石墨烯改性有机膨润土吸附性能及其动力学

为提高有机膨润土的吸附性能,采用微波合成法,以石墨烯对有机膨润土进行改性,制备一种吸附效果好且回收效率高的新型石墨烯改性有机膨润土复合材料,研究其结构和吸附性能,探讨新吸附材料的作用机理。通过扫描电镜、红外光谱和X射线衍射对有机膨润土及石墨烯改性有机膨润土进行表征,并将其用于水中腐殖酸的吸附。结果表明：石墨烯与有机膨润土均匀复合,有机膨润土的层间距由1.37 nm增大至2.68 nm；当温度为25℃、pH值为6、吸附剂的用量为5 g·L-1及吸附时间为1 h时,溶液中腐殖酸的去除率达到95.52%；石墨烯改性有机膨润土对腐殖酸的吸附等温线符合Langmuir模型和准二级动力学模型,最大理论吸附量为52.08 mg·g-1,且为放热反应。利用0.1 mol·L-1 NaOH溶液对石墨烯改性有机膨润土进行解吸再生,5次再生后其对腐殖酸的去除率为86.3%。

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 mech-anism 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 pH value of 6, the composite dosage of 5 g·L-1 and 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 NaOH, and the regeneration efficiency reaches 86% after the fifth regeneration when the NaOH concentration is 0. 1 mol·L-1 .