芦苇秸秆生物炭吸附铅的动力学与等温线

Adsorption Kinetic and Isotherm of Lead Ions Onto Reed Straw Derived-biochar

研究了芦苇秸秆生物炭对水体中Pb(Ⅱ)的吸附特性,通过单因素条件试验考察了吸附动力学及吸附等温方程。结果表明:用芦苇秸秆生物炭吸附处理含Pb(Ⅱ)污水,水体中的Pb(Ⅱ)去除率随溶液pH升高而提高,当pH=6时,Pb(Ⅱ)去除率达95.56%以上;随生物炭投加量加大,Pb(Ⅱ)吸附量下降,而去除率升高;生物炭投加量为0.15g/100mL时,Pb(Ⅱ)去除率为99.39%;芦苇秸秆生物炭对Pb(Ⅱ)的吸附动力学符合准二级动力学模型,通过颗粒内扩散方程得其具体吸附过程由膜扩散和内扩散共同控制,Langmiur与Freundlich模型都能很好地描述等温吸附行为。

The reed straw biochars was prepared under a limited oxygen condition.The adsorptionpropertities of lead ions on the biochars were investigated by conducting a series of batch adsorption experiments.And the adsorption kinetics,thermodynamic behavior and mechanism were also discussed.The results show that the removal rate of Pb（Ⅱ）is enhanced significantly with increasing pH of aqueous solution.When the pH is over 6,the removal rate of Pb（Ⅱ）reaches95.56%.With increasing of the biochar mass,Pb（Ⅱ）adsorption decreases but its removal rate increases.When the the biochar amount is above 0.15g/100 mL,the removal rate of Pb（Ⅱ）reaches99.39%.The adsorption process can well fit pseudo-second-order model,and through intraparticle diffusion model,the specific process is controlled by both membrane diffusion and internal diffusion.The adsorption isotherm of Pb（Ⅱ）on biochar is well described by the Langmiur isotherm and Freundlich isotherm.