Adsorption performance and kinetics of organobentonite modified with graphene

A kind of novel modified organobentonite composite owning good adsorption effect and high recovery efficiency was made to improve the adsorption property of organobentonite. Graphene was chosen to modify organobentonite. The modifying process was conducted by microwave irradiation. The structure and adsorption properties of the adsorption material were studied and the mechanism of action was discussed. Organobentonite and the modified organobentonite were used to adsorb humic acid from water after being characterized by scanning electron microscopy,Fourier transform infrared spectrometry and X-ray diffraction analysis. It is found that graphene and organobentonite composite uniformly and the basal spacing increases from 1.37 to 2.68 nm. The humic acid removal rate reaches 95.52% under the conditions of the temperature of 25℃,the p H value of 6,the composite dosage of 5 g·L^-1and the adsorption time of 1 h. The adsorption data fits well the Langmuir isotherm model and the pseudo-second-order model,the maximum theoretical adsorption capacity of the composite is 52.08 mg·g^-1,and the adsorption is an exothermic process. The graphene modified organobentonite can be regenerated with Na OH,and the regeneration efficiency reaches 86% after the fifth regeneration when the Na OH concentration is 0.1 mol·L^-1.