镁改性赤泥强化去除雨水径流氮磷污染物效果  

Effects of Enhanced Nitrogen and Phosphorus Pollutants Removal from Stormwater Runoff by Magnesium-modified Red Mud

作　　者：薛恬鑫 李京玲[1] 王洪浩 XUE Tian-xin;LI Jing-ling;WANG Hong-hao(College of Hydro Science and Engineering,Taiyuan University of Technology,Taiyuan 030024,China)

机构地区：[1]太原理工大学水利科学与工程学院,山西太原030024

出　　处：《水电能源科学》2024年第3期64-67,72,共5页Water Resources and Power

基　　金：山西省自然科学基金项目(202403021211128,201901D111059);国家自然科学基金项目(51409184)。

摘　　要：传统生物滞留系统存在填料层组成单一,氮、磷去除效果不稳定的问题,为评估赤泥作为生物滞留系统填料层改良剂的可行性,以拜耳法赤泥为原料制备载镁改性赤泥,通过改性试验、等温吸附试验和材料表征,探究镁改性赤泥对雨水径流氮、磷的去除效果与吸附机理。结果表明,利用MgCl_(2)溶液制备改性赤泥的优选浓度为0.5 mol/L;改性赤泥(RM_(0.5))对NH_(4)^(+)-N和PO_(4)^(3-)-P的平均去除率分别可达41.83%、97.24%,相对于原状赤泥(RM)分别提高了17.15%、5.74%;RM和RM_(0.5)对NH_(4)^(+)-N的吸附符合Langmuir模型,RM_(0.5)对NH_(4)^(+)-N的理论饱和吸附量为1.383 mg/g,是RM的1.83倍,而RM和RM_(0.5)对PO_(4)^(3-)-P的吸附更适合用Freundlich模型描述;改性后赤泥表面更为粗糙,且表面生成了镁氧化物覆盖层,可进一步实现对氮、磷的去除。RM_(0.5)略优于RM对PO_(4)^(3-)-P的去除效果,而在对NH_(4)^(+)-N的去除上,RM_(0.5)明显优于RM,因此在处理高浓度含氮雨水径流时,更倾向于选择RM_(0.5)作为填料改良剂。The traditional bio-retention system has the problem of a single composition of the filler layer and unstable nitrogen and phosphorus removal efficiency.To evaluate the feasibility of red mud as a bio-retention system filler layer modifier,this study used Bayer red mud as a raw material to prepare magnesium-loaded modified red mud.Through modification experiments,isothermal adsorption experiments and material characterization,this study explored the effect of magnesium-loaded modified red mud on the removal efficiency and adsorption mechanism of nitrogen and phosphorus in rainwater runoff.The results show that the optimal concentration for preparing modified red mud using MgCl_(2) solution was 0.5 mol/L.Compared with red mud(RM),modified red mud(RM_(0.5))increased the average removal rates of NH_(4)^(+)-N and PO_(4)^(3-)-P by 17.15%and 5.74%,with average removal rates of 41.83%and 97.24%,respectively.RM and RM_(0.5) can be described as Langmuir monolayer adsorption for ammonium nitrogen adsorption,whereas they exhibit the opposite behavior for phosphate adsorption,which is more in line with the Freundlich isothermal adsorption model.The theoretical saturation adsorption amount of RM_(0.5) for nitrogen was 1.383 mg/g,which was 1.83 times that of RM.The surface of the modified red mud was rougher than that of the original red mud,and a magnesium oxide coating was formed on the surface.RM_(0.5) has a slightly better removal effect on PO_(4)^(3-)-P than RM,while for NH_(4)^(+)-N,RM_(0.5) is significantly better than RM.Therefore,when dealing with high-concentration nitrogen-containing rainwater runoff,RM_(0.5) is more likely to be selected as a filler modifier.

关 键 词：赤泥 改性赤泥 生物滞留系统 铵态氮 磷酸盐 等温吸附 

分 类 号：X703[环境科学与工程—环境工程] TU992[建筑科学—市政工程]