Surface Area Of Bentonite Research Articles

Calcined biomass-bentonite composites as eco-friendly adsorbents for the treatment of toxic anionic and cationic dye wastewater

Adsorption is a suitable technique for decontamination of organic dye wastewaters. Herein, we comparatively investigated the adsorption performance of bentonite (BEN) and its modification with groundnut shell (BGS) and palm kernel shell (BPS) for methylene blue (MB) and congo red (CR) dyes removal from aqueous solution. BGS and BPS were prepared by calcination at 300 °C for 6 h and were characterized using BET, SEM, EDS and FTIR to determine their textural properties, morphologies, elemental compositions, and functional groups. The BET surface examination revealed that the surface area of BEN was enhanced from 78 m2/g to 195 m2/g and 141 m2/g after modification with groundnut shell (BGS) and palm kernel shell (BPS), respectively. The adsorption process in a batch system was subjected to comprehensive experimentation to investigate the effect of adsorbent dosage, contact time, temperature, initial concentration, and pH. The adsorption was fitted to adsorption isotherm and kinetic models and the results revealed that the adsorption process of BEN, BGS, and BPS towards MB and CR adsorption can be best described by Temkin, Freundlich and pseudo-second order kinetic models. The adsorption capacities (qmax) for uptake of MB by BEN, BGS and BPS are 10.61, 10.85 and 10.93 mg, while CR exhibited 8.83, 6.87 and 5.86 mg/g, respectively. The thermodynamics study revealed that the adsorption process was spontaneous, feasible, endothermic in nature. The adsorption process is governed by electrostatic attraction with the involvement of physical and chemical adsorption. This study suggests that biomass-modified bentonite is a sustainable, cost-effective, non-toxic, and greener approach for eliminating MB and CR from aqueous solution. Furthermore, the modification method does not only achieve substantial removal of MB and CR dyes, but also offers considerable energy savings and operational cost reductions in real-time based on water quality data. This study does present a novel, sustainable approach to improve natural water treatment efficiency and compliance.

ADSORPTION OF URANIUM SIMULATION WASTE USING BENTONITE:TITANIUM DIOXIDE

ADSORPTION OF URANIUM SIMULATION WASTE USING BENTONITE TANIUM DIOXIDE. Bentonite is a clay material of high surface area that have galleries within its structure. Bentonite that is modified with TiO2 will have high adsorption capability. In this study, natural bentonite and bentonite:TiO2 were characterized with FTIR, XRD and BET instruments to determine functional group, basal spacing, and specific surface area. This study also investigates the adsorption of bentonite:TiO2 in various environmental factors, such as pH (pH 1, 3, 5, and 8), contact time (10, 20, 30, 40, 50, 60, 70, 90, and 120 min), and initial uranium concentration (20, 40, 60, 80 ppm), and their influences on adsorption capacity, and determine the kinetics equation and adsorption isotherm. Based on FTIR analysis, a decrease in the band of O-H bond from water molecule was observed, which indicates the presence of TiO2 in bentonite interlayer structure. The XRD characterization of bentonite:TiO2 does not show diffraction peak in 001 plane. This is due to delamination of bentonite interlayer structure. Delamination is caused by the presence of TiO2 in large quantities, thus damaging the bentonite interlayer structure into irregular sheets. Bentonite as sheets will cause the basal spacing to increase and it is anticipated that XRD will find it difficult in detecting the 001 plane at a low 2 theta angle. The surface area of bentonite:TiO2 has increased by 12.04 m2/g. The maximum adsorption capacity of U(VI) took place at pH 5.0 for 70 minutes contact time and uranium concentration of 60 ppm. In this study, the adsorption kinetic and adsorption isotherm are pseudo second-order kinetic and Langmuir isotherm. The kinetic constant and maximum adsorption capacity of bentonite:TiO2 are 0.075 g/mg.min and 5.848 mg/g respectively.Keywords: Bentonite, TiO2, Adsorption, Uranium

Green synthesis of Xanthan gum/Methionine-bentonite nanocomposite for sequestering toxic anionic dye

The present paper deals with the synthesis of a novel and ecofriendly Xanthan gum/Methionine-bentonite (XG/Meth-bent) nanocomposite and was further explored for the removal of toxic congo red dye (85%) from aqueous solution. The nanocomposite was characterized by various techniques such as SEM, FTIR, XRD, TGA and zeta potential analysis. The surface area of bentonite and nanocomposite were found to be 23mg2g−1 and 71mg2g−1 respectively. The maximum adsorption was found at pH 3, contact time 60min and temperature 323K respectively. The point of zero charge was found to be 7. The adsorption isotherm and kinetic were best fitted by Langmuir isotherm and pseudo-second order kinetic model with Langmuir monolayer adsorption capacity 530.549mgg−1 at 323K. Thermodynamic studies showed that the adsorption was endothermic, spontaneous with increased randomness at solid/solution interface. Desorption with regeneration (upto fifth cycle) was best observed by NaOH.

