Kinetic study and Box–Behnken design approach to optimize the sorption process of toxic azo dye onto organo-modified bentonite

2020 ◽  
Vol 98 (5) ◽  
pp. 215-221
Author(s):  
Brahim Guezzen ◽  
Mehdi Adjdir ◽  
Baghdad Medjahed ◽  
Mohamed A. Didi ◽  
Peter G. Weidler

Kinetic study was applied for sodium bentonite (Na-B) and hexadecylpyridinium bentonite (HDP-B) under different amounts, namely 50% (50HDP-B), 100% (100HDP-B), and 200% (200HDP-B) with respect to cation exchange capacity (CEC). Pseudo first-order and pseudo second-order kinetic models were performed to optimize the sorption of Congo red (CR) dye from aqueous solution. The experimental data fit the pseudo second order kinetic model well. The sorption capacity (qe) of CR dye by the organo-bentonites at equilibrium was 36.0 mg g−1 (72.1%) for 50HDP-B, 48.05 mg g−1 (96.1%) for 100HDP-B, and 49.2 mg g−1 (98.4%) for 200HDP-B. These results were considerably higher than that found by Na-B. Response surface methodology with three-variable, three-level Box–Behnken design was applied for 100HDP-B to describe the removal of CR dye. The effects of three variables, namely temperature, adsorbent dosage, and initial dye concentration, were studied. Predicted values of adsorption efficiency were found to be in good agreement with the obtained experimental values (R2 = 0.97). A second-order polynomial model successfully described the effects of independent variables on the CR dye removal. At the optimized condition, the toxic azo dye could be quantitatively removed from aqueous solution. The results of the present study suggest that the organo-bentonite can be used as an efficient sorbent for dye removal from aqueous solution.

2019 ◽  
Vol 70 (4) ◽  
pp. 1108-1113 ◽  
Author(s):  
Rana Abdullah Abbas ◽  
Ahlam Abdul-Rheem Farhan ◽  
Hussam Nadum Abdalraheem Al Ani ◽  
Aurelia Cristina Nechifor

Eggshells was used as a natural adsorbent to remove direct blue(DB) dye from aqueous solution and investigating the four factors that affect the adsorption of DB dye ; amount of eggshell rang (0.1 - 1g), initial concentration (10 - 60 mg/L ), time ( 5 - 45 min.) and pH (3 - 11). Central Composition Design with four variables and five levels coupled with response surface method was adopted to get a second order polynomial equation for dye removal percentage as the response, and to obtain the optimum conditions for maximum dye removal percentage ; which reach 84% with optimum point , eggshell (0.835 g) ,time (24min.) , initial dye concentration ( 10 mg/L) , pH (4.2). The most effecting factors on dye removal are pH and initial dye concentration. Langmuir, Freundich model gives good fitting with (R2 ]0.98). The process of adsorption of DB dye on eggshell fitted a pseudo-second order kinetic model.


2018 ◽  
Vol 6 (3) ◽  
pp. 104-107 ◽  
Author(s):  
Suhad A. Yasin ◽  
Amin K. Qasim

Laurus nobilis (Bay leaf), was examined for its capacity to remove hexavalent chromium Cr(VI) poisonous, from aqueous solution. The bio-adsorbent using bay leaf obtained from Laurus nobilis was investigated in batch experiments. The influence of main parameters such as chromium concentration, pH and shaking time are tests. The effect of beginning concentration of Cr(VI) ion (10 to 50 mg/dm ), pH (1 to 6) and shaking time (5 to 180 min) have been reported. The optimum pH was found to be pH 4.. Results show that the most appropriate model was pseudo second-order kinetic and it correlate with the trial statistics well.


