胺化改性米糠对水中Cr(Ⅵ)的吸附

Adsorption of Cr (Ⅵ) in aqueous solutions using aminated rice bran

以环氧氯丙烷活化米糠,与乙二胺反应引入氨基制备了胺化米糠吸附剂。系统研究胺化米糠对Cr(Ⅵ)的吸附特性。结果表明,胺化米糠对Cr(Ⅵ)有很强的吸附作用,3.5 h能达到吸附平衡,吸附动力学符合准一级吸附方程。吸附容量随Cr(Ⅵ)浓度增加而增大,胺化米糠与Cr(Ⅵ)离子发生单层吸附,对Cr(Ⅵ)最大吸附容量为36.1 mg/g。溶液的pH和吸附温度对吸附特性有较大影响,最佳吸附pH为3,同时,升温有利于吸附的进行。热力学参数ΔH为正值和ΔG为负值表明胺化米糠吸附Cr(Ⅵ)是吸热的自发吸附。

Aminated rice bran （ARB） was prepared by introducing amido through reaction of rice bran ac- tivated by epoxy chloropropane and ethylenediamine. The adsorption performance of Cr（VI） from aqueous solu- tion by ARB was investigated in detail. The results showed that ARB possesses strong adsorption ability for Cr （ VI）, the adsorption equilibrium can be achieved in 3.5 h and the adsorption kinetics is well described by pseu- do-first-order model. The adsorption capacities increase along with the increase of Cr（VI） concentration, the in- teraction between Cr（VI） and ARB is monolayer adsorption process, and the saturated adsorption capacities reach a maximum of 36.1 mg/g. It was found that pH and temperature had a great influence on the adsorption process, the optimal pH was found to be 3 and the sorption process was more favorable at higher temperatures. Thermodynamic parameters were also evaluated and the positive value of AH and negative value of AG indicated that adsorption of Cr（VI） on ARB is an endothermic process and soontaneous in nature.