Kinetic study and equilibrium isotherm analysis of Congo Red adsorption by clay materials (original) (raw)
Related papers
The textile effluents are considered as potential source of water contaminations. Thus the effective methods were adopted for the removal of dyes and colorants from the textile effluents. In the present research, the removal of textile dye Congo red was carried out by bentonite clay blend with kaolin. The kaolin-bentonite clay (KBC) was used as adsorbent. The adsorption properties of KBC towards Congo red were investigated, at various temperatures 303-318 ±2 K under the optimized conditions. The adsorption equilibrium data were fitted in Langmuir, Freundlich and Dubinin-Radushkevich adsorption isotherm models and the values of the respective constants were evaluated by employing standard graphical method. From the graph, it was founded that Langmuir model is the best fitted isotherm. Feasibility of adsorption process (RL) and sorption energy (Es) was also determined. The pH of adsorbent was estimated by pH drift method. Kinetics of dye removal was investigated that it follows pseudo second order rate constant. The surface morphology of adsorbent was observed by the Scanning Electron Microscope (SEM).
Arab Journal of Basic and Applied Sciences
The abundant natural bentonite from Sarolangun deposit of Jambi Province, Indonesia, has been successfully activated by a wet acid activation method and applied as a low-cost, and environmental-friendly adsorbent for Congo red dye removal from aqueous solution. The activated bentonite samples were characterized by powder X-ray diffraction (XRD), Fouriertransform infrared spectroscopy (FTIR), N 2 adsorption-desorption, and X-ray fluorescence (XRF). The batch adsorption technique has been conducted to study the adsorption behavior of Congo red on activated bentonite. The effects of operational parameters toward the Congo red adsorption on activated bentonite, including adsorbent dosage, initial pH, contact time, initial concentration, and temperature were investigated. Moreover, the properties of adsorption kinetics, adsorption isotherm, and adsorption thermodynamic were also investigated. The results of material characterization showed that acid-activated bentonite has better properties than natural bentonite. For instance, the surface area of acid-activated bentonite elevated almost five-fold compared with natural bentonite. The batch adsorption study showed that the Congo red adsorption on acid-activated bentonite was significantly affected by adsorbent dosage, initial pH, contact time, dye concentration, and temperature. The adsorption kinetics investigation revealed that adsorption was best evaluated by a pseudo-second-order model rather than pseudo-first-order model. The adsorption equilibrium study described that the adsorption process followed the Langmuir isotherm model. The result of thermodynamic investigation revealed that the adsorption process occurred spontaneously and favorably in high-temperature conditions.
In the study, montmorillonite was used as an adsorbent for the removal of methylene blue (MB) from aqueous solutions. Batch studies were performed to address various experimental parameters like contact time, pH, temperature, stirring speed, ionic strength, adsorbent dosage and initial concentration for the removal of this dye. Adsorption rate increased with the increase in initial dye concentration, ionic strength, stirring speed, pH and temperature. Kinetic study showed that the adsorption of dye on montmorillonite was a gradual process. Quasi-equilibrium reached in 3 h. Pseudo-first-order, pseudo-second-order, Elovich, Bangham, mass transfer and intra-particle particle diffusion models were used to fit the experimental data. Pseudo-second-order rate equation was able to provide realistic description of adsorption kinetics. Intra-particle diffusion process was identified as the main mechanism controlling the rate of the dye sorption. The diffusion coefficient, D, was found to increase when the stirring speed, ionic strength and temperature were raised. Thermodynamic activation parameters such as ΔG*, ΔS* and ΔH* were also calculated.
Adsorption Science & Technology, 2012
The < 25 µm fraction of natural clay containing kaolinite, chlorite, illite and illite/smectite mixed layered clay minerals was characterized and used as a potential adsorbent for the removal of Rhodamine B (RB) dye from aqueous solution. Adsorption experiments were carried out in batch mode by varying the following parameters: pH, temperature, initial dye concentration, adsorbent dosage and time of contact. The equilibrium data were well fitted by both the Langmuir and Freundlich adsorption isotherms. The Langmuir monolayer adsorption capacity was found to be 4.77 mg/g, which was better than the value reported for kaolinite (1.95 mg/g). The adsorption process followed pseudo-second-order kinetics. Negative ∆G 0 values indicated that adsorption onto this clay was a spontaneous process. A maximum dye uptake of > 90% was achieved at 313 K employing an initial dye concentration of 4.8 × 10-6 M, a pH value of 2 and an adsorbent dosage of 1 g/ .
Equilibrium and kinetic data and process design for adsorption of Congo Red onto bentonite
Journal of Hazardous Materials, 2008
The adsorption of Congo Red onto bentonite in a batch adsorber has been studied. Four kinetic models, the pseudo first-and second-order equations, the Elovich equation and the intraparticle diffusion equation, were selected to follow the adsorption process. Kinetic parameters; rate constants, equilibrium adsorption capacities and correlation coefficients, for each kinetic equation were calculated and discussed. It was shown that the adsorption of Congo Red onto bentonite could be described by the pseudo second-order equation. The experimental isotherm data were analyzed using the Langmuir, Freundlich and Temkin equations. Adsorption of Congo Red onto bentonite followed the Langmuir isotherm. A single stage batch adsorber was designed for different adsorbent mass/treated effluent volume ratios using the Langmuir isotherm.
