不同温度热解残余生物质半焦对磷的吸附

Phosphate Adsorption of Residual Biomass Char by Pyrolysis

[目的]研究生物质热解制备生物油的残余半焦对水中磷的吸附性能。[方法]研究了不同温度(550、650和750℃)热解半焦吸附磷的动力学和等温线,分别采用准一级、准二级和颗粒内扩散3种模型及Langmuir、Freundlich等温吸附方程对实验数据进行拟合。[结果]结果表明准二级动力学模型能较好描述磷在半焦表面的吸附行为,平衡吸附量和吸附速率随着热解温度的升高而增加。此外,等温吸附过程能较好地用Freundlich吸附等温线方程描述,表明磷在半焦表面的吸附受多种机制影响。3种温度下热解所得半焦对磷的吸附活化能分别为10.86、11.27和10.95kJ/mol,说明该吸附过程主要为物理吸附。[结论]生物质热解半焦对水中磷具有良好的吸附去除效果。

[Objective]The aim was to study adsorption of phosphorus in water by residual biomass char.[Method]The adsorption kinetics and isotherm of phosphate by biomass char obtained at different temperatures were studied.The pseudo first-order,pseudo second-order,intra-particle diffusion models and Langmuir,Freundlich isotherm models were employed to fit experimental data.[Result]The results showed that the adsorption of phosphate followed the pseudo second-order kinetics model and the equilibrium adsorption capacity and adsorption rate increased with the increasing of pyrolysis temperature.The adsorption isotherm was described by Freundlich model,which suggested that multiple processes controlled the sorption of phosphate by biomass char.The adsorption activation energy of biomass chars at different temperatures were 10.86,11.27 and 10.95 kJ/mol,which indicated that it belonged to physics adsorption.[Conlusion]The biomass char was approved that it had a good effect on adsorbing phosphate.