Adsorptive removal of bisphenol-A by rice husk ash and granular activated carbon—A comparative study

1
Adsorptive Removal of Bisphenol-A
Being Presented by P SUDHAKAR M.Tech. 2nd year
Under the guidance of Dr. I.D. MALL
2
CONTENT
1
INTRODUCTION
2
LITERATURE REVIEW
3
OBJECTIVE
4
METHODOLOGY
5
RESULTS and DISCUSSIONS
6
CONCLUSIONS
REFERENCES
7
3
INTRODUCTION
In the past few years, the research on the
endocrine disrupting chemicals (EDCs) has been
increased with great interest in the area of
environmental science and technology owing to the
reason that these chemicals (EDCs) have various
properties such as estrogenic, antiestrogenic or
antiandrogenic and hence their existence leads to
the potential damage the endocrine systems of
human beings and wildlife. One of the ECDs such
as Bisphenol A 2, 2-bis(4- hydroxyphenyl)propane
or BPA is of the important concern due its
adverse potentiality to the human health(European
Food Safety Authority, 2006) and environment.).
BPA is mainly used in the manufacturing of
resins and polycarbonate plastics. There is
chance of entering the BPA into water bodies
while manufacturing plastic products, leaching
from plastic products, disposed at the landfill
sites .
4
PRODUCTION of BISPHENOL-A
Fig. 1.1 Synthesis of Bisphenol A
Figure 1.2 Reaction of Biphenol-A with diphenyl
carbonate
5
Bisphenol-A

• Synonyms4,4'-(propane-2,2-diyl)diphenol
  Bisphenol-A (BPA)
• p,p'-isopropylidenebisphenol,or
  2,2-bis(4-hydroxyphenyl)propane
• Table Physicochemical Properties Bisphenol-A

Molecular formula C15H16O2
Molar mass 228.29 g mol-1
Appearance White solid
Melting point 158-1590C
Boiling point 2200C
Solubility in water 300 mgL-1
Acid dissociation constant 9.60 10.2
6
MAJOR ISSUES OF BISPHENOL-A ON HUMAN HEALTH
Figure 1.4 1.5 effects of BPA found Effcets
of BPA yet to found  
7
DISCHARGE STANDARDS
DISCHARGE STANDARDS FOR INDUSTRIAL WASTEWATER The
wastewater as well as emissions from any
manufacturing complex must adhere to the
standards set by regulatory authorities. In
India, these standards are set by the Central
Pollution Control Board (CPCB) under the guidance
of Ministry of environment and forest (MOEF).
These have been communicated in the form of MINAS
(Minimum National Standards) for the discharge of
pollutant from these industries. Various water
treatment techniques focused on water treatment
to match these standards have been developed.
8
DISCHARGE STANDARDS
Discharge effluent standard for chemical industry
CPCB, 2012
Parameter Value (mg/l except pH)
pH 6.5 8.5
BOD (3 days 27ºC) 50
COD 250
Sulphide as S 2
Phenol 5
Fluoride 15
Cyanide 2
Total Suspended Solids 100
9
OBJECTIVE OF THE STUDY
1. To characterize the Rice husk Ash and GAC
before and after adsorption of Bisphenol-A (BPA)
by using FTIR, BET Surface Area, SEM, XRD and TGA
and Proximate Analysis. 2. To optimize the
process variables such as a. Initial pH of
solution b. Dose of RHA and GAC c.
Initial concentration of Bisphenol-A d.
Contact time  3.To study the equilibrium data
for removal efficiency of the adsorbent using
Freundlich adsorption isotherm, Langmuir
adsorption, Tempkin, isotherm models using a non
linear regression method.
10

• 4 .To study the adsorption kinetics of BPA-RHA
  system by using various models such as pseudo
  first order, pseudo second order
• 5. Comparative study of low cost RHA with high
  cost GAC on removal of Bisphenol-A

