Preparation Of Carbon Nanomaterials Using Spent Bentonite

Bentonite due to its large theorical specific surface area, expandable interlayerstructure, cationic interlayer exchangeable property and its others charateristics, is anatural absorbent material of various wastewater pollutants. Bentonite is especially agood cationic dyestuff used for dye wastewater. However, research about thetreatment of the bentonite waste originate from the adsorption of cationic dye are few.This paper investigate the adsorption of cationic dye onto bentonite by carbonizationprocess. This processing include the preparation of two-dimensional special kind ofgraphene carbon material nanostructures, and the implementation of an approach ofrecycling bentonite waste. The paper further studies the adsorption performance ofthis new kind of organic pollutants, discuss the feasibility of its application insupercapacitors, and investigate some electrical parameters test. Experiment resultsare as follows:(1) The use of bentonite dyestuff waste which is already pass the absorptionprocess, is from the successful preparation of graphene carbon nanomaterials. Afterthe distinguish adsorption of the crystal violet, methylene blue, malachite greencationic dye, the bentonite under nitrogen protection and high-temperature go throughcarbonization treatment. After the carbonization process, the XRD spectrum showedthat the interlayer of the bentonite has formed a layer height of0.34-0.41nm oftwo-dimensional carbon nanomaterials, after the using of acid pickling to remove thebentonite layer, the carbon nanomaterial is obtained. The XRD and Ramanspectroscopy analysis results proved that the material had a high graphitizationproperty. Moreover, the BET experiment showed a mesoporous carbon-basednanomaterials.(2) Nitrobenzene,2-Naphthol and phenol have good adsorption efficiency. Thesethree different kinds of organic compounds have been prepared to obtain carbonnanomaterials and their effect in comparison with nitrobenzene showed that they hadalmost the same adsorption efficiency, and the optimum condition for the preparationof the carbon nanomaterials adsorption is600℃. The experiment carried out with theCarbon nanomaterials and the nitrobenzene,2-naphthol and phenol these threeorganics compounds three presented a isothermal curve and follow the Langmuirequation. The three organic compounds saturation adsorption capacity arerespectively69.9,85.5and40.3mg/g. The kinetics and thermodynamics adsorption experiment of the nitrobenzene showed that the adsorption process followed thepseudo second-order kinetic equation, the reaction process is exothermic, and a hightemperature is benefit to conduct this reaction. Nitrobenzene carbon nanomaterialshas obviously better adsorption efficiency than the traditional organic bentonite.(3) The electrical parameters testing of the carbon nanomaterial, showed that thematerial had a perfect electrical double-layer capacitor structure, and the electrode hada good reversibility. Cyclic voltammetry experiment determined that the scanningspeed of the electrode was less than1mV/s, the specific capacitor reached201F/g,charging-discharging curve showed a significant symmetrical triangular distribution,and the AC impedance test, a straight line close to90o. After3000charge anddischarge cycle, the capacitor capacitance basically remain unchanged, the selfdischarge efficiency was low, that showed that the carbon nanomaterial is a goodsupercapacitor electrode material.