富铁污泥生物炭对亚甲基蓝吸附性能的研究

Study on methylene blue adsorption capacity by iron-rich sludge biochar

给水厂富铁污泥(WIS)添加质量分数为20%的核桃壳,在高温缺氧条件下进行热解,制备富铁污泥生物炭(Fe-SBC),通过扫描电镜(SEM)、比表面积分析(BET)对Fe-SBC的表面结构进行分析,并研究其吸附亚甲基蓝的性能和机理。结果表明,Fe-SBC表面粗糙程度增加,孔隙增多,比表面积增大。在碱性条件下,20 mg/L亚甲基蓝,0.5 g/L Fe-SBC,反应60 min时,亚甲基蓝去除率超过99%。Fe-SBC对亚甲基蓝的吸附过程符合准二级反应动力学模型及Langmuir等温吸附模型,吸附速率主要受液膜扩散控制,整个吸附过程以化学络合吸附为主,属于单分子层吸附,吸附过程为吸热反应,自发进行,且不可逆。

Waterworks iron-rich sludge(WIS)and 20%walnut shell were mixed under high temperature with nitrogen atmosphere to prepare iron-based sludge biochar(Fe-SBC).The surface structure of Fe-SBC were analyzed by scanning electron microscopy(SEM),specific surface area analysis(BET).The adsorption performance and mechanism of methylene blue were further studied.The results showed that the surface roughness of Fe-SBC increases,the porosity increases,and the specific surface area increases.Under the alkaline condition,the methylene blue removal rate of 20 mg/L methylene blue and 0.5 g/L Fe-SBC was over 99%when the reaction time was 60 min.The methylene blue adsorption process by Fe-SBC conforms to the quasi-secondary-order reaction kinetic model and the Langmuir isotherm adsorption model;the adsorption rate is mainly controlled by liquid film diffusion;the adsorption process is dominated by chemical complexation adsorption,and it belongs to the monolayer adsorption.The adsorption process is endothermic reaction,which is spontaneous and irreversible.