东乌珠穆沁旗草原砂土对汞的吸附特征及其影响因素
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摘要
以东乌珠穆沁旗的草原砂土为研究对象,采用正交试验设计的方法,研究了土壤/溶液(固/液)、初始汞浓度、溶液pH、腐殖酸、硝酸钠浓度对东乌珠穆沁旗草原砂土吸附HgCl2的影响。结果表明:固/液越小,初始汞浓度越大,土壤吸附能力越强;土壤对汞的吸附量随溶液pH,外源腐殖酸浓度,硝酸钠浓度的增大而呈现先增大后减小的趋势,当溶液pH为7.5,外源腐殖酸浓度为0.6mg/g,硝酸钠浓度为0.08mg/L时,土壤对汞的吸附量分别达到最大。影响砂土吸附HgCl2的因素大小依次为初始汞浓度>固/液>pH>硝酸钠浓度>腐殖酸浓度。草原地区砂土对汞的吸附动力学过程与Lagergren准二级动力学模型拟合有较好的相关性,表明该吸附过程主要以化学吸附为主,且吸附过程不可逆。
Taking the grassland sandy soil of East Wuzhumuqi as the research object,and simulating mercury deposition,orthogonal experiment was adopted.The effects of soil/solution ratio,initial mercury concentration,pH,humic acid and concentration of sodium nitrate on the adsorption of grassland sandy soil for HgCl2 were studied through the method of orthogonal experimental design.The mercury determination in soil were determined by water bath digestion atomic fluorescence spectrometry.The results showed that the smaller the soil/solution ratio was,the larger the initial mercury concentration and the stronger the soil adsorption capacity.The amount of mercury adsorbed by soil was affected by the amount of humic acid,the concentration of sodium nitrate and solvent pH,and the adsorption amount increased first and then decreased with the increasing of the above three factors.When the solvent pH was 7.5,the concentration of exogenous humic acid was 0.6 mg/g and the concentration of sodium nitrate was 0.08 mg/L,the soil adsorption capacity reached the maximum.The factors affected the adsorption of sand for HgCl2 followed the order of initial mercury concentration> soil/solution ratio > pH > sodium nitrate concentration > humic acid content.Fitting experimental data showed that the accumulation behavior of mercury in sandy soil accorded with the adsorption kinetics process and well correlated with Lagergren quasi-second-order kinetic model,which indicated that the adsorption process was mainly chemical adsorption and the adsorption process was irreversible.
Taking the grassland sandy soil of East Wuzhumuqi as the research object,and simulating mercury deposition,orthogonal experiment was adopted.The effects of soil/solution ratio,initial mercury concentration,pH,humic acid and concentration of sodium nitrate on the adsorption of grassland sandy soil for HgCl2 were studied through the method of orthogonal experimental design.The mercury determination in soil were determined by water bath digestion atomic fluorescence spectrometry.The results showed that the smaller the soil/solution ratio was,the larger the initial mercury concentration and the stronger the soil adsorption capacity.The amount of mercury adsorbed by soil was affected by the amount of humic acid,the concentration of sodium nitrate and solvent pH,and the adsorption amount increased first and then decreased with the increasing of the above three factors.When the solvent pH was 7.5,the concentration of exogenous humic acid was 0.6 mg/g and the concentration of sodium nitrate was 0.08 mg/L,the soil adsorption capacity reached the maximum.The factors affected the adsorption of sand for HgCl2 followed the order of initial mercury concentration> soil/solution ratio > pH > sodium nitrate concentration > humic acid content.Fitting experimental data showed that the accumulation behavior of mercury in sandy soil accorded with the adsorption kinetics process and well correlated with Lagergren quasi-second-order kinetic model,which indicated that the adsorption process was mainly chemical adsorption and the adsorption process was irreversible.
引文
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[20]王金贵.我国典型农田土壤中重金属镉的吸附-解吸特征研究[D]:陕西杨凌:西北农林科技大学,2012.
[2] Soares L,Egreja F,Linharesl A,et al.Accumulation and oxidation of elemental mercury in tropicalsoils[J].Chemosphere,2015,134(1):181-191.
[3] Elsayed E,Mohamed M,Ahmed M,et al.Sorption,release and forms of mercury in contaminated soils stabilized with water treatment residual nanoparticles[J].Land Degradation&Development,2017,28(2):752-761.
[4]陈毛华,刘明广,郭斌,等.阜阳市城郊菜地重金属污染调查与评价[J].地球与环境,2017,45(3):322-328.
[5]陈绍杨,王里奥,王惠俊,等.汞矿区周边土壤和溪流底泥对汞的吸附解吸特征[J].环境工程学报,2017,11(3):1913-1919.
[6] Kocman D,Horvat M,Kotnik J.Mercury fractionation in contaminated soils from the Idrija mercury mine redion[J].Journal of Environmental Monitoring,2004,6(8):696-703.
[7] Garcua-sanchez A,Contreras F,Adams M,et al.Atmospheric mercury emissions from polluted gold mining areas(Venezuela)[J].Environmental Geochemistry and Health,2006,28(6):529-540.
[8]邹婷婷,王宁,张刚,等.松花江上游金矿开采区环境中汞污染的空间分布特征[J].环境科学,2010,31(9):2228-2233.
[9] Yuan C G,Li Q P,Feng Y N,et al.Fractions and leaching characteristics of mercury in coal[J].Environmental Monitoring and Assessment,2010,167(1):581-586.
[10]张成,陈宏,王定勇,等.三峡库区消落带土壤汞形态分布与风险评价[J].环境科学,2014,35(3):1060-1067.
[11]王梅,黄标,孙维侠,等.强烈人为作用下城镇周围汞的空间变异及其积累迁移规律[J].土壤学报,2011,48(3):506-515.
[12] Chen L,Xu Z,Ding X,et al.Spatial trend and pollution assessment of total mercury and methylmercury pollution in the Pearl River Delta soil,South China[J].Chemosphere,2012,88(5):612-619.
[13]陈宁,陈艳,田超,等.无机汞和甲基汞在土壤中的吸附-解吸特性研究[J].农业环境科学学报,2013,32(6):1159-1165.
[14]朱霞萍,汪模辉,倪师军.固相微萃取-原子荧光测定鱼样品中痕量甲基汞[J].分析实验室,2006,25(9):49-52.
[15]张杰.重金属汞在典型土壤腐植酸上的吸附解吸特性的研究[D].济南:山东大学,2008:29-35.
[16]李颜雪.汞在土壤中的吸附-解吸及其非生物甲基化[D].合肥:安徽农业大学,2012.
[17]荆延德,赵石萍.土壤中汞的吸附-解吸行为研究进展[J].土壤通报,2010,41(5):1270-1274.
[18]李永富,孟范平,杜秀萍,等.负载镧的EGDE交联壳聚糖微球对氟离子的吸附平衡与吸附动力学[J].中国海洋大学学报,2012,42(6):034-039.
[19]冯新斌,尹润生,俞奔,等.贵州不同汞污染区表层土壤汞同位素组成变化[J].科学通报,2012,57(33):3119-3124.
[20]王金贵.我国典型农田土壤中重金属镉的吸附-解吸特征研究[D]:陕西杨凌:西北农林科技大学,2012.