生物炭对水中五氯酚的吸附性能研究

利用小麦秸秆和花生壳在300,400,600℃条件下制备生物炭,运用元素分析仪、扫描电镜和比表面积仪对生物炭的理化性质进行表征,同时探讨其对水中五氯酚(PCP)的吸附特性.结果表明,随炭化温度升高,生物炭芳香性增加,极性降低.花生壳生物炭对水中PCP的吸附效果优于小麦秸秆生物炭,3种温度制备的生物炭对PCP吸附量表现为400℃>600℃>300℃.随着生物炭添加量增大,水中PCP去除能力由81.79%提高至89.02%,生物炭的吸附量由30.32减小至5.54mg/g.生物炭对PCP的吸附动力学更符合准二级动力学方程,吸附等温线符合Freundlich方程.吸附过程主要受快速反应控制,降低反应温度有利于生物炭对水中PCP的吸附.

Adsorption efficiencies of pentachlorophenol from aqueous solution onto biochars

The biochars were produced from wheat straw and peanut hull at three pyrolysis temperatures of 300, 400 and 600℃, respectively. The physico-chemical properties of biochars were characterized by elemental analyzer, scanning electron microscope and BET surface area analyzer, and the adsorption capability of biochars for the removal of pentachlorophenol (PCP) from aqueous solution was evaluated. The results showed that the aromaticity of biochars gradually increased and the polarity decreased with the increasing pyrolysis temperature. The adsorption capability of peanut hull biochars was higher than that of wheat straw biochars. In addition, the adsorption amount of peanut hull and wheat straw biochars under different carbonization temperature followed the order of 400℃ >600℃ >300℃. The removal capacity for PCP increased from 81.79% to 89.02% with biochar dosages increase, while the adsorption amount of biochars decreased from 30.32to 5.54mg/g. The adsorption kinetics and isotherms of PCP onto biochars were better fitted by pseudo-second-order kinetic and Freundlich equation, respectively. The fast adsorption reaction was the controlled process and lower temperature enhanced the adsorption of PCP from aqueous solution.