改性甘薯渣吸附剂的制备及其对Cr6+和Zn2+的吸附性能

以甘薯渣为原材料经改性制备甘薯渣吸附剂，配制不同浓度的Cr6+、Zn2+水溶液，研究甘薯渣吸附剂对水中Cr6+、Zn2+的吸附效果。分析溶液初始浓度、吸附剂用量、pH、温度、吸附时间、吸附剂粒径对吸附性能的影响。结果表明，改性甘薯渣对水中Cr6+和Zn2+的吸附效果显著优于活性炭，对Cr6+、Zn2+的吸附机理为以化学吸附为主的化学物理吸附，遵循准二级吸附动力学模型。Freundlich吸附等温式能很好的描述改性甘薯渣对Cr6+、Zn2+吸附规律。扫描电子显微镜（SEM）观测和傅氏转换红外线光谱（FTIR）分析结果表明，改性甘薯渣表面疏松多孔结构可提供多吸附位点，且羟基、羧基等基团有利于对Cr6+、Zn2+的吸附。该吸附剂解吸处理后可重复使用。

Preparation of Modified Sweet Potato Residue Adsorbent and Its Adsorption Properties for Cr6+ and Zn2+

The sweet potato residue adsorbent was prepared by modification of discarded sweet potato residue, and different concentrations of Cr6+ and Zn2+ solution were prepared to study adsorption effect of the sweet potato residue adsorbents on Cr6+ and Zn2+ in water. The influences of solution initial concentration, adsorbent addition, pH, temperature, adsorption time, adsorbent particle size on adsorption properties were studied. The results showed that, the adsorption effects of residue sweet potato residue on Cr6+ and Zn2+ were obviously superior to that of activated carbon. The adsorption of Cr6+ and Zn2+ by modified products was chemical-physical adsorption dominated by chemical adsorption, which fitted the quasi-second-order kinetic model. And the Freundlich isotherm equation could better describe the adsorption behavior of modified sweet potato residue for Cr6+ and Zn2+. SEM and FTIR results showed that, the loose and porous structure on modified sweet potato residue surface could provide more adsorption sites, and -OH, -COOH groups were beneficial to the adsorption of Cr6+ and Zn2+. The adsorbent could be reused after desorption treatment.