11
LITERATURE REVIEW
Many natural adsorbents and polymeric adsorbents
were used for the removal of BPA from the waste
water like chitosan, bark, wood chips, sugarcane,
peat, bagasse, rice husks, straw and activated
bamboo,polysulphone etc. in this chapter the
adsorption studies of various researchers for the
removal of BPA using different adsorbents were
presented.
S.NO Adsorbent AET pH Results Ref
1 carbonaceous materials produce from Sugi sawdust, Hinoki sawdust, Kenaf sawdust, and activated carbon.  48 h.    NA The amount of Bisphenol-A adsorbed on the carbonized materials at a carbonization temperature 1073K is higher than that of activated carbon. The Freundlich constant is similar for activated carbon and that of carbonaceous materials from chips, sugi, Hinoki and sugi sawdust. Results have shown similarity in affinity of Bisphenol-A and carbonaceous material or activated carbon. The Freundlich constant, K was greater than that of activated carbon Nakanishi et al. (2002).
12
S.NO Adsorbent AET pH Results Ref
2 Coal-based activated carbon, Wood based activated carbon, Coconut-based activated carbon    NA    NA  Highest adsorption is observed in coal based carbon than other carbons. There is decrease in adsorption capacity with operation. Wood based carbon was exception. The used carbon showed higher K values than virgin carbon bisphenol-A. Gac adsorption was effective in removal of EDCs eith high Kow value.    K.J. Choi et al. (2005).
3 Andesite, Diatomaceous earth, Titanium dioxide, Activated bleaching earth, Coal-based activated carbon, Coconut-based activated carbon.         2h         7.0 The adsorption of Bisphenol-A onto carbon adsorbents is more than mineral adsorbents. The pore volume and/or particle surface area in case of mineral adsorbents are not determining factors for removal of Bisphenol-A. As the adsorbent particle size increase, adsorption capacity of activated carbon decreases. As the adsorbent dosage increased, adsorption capacity decreases. The adsorption capacity exhibits a constant extent as pH was increased from 3 to 9. Bisphenol-A adsorption decreases at higher pH ranging from 9 to 11. Equilibrium adsorption capacity of Bisphenol-A increase with initial concentration.         W.-T. Tsai et al. (2006).
13
S.NO Adsorbent AET pH Results Ref
4 Sediments           8h           7.0 BPA on sediment decreasd as sediment concentration increases at equilibrium point. With increase in pH from 2.6 to 7.0, decreasing adsorption of BPA is observed. From 7.0-10.6 pH, adsorption is slightly varied but going steadily as a whole. The adsorption behaviour of BPA on sediments is influenced by temperature. It is due to a exothermic reaction, which is attributed to physical adsorption and is dominated by dispersive forces and driven by enthalpy only.           G. Zeng et al. (2006).
5 Polyethersulfone (PES)organophilicmontmorillonite (OMMT) hybrid particles   5h   NA The adsorbed BPA amount per unit mass of hybrid particles increase with increase of OMTT in particles. The adsorption of BPA onto the PES-OMTT particles fitted pseudo-second order kinetic model very well. The adsorbed BPA can be removed by ethanol effectively. This indicates that the hybrid particles can be reused.      F.Cao et al. (2009).
14
S.NO Adsorbent AET pH Results Ref
6 Surfactant-modified ZFA (SMZFA) (Zeolite synthesized from coal fly ash (ZFA) was modified with hexadecyltrimethylammonium (HDTMA))           24h    10.4   9.6   11.2   10.5    Results show that while ZFA had no affinity for BPA, the surfactant-modified ZFA showed greatly enhanced adsorption capacity. The SMZFA with higher BET area and higher amount of loaded HDTMA showed greater retention for BPA. The adsorption of BPA by SMZFA exhibited high dependence on pH, being enhanced at alkaline pH levels which enable the formation of anionic species. The amount of BPA adsorbed decreased with increase in temperature.           Y. Dong et al. (2010).
7 Organicinorganic hybrid mesoporous material (Ph-MS)    6h     NA Introduction of phenyl groups into the pore structure of mesoporous silica led to selectivity and high adsorption affinity for BPA. Ph-MS adsorbed most of BPA faster than powder activated carbon. The kinetic adsorption data of ph-MS fitted well to pseudo-second order kinetic model. Maximum adsorption capacities of adsorbents were estimated from isotherm data using Langmuir model. Ph-MS exhibited high adsorption affinity to BPA of 351 mg/g.     Y.H. Kim et al. (2011).
15
S.NO Adsorbent AET pH Results Ref
8 Polysulphone membrane                     NA                     8.0 The adsorption of BPA on the membrane is pH dependent and deprotonationof BPA leads to significant decrease in retention. The adsorption of BPA on PS membrane is promoted both by hydrophobic adsorption and by hydrogen bonding. The presence of NOM will compete for the limited adsorption sites with BPA molecules. This leads to decrease in BPA retention/adsorption slightly. This study reveals that an accurate evaluation of given membrane in terms of retention of a contaminant is not possible until the saturation of the membrane with component of interest is accomplished. Both physical and chemical adsorption exist between BPA molecules and membrane function groups caused by the hydrophobicity of them and the possibility of hydrogen bonding forming between hydroxyl groups of BPA and polysulphone                     W.Su-Hua et al. (2010).
16
S.NO Adsorbent AET pH Results Ref
9 Powdered activated carbons (PAC)  24h   5.8 Improvement in compound removal is observed by increasing PAC dose and contact time. To the experimental data, Freundlich isotherm parameters were fit. Y.Yoon et al. (2003).
10 Biosorbent such as Peat, Rice husk, Bagasse, and Sawdust          2h          7.0 The BPA removal capacities of natural sorbents are significantly lower than those of activated carbon. The sorption kinetics can be fitted with pseudo-second order model. The maximal BPA removal efficiency was reached within pH range of 6-8. Its value is fluctuating between 97 and 98. The increase in sorbent dose resulted in greater surface area. An increased amount of available binding sites for BPA. This results in increased BPA percentage removal            Y. Zhou et al. (2012).
17
ADSORBATE AND ADSORBENTS

