垂直流动态强化下基质对污染物的吸附活性及机理

ADSORPTION ACTIVITY AND MECHANISM OF POLLUTANTS REMOVAL BY SUBSTRATES UNDER THE DYNAMIC STRENGTHENING OF VERTICAL FLOW

基质作为人工湿地的骨架部分,对污染物的去除发挥着重要作用。选择黄土球、无烟煤与页岩陶粒,在不同进水负荷的垂直流动态条件下,对污染物去除进行比较,并通过X射线衍射(XRD)和扫描电镜(SEM)对其矿物组成与表面形貌进行分析,以深入探讨黄土球等基质的吸附活性及机理。结果表明:黄土球因其本身的去质子化作用,对NH^(+)_(4)-N具有极好的吸附活性,试验初始阶段NH^(+)_(4)-N去除率达到80%;同时,在较高磷浓度的进水负荷下,黄土球的静电作用与原子配位反应提升了其对可溶性反应磷(SRP)及颗粒磷(PP)的吸附能力;此外,黄土球的物理吸附作用对于COD的去除率均值达到50%,并改善水体中以芳香类为主的溶解性有机质(DOM)组成;无烟煤同样具有高效的吸附活性,对TP去除率能达到80%,单位基质磷吸附能力为6.89 mg/kg;无烟煤吸附机理以静电吸附为主,致使去除水体中的SRP效率更高,占据磷去除总量的44%;页岩陶粒则源于自身丰富的金属矿物成分,对PP有良好的结合吸附作用。3种基质在连续试验中均表现出对不同污染物的吸附活性,在连续试验中对污染物的“吸附疲性”也有着显著差异。基于试验结果和机理分析发现,黄土球具有潜在的湿地基质应用价值,并有助于改善水质中的DOM组分。

As the skeleton part of the constructed wetland,the substrates play an important role in removing pollutants.Under the vertical flow dynamic conditions with different influent loads,the experiments selected loess balls,anthracite coal,and shale ceramsite for pollutant removal.For in-depth research about the adsorption activity and mechanism of three substrates,the mineral composition,and surface morphology were analyzed by X-ray diffraction(XRD)and scanning electron microscopy(SEM).The test results showed that due to its own deprotonation,loess balls could remove 80%of NH^(+)_(4)-N in the initial stage.Under high phosphorus load,the electrostatic interaction and atomic coordination reaction of loess balls improved their adsorption capacity for soluble reactive phosphorus(SRP)and particulate phosphorus(PP).In addition,the physical adsorption of loess balls had an average removal rate of 50%on COD,and improved the composition of dissolved organicmatter(DOM)dominated by aromatics in water.The TP removal rate of anthracite could reach 80%,while the adsorption capacity of phosphorus for per unit matrix was 6.89 mg/kg.Due to the electrostatic adsorption of anthracite,the removal of SRP accounted for 44%of the TP removal.Shale ceramsite was derived from its own rich metal mineral composition,which was better in PP removal.The three substrates all showed certain adsorption activity on different pollutants in the continuous test,and"adsorption fatigue"of the pollutants also had significant differences in the continuous test.It was found that loess balls had potential application value of wetland substrates and helped to optimize the DOM components in water.