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为扩大纤维素类生物吸附剂的开发利用资源,采用五因子二次回归正交旋转组合设计方法对影响皂化麦麸吸附Cd2+的因子进行优化,得出在吸附时间为1h、加入量为0.20g、pH=6、温度20℃、浓度2.00mg·L-1时,皂化麦麸有最大吸附率(YMax=99.19%)。对比试验表明,皂化麦麸对Cd2+的吸附优于活性炭,纤维素在吸附中起主要作用。扫描电镜下皂化麦麸表面显示粗糙和多褶皱的物理吸附特征,红外光谱显示皂化麦麸中-OH、-CH3、C≡C、C=C、C=O、C-O基团可能参与吸附作用。吸附等温线和吸附动力学模型显示,皂化麦麸对Cd2+吸附符合Freundlich等温式和二级动力学模型。皂化麦麸经过解吸附可以反复使用。
In order to expand the resources for the development and utilization of cellulose biosorbents, the factors influencing the adsorption of Cd2 + on saponified wheat bran were optimized by the five-factor quadratic regression orthogonal rotation combination design method. The results showed that when the adsorption time was 1h and the addition amount was 0.20g , PH = 6, temperature 20 ℃, the concentration of 2.00mg · L-1, the maximum adsorption rate of saponified wheat bran (YMax = 99.19%). Comparative tests showed that the adsorption of Cd2 + by saponified wheat bran was better than that of activated carbon, and cellulose played a major role in the adsorption. Scanning electron microscopy showed that the surface of saponified wheat bran showed rough and multifold physical adsorption characteristics. The infrared spectra showed that -OH, -CH3, C≡C, C = C, C = O and C-O groups in saponified wheat bran might be involved in the adsorption. Adsorption isotherms and adsorption kinetics models showed that adsorption of Cd2 + by saponified wheat bran conforms to Freundlich isothermal and second-order kinetic models. Saponified wheat bran can be repeatedly used after desorption.