Adsorption performance and kinetics of organobentonite modified with graphene
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摘要: 為提高有機膨潤土的吸附性能,采用微波合成法,以石墨烯對有機膨潤土進行改性,制備一種吸附效果好且回收效率高的新型石墨烯改性有機膨潤土復合材料,研究其結構和吸附性能,探討新吸附材料的作用機理。通過掃描電鏡、紅外光譜和X射線衍射對有機膨潤土及石墨烯改性有機膨潤土進行表征,并將其用于水中腐殖酸的吸附。結果表明:石墨烯與有機膨潤土均勻復合,有機膨潤土的層間距由1.37 nm增大至2.68 nm;當溫度為25℃、p H值為6、吸附劑的用量為5 g·L-1及吸附時間為1 h時,溶液中腐殖酸的去除率達到95.52%;石墨烯改性有機膨潤土對腐殖酸的吸附等溫線符合Langmuir模型和準二級動力學模型,最大理論吸附量為52.08 mg·g-1,且為放熱反應。利用0.1 mol·L-1Na OH溶液對石墨烯改性有機膨潤土進行解吸再生,5次再生后其對腐殖酸的去除率為86.3%。Abstract: 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.
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Key words:
- graphene /
- bentonite /
- adsorption kinetics /
- humic acid /
- water treatment
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