Heavy metals often have their highest solubility
immediately after addition to soil
...
, which results in the conversion of highly soluble forms
into less soluble ones
...

Among the heavy metals, Cadmium (Cd) is widely distributed in nature and present in soil,
plant and animals
...
01 ppm to 01 ppm
...
Cd toxicity in human and environment is well known and different
diseases like kidney damage, bone cancer and lungs infection caused due to high Cd concentration
...
The objective of this research is to assess the effect of calcium
on adsorption and desorption of Cd by susing Freundlich and Langmuir Isotherm
A Lab experiment was conducted to study the effect of calcium on adsorption and desorption of
Cd by using Freundlich and Langmuir Isotherm
...
Soil was
collected from research area of Institute of Soil and Environmental Sciences University of
Agriculture, Faisalabad
...
After
soil preparation and basic analysis, different levels of calcium sulfate and cadmium sulfate will be
applied to the soil
...
Three replication of each treatment
will be used and was arranged according to complete randomized design (CRD)
...
In
order to achieve equilibrium, the suspension will be kept for seven days and shaken for 30 minutes

period twice daily
...
Filtrate will be analysed by Atomic Absorption
Spectrophotometer
...
Desorption filtrate was analyzed using AAS According to linear form of Freundlich and
Langmuir equation data of adsorption and desorption will be plotted
...
1
...
At Ca-10 mg kg-1 maximum adsorption was observed (6-90 mg
kg-1) and at Ca-20 adsorption was (5-86 mg kg-1) while minimum adsorption was observed at Ca30 (3-82 mg kg-1)
...
It was concluded that maximum adsorption was
observed at Ca-10 mg kg-1 while maximum adsorption was observed at Ca-30 mg kg-1
...
Amendments containing Ca can play a vital role in the rehabilitation of Cd
contaminated soils
...
Ca is thought to be a tough opponent of Cd on
exchange site of soil
...
Through research it was observed that as Ca level increased it
reduce the Cd adsorption and increase the desorption of Cd in soil
...
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