scholarly journals Enhanced biosorption of Cr(VI) using cotton fibers coated with chitosan – role of ester bonds

2018 ◽  
Vol 78 (3) ◽  
pp. 476-486 ◽  
Author(s):  
Sergio I. Rojas ◽  
Diana C. Duarte ◽  
Sergio D. Mosquera ◽  
Felipe Salcedo ◽  
Juan P. Hinestroza ◽  
...  
Keyword(s):  
Hexavalent Chromium ◽  
Freundlich Isotherm ◽  
Kinetic Studies ◽  
Chitosan Solution ◽  
Cotton Fibers ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Amino Groups ◽  
Removal Capacity

Abstract We report on the role of ester bonds in the enhanced removal of hexavalent chromium from water using cotton fibers coated with chitosan. Adsorption capacities up to five times higher than those of the unmodified fibers were observed when the cotton fibers were exposed to an NaOH, followed by citric acid (0.97 M), and a chitosan solution (2%). We found that the use of NaOH favors the formation of ester bonds over amide bonds on the surface of the cotton fibers. This increase in the surface density of ester bonds generates an increase in the amount of exposed amino groups from the chitosan, hence increasing the removal capacity of the modified fibers. Experimental results also reveal that the adsorption is induced by the electrostatic attraction between the protonated amino groups on the surface and the negatively charged chromium ions in the water. Adsorption isotherms and kinetic studies indicated that the adsorption process fits the Langmuir and the Freundlich isotherm models as well as the pseudo-first and pseudo-second order kinetic models. These results can open a new avenue for the manufacturing of fibers with enhanced removal capacities for hexavalent chromium.

scholarly journals Adsorption of Hexavalent Chromium from Aqueous Solution Using Chemically Activated Carbon Prepared from Locally Available Waste of Bamboo (Oxytenanthera abyssinica)

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Tamirat Dula ◽  
Khalid Siraj ◽  
Shimeles Addisu Kitte
Keyword(s):  
Activated Carbon ◽  
Hexavalent Chromium ◽  
Freundlich Isotherm ◽  
Kinetic Studies ◽  
Batch Adsorption ◽  
Koh Activation ◽  
Order Kinetic ◽  
Oxytenanthera Abyssinica ◽  
Equilibrium Data ◽  
Order Kinetic Model

This study reports on the adsorption of Hexavalent Chromium from aqueous solutions using activated carbon prepared from bamboo (Oxytenanthera abyssinica) waste by KOH activation heating in an electrical furnace at 1073 K for 3 hrs. Batch adsorption experiments were also carried out as a function of pH, contact time, initial concentration of the adsorbate, adsorbent dosage, and temperature of the solution. Kinetic studies of the data showed that the adsorption follows the pseudo-second-order kinetic model. Thermodynamic parameters showed that adsorption on the surface of BWAC was feasible, spontaneous in nature, and exothermic between temperatures of 298 and 318 K. The equilibrium data better fitted the Freundlich isotherm model for studying the adsorption behavior of Hexavalent Chromium by BWAC. IR spectrum for loaded and unloaded BWAC was obtained using FT-IR spectrophotometer. Adsorption efficiency and capacity of Hexavalent Chromium were found to be 98.28% at pH 2 and 59.23 mg/g at 300 K.

scholarly journals Parametric, equilibrium and kinetic studies on the removal of mercury using ion exchange resin

2017 ◽  
Vol 12 (2) ◽  
pp. 305-313 ◽  
Author(s):  
N. Rajamohan ◽  
M. Rajasimman
Keyword(s):  
Freundlich Isotherm ◽  
Kinetic Studies ◽  
Strong Acid ◽  
Ion Exchange Resin ◽  
Second Order ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Acid Cation ◽  
Pseudo Second Order ◽  
Langmuir Constants

This experimental research was an investigation into removal of mercury by using a strong acid cation resin, 001 × 7. Parametric experiments were conducted to determine the optimum pH, resin dosage, agitation speed and the effect of change in concentration in the range of 50–200 mg/L. High resin dosages favoured better removal efficiency but resulted in lower uptakes. Equilibrium experiments were performed and fitted to Langmuir and Freundlich isotherm models. Langmuir model suited well to this study confirming the homogeneity of the resin surface. The Langmuir constants were estimated as qmax = 110.619 mg/g and KL = 0.070 L/g at 308 K. Kinetic experiments were modeled using Pseudo second order model and higher values of R2 (>0.97) were obtained. The Pseudo second order kinetic constants, namely, equilibrium uptake (qe) and rate constant (k2), were evaluated as 59.17 mg/g and 40.2 × 10−4 g mg−1 min−1 at an initial mercury concentration of 100 mg/L and temperature of 308 K.

