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生物质粒径对负载MgO生物炭吸附水体中磷的影响

本站小编 Free考研考试/2021-12-31

中文关键词芦苇生物质粒径MgO生物炭吸附 英文关键词Phragmites australiasbiomass particle sizeMgObiocharadsorptionphosphorus
作者单位E-mail
王鹏飞中国环境科学研究院, 湖泊水污染治理与生态修复技术国家工程实验室, 国家环境保护湖泊污染控制重点实验室, 北京 100012wangpf01@craes.org.cn
郅蒙蒙西安建筑科技大学环境与市政工程学院, 西安 710055
储昭升中国环境科学研究院, 湖泊水污染治理与生态修复技术国家工程实验室, 国家环境保护湖泊污染控制重点实验室, 北京 100012chuzs@craes.org.cn
崔冠楠北京工商大学轻工科学技术学院, 北京 100048
中文摘要 为研究生物质粒径对负载MgO芦苇生物炭(MBC)去除水体中磷的速率和能力的影响,以0~0.5、1~2和6~8 mm这3种不同粒径的芦苇颗粒为原料、MgCl2为改性剂制备MBC,用傅里叶变换红外光谱仪(FTIR)、X射线衍射仪(XRD)和扫描电子显微镜(SEM)等对MBC表征,开展MBC吸附溶液中磷酸盐(PO43--P)动力学和等温线实验以及实验数据模型拟合.结果表明,MBC对溶液中PO43--P的吸附速率随生物质粒径增大而增大,0~0.5、1~2和6~8 mm芦苇颗粒制备的MBC对PO43--P的吸附量在2 h内分别达到平衡吸附量的15.4%、25.8%和80.8%,而生物质粒径对MBC的PO43--P最大吸附量(249.0~254.7 mg·g-1)无明显影响.6~8 mm芦苇颗粒制备的MBC保留了较完整的芦苇细胞壁结构,且含有丰富的微孔和中孔,形成多层次、规则的、连通性好的孔隙结构.0~0.5 mm和1~2 mm芦苇颗粒制备的MBC孔隙结构较差,孔隙连通性受损,影响了磷酸根离子在MBC内部的扩散速率,限制了对磷的吸附速率.因此,以人工湿地收割的废弃植物芦苇为原料制备MBC用于去除水体中磷时,将芦苇破碎至6~8 mm即可,过度破碎会破坏MBC的孔隙结构,减小MBC对磷的去除速率. 英文摘要 To study the effect of biomass particle size on the rate and ability of phosphorus removal from aqueous solution by MgO-loaded Phragmites australis biochar (MBC), MBC was prepared using 0.0-0.5, 1.0-2.0, and 6.0-8.0 mm Phragmites australis particles as the feedstock and MgCl2 as the modification material. The MBC was characterized using FTIR, XRD, and SEM techniques. Kinetic and isotherm experiments of phosphate (PO43--P) adsorption from aqueous solution by the MBC were conducted, and the experimental data were fitted with various kinetic and isotherm models. The results showed that the adsorption rate of PO43--P by the MBC increased with the increase in biomass particle size. The amount of PO43--P adsorbed by the MBC prepared from 0.0-0.5, 1.0-2.0, and 6.0-8.0 mm particles reached 15.4%, 25.8%, and 80.8%, respectively, within 2 h. The biomass particle size did not affect the maximum PO43--P adsorption capacity (249.0-254.7 mg·g-1) of the MBC. MBC prepared from the 6-8 mm particles retained the complete cell wall structure of the Phragmites australis, and a large number of micropores and mesopores were generated during pyrolysis, thereby forming a hierarchical, regular, and well-connected pore structure. MBC prepared from the 0.0-0.5 mm and 1.0-2.0 mm particles had inferior pore structures with inferior pore connectivity, which affected the diffusion rate of PO43- ions inside the MBC and limited the PO43--P adsorption rate. Therefore, when using waste Phragmites australis harvested from a constructed wetland to produce MBC and remove phosphorus from water, the Phragmites australis should be crushed into 6-8 mm particles. Over-crushing deteriorates the pore structure of the produced MBC and reduces the removal rate of phosphorus by the MBC.

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