镁改性生物炭制备条件对其氮、磷去除性能的影响

摘要

以林木废弃物为原料,通过干式热解和湿式热解,制备镁改性生物炭,并探索其对污水中氮、磷的同步去除性能.研究表明:干式混合热解和湿式浸渍热解制备的生物炭吸附效果无显著差异;MgCl2浸渍制备改性是生物炭制备的适宜方法,浸渍浓度、热解温度、热解速度及生物炭粒径均会对吸附效果有影响;最优条件下,镁改性生物炭对氮和磷的吸附量分别为35.28,110.29 mg/g.除了吸附作用,镁改性生物炭表面形成了鸟粪石沉淀(MgNH4PO4·6H2O),可作为一种缓释型炭基氮磷复合肥.%This study investigated the simultaneous removal of ammonium and phosphate in wastewater via Mg-modified biochar produced through wet-pyrolysis and dry-pyrolysis of wood waste.Results showed that there was no obvious difference on the adsorption efficiency of Mg-modified biochar yielded via dry-pyrolysis or wet-pyrolysis.Biochar modfied by MgCl2 was prepared with inpregnatio method,which was considered as a proper approach.Impregnation concentration,pyrolysis temperature,heating rate and biochar size all had obvious effects on the adsorption efficiency.The maximum adsorption capacity of ammonium and phosphate in wastewater via Mg-modified biochar could reach 35.28,110.29 mg/g,respectively.Besides adsorption,the precipitation of MgNH4PO4 ·6H2O on the biochar surface also responded for the nutrient removals,which yielded a slow-release multi-fertilizer.