• Adsorbate Bisphenol-A was used as an adsorbate
  Bisphenol-A provided by S.D Fine chemicals Pvt.
  Ltd., Mumbai, India.
• Adsorbent Rice Husk ash (RHA) was used as
  adsorbent and obtained from Kanha Chamber
  Tejgarhi Crossing, University Road,),
  Meerut,Uttar Pradesh, India. Laboratory grade GAC
  was supplied by GSE Chemical Testing Laboratory
  and Allied industry, New Delhi and it was used
  and adsorbent as procured
• The percentage removal (Y) of Bisphenol-A at any
  time(t) was calculated as
• Adsorption capacity (mg/g) at any time t was
  calculated as

18
EXPERIMENTAL PROGRAMME
Step 1 Removal with RHA And GAC Parameter
optimization Effect of parameters Step 2
Establish optimum condition Step 3 Adsorbent
characterization Step 4 Comparative removal by
RHA and GAC Kinetic study Isotherm
Study Thermodynamics Parameters
19
Calibration curve of Bisphenol-A
20
Removal by GAC and RHA Finding optimum
condition
Figure 2.1 Effect of Adsorbent dose on the
removal of Bisphenol-A by (a) RHA (t180min, pH
6 and T300C, C0 100 mg/L (b) GAC (t120min,
pH 6 and T300C, C0 100 mg )
21
Figure 2.2 Effect of contact time on the removal
of Bisphenol-A by (a) RHA (m30g/L, pH 6,
T300C, C0 100 mg/L) (b) GAC (m20g/L, pH 6,
T300C, C0 100 mg/L)
22
Figure 2.3 Effect of initial Bisphenol-A
concentration on the removal of Bisphenol-A by
(a) RHA (t180min, pH 6, m30g/L,C010-400mg/L)
(b) GAC (t120min, pH 6, m20g/L,C010-400mg/L)
23
Figure 2.4 Effect of contact time on the removal
of Bisphenol-A by (a) RHA (t180min, pH 6,
m30g/L,C010-400mg/L) (b) GAC (t120min, pH 6,
m20g/L,C010-400mg/L)
24
Figure 2.5 Effect of time on capacity of
Bisphenol-A adsorption of by (a) RHA (m30g/L, pH
6, T300C, C0100mg/L) (b) GAC (m20g/L, pH 6,
T300C, C0100mg/L)
25
Adsorbent Characterization of Adsorbents
Fig. 3.1 X-ray diffraction pattern of RHA for
before and after adsorption
26
Fig. 3.2 X-ray diffraction pattern of GAC for
before and after adsorption
27
FTIR spectra of RHA
Fig. 3.3 FTIR spectra of RHA
28
FTIR spectra of GAC
Fig. 3.4 FTIR spectra of GAC
29
SEM of RHA
a
b
Fig. 3.5 Scanning electron micrograph of
(a)Virgin RHA (b)Bisphenol-A loaded RHA
30
SEM of GAC
a
b
Fig. 3.6 Scanning electron micrograph of
(a)Virgin GAC (b)Bisphenol-A loaded GAC
31
Adsorbent Characterization TGA/DTA/DTG
Fig. 3.6 TGA/DTG/DTA curve for Blank RHA
32
Fig. 3.7 TGA/DTG/DTA curve for Bisphenol-A
loaded RHA
33
