镧离子改性蒙脱石同步脱氮除磷  

Simultaneous removal of ammonium and phosphate using lanthanum ion-modified montmorillonite

作　　者：吴成秀 姚鸳 罗武辉 WU Chengxiu;YAO Yuan;LUO Wuhui(Jiangxi Provincial Key Laboratory of Environmental Pollution Prevention and Control in Mining and Metallurgy,Ganzhou 341000,China;School of Resources and Environmental Engineering,Jiangxi University of Science and Technology,Ganzhou 341000,China)

机构地区：[1]矿冶环境污染防控江西省重点实验室,赣州341000 [2]江西理工大学资源与环境工程学院,赣州341000

出　　处：《江西冶金》2024年第5期375-382,共8页Jiangxi Metallurgy

基　　金：中国博士后科学基金项目(2018M640604)。

摘　　要：氮、磷浓度过高是水体富营养化的主要诱因,Phoslock®(镧离子改性膨润土)在实际富营养化水体治理领域已广泛应用。早期研究多侧重于Phoslock®的除磷机制与稳定性,对共存氨氮的同步吸附鲜有报道。本研究通过制备La3+改性高纯蒙脱石模拟Phoslock®除磷关键组分,探究了溶液pH值、吸附时间和初始浓度等实验条件对改性蒙脱石同步脱氮除磷的影响。结果表明,在pH=4~12范围内,此改性蒙脱石具有良好的除磷稳定性;当pH=10时,氨氮吸附量达到最大值,约为9.7 mg/g。相较于单一体系,共存体系中氮、磷吸附相互促进,缩短彼此的吸附平衡时间;此外,氨氮共存提高了磷的最大吸附量,而PO_(4)^(3‒)共存却降低了氨氮的最大吸附量。PO_(4)^(3‒)吸附几乎不受共存离子影响,Ca^(2+)和Mg^(2+)降低了氨氮吸附量,而HCO_(3)^(‒)和SiO_(3)^(2‒)促进了氨氮的吸附。改性蒙脱石主要通过表面沉淀(LaPO_(4))的方式除磷,分布于蒙脱石层间边缘的LaPO4形成的空间位阻降低了层间La^(3+)的利用率,阻碍了氨氮的离子交换过程。Nitrogen(N)and phosphorus(P)of high concentrations are the leading causes of water eutrophication,and Phoslock®,a lanthanum ion(La^(3+))-modified bentonite,has been widely used in the treatment of eutrophication water.Early studies mainly focused on the mechanism and stability of Phoslock®for P removal,and there are few reports on the simultaneous adsorption of coexisting ammonium(NH4^(+)).In this study,La^(3+)-modified high-purity montmorillonite(Mt)was prepared to simulate the Phoslock®key component responsible for P removal and the influences of pH value,adsorption time,and initial concentration on simultaneous removal of NH4^(+)and phosphate(PO_(4)^(3–))by the modified Mt were investigated.The results show that the modified Mt had good P removal stability in the range of pH 4-12,and uptake of NH4^(+)reached the maximum(ca.9.7 mg/g)at pH=10.Compared with the single system,the adsorption of N and P in the coexisting system promoted each other and shortened the individual adsorption equilibrium time.In addition,the coexisting NH4^(+)increased the maximum uptake of P,while the coexisting PO_(4)^(3–)decreased the adsorption capacity of NH4^(+).Adsorption of PO_(4)^(3-)was almost unaffected by coexisting ions.Ca^(2+)and Mg^(2+)reduced the amount of adsorbed NH4^(+),while HCO3‒and SiO_(3)^(2‒)promoted the adsorption of NH4^(+).Phosphate was removed through surface precipitation(in LaPO_(4)form)on Mt,and the steric hindrance stem from the formed LaPO_(4)at the edge of Mt interlayers reduced the utilization rate of La^(3+)and hindered the ion exchange of NH_(4)^(+).

关 键 词：蒙脱石 镧离子 同步去除 氨氮 磷酸根 

分 类 号：X703[环境科学与工程—环境工程] TD985[矿业工程—选矿]