下凹式绿地人工滤层对初期雨水中Cu^(2+)的截留实验研究

Experimental study on interception of Cu^(2+) in early rainwater by artificial concave greenbelt filter layer

通过人工配水模拟道路径流,以动态土柱实验为手段,研究了Cu^(2+)初始浓度(100~200 mg/L)、下凹式绿地水深(5~15 cm)、溶液pH(3~7)等因素对下凹式绿地人工滤层吸附截留Cu^(2+)的影响规律,同时对吸附穿透曲线进行了拟合,依此推论了实际初期雨水中Cu2+的吸附截留规律.结果表明,随着Cu2+初始浓度的增大、水深的增大、pH的减小,穿透时间缩短,饱和吸附总量减小,Cu^(2+)去除率也减小.总体上穿透规律符合Thomas模型(R^(2)>0.9631).在路面径流Cu^(2+)的统计最大浓度(0.9355mg/L)下,下凹式绿地人工滤层可以对Cu^(2+)有较长时间的吸附,但酸性雨水和积水深度较大时穿透性增强.

As a low-impact development facility for sponge cities,concave green space has the advantages such as reducing flow,intercepting runoff pollutants,and improving rainwater quality. Through artificial water distribution to simulate the path flow of the road,and taking dynamic soil column experiments as the means,the influence rules of operation factors on interception of Cu^(2+) by artificial concave greenbelt filter layer are studied,including the initial concentration of Cu^(2+)( 100-200 mg·L^(-1)),the water depth of sunken green space( 5-15 cm),and the solution pH( 3-7).The adsorption penetration curve is fitted,and the adsorption and retention rules of Cu^(2+) in actual initial rainwater are deduced accordingly.Results show that the penetration time,the total saturated adsorption and the removal rate of Cu^(2+) all decreases as the initial Cu^(2+) concentration increases,or the water depth increases,or the pH value decreases.In general,the penetration rule conforms to Thomas model( R^(2)=0.963 1).In the case of the maximum statistical concentration of Cu^(2+)in road runoff( 0. 935 5 mg·L^(-1)),the artificial filter layer in concave green space can adsorb Cu^(2+) for a long time,but the penetrability is enhanced when the rainwater is acidic or the depth of ponding water is large.