镁浸渍生物炭吸附氨氮和磷:制备优化和吸附机理  

Adsorption of ammonia nitrogen and phosphorus by magnesium impregnated biochar:preparation optimization and adsorption mechanism

作　　者：李安玉 李双莉 余碧戈 马爱英 周鑫兰 谢建慧 蒋艳红 邓华 LI Anyu;LI Shuangli;YU Bige;MA Aiying;ZHOU Xinlan;XIE Jianhui;JIANG Yanhong;DENG Hua(Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection(Guangxi Normal University),Ministry of Education,Guangxi Normal University,Guilin 541004,Guangxi,China;Key Laboratory of Karst Ecology and Environment Change of Guangxi Department of Education,Guilin 541004,Guangxi,China)

机构地区：[1]广西师范大学珍稀濒危动植物生态与环境保护教育部重点实验室,广西桂林541004 [2]岩溶生态与环境变化研究广西高校重点实验室,广西桂林541004

出　　处：《化工学报》2020年第4期1683-1695,共13页CIESC Journal

基　　金：广西师范大学珍稀濒危动植物生态与环境保护教育部重点实验室基金项目(ERESEP2019Z07);国家自然科学基金项目(41301343);岩溶生态与环境变化研究广西高校重点实验室基金项目(YRHJ15Z009)。

摘　　要：利用废弃的木薯杆制备了载镁的生物炭吸附剂。以氨氮、磷为目标污染物,采用控制变量法研究了不同镁盐改性、MgCl2浓度、碳化温度、固液比和碳化时间对氨氮、磷吸附性能的影响,制备最具吸附性能的载镁木薯秆基生物炭(Mg-BC),进行批量吸附氨氮和磷实验。利用等温模型(Langmuir和Freundlich模型)和动力学模型(准一级动力学、准二级动力学和颗粒内扩散模型)探究其吸附特性,在其吸附特性研究的基础上,运用FTIR、XRD、SEM-EDS、XPS等表征手段对其吸附机理进行探讨。结果表明,Mg-BC对氨氮和磷的吸附过程均符合Freundlich模型和准二级动力学模型,为多分子层的化学吸附,理论饱和吸附量分别为43.48 mg·g^-1和96.00 mg·g^-1。结合表征结果推测,Mg-BC吸附氨氮、磷主要通过官能团作用、络合沉淀和离子交换等多过程协同完成。Magnesium-loaded biochar adsorbent was prepared from waste cassava stalks.The effects of modification of different magnesium salts,MgCl2 concentration,carbonization temperature,solid-liquid ratio and carbonization time on the adsorption of ammonia-nitrogen and phosphorus were studied using the controlled variable method.Samples of magnesium-loaded cassava stalk-based biochar(Mg-BC)using the process with the best adsorption performance were prepared and batch adsorption experiments for ammonia-nitrogen and phosphorus were carried out.The adsorption characteristics were studied using isothermal models(Langmuir and Freundlich model)and kinetic models(quasi-first-order kinetics,quasi-second-order kinetics and intra-particle diffusion model).The adsorption mechanism was also studied using FTIR,XRD,SEM-EDS and XPS.The results show that the adsorption process of ammonia-nitrogen and phosphorus by Mg-BC conforms to the Freundlich model and quasi-second-order kinetic model,and is multilayer chemisorption.The theoretical saturated adsorption capacities were 43.48 mg·g-1 and 96.00 mg·g-1 for ammonia-nitrogen and phosphorus respectively.Combined with the characterization results,it is speculated that magnesium-titanium-based biochar(Mg-BC)adsorbs ammonia nitrogen and phosphorus mainly through functional groups,complex precipitation and ion exchange and other processes.

关 键 词：负载镁 生物炭 木薯秸秆 吸附 吸附剂 吸附机制 

分 类 号：X53[环境科学与工程—环境工程]