摘要
本文系统研究了雨水集中入渗设施的土壤对模拟雨水径流中常见6种重金属的吸附过程,探究了不同浓度梯度下重金属的竞争吸附情况,分析了不同pH及不同土壤类型理化性质的差异对土壤吸附重金属的影响.在综合分析研究结果及全国各省锌矿、铅矿及铜矿储量,全国土壤pH分布和土壤有机质含量分布的基础上,对全国各省海绵城市建设中可能存在的重金属污染风险提出控制建议.土壤对模拟雨水径流混合溶液吸附实验结果表明,土壤对As、Cr、Cd、Pb、Cu、Zn6种重金属的吸附在40-60 min内可达到吸附平衡.其中Pb在3 min内即可吸附完全,但土壤对Cr的吸附量很低,对As吸附率约为55％,对Cu、Zn和Cd的吸附率均可达90％以上;在探究不同浓度梯度下多种重金属的吸附时,当溶液浓度超过60mg·L-1后,竞争吸附现象较为明显;碱性条件下更利于土壤对Cd、Cu、Zn的吸附,酸性条件下更利于土壤对As的吸附;不同类型土壤对重金属吸附的实验结果显示,土壤有机质含量与重金属吸附量呈正相关;在对土壤pH、有机质含量和锌、铜、铅矿产资源储量五种因素可能带来的重金属风险分析中,内蒙古自治区、云南省和江西省等地区的综合指数较高,在海绵城市建设中应加强对雨水径流和集中入渗土壤中重金属浓度的监测.本研究可为我国在建设海绵城市过程中防范重金属污染风险提供参考和科学依据.
Abstract
This research systematically studied the adsorption process of six common heavy metals in simulated rainfall runoff in the soil of rainfall centralized infiltration facilities.It explored the competitive adsorption of heavy metals under different concentration gradients,and analyzed the differences in pH and the physicochemical properties of different type soils and their impacts on heavy metal adsorption in soil.Based on the comprehensive analysis of this research results,the reserves of zinc,lead,and copper mines in various provinces across the country,and the distribution of soil pH and soil organic matter content across the country,this study proposed the control suggestions on heavy metal pollution risks that may exist in the construction of sponge cities in various provinces across the country.The adsorption experiment results of simulated rainfall runoff in soil show that the adsorption of six heavy metals including As,Cr,Cd,Pb,Cu,and Zn can reach adsorption equilibrium within 40-60 minutes.Among them,Pb can be completely adsorbed within 3 minutes,but the adsorption capacity of soil for Cr is very low.The adsorption rate for As is about 55％,and the adsorption rates for Cu,Zn,and Cd can all reach more than 90％.When exploring the adsorption of various heavy metals under different concentration gradients,the phenomenon of competitive adsorption becomes more obvious when the solution concentration exceeds 60 mg L-1.Alkaline conditions are more conducive to the adsorption of Cd,Cu,and Zn in soil,while acidic conditions are more conducive to the adsorption of As.The experimental results on the adsorption of heavy metals by different types of soils show that the organic matter content of soil is positively correlated with the adsorption capacity of heavy metals.In the analysis of the five factors,including soil pH,organic matter content,and reserves of zinc,copper,and lead mineral resources that may influence heavy metal risks,the comprehensive indices of Inner Mongolia Autonomous Region,Yunnan Province and Jiangxi Province are relatively high.Therefore,monitoring the heavy metal concentrations in rainfall runoff and centralized infiltration soil should be strengthened in the construction of sponge cities in these areas.This study can provide references and scientific basis on the prevention of heavy metal pollution risks during the construction of sponge cities in our country.
维普
万方数据