施硅对含镉土壤中铵态氮等温吸附的影响  

The Effects of Silicon Application on Isothermal Adsorption of Ammonium Nitrogen in Cadmium Contaminated Soil

作　　者：高晶晶 李龙国[1,2] 谭霄 GAO Jing-jing;LI Long-guo;TAN Xiao(State Key Laboratory of Hydraulics and Mountain River Engineering,Sichuan University,Chengdu 610065,China;College of Water Resources and Hydropower,Sichuan University,Chengdu 610065,China)

机构地区：[1]四川大学水力学与山区河流开发保护国家重点实验室,成都610065 [2]四川大学水利水电学院,成都610065

出　　处：《中国农村水利水电》2022年第3期134-139,共6页China Rural Water and Hydropower

基　　金：四川省科技厅重点研发项目(2019YFN0153);国家自然科学基金项目(51909175)。

摘　　要：为探明镉和硅及其相互作用对NH4^(+)在土壤中吸附过程的影响规律及机理,研究设置两个镉添加水平(2.5,5 mg/kg),3个硅添加水平(0,100,200 kg SiO_(2)/hm^(2))及对照组,共7组处理,分别记为CK、Cd_(2.5)、Cd_(5)、Cd_(2.5)S_(1)、Cd_(2.5)S_(2)、Cd_(5)S_(1)、Cd_(5)S_(2),测量各处理土壤对NH_(4)^(+)的等温吸附曲线,并采用线性模型、Freundlich模型以及Langmuir模型等五种模型对实验结果进行模拟。结果表明:由于土壤中Cd^(2+)与NH_(4)^(+)的竞争吸附,镉含量越高,土壤对NH_(4)^(+)的吸附能力越差,重金属污染增加了面源污染的风险;硅添加能显著提升含镉土壤对NH_(4)^(+)吸附,吸附量和吸附率具体表现为Cd_(5)<Cd_(2.5)<CK<Cd_(5)S_(1)<Cd_(5)S_(2)<Cd_(2.5)S_(1)<Cd_(2.5)S_(2);6种模型均能对实验结果进行拟合,其中Langmuir模型的拟合效果最好,R^(2)在0.9486~0.9963之间,说明Langmuir方程能够更好地描述施硅对含镉土壤中NH_(4)^(+)吸附过程的影响。在含镉土壤中施加硅肥,可有效提高土壤对NH_(4)^(+)的吸附能力,减少氮肥流失,有利于重金属污染及面源污染的协同治理。Batch experiment is conducted to investigate the influences of Si application(0,100,and 200 kg SiO_(2)/hm^(2),abbreviated as S_(1) and S_(2))on the isothermal adsorption of ammonium nitrogen in soils contaminated by Cd(2.5 and 5 mg Cd/kg CdBr_(2),Cd_(2.5) and Cd_(5) for short).Af⁃ter that,five models including linear model,Freundlich model,Langmuir model etc.are used to fit the experiment data.The results show that①the adsorption of NH_(4)^(+)decreases with the increasing Cd content due to the competitive adsorption between Cd^(2+)and NH_(4)^(+)in soil,which implies that the heavy metal pollution might increase the risk of non-point source pollution;②the addition of exogenous silicon signif⁃icantly improves the adsorption capacity and adsorption rate of NH_(4)^(+) in the following order:Cd_(5)<Cd_(2.5)<CK<Cd_(5)S_(1)<Cd_(5)S_(2)<Cd_(2.5)S_(1)<Cd_(2.5)S_(2);③the experiment data can be simulated by all the six models among which Langmuir model has the best fit with the R^(2) ranging from 0.9486 to 0.9963,indicating that Langmuir model can better describe the influence of silicon application on the adsorption of NH_(4)^(+) in the Cd contami⁃nated soil.Silicon application can effectively improve the adsorption capacity of NH_(4)^(+) in the Cd contaminated soil and reduce the loss of nitro⁃gen fertilizer,which is significant to the cooperative governance of heavy metal pollution and non-point source pollution.

关 键 词：镉 硅肥 铵态氮 等温吸附 

分 类 号：TV93[水利工程—水利水电工程] S27[农业科学—农业水土工程]