Parametric and adsorption kinetic studies of methylene blue removal from simulated textile water using durian (Durio zibethinus murray) skin

2015 ◽  
Vol 72 (6) ◽  
pp. 896-907 ◽  
Author(s):  
S. M. Anisuzzaman ◽  
Collin G. Joseph ◽  
D. Krishnaiah ◽  
A. Bono ◽  
L. C. Ooi
Keyword(s):  
Methylene Blue ◽  
Adsorption Capacity ◽  
Dye Adsorption ◽  
Freundlich Isotherm ◽  
Kinetic Studies ◽  
Isotherm Models ◽  
Batch Adsorption ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Durio Zibethinus

In this study, durian (Durio zibethinus Murray) skin was examined for its ability to remove methylene blue (MB) dye from simulated textile wastewater. Adsorption equilibrium and kinetics of MB removal from aqueous solutions at different parametric conditions such as different initial concentrations (2–10 mg/L), biosorbent dosages (0.3–0.7 g) and pH solution (4–9) onto durian skin were studied using batch adsorption. The amount of MB adsorbed increased from 3.45 to 17.31 mg/g with the increase in initial concentration of MB dye; whereas biosorbent dosage increased from 1.08 to 2.47 mg/g. Maximum dye adsorption capacity of the durian skin was found to increase from 3.78 to 6.40 mg/g, with increasing solution pH. Equilibrium isotherm data were analyzed according to Langmuir and Freundlich isotherm models. The sorption equilibrium was best described by the Freundlich isotherm model with maximum adsorption capacity of 7.23 mg/g and this was due to the heterogeneous nature of the durian skin surface. Kinetic studies indicated that the sorption of MB dye tended to follow the pseudo second-order kinetic model with promising correlation of 0.9836 < R2 < 0.9918.

scholarly journals The effect of alkaline pretreatment on surfactant-modified clinoptilolite for diclofenac adsorption: isotherm, kinetic, and thermodynamic studies

2020 ◽  
Author(s):  
Fateme Poorsharbaf Ghavi ◽  
Fereshteh Raouf ◽  
Ahmad Dadvand Koohi
Keyword(s):  
Ph Effect ◽  
Freundlich Isotherm ◽  
Kinetic Studies ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Thermodynamic Studies ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Modified Clinoptilolite ◽  
Kinetic And Thermodynamic Studies

Abstract The elimination of diclofenac traces from aqueous environments is important. In this research, the effect of alkaline (NaOH) pretreatment on clinoptilolite before its modification with a surfactant (HDTMA) for diclofenac adsorption under the speculation of the sole presence of diclofenac in the aqueous solution is investigated. The results are compared through isotherm, kinetic, and thermodynamic studies and supplemented by FTIR, SEM, BET, and the zeta potential analyses. The contact time was investigated in a 0–180-min range. The pH effect was studied in a range of 5–10 because of diclofenac dissociation below pH = 5. The effect of the temperature on diclofenac adsorption was also considered by establishing the experiments at 25, 35, and 45 °C. For HDTMA-modified clinoptilolite, Temkin, and for NaOH-HDTMA-modified clinoptilolite, Dubinin–Radushkevich, and Freundlich isotherm models and in both cases, the pseudo-second-order kinetic model fitted the experimental data best. All the enthalpy and the entropy changes were negative, suggesting exothermic adsorption with a decrease in the degree of freedom of diclofenac anions after the adsorption. Furthermore, diclofenac physisorption was confirmed through isotherm and kinetic studies.

scholarly journals Equilibrium and kinetic studies of sorption of 2.4-dichlorophenol onto 2 mixtures: bamboo biochar plus calcium sulphate (BC) and hydroxyapatite plus bamboo biochar plus calcium sulphate (HBC), in a fluidized bed circulation column

2016 ◽  
Vol 18 (2) ◽  
pp. 59-67 ◽  
Author(s):  
Ahmed Hassan Alamin ◽  
Lupong Kaewsichan
Keyword(s):  
Fluidized Bed ◽  
Low Cost ◽  
Freundlich Isotherm ◽  
Kinetic Studies ◽  
Calcium Sulphate ◽  
Isotherm Models ◽  
Process Time ◽  
Order Kinetic ◽  
Column Adsorption ◽  
Order Kinetic Model

