湿地沉积物对铊、镉的吸附性能  

Adsorption of thallium and cadmium by wetland sediments

作　　者：邵思婷 邓红梅[1,2] 宋永欣 朱伟俊 吴倩雯 罗梦婷 陈永亨[1,2] 李伟新[3] 黄雯孝 SHAO Siting;DENG Hongmei;SONG Yongxin;ZHU Weijun;WU Qianwen;LUO Mengting;CHEN Yongheng;LI Weixin;HUANG Wenxiao(School of Environmental Science and Engineering,Guangzhou University,Guangzhou,510006,China;Key Laborotary of Water Safety and Protection in Pearl River Delta,Ministry of Education,Guangzhou University,Guangzhou,510006,China;Key Laboratory of Radioactive and Rare Scattered Minerals,Ministry of Land and Resources,Shaoguan,512026,China)

机构地区：[1]广州大学环境科学与工程学院,广州510006 [2]广州大学珠江三角洲水质安全与保护省部共建重点实验室,广州510006 [3]国土资源部放射性与稀有稀散矿产重点实验室,韶关512026

出　　处：《环境化学》2018年第7期1534-1544,共11页Environmental Chemistry

基　　金：国家自然科学基金(41170399;41573119);广州市教育局科技计划(1201620157);国土资源部放射性与稀有稀散矿产重点实验室基金(RRSM-KF2018-04);广州大学大学生创新训练项目(CX2016007)资助~~

摘　　要：为了研究广州大学城湾咀头湿地公园(D)和南沙湿地公园(N)表层沉积物对典型重金属铊(Tl)和镉(Cd)吸附性能的研究,采用静态批处理实验,探讨了pH、沉积物中有机质含量、反应时间、Tl(Ⅰ)和Cd(Ⅱ)的初始浓度、温度等因素对吸附的影响.结果表明,溶液初始浓度为10 mg·L^(-1),随溶液初始pH值的升高,沉积物对Tl(Ⅰ)和Cd(Ⅱ)的吸附量增大,在pH 3.0—9.0时,沉积物D和N对Tl(Ⅰ)均达到较大的吸附量,分别为159.5 mg·kg^(-1)和156.7 mg·kg^(-1);在pH值为2.0—6.0时,对Cd(Ⅱ)的吸附急剧增大,沉积物D的吸附量达到了220.1 mg·kg^(-1),沉积物N的值则达到247.8 mg·kg^(-1),当pH>6.0时,吸附量呈下降趋势;沉积物中的有机质对Cd(Ⅱ)的吸附有显著影响,对Tl(Ⅰ)吸附影响程度小于Cd(Ⅱ).动力学实验显示,沉积物对Tl(Ⅰ)和Cd(Ⅱ)的吸附过程迅速,分别在4 h和1 h达到平衡;沉积物对Tl(Ⅰ)和Cd(Ⅱ)的吸附与准二级动力学拟合程度高(R2>0.99),由此可知该吸附过程为化学吸附.等温吸附实验表明,随Tl(Ⅰ)和Cd(Ⅱ)初始浓度增加,沉积物的吸附量也随之上升,当温度升高时,沉积物对Cd(Ⅱ)的吸附量增大,对Tl(Ⅰ)的吸附效果则相反;沉积物对Tl(Ⅰ)和Cd(Ⅱ)的吸附效果用Langmuir和Freundlich方程拟合均较好.The characteristics of typical heavy metals of thallium（ Tl） and cadmium（ Cd）adsorption onto Guangzhou University Wanjutou Wetland Park（ D） and Nansha Wetland Park（ N）were investigated by static adsorption batch technique. The effects of parameters of solution initial pH,sediment organic matter,heavy metal initial concentration,reaction time,temperature weretaken into account. The results showed that when the initial concentration of solution was 10 mg·L^（-1）,the adsorption of Tl（Ⅰ） and Cd（ Ⅱ） onto the two wetland sediments increases with the increase of pH after the experiment. The Tl（Ⅰ） adsorption capacity onto sediments of D and N was kept evenly maximum at pH 3.0—9.0,which were 159.5 mg·kg^（-1） and 156.7 mg·kg^（-1） respectively. Whereas the Cd（ Ⅱ） adsorption capacity onto sediments increased sharply at pH 2. 0—6. 0,the adsorption amount of sediment D reached 220.1 mg·kg^（-1）,and the value of sediment N reached 247.8 mg·kg^（-1）.When pH was over 6, the adsorption amount was decreasing. Organic matter has remarkably influenced on the adsorption of Cd（ Ⅱ） onto sediments than that of Tl（ Ⅰ） due to the strong complexation. According to the Kinetic experiments,the adsorption process of Tl（Ⅰ） and Cd（ Ⅱ）onto the sediments was rapidly,with the adsorption equilibrium time of 4 h and 1 h,respectively.The adsorption of Tl（Ⅰ） and Cd（ Ⅱ） onto sediments highly matched well with the quasi two order kinetics（ R2 〉0. 99）,indicating the adsorption process was chemisorption. From the isothermal adsorption experiments,sediment adsorption capacity increased with increasing initial concentration of Tl（ I） and Cd（ Ⅱ）. The adsorption capacity of Cd（ Ⅱ） increased with the increase of temperature,but the adsorption of Tl（ I） was the opposite. The data of the adsorption of Tl（ I） and Cd（ Ⅱ） onto sediments fitted well with both Langmuir and Freundlich equation.

关 键 词：铊 镉 吸附 沉积物 湿地 

分 类 号：X703[环境科学与工程—环境工程]