2021 ◽  
Vol 46 (2) ◽  
Author(s):  
O.K. Amadi ◽  
F.K. Ekuma ◽  
B. N. Uche

This study investigates the biosorption of Ni2+, Cd2+ and Pb2+ from aqueous solution by modified Newbouldia Leavis seed pod. The modification was done by acid treating air-dried activated Newbouldia Leavis seed pod by dissolving it in excess 1.0 M Mercapto acetic acid (HSCH2COOH) solution, stirred for 30 minutes and left to stand for 24 hours at 30 oC, filtered off using WhatmanNo. 41 filter paper and were air dried. The effects of solution pH and contact time were evaluated. The results showed that maximum Cd2+ and Ni2+ adsorption of 7.9872 mg/g and 7.9809 mg/g respectively occurred at pH of 6.0 while that of Pb2+ was 8.0000 mg/g, at a pH of 4.0. The optimum time for maximum adsorption of the three heavy metal ions were 110 min. The kinetic data revealed that the sorption process could best be described by the pseudo – second order kinetic model. The R2 values for the pseudo – second order kinetic plots were unity and were higher than first order reversible model and pseudo – first order plots. Moreover, the values of qcal and qexp obtained for pseudo – second order plots were very close indicating that the biosorption process followed the pseudo-second order kinetics. However, the transport mechanism for the process involved both intra-particle and liquid film diffusion.


2019 ◽  
Vol 233 (9) ◽  
pp. 1275-1292 ◽  
Author(s):  
Atta ul Haq ◽  
Muhammad Rasul Jan ◽  
Jasmin Shah ◽  
Maria Sadia ◽  
Muhammad Saeed

Abstract The presence of heavy metals in water causes serious problems and their treatment before incorporating into the water body is a challenge for researchers. The present study was conducted to compare the sorption study of Ni (II) using silica gel, amberlite IR-120 and sawdust of mulberry wood in batch system under the influence of pH, initial Ni (II) concentration and contact time. It was observed that sorption process was depending upon pH and maximum sorption was achieved at pH 7.0. Kinetic data were well fitted into pseudo-second order kinetic model due to high R2 values and closeness of experimental sorption capacity and calculated sorption capacity of pseudo-second order. Isotherms study showed that Langmuir is one of the most suitable choices to explain sorption data due to high R2 values. The monolayer sorption capacities of silica gel, amberlite IR-120 and sawdust were found to be 33.33, 25.19, and 33.67 mg g−1, respectively. Desorption study revealed that NaCl is one of the most appropriate desorbent. It may be concluded from this study that sawdust is a suitable sorbent due to low cost, abundant availability and recycling of the materials for further study.


2012 ◽  
Vol 27 ◽  
pp. 11-18
Author(s):  
Timi Tarawou ◽  
Michael Horsfall

The adsorption of chromium (VI) ions from aqueous solution was studied using pure and carbonized fluted pumpkin waste biomass (FPWB). The kinetic data shows a pseudo-first-order mechanism with rate constants of 1.26 × 10-2 and 1.933 × 10-2 mg g-1 min-1 for the pure and carbonized FPWB, respectively. While the pseudo-second-order mechanism has rate constants of 0.93 × 10-1 and 1.33 × 10-1 mg g-1 min-1 for the pure and carbonized waste biomass respectively. The pseudo-second order kinetic model was found to be more suitable for describing the experimental data based on the correlation coefficient values (R2) of 0.9975 and 0.9994 obtained for pure waste biomass (PWB) and carbonized waste biomass (CWB), respectively. The results obtained from this study show that PWB and CWB have very high removal capacity for chromium (VI) from aqueous solution over a range of reaction conditions. Thus, fluted pumpkin waste biomass (Telfairia occidentalis Hook F) is a potential sorbent for the treatment of industrial effluents containing chromium (VI) contaminant.DOI: http://dx.doi.org/10.3126/jncs.v27i1.6436 J. Nepal Chem. Soc., Vol. 27, 2011 11-18Uploaded date: 16 July, 2012