Abstract Sorption studies were carried out to investigate removal of 2.4-dichlorophenol (2.4-DCP) from aqueous solution in a fluidized bed by two types of adsorbent mixtures: BC (Bamboo char plus Calcium sulphate), and HBC (Hydroxyapatite plus Bamboo char plus Calcium sulphate); both manufactured in ball shape. The main material bamboo char was characterized by FTIR, DTA and SEM. The adsorption experiments were conducted in a fluidized bed circulation column. Adsorption, isotherms and kinetic studies were established under 180 min operating process time, at different initial 2.4-DCP solution concentrations ranging from 5–10 mg/L, and at different flow rates ranging from 0.25–0.75 L/min. The data obtained fitted well for both the Langmuir and Freundlich isotherm models; indicating favorable condition of monolayer adsorption. The kinetics of both adsorbents complies with the pseudo second-order kinetic model. BC was proven a new effective composite and low cost adsorbent which can be applied in the field of wastewater treatment, and it can also play an important role in industry water treatment.

scholarly journals Removal of Patent Blue (V) Dye Using Indian Bael Shell Biochar: Characterization, Application and Kinetic Studies

2018 ◽  
Vol 10 (8) ◽  
pp. 2669 ◽  
Author(s):  
Kangkan Roy ◽  
Kapil Verma ◽  
Kumar Vikrant ◽  
Mandavi Goswami ◽  
Ravi Sonwani ◽  
...  
Keyword(s):  
Freundlich Isotherm ◽  
Kinetic Studies ◽  
Active Role ◽  
Batch Adsorption ◽  
Order Kinetic ◽  
Operational Conditions ◽  
Maximum Sorption Capacity ◽  
Patent Blue ◽  
Maximum Sorption

The prospective utilization of bael shell (Aegle marmelos) as an agro-waste for the production of biochar was investigated along with its characterization and application for the abatement of hazardous aqueous Patent Blue (PB) dye solution. The sorptive removal of PB on bael shell biochar (BSB) was investigated under the following operational conditions: (pH, 2.7–10.4; biochar dosage, 2–12 g/L; and contact time, 0–60 min). The removal efficiency of PB by BSB in a batch adsorption experiment was 74% (pH 2.7 and 30 ± 5 °C). In addition, a clear relationship between the adsorption and pH of the solution was noticed and the proposed material recorded a maximum sorption capacity of 3.7 mg/g at a pH of 2.7. The adsorption of PB onto BSB was best explained by the pseudo-second order kinetic model (R2 = 0.972), thereby asserting the predominant role of chemisorption. The active role of multiple surface-active functionalities present on BSB during PB sorption was elucidated with the help of Freundlich isotherm (R2 = 0.968). Further, an adsorption mechanism was proposed by utilizing Fourier transform infrared spectroscopy (FTIR).

Sr(II) Removal from Aqueous Solution by Bacillus cereus Biomass, Equilibrium and Kinetic Studies

2011 ◽  
Vol 230-232 ◽  
pp. 1129-1132 ◽  
Author(s):  
Ya Li He ◽  
Tian Hai Wang ◽  
Jun Cao Shi
Keyword(s):  
Aqueous Solution ◽  
Bacillus Cereus ◽  
Practical Implication ◽  
Freundlich Isotherm ◽  
Kinetic Studies ◽  
Isotherm Models ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Order Kinetic Model ◽  
Economic Technology

Batch experiments were carried out to determine the capacity of Bacillus cereus biomass to adsorb Sr(II) ions from aqueous solution with respect to pH, initial Sr(II) concentration, contact time and biomass dose. The experimental data were modeled by Langmuir and Freundlich isotherm models. Langmuir model resulted in the best fit of the adsorption data. The maximum adsorption capacity for Sr(II) was 78.34 mg/g. The best correlation was provided by the second-order kinetic model, implying that chemical sorption was the rate-limiting step. The practical implication of this study is the development of an effective and economic technology for Sr(II) removal from contaminated waters.

scholarly journals Phenol adsorption from wastewater using cashew nut shells as adsorbent

2018 ◽  
Vol 7 (3) ◽  
pp. 966
Author(s):  
Kartik Kulkarni ◽  
Varsha Sudheer ◽  
C R Girish
Keyword(s):  
Agricultural Waste ◽  
Freundlich Isotherm ◽  
Isotherm Models ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Multilayer Adsorption ◽  
Phenol Adsorption ◽  
Cashew Nut ◽  
Experimental Parameters ◽  
Order Kinetic Model

