铅在三峡库区消落带土壤中的吸附-解吸特性  

Properties of Adsorption-Desorption of Pb in Soil of the Water-Level-Fluctuating in Three Gorges Reservoir Region

作　　者：方卢秋[1] 

机构地区：[1]长江师范学院化学化工学院,重庆涪陵408100

出　　处：《重庆师范大学学报（自然科学版）》2010年第3期27-31,共5页Journal of Chongqing Normal University:Natural Science

基　　金：重庆市教育委员会科学技术研究项目(No.KJ071304)

摘　　要：研究pH、有机质、离子强度和铅离子(Pb2+)浓度对三峡库区消落带土壤吸附和解吸Pb2+特性的影响,揭示三峡库区消落带土壤吸附和解吸Pb2+的规律,为三峡库区铅污染的风险评价与预测、污染治理与土地资源利用提供基础资料。选取消落带主要土壤类型紫色土为研究对象,采用模拟实验及恒温振荡平衡法,以原子吸收分光光度计测定Pb2+的吸附量和解吸量。实验结果显示,1)pH极显著地影响Pb2+的土壤吸附量(p<0.01),吸附等温线符合Henry型,最大土壤吸附量为9.720 3 mg.g-1;随着pH升高,土壤解吸量总体呈下降趋势,pH=4时土壤解吸量达最高点0.543 7 mg.g-1。2)去除土壤有机质,土壤Pb2+的吸附量和解吸量都上升,土壤吸附量上升46.04%,土壤解吸量上升为17.21%。3)离子强度极显著地影响Pb2+的土壤吸附量和解吸量(p<0.01),吸附等温线符合Henry型,最大土壤吸附量为10.049 0mg.g-1;随着离子强度增加,土壤解吸量从0.031 94 mg.g-1增加到最高点0.972 6mg.g-1而趋于稳定。4)Pb2+浓度极显著地影响土壤吸附量和解吸量(p<0.01),加入Pb2+浓度的增加,土壤吸附量逐渐增加到最高点2.566 8 mg.g-1,吸附等温线符合Langmuir型,土壤解吸量逐渐增加到最大值后趋于稳定,最大解吸量为0.948 4 mg.g-1。研究表明上述因素不同程度地影响Pb2+的土壤吸附量和解吸量,从最大土壤吸附量和解吸量来看,影响Pb2+土壤吸附量的顺序是:离子强度>pH>有机质>Pb2+浓度,影响Pb2+土壤解吸量的顺序是:pH<Pb2+浓度<离子强度<有机质;可以推测三峡库区蓄水后,消落带土壤受各种因素影响,导致土壤性质变化,影响重金属元素的环境行为,重金属可引起环境污染与生态危害。The soil of water-level-fluctuating adsorption and desorption characteristics of Pb^2＋ ion in the Three Gorges Reservoir region are studied on pH, organic matter, ionic strength and effect of Pb^2＋ ion concentration. It is revealed in the law of soil adsorption and desorption of Pb^2＋ ion in water-level-fluctuating of the Three Gorges reservoir region, for providing the basis on lead contamination risk assessment and forecasting, pollution control and the use of land resources. Electing purple soil of the main soil type is also studied by using simulation experiments and constant temperature oscillation balance method. With atomic absorption spectrophotometer determination of Pb^2＋ ion adsorption aod desorption volume. The results show that ： 1 ） pH value very significantly ＇affects the soil adsorption capacity of Pb^2＋ ion （p 〈 0.01 ） , adsorption isotherm accords with Henry type to calculate the maximum Pb^2＋ ion adsorption capacity of the soil is 9. 720 3 mg · g^-1 As the pH value increases, the amount of Pb^2＋ ions in the soil desorption is in overall declining trend; while the highest desorption of the soil is 0. 543 7 mg · g ^-1 when pH value reaches 4. 2 ） Takeoff soil organic matter, soil adsorption and desorption capacity of Pb^2 ＋ ion increase, the soil adsorption capacity increases 46.04% , and the soil desorption capacity increases 17.21%. 3） The ionic strength significantly affects the anaount of Pb^2 ＋ ion adsorption and desorption capacity in soil （p 〈0.01 ）. Adsorption isotherm accords with Henry type, calculating the maximum adsorption capacity of Pb^2＋ ion in soil is 10. 049 0 mg· g^-1. As the ionic strength increases, the amount of soil desorption from 0. 031 94 mg· g^-1 to the highest point of O. 972 6 mg· g^-1 ,then stabilizes. 4）Pb^2＋ ion concentration significantly affects the amount of soil adsorption and desorption （p 〈0.01 ）. With its accession to the increase in the concentration of Pb^2 ＋ ions and Pb^2＋ ions, adsorption capa

关 键 词：三峡库区 消落带 土壤 铅 吸附 解吸 

分 类 号：X703[环境科学与工程—环境工程]