Fig. 3.8 TGA/DTG/DTA curve for Blank GAC
34
Fig. 4 TGA/DTG/DTA curve for Bisphenol-A loaded
GAC
35
Comparative Removal by RHA and GAC Kinetics of
adsorption
Pseudo first order and Pseudo second order
model Pseudo-first order-equation is represented
in mathematical form as fallow
Pseudo second order equation is represented in
the fallowing form Ho and McKay, 199
Integrating and rearranging above equation at
initial condition qt0 at t0, we get
Initial sorption rate, h (mg/g min) is defined as
36
Kinetic parameters Determination for Bisphenol-A
system
Figure 4.1 Pseudo-second-order kinetic plot for
removal of Bisphenol-A on RHA(C0 100 mg/L
m30g/L, t 180min) GAC(C0 100 mg/L m20g/L, t
120min)
37
Rate controlling mechanism
Fig. 4.2 . Webber-Morris plot for Bisphenol-A
removal by (a) RHA (C0 100, t 3h, mg/l, m
30g/) (b) GAC (C0 100, t2h, m20 g/l ).
38
Kinetic parameters for Bisphenol-A system
1. Pseudo-first order
Adsorbent C0(mg/L)   qe kf(1/min) R2
RHA 100    3.16 0.0391 0.9931
GAC 100 5.41 0.0658 0.994
2.Pseudo-Second order
Adsorbent C0(mg/L) qe kf(1/min) R2 h
RHA 100   2.65 0.0242 0.9981 0.170
GAC 100   4.88   0.0295 0.9995 0.68
3.Intra Particle Diffusion
Adsorbent Kd1   I1 R2 Kd2 I2 R2
RHA 0.3879   0.8993 0.993 0.0351 1.8953 0.895
GAC 0.3912   1.5061 0.9935 0.0242 4.3307 0.9701
39
Comparative removal by RHA and GAC Effect
of temperature
Qe (mg/g)
(b)
(a)
Fig. 4.3 Equilibrium adsorption isotherms at
different temp for (a) Bisphenol-A loaded RHA
system, t 3h, Co 20- 200 mg/l m30 g/l. (b)
Bisphenol-A loaded GAC system, t 2h, Co 20- 200
mg/l m20 g/l.
40
Isotherm parameters for the removal of
Bisphenol-A by RHA (t3 h, m30 g/l) and GAC
(t3h, m20 g/l)
  Isotherms   Parameters RHA RHA RHA GAC GAC GAC
  Isotherms   Parameters Temperature Temperature Temperature Temperature Temperature Temperature
  Isotherms   Parameters 288 303 318 288 303 318
Langmuir 8.6655 8.7183 10.548 3.1420 3.5360 3.8446
Langmuir b 0.03624 0.0598 0.0496 0.0876 0.0922 0.0884
Langmuir R2 0.947 0.9751 0.976 0.9594 0.9777 0.9755
Freundlich KF 0.6528 0.8772 0.8519 0.8497 0.8147 0.7968
Freundlich 1/n 0.5422 0.5225 0.5689 0.2589 0.3040 0.3322
Freundlich R2 0.9908 0.9742 0.9971 0.9789 0.9976 0.9974
Temkin B1 1.6605 1.7533 2.0462 0.452 0.542 0.6169
Temkin KT 0.5222 0.7559 0.6767 5.843 3.1751 2.5030
Temkin R2 0.9274 0.9686 0.9506 0.9440 0.9963 0.9505
41
ADSORPTION THERMODYNAMIC PARAMETERS