The potential of agricultural waste cashew nut shells as an adsorbent for removing phenol from wastewater is presented in this paper. The adsorbent was treated with 3M sulphuric acid in order to improve the properties. The experimental parameters such as adsorbent dosage, concentration and temperature were optimized with response surface methodology (RSM). The isotherm data were tested with different isotherm models and it obeyed Freundlich Isotherm showing the multilayer adsorption. The kinetic data satisfied pseudo-first order kinetic model. The maximum adsorption capacity was calculated to be 35.08 mg/g proving the capability of cashew nut shells for removing phenol from wastewater.  

scholarly journals Multi-Component Adsorption of Benzene, Toluene, Ethylbenzene, and Xylene from Aqueous Solutions by Montmorillonite Modified with Tetradecyl Trimethyl Ammonium Bromide

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
H. Nourmoradi ◽  
Mehdi Khiadani ◽  
M. Nikaeen
Keyword(s):  
Experimental Data ◽  
Aqueous Solutions ◽  
Structural Changes ◽  
Freundlich Isotherm ◽  
Isotherm Models ◽  
Ammonium Bromide ◽  
Order Kinetic ◽  
Multicomponent Adsorption ◽  
Benzene Toluene ◽  
Kinetic And Isotherm Models

Multicomponent adsorption of benzene, toluene, ethylbenzene, and xylene (BTEX) was assessed in aqueous solutions by montmorillonite modified with tetradecyl trimethyl ammonium bromide (TTAB-Mt). Batch experiments were conducted to determine the influences of parameters including loading rates of surfactant, contact time, pH, adsorbate concentration, and temperature on the adsorption efficiency. Scanning electron microscope (SEM) and X-ray diffractometer (XRD) were used to determine the adsorbent properties. Results showed that the modification of the adsorbent via the surfactant causes structural changes of the adsorbent. It was found that the optimum adsorption condition achieves with the surfactant loading rate of 200% of the cation exchange capacity (CEC) of the adsorbent for a period of 24 h. The sorption of BTEX by TTAB-Mt was in the order ofB<T<E<X. The experimental data were fitted by many kinetic and isotherm models. The results also showed that the pseudo-second-order kinetic model and Freundlich isotherm model could, respectively, be fitted to the experimental data better than other available kinetic and isotherm models. The thermodynamic study indicated that the sorption of BTEX with TTAB-Mt was achieved spontaneously and the adsorption process was endothermic as well as physical in nature. The regeneration results of the adsorbent also showed that the adsorption capacity of adsorbent after one use was 51% to 70% of original TTAB-Mt.

scholarly journals Effective Removal of Malachite Green from Aqueous Solutions Using Magnetic Nanocomposite: Synthesis, Characterization, and Equilibrium Study

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Ali Q. Alorabi
Keyword(s):  
Surface Area ◽  
Malachite Green ◽  
Chemical Activation ◽  
Aqueous Media ◽  
Kinetic Studies ◽  
Cost Effective ◽  
Magnetic Nanocomposite ◽  
Bet Surface Area ◽  
Isotherm Models ◽  
Order Kinetic

In this work, magnetized activated Juniperus procera leaves (Fe3O4@AJPL) were successfully prepared via chemical activation of JPL and in situ coprecipitation with Fe3O4. A Fe3O4@AJPL nanocomposite was successfully applied for the elimination of malachite green (MG) dye from aqueous media. The prepared Fe3O4@AJPL adsorbent was characterized by SEM, EDX, TEM, XRD, FTIR, TGA, and BET surface area analyses. The BET surface area and pore size of the Fe3O4@AJPL nanocomposite were found to be 38.44 m2/g and 10.6 nm, respectively. The XRD and FTIR results indicated the formation of a Fe3O4@AJPL nanocomposite. Different parameters, such as pH of the solution (3–8), adsorbent dosage (10–100 mg), temperature (25–45°C), contact time (5-240 min), and initial MG concentrations (20–350 mg/L), for the elimination of the MG dye using Fe3O4@AJPL were optimized and found to be 7, 50 mg, 45°C, 120 min, and 150 mg/L, respectively. The nonlinear isotherm and kinetic studies exhibited a better fitting to second-order kinetic and Langmuir isotherm models, with a maximum monolayer adsorption capacity of 318.3 mg/g at 45°C, which was highly superior to the previously reported magnetic nanocomposite adsorbents. EDX analyses confirmed the presence of nitrogen on the Fe3O4@AJPL surface after MG adsorption. The calculated thermodynamic factors indicated endothermic and spontaneous processes. The desorption of MG dye from Fe3O4@AJPL was performed using a solution of 90% ethanol. Finally, it could be concluded that the designed Fe3O4@AJPL magnetic nanocomposite will be a cost-effective and promising adsorbent for the elimination of MG from aqueous media.

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