关键词: 吸附, 动力学, 复合吸附剂, 锰离子

Abstract: A compound adsorbent was prepared with bentonite and activate carbon，and was used to adsorb Mn2+ from waste- water.The Mn2+ removal effects under different conditions were investigated.The kinetic characteristics and isothermal adsorption process were also studied.Results showed that the bentonite-activate carbon compound adsorbent had an excellent adsorbent capacity to the Mn2+ in wastewater and the maximum Mn2+ removal rate was 93.2%，under the conditions as follows：tempera- ture was 25 ℃，Mn2+ initial concentration was 50 mg/L，adsorption time was 180 min，pH=6，and adsorbent dosage was 4 g/L.The kinetic models including a first-order equation，pseudo-second-order，and internal diffusion equation were selected to simula- te the adsorption process.The process followed a pseudo-second-order kinetics，adsorption rate constant was 0.003 6 g/（mg·min），the internal diffusion was not the control step and there was restriction of adsorption mechanism.Langmuir and Freundlich models were used to describe adsorption equilibrium data.Results indicated that the Langmuir model gave an acceptable fit to the experimental data than the Freundlich equation. Maximum Mn2+ uptake obtained was Qm=27.781 mg/g.

Key words: adsorption, kinetics, compound adsorbent, manganese ion