Saudi Journal of Engineering and Technology
Decolourisation of wastewater, particularly from textile industries is one of the major environmental concerns these days. The limitations of most of these treatment methods are their high operational and maintenance costs cannot effectively be used to treat wide range of such wastewater. This work describes the use of kaolinite clay as an efficient adsorbent material for anionic azo dye methyl orange removal from synthesized wastewater. Batch adsorption experiment of 200 mgL-1 azo dye methyl orange contaminant removal using kaolinite clay at different stirring speed: 100, 200, 300, 400 and 500 rpm at constant pH4 and contact time of (0-180) minutes were investigated, thus, adsorption increases with increase in stirring speed with maximum removal of 69.90% and maximum adsorptive capacity of 3.476 mg/g at 500 rpm. The adsorption equilibrium data were well described by Langmuir>Freundlich>Koble-Corrigan whilst adsorption kinetic data by pseudo second-order>pseudo first-order>intraparticle diffusion>Reichenberg equation in the stated order based on high correlation coefficients and relatively small values of error function analyses (χ 2 , RMSE, NSD and ARE). The adsorption processes were controlled by chemisorption. The potential applicability of Alkaleri kaolinite clay from Northeast-Nigeria could be employed as a low-cost adsorbent alternative to commercial/activated carbon in the removal of azo dye methyl orange from wastewater.
Water Resources and Industry, 2015
Inexpensive and easily available Moroccan natural clays were investigated for the removal availability of textile dyes from aqueous solution. For this purpose, the adsorption of methylene blue (MB) as reference molecule, malachite green (MG) representative of cationic dyes and methyl orange (MO) representative of anionic dyes, was studied in batch mode under various parameters. The clays were characterized by means of XRD, cationic exchange capacity and BET surface area analysis. The experimental results show that, the adsorption was pH dependent with a high adsorption capacity of MB and MG in basic range and high adsorption of MO in acidic range. The pseudo-second-order kinetic model provided the best fit to the experimental data for the adsorption of MB and MG by the clays. However, the adsorption of MO was more suitable to be controlled by an intra-particle diffusion mechanism. The equilibrium adsorption data were analyzed by Langmuir, Freundlich and Dubinin-Radushkevich isotherm models. The adsorption process was found to be exothermic in nature in the case of MB and MO. However, the adsorption of MG was endothermic.
PONTE International Scientific Researchs Journal, 2021
The current study investigates the potential use of Algerian clay as an adsorbent for the elimination of Crystal Violet (CV) dye. Mchouneche Clay (MC) has been introduced as a lowcost biosorbent for batch manner removal of CV. Essential criteria were examined to determine the optimal conditions. In addition, several kinetic and isothermal models were fitted with experimentally obtained data. The uptake of CV correlated with the initial pH, due to the ionic nature of CV and the mineral surface of MC. Indeed, the adsorption behavior was found to depend on the initial concentration of CV as the number of collisions increased. The analytical study revealed that Pseudo-Second Order (PSO) is the most suitable fitting model. The isothermal study has also shown that the results are consistent with the Langmuir model. The thermodynamic investigation has shown that the adsorption phenomenon is feasible, spontaneous, and endothermic.
Potentiality of open burnt clay as an adsorbent for the removal of Congo red from aqueous solution
International Journal of Environmental Science & Technology, 2007
Open burnt clay was studied as a potential adsorbent for the adsorption of Congo red (a reactive dye) from aqueous solution. The effect of contact time, pH, adsorbent dosage and temperature were studied. It was observed that the amount of Congo red retained increase with decreasing pH and increasing initial concentration. Removal percentage at pH 2 and 3 are almost same. The adsorption capacity of regenerated burnt clay was showed more than 98 % recovery of the adsorption efficiency of initial virgin adsorbent. The equilibrium data were described well by both Langmuir and Freundlich isotherm model. The adsorption capacity of some natural adsorbents, namely rice husk, wood charcoal, tea waste etc. were also investigated and compared with that of open burnt clay.
Removal of a cationic dye from aqueous solutions by adsorption onto bentonite clay
Chemosphere, 2006
The ability of bentonite to remove malachite green from aqueous solutions has been studied for different adsorbate concentrations by varying the amount of adsorbent, temperature, pH and shaking time. Maximum adsorption of the dye, i.e. >90% has been achieved in aqueous solutions using 0.05 g of bentonite at a pH of 9. Thermodynamic parameters such as DH°, DS°and DG°were calculated from the slope and intercept of the linear plots of ln K D against 1/T. Analysis of adsorption results obtained at 298, 308, 318 and 328 K showed that the adsorption pattern on bentonite seems to follow the Langmuir, Freundlih and D-R isotherms. The temperature increase reduces adsorption capacity by bentonite, due to the enhancement of the desorption step in the mechanism. The numerical values of sorption free energy (E a ) of 1.00-1.12 kJ mol À1 indicated physical adsorption. The kinetic data indicated an intraparticle diffusion process with sorption being first order. The rate constant k was 0.526 min À1 . The concentration of malachite green oxalate was measured before and after adsorption by using UV-Vis spectrophotometer.