Guo Huan, Xia Kai, Cao Mingzhao, Zhang Xiaodong
College of Chemistry and Chemical Engineering, Qingdao University, Qingdao 266071, China.
Technological Research and Development Department, Shandong Tiexiong Xinsha Energy Co., Ltd., Heze 274916, China.
Materials (Basel). 2021 Feb 7;14(4):792. doi: 10.3390/ma14040792.
In this study, the cationic polymer poly-epichlorohydrin-dimethylamine was immobilized on natural attapulgite to improve the dye adsorption capacities. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction, nitrogen adsorption-desorption isotherms, scanning electron microscope (SEM) analysis, zeta potential analysis, and particle size analysis were used to determine the characteristics of modified attapulgite. Results showed that the poly-epichlorohydrin-dimethylamine had been successfully grafted onto the surface of attapulgite without altering its crystal structure. After cationic modification, the specific surface area of attapulgite obviously decreased, and its surface zeta potentials possessed positive values in the pH range from 3 to 11. The cation-modified attapulgite displayed high adsorption capacities for anionic dyes, and its maximum adsorption capacities were 237.4 mg/g for Reactive Black 5 and 228.3 mg/g for Reactive Red 239; this is corroborated by Langmuir's isotherm studies. It was demonstrated that the two reactive dyes could be 100% removed from effluents when cation-modified attapulgite was used in column operation modes. Its treatment capacities were more than three times larger than that of activated carbon. The regeneration study verified better utilization and stability of the fabricated adsorbent in column operation. This work has conclusively confirmed the potential of the new modified attapulgite for effectively treating dye wastewaters.
在本研究中，将阳离子聚合物聚环氧氯丙烷二甲胺固定在天然凹凸棒石上，以提高其对染料的吸附能力。采用傅里叶变换红外光谱（FTIR）、X射线衍射、氮吸附-脱附等温线、扫描电子显微镜（SEM）分析、zeta电位分析和粒度分析来确定改性凹凸棒石的特性。结果表明，聚环氧氯丙烷二甲胺已成功接枝到凹凸棒石表面，而未改变其晶体结构。阳离子改性后，凹凸棒石的比表面积明显减小，其表面zeta电位在pH值为3至11的范围内呈正值。阳离子改性凹凸棒石对阴离子染料表现出高吸附能力，其对活性黑5的最大吸附容量为237.4 mg/g，对活性红239的最大吸附容量为228.3 mg/g；朗缪尔等温线研究证实了这一点。结果表明，在柱操作模式下使用阳离子改性凹凸棒石时，两种活性染料可从废水中100%去除。其处理能力比活性炭大三倍以上。再生研究证实了所制备吸附剂在柱操作中的更好利用和稳定性。这项工作最终证实了新型改性凹凸棒石有效处理染料废水的潜力。