Author(s):  
Jurgita Seniūnaitė ◽  
Rasa Vaiškūnaitė ◽  
Kristina Bazienė

Research studies on the adsorption kinetics are conducted in order to determine the absorption time of heavy metals on coffee grounds from liquid. The models of adsorption kinetics and adsorption diffusion are based on mathe-matical models (Cho et al. 2005). The adsorption kinetics can provide information on the mechanisms occurring be-tween adsorbates and adsorbents and give an understanding of the adsorption process. In the mathematical modelling of processes, Lagergren’s pseudo-first- and pseudo-second-order kinetics and the intra-particle diffusion models are usually applied. The mathematical modelling has shown that the kinetics of the adsorption process of heavy metals (copper (Cu) and lead (Pb)) is more appropriately described by the Lagergren’s pseudo-second-order kinetic model. The kinetic constants (k2Cu = 0.117; k2Pb = 0,037 min−1) and the sorption process speed (k2qeCu = 0.0058–0.4975; k2qePb = 0.021–0.1661 mg/g per min) were calculated. After completing the mathematical modelling it was calculated that the Langmuir isotherm better reflects the sorption processes of copper (Cu) (R2 = 0.950), whilst the Freundlich isotherm – the sorption processes of lead (Pb) (R2 = 0.925). The difference between the mathematically modelled and experimen-tally obtained sorption capacities for removal of heavy metals on coffee grounds from aqueous solutions is 0.059–0.164 mg/l for copper and 0.004–0.285 mg/l for lead. Residual concentrations of metals in a solution showed difference of 1.01 and 0.96 mg/l, respectively.


2013 ◽  
Vol 726-731 ◽  
pp. 2736-2741
Author(s):  
Ming Da Liu ◽  
Ge Tian ◽  
Liang Jie Zhao ◽  
Yao Sheng Wang ◽  
Lei Guo ◽  
...  

Five blast-furnace slags were used as adsorbents to remove Pb (II) from aqueous solution. Kinetic studies showed that the sorption process was best described by pseudo-second-order model. Among Langmuir, Freundlich and Temkin isotherms, the Freundlich isotherm had a better fit with the simulation of the adsorption of Pb (II).


2012 ◽  
Vol 65 (10) ◽  
pp. 1729-1737 ◽  
Author(s):  
Messaouda Safa ◽  
Mohammed Larouci ◽  
Boumediene Meddah ◽  
Pierre Valemens

The adsorption of Cu2+, Zn2+, Cd2+ and Pb2+ ions from aqueous solution by Algerian raw diatomite was studied. The influences of different sorption parameters such as contact pH solution, contact time and initial metal ions concentration were studied to optimize the reaction conditions. The metals ions adsorption was strictly pH dependent. The maximum adsorption capacities towards Cu2+, Zn2+, Cd2+ and Pb2+ were 0.319, 0.311, 0.18 and 0.096 mmol g−1, respectively. The kinetic data were modelled using the pseudo-first-order and pseudo-second-order kinetic equations. Among the kinetic models studied, the pseudo-second-order equation was the best applicable model to describe the sorption process. Equilibrium isotherm data were analysed using the Langmuir and the Freundlich isotherms; the results showed that the adsorption equilibrium was well described by both model isotherms. The negative value of free energy change ΔG indicates feasible and spontaneous adsorption of four metal ions on raw diatomite. According to these results, the high exchange capacities of different metal ions at high and low concentration levels, and given the low cost of the investigated adsorbent in this work, Algerian diatomite was considered to be an excellent adsorbent.


2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Siti Kartina Abdul Karim ◽  
Soh Fong Lim ◽  
S. N. David Chua ◽  
Shanti Faridah Salleh ◽  
Puong Ling Law

In this study, banana fibers extracted from banana leaves, stem, and stalk were used to remove acid green dye from aqueous solution. Three initial concentrations (750, 1000, and 1500 ppm) were chosen to determine the kinetic characteristics of the banana fiber sorbents at 25°C, agitation speed of 200 rpm, and total contact time of 3 hours. The pseudo-first-order, pseudo-second-order, and Dunwald-Wagner kinetic models were applied to the experimental kinetic data. For isotherm study, the batch experiments were performed at 25°C, initial pH 2, agitation speed of 200 rpm, and initial concentrations between 100 and 2000 ppm. The experimental data was fitted to the Langmuir, Freundlich, Dubinin-Radushkevich, and Temkin isotherms. The equilibrium was achieved in less than 90 minutes. The removal of the acid green dye was found to be following closely the pseudo-second-order kinetic model. For equilibrium study, the Freundlich isotherm was found to fit well with adsorption of acid green dye on the banana leaves, stem, and stalk sorbents. The calculated mean free energy of 4–11 J/mol indicated that the sorption process was mostly physical in nature. Experimental results also showed the adsorption performance is greatly affected by the initial solution pH.


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