改性高粱秸秆对Cu(Ⅱ)吸附性能及热力学和动力学分析

Kinetic and Thermodynamic Investigation of Adsorption Property of Cu(Ⅱ) on Modified Sorghum Stalk

研究了改性高粱秸秆对Cu(Ⅱ)的吸附性能。结果表明,pH对改性高粱秸秆吸附Cu(Ⅱ)影响显著。常温(30℃)下,对20mL pH=5.0的20mg/L的Cu(Ⅱ)溶液,改性高粱秸秆投加量0.35g,吸附时间60min,Cu(Ⅱ)去除率可达84.82%。改性高粱秸秆对Cu(Ⅱ)的吸附符合Langmuir吸附等温方程和准二级动力学模型,吸附过程的△G0<0,△H0>0且仅为4.31kJ/mol,△S0>0说明改性高粱秸秆对Cu(Ⅱ)的吸附是以单分子层物理吸附为主的自发吸热过程。

The adsorption properties of Cu（ Ⅱ） on modified sorghum stalk was investigated in this paper. The results showed that the adsorbing property of modified sorghum stalk to Cu （Ⅱ） was largely affected by pH value; at ambient temperature, for a-20 mL Cu （Ⅱ） solution with pH = 5. 0 and concentration of 20 mg/L,when the amount of modified sorghum stalk was 0.35 g, adsorbing time was 60 minutes,adsorption could lead to a clearance rate up to 84.82 %. The adsorption behavior of Cu（ Ⅱ ） on modified sorghum stalk accorded with Langmuir adsorption isotherm and pseudo-second-order kinetic model,and the corresponding Hwas 4.31 kJ/mol with AG〈O and S〉0,which implied that the adsorption of Cu （Ⅱ） on modified sorghum stalk was an endothermic process showing monolayer adsorption.