磷基改性秸秆-牛粪生物炭优化制备

Optimization and preparation of phosphor-based modified straw-cow dung biochar

探究了磷基改性生物炭的最佳制备条件及其对铅的吸附机理。以玉米秸秆和牛粪为原料、磷酸二氢钾(KH_(2)PO_(4))为改性剂制备生物炭,采用响应面模型研究热解温度、原料与改性剂溶液的固液比和原料质量比对铅吸附量的影响,确定最佳制备条件。并利用SEM、BET、FTIR等手段对材料进行表征,揭示生物炭形貌与结构的变化。结果表明,该生物炭最佳制备条件为热解温度481.1℃,改性固液比1∶10,秸秆质量占牛粪的20%,生物炭最大铅吸附量为363.54 mg/g,与实验值(368.28 mg/g)基本相符,表明模型预测结果可靠。优化后的生物炭表面负载含磷基团,比未改性生物炭(81.93 mg/g)提高349.5%,对铅的吸附性能大幅提高。该研究对水中重金属去除、农业废弃物利用以及实现“双碳”目标提供了一定参考。

The optimum preparation conditions of phosphorus-based modified biochar and its adsorption mechanism for Pb(Ⅱ)were explored.The modified biochar was prepared by using corn stover and cow dung as raw material and KH_(2)PO_(4) as activating agent.The interactive effects of various factors on Pb(Ⅱ)adsorption,including pyrolysis temperature,solid liquid ratio of raw material to modifier solution and mass ratio of raw materials,were investigated through response surface methodology model.The optimum preparation conditions were determined.SEM,BET and FTIR were used to characterize the material,revealing the changes in the morphology and structure of biochar.The results show that the optimized preparation conditions are pyrolysis temperature 481.1℃,modified solid liquid ratio 1∶10,and straw quality accounting for 20%of cow dung quality.Under this conditions,the maximum Pb(Ⅱ)adsorption value of the modified biochar was predicted as 363.54 mg/g.It is basically consistent with the experimental value(368.28 mg/g),demonstrating that the model is reliable.The surface of the optimized biochar is loaded with phosphorous groups,and its adsorption of Pb(Ⅱ)is 349.5%higher than that of unmodified biochar(81.93 mg/g),displaying outstanding adsorption potential.This study provides an application reference for removal of heavy metals from water,utilization of agricultural and the realization of"dual carbon"target.