新型大榕树叶吸附剂的制备及其对镉的吸附研究

Preparation of New Big Banyan Leaves Absorbent and Its Adsorption of Cd^(2+)

以大榕树叶为原料,分别采用皂化、交联和接枝共聚3种化学方法对大榕树叶粉末进行改性,并研究了其对水中Cd2+的吸附行为.考察了吸附过程中的溶液p H、固液比、温度、吸附时间对吸附性能的影响,并通过测定化学耗氧量(COD)和傅里叶变换红外光谱(FTIR)对大榕树叶吸附剂结构特性进行表征.研究结果表明:当Cd2+初始浓度为50 mg·L-1,p H值为5.5~6.0,温度为35°C,3种改性方法制得的大榕树叶吸附剂在60 min内能达到吸附平衡,吸附过程符合准二级吸附动力学方程.

Big banyan leaves（BL）was modified with three chemical methods, saponification, crosslinking and copolymerization, and then was examined its adsorption of Cd^2＋ from aqueous solution. The surface and structure of modified big banyan tree leaves powder were characterized using chemical oxygen demand（COD）, scanning electron microscope（SEM）and Fourier transform infrared spectroscopy（FTIR）. Effects of various parameters including equilibrium p H, adsorption time, biosorbent dosage and initial Cd^2＋ concentration were studied in batch experiments.Under the conditions of initial concentration of Cd^2＋50 mg·L^-1, p H5.5～6.0, temperature of 35℃ and dosage of adsorbent 0.5 g·L^-1, adsorption of Cd^2＋by three modified big banyan tree leaves powder was fast and it reached an equilibrium within 60 min, and adsorption kinetics of Cd^2＋could be expressed by pseudo-second-order kinetics model.