Sulfuric Acid Modified Bentonite as the Support of Tetraethylenepentamine for CO2 Capture

In this work, an inexpensive and commercially available bentonite was modified by sulfuric acid and explored as the new type of support to immobilize tetraethylenepentamine (TEPA) for CO2 capture from flue gas. By applying sulfuric acid treatment, the textural properties, in particular, pore volume and surface area of bentonite, were significantly improved. Bentonite treated with 6 M sulfuric acid (Ben_H2SO4_6M) can reach a pore volume of 0.77 cc/g from that of the parent bentonite of 0.15 cc/g. With the maximum TEPA loading of 50 wt % onto the Ben_H2SO4_6M sorbent, the maximum CO2 breakthrough sorption capacity reached 130 mg of CO2/g of sorbent at 75 °C under a dry condition. With an addition of moisture to the simulated flue gas, the CO2 sorption capacity can be further improved to 190 mg of CO2 at 18 vol% of moisture addition sorbent due to the bicarbonate formation under a wet condition. The TEPA/Ben_H2SO4_6M sorbents show a good regenerability and thermal stability below 130 °C. The high CO2 sorptio...

Study on the Industrial Wastewater Treatment by Modified Bentonite

The natural bentonite as raw material, chitosan as a modifier to prepare chitosan modified bentonite. The use of modified bentonite, each dealing with a high concentration of COD monosodium glutamate (MSG)wastewater and coking wastewater .The optimal conditions: mixing time : 10 ~ 12 min;centrifugation time :25 ~ 30min; PH: 8.5 ~ 9.5; dosage: 10~14g / L. The results showed that the treatment of modified bentonite is better than the bentonite and chitosan. The COD removal rate of MSG wastewater and coking wastewater were 60.1% and 82.3%. So the treatment of coking wastewater is efficiency.. By scanning electron microscopy, surface area and X-ray diffraction analysis shows that modification does not change the basic structure of the bentonite only increased the specific surface area of bentonite, and the adsorption capacity of pollutants.

Response surface optimisation for activation of bentonite with microwave irradiation

In this study, the statistical design of the experimental method was applied on the acid activation process of bentonite with microwave irradiation. The influence of activation parameters (time, acid normality and microwave heating power) on the selected process response of the activated bentonite samples was studied. The specific surface area was chosen for the process response, because the chemical, surface and structural properties of the activated clay determine and limit its potential applications. The relationship of various process parameters with the specific surface area of bentonite was examined. A mathematical model was developed using a second-order response surface model (RSM) with a central composite design incorporating the above mentioned process parameters. The mathematical model developed helped in predicting the variation in specific surface area of activated bentonite with time (5-21 min), acid normality (2-7 N) and microwave heating power (63-172 W). The calculated regression models were found to be statistically significant at the required range and presented little variability. Furthermore, high values of R2 (0.957) and R2 (adjusted) (0.914) indicate a high dependence and correlation between the observed and the predicted values of the response. These high values also indicate that about 96% of the result of the total variation can be explained by this model. In addition, the model shows that increasing the time and acid normality improves the textural properties of bentonites, resulting in increased specific surface area. This model also can be useful for setting an optimum value of the activation parameters for achieving the maximum specific surface area. An optimum specific surface area of 142 m2g-1 was achieved with an acid normality of 5.2 N, activation time of 7.38 min and microwave power of 117 W. Acid activation of bentonite was found to occur faster with microwave irradiation than with conventional heating. Microwave-assisted processes have the potential to develop into a cost efficient route for acid activation of bentonite.

Determination of the cation exchange capacity and the surface area of bentonite, illite and kaolinite by methylene blue adsorption

Dye cations like methylene blue will mainly adsorb on clay minerals by cation exchange. Therefore, the methylene blue adsorption is depending on the exchangeable cations of the clay mineral, on the pH and on the dye cation concentration. The cation exchange capacity of clays by methylene blue adsorption can be determined when the samples are in the sodium exchanged form and the pH is neutral. So one obtains the same values as determined with the ammonium acetate method. The surface area of bentonites can only be calculated with methylene blue adsorption when the montmorillonite surface area per charge corresponds with the area of the methylene blue cation of 130 Å 2, i.e. the interlayer charge of the montmorillonites must amount to 0.28–0.33 charges per half unit cell. Our investigations have confirmed the experiences in the application of the methylene blue method that it is necessary to work with optimum dispersion, a fixed clay:water ratio as well as a constant pH and a given initial amount of methylene blue in order to achieve reproducible results. With these assumptions the methylene blue adsorption can be used for the quality control of the same clay.