【摘要】 以空白土壤和人工制备的不同浓度铜、砷、镉和铅污染土壤为对象,研究了在不同pH值、温度和柠檬酸浓度条件下重金属污染对土壤吸附磷的影响,并对其进行了相关过程的等温和吸附动力学的机理分析。研究结果表明,空白土壤和As污染土壤吸附磷的等温吸附过程符合Temkin方程,Cu、Pb、Cd污染土壤吸附磷的等温吸附过程符合Freundlich方程,空白土壤和重金属污染土壤吸附磷的动力学过程均符合Elovich方程;重金属污染对土壤吸附磷有一定的抑制作用,抑制程度与污染物浓度呈现显著的正相关,且随外在环境因子的改变而不同。当重金属元素铜、铅、砷、镉的含量分别为200、80、25、0.8 mg kg-1时:pH值为5时,重金属对土壤吸附磷抑制作用最小,土壤吸附磷量分别降低了30.18%、13.54%、30.74%、37.23%,其抑制作用程度为:Cd> As> Cu> Pb;土壤吸附磷量与温度呈现显著的正相关,温度变化为25～45℃时,土壤对磷的吸附量分别增大了17.14%～28.83%、6.72%～16.05%、8.68%～9.13%、10.30%～23.45%,同一条件下重金属对土壤吸附磷抑制作用程度为Cu> Cd> As> Pb;重金属污染土壤吸附磷量与柠檬酸浓度成负相关,柠檬酸浓度为50 mg L-1时,土壤吸附磷量分别降低了19.87%、21.94%、23.18%、24.84%,相同柠檬酸浓度下其抑制作用程度为Cd> As> Pb> Cu。更多还原

【Abstract】 The effects of heavy metal pollution on soil phosphorus(P) adsorption were studied under different pH values, temperatures and citric acid concentrations by artificially preparing copper(Cu), arsenic(As), cadmium(Ca)and lead(Pb) contaminated soils. Then the mechanisms of isothermal and adsorption kinetics were analyzed. The results showed that the isotherm adsorption process of P in the control soil and As contaminated soil was better fitting with the Temkin equation, while that in Cu, Pb and Cd contaminated soils was according with the Freundlich equation.The kinetics of P adsorption in both blank soil and heavy metal contaminated soils was all better described with the Elovich equation. The heavy metal pollution certainly inhibited the soil P adsorption, and the degree of inhibition was significantly positively correlated with the concentration of pollutants and varied among the external environmental factors. Under the concentrations of Cu, Pb, As and Cd of 200, 80, 25 and 0.8 mg kg-1, respectively and pH value of5, their inhibitory effects on soil P adsorption were the smallest, the amount of P adsorption by soil was reduced by30.18%, 13.54%, 30.74%, 37.23%, respectively, and the degree of inhibition was in the order of Cd > As > Cu > Pb.P adsorption by soil was significantly positive correlated with temperature. Under the temperature at 25 ～ 45℃, the amount of P adsorption by soil increased by 17.14%-28.83%, 6.72%-16.05%, 8.68%-9.13%, 10.30%-23.45%in the Cu, Pb, As and Cd contaminated soils, respectively, and the degree of inhibition was Cu > Cd > As > Pb. The amount of P adsorption by soil was negatively correlated with the concentration of citric acid. Under the concentration of citrate of 50 mg L-1, the amount of P adsorption by soil was decreased by 19.87%, 21.94%, 23.18%, 24.84% in the Cu, Pb, As and Cd contaminated soils, respectively, with degree of inhibition as Cd > As > Pb > Cu.更多还原