摘要
镉污染土壤对生态环境具有潜在危害,开展镉污染土壤的治理具有重要意义。本文以鸟粪石为材料,研究其对镉的吸附能力及其影响因素,并采用盆栽实验,探究了鸟粪石对污染土壤中镉的钝化效果。结果表明,随着pH值由6增加至9,鸟粪石对镉的去除率增加。当镉初始质量浓度为50 mg·L^(-1)、鸟粪石投加量为4 g·L^(-1)且pH值为9时,鸟粪石对镉的去除率为93.55%。鸟粪石对镉的吸附符合伪二阶动力学模型和Langmuir等温吸附模型,其对镉的最大吸附量为49.857 mg·g^(-1),是水稻秸秆生物炭对镉吸附量的5.8倍。与未施肥对照相比,施用鸟粪石后,豌豆地上部分和地下部分镉含量以及根茎转运系数(TF S/R)分别降低32.12%、2.74%和30.24%,且TF S/R降低率高于施用竹炭处理的TF S/R降低率(17.91%)。鸟粪石对土壤中镉的钝化率为22.72%,其机理可能与施用鸟粪石可促进土壤中弱酸提取态镉向残渣态镉转化有关。与对照相比,施用鸟粪石后,豌豆地上部分磷和氮含量分别增加4.9%和9.7%。该研究结果表明,鸟粪石是具有一定钝化能力的缓释肥。
Research on the treatment of cadmium-contaminated soil is of great significance due to the potential ecological hazards posed by cadmium.This study investigated the cadmium(Cd 2+)adsorption capacity of struvite and the factors influencing this process,as well as the passivation effect of struvite on cadmium in contaminated soil.The results indicate that the removal efficiency of Cd 2+by struvite increased with pH(from 6 to 9),reaching 93.55%at pH 9 when 4 g·L^(-1)of struvite was added to a 50 mg·L^(-1)Cd 2+solution.The adsorption process followed the pseudo-second-order kinetic model and fitted well with the Langmuir isotherm model,with a maximum adsorption capacity of 49.857 mg·g^(-1).This capacity was 5.8 times greater than that of rice straw biochar.In soil experiments,compared to untreated soil,the application of struvite reduced cadmium content in the above-ground and below-ground parts of peas by 32.12%and 2.74%,respectively,and decreased the stem/root translocation factor(TF S/R)by 30.24%.The reduction in TF S/R was higher than that achieved by bamboo biochar(17.91%).The cadmium passivation rate following struvite application was 22.72%,potentially due to enhanced conversion of weak acid-extractable cadmium into the residual fraction.Additionally,phosphorus and nitrogen content in the above-ground parts of peas increased by 4.9%and 9.7%,respectively.These findings suggest that struvite functions as a slow-release fertilizer with notable cadmium passivation capacity.
作者
苏静
徐德福
吴蝶
陈丝
陈赞美
卢挺天
SU Jing;XU De-fu;WU Die;CHEN Si;CHEN Zan-mei;LU Ting-tian(School of Environmental Science and Engineering,Nanjing University of Information Science and Technology,Nanjing 210044,China)
出处
《生态与农村环境学报》
北大核心
2025年第8期1095-1103,共9页
Journal of Ecology and Rural Environment
基金
江苏高校“青蓝工程”项目(20161507)
江苏省“六大人才高峰”项目(R2016L06)。
关键词
鸟粪石
镉
吸附
钝化
struvite
cadmium
adsorption
passivation