• Change in the Gibbs free energy (?Go )
• It indicates degree of spontaneity and must be
  negative.
• The effect of temperature on the equilibrium
  constant is determined
• as follows
• Also,
• After integration and rearrangements gives (vant
  Hoff equation)
• where,
• ?Go is the Gibbs free energy change (kJ/mol),
• ?Ho is the change in enthalpy (kJ/mol),
• ?So is the entropy change (J/mol K),
• T is the absolute temperature (K),
• Kqe/Ce and is called as linear adsorption
  distribution coefficient.

42
Thermodynamic parameter for adsorption of
Bispheno-A by RHA (t3 h, m30 g/l) and GAC
(t2h, m20 g/l)
Temp (K) Kd ?Go   (kJ/mol) ?Ho   (kJ/mol) ?So   (kJ/molK) ?So   (kJ/molK)  Kd o?G  (kJ/mol) ?Ho   (kJ/mol) ?So (kJ/mol K) ?So (kJ/mol K)
  Bisphenol-A-RHA system   Bisphenol-A-RHA system   Bisphenol-A-RHA system   Bisphenol-A-RHA system   Bisphenol-A-GAC system   Bisphenol-A-GAC system   Bisphenol-A-GAC system   Bisphenol-A-GAC system   Bisphenol-A-GAC system   Bisphenol-A-GAC system   Bisphenol-A-GAC system
288 6.77 -4.58   0.33565     0.02138   6.07 6.07 -4.32   4.032   4.032   0.029600
303 6.72 -4.80   0.33565     0.02138   6.60 6.60 -4.75   4.032   4.032   0.029600
318 6.81 -5.02   0.33565     0.02138   6.62 6.62 -5.18   4.032   4.032   0.029600
43
CONCLUSION

• The present study involves the removal of
  Bisphenol-A (BPA) from aqueous solution by
  adsorption process using Rice husk ash (RHA)
  (which is low cost ) and granular activated
  carbon (high cost ) as an adsorbent. In the
  present study important process parameters
  affecting adsorption process were optimized.
  Following conclusions can be drawn from the
  experimental studies
• The optimized condition for the experiment was
  found as pH6, adsorbent dose30g/l, initial
  concentration100 mg/l and time 3h.and for GAC
  pH6, adsorbent dose20g/l, initial
  concentration100 mg/l and time 2h.
• At optimized condition, the removal efficiency of
  Bisphenol-A onto RHA and GAC was found to be
  73.2 and 94 .
• Adsorption uptake of RHA and GAC was found to be
  2.3and 4.5 mg/g, respectively.

44

• Adsorbent dose and contact time have synergistic
  effect while pH and initial adsorbate
  concentration have antagonistic effect on percent
  removal of Bisphenol-A.
• Suitable kinetic model was determined on the
  basis of coefficient correlation values, these
  values suggest that pseudo-second-order model
  best fitted the adsorption kinetic data for
  Bisphenol-A removal onto RHA and GAC.
• Adsorption capacity of RHA was compared with GAC
  and results shows that GAC has better adsorption
  capacity for Bisphenol-A removal.
• Various isotherm models were investigated for
  equilibrium isotherm, R2 indicate Freundlich and
  Temkin model were best fitted for RHA and GAC,
  respectively

45

• Effect of temperature and feasibility of the
  process was accessed by evaluating thermodynamic
  parameters. Positive values of ?H0 suggest that
  the adsorption process was endothermic in nature.
  
• Increase randomness signifies the increase in the
  entropy of the system. Negative values of
  indicates that the adsorption process is feasible
  and spontaneous.

• RECOMMENDATIONS
• Based on the present experiments and results,
  following recommendations can be made
• Further studies are required for treatment of
  other compounds present in the wastewater.
• Further pilot scale studies are required to
  evaluate the suitability of RHA for the
  adsorptive removal on plant scale.

46
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