摘要
重金属污染水的防范和治理一直是国际上的难点和热点研究课题。吸附法具有经济可行和环境友好等优点,被认为是去除水中重金属离子的最佳技术。球黏土具有潜在的高吸附性能,为进一步探索利用球黏土治理重金属污染水的可行性,该研究通过单组分与多组分重金属离子的批式吸附试验,重点考察球黏土对Pb^(2+)、Cu^(2+)、Zn^(2+)、Cd^(2+)、Cr^(6+)的吸附效果和竞争吸附关系。单组分离子吸附试验表明,球黏土对重金属离子的吸附量遵循先快速增加后缓慢增长,随pH值的增大而增大,随初始浓度增加而增加,直至吸附饱和的规律。最佳吸附平衡时间为90 min;最佳溶液pH值为5。pH值对球黏土吸附5种重金属离子的影响程度由大到小依次为Zn^(2+)、Cd^(2+)、Cr6+、Cu^(2+)、Pb^(2+),当pH值从2增到5时,Zn^(2+)吸附量提高了184%。球黏土对5种离子Pb^(2+)、Cr^(6+)、Zn^(2+)、Cd^(2+)、Cu^(2+)的饱和吸附量分别为311.847、301.437、263.213、195.435和179.635 mg/g。通过动力学模型和等温线模型拟合,吸附数据更加符合准二阶动力学模型和Langmuir等温吸附模型,说明吸附过程为单层吸附,吸附方式为化学吸附,最大吸附量依次为Pb^(2+)(497.593 mg/g)>Cr6+(442.868 mg/g)>Zn^(2+)(339.376 mg/g)>Cd^(2+)(290.039 mg/g)>Cu^(2+)(194.941 mg/g)。多组分离子吸附试验表明,球黏土对4种离子的吸附量同样呈先快速后缓慢增长,直至平稳的趋势。各离子在球黏土的活性位点上表现出的竞争能力由强到弱依次为Cr^(6+)、Zn^(2+)、Cd^(2+)、Cu^(2+)。通过等温线模型拟合,发现多组分重金属离子吸附数据更加符合Langmuir等温吸附模型,吸附方式和吸附过程与单组分一致,各组分的最大吸附量与单组分相比有所下降,但吸附总量却大大增加,说明球黏土对多组分重金属离子具有良好的吸附能力。与其他原生矿物材料相比,球黏土对重金属离子具有更大的吸附量,该研究成果可为球黏土作为吸附剂的利用和推广提供理论依据和数据支持,具有较大的现实意义。
Heavy-metal-contaminated water has posed a serious risk to health and survival in recent years.It is urgent to prevent and treat heavy metal water pollution.Adsorption can be an economically feasible and environmentally friendly way for the removal of heavy metal ions from water.Clay minerals can be directly used for natural adsorption,due to their high adsorption properties.Among them,ball clay is characterized by fine particles,high content of disordered kaolinite,and high activity,indicating high potential adsorption.However,it is still lacking in the adsorption performance at present.This study aims to investigate the adsorption properties and competitive adsorption relationship of ball clay for Pb^(2+),Cu^(2+),Zn^(2+),Cd^(2+),and Cr^(6+).Batch adsorption tests were performed on the mono and multi-heavy metal ions.The mono-component heavy ion adsorption tests showed that the adsorption capacity of ball clay for the heavy metal ions followed a pattern of rapid increase followed by slow increase with the increase of pH value and the initial concentration,and finally reaching adsorption saturation.The optimal duration of adsorption equilibrium was 90 min,and the optimal solution pH value was 5.The influence level of pH value on the adsorption was ranked in the descending order of Zn^(2+),Cd^(2+),Cr6+,Cu^(2+),Pb^(2+).The adsorption capacity for Zn^(2+)(the most influential ion)increased by 184%when pH value varied from 2 to 5.The weights of saturated adsorption for the five ions Pb^(2+),Cr6+,Cd^(2+),Zn^(2+),and Cu^(2+)were 311.847,301.437,263.213,195.435 and 179.635 mg/g,respectively.The kinetic and isotherm models displayed that the adsorption data was more consistent with the pseudo-second-order kinetic and Langmuir isothermal adsorption models,indicating the single-layer and chemical adsorption.The maximum adsorption was ranked in the order of the Pb^(2+)(497.593 mg/g)>Cr^(6+)(442.868 mg/g)>Cd^(2+)(339.376 mg/g)>Zn^(2+)(290.039 mg/g)>Cu^(2+)(194.941 mg/g).Multi-component adsorption tests showed that the adsorption capacity of ball clay for the four types of ions also shared a trend of rapid increase followed by slow increase until it was stable.The intensities of four heavy metal ions on the active sites of ball clay were ranked in the descending order of Cr6+,Cd^(2+),Zn^(2+),and Cu^(2+).Isotherm fitting found that the multi-component heavy metal ion adsorption was more consistent with the Langmuir isothermal adsorption model.The adsorption mode and process were consistent with those of the mono-component heavy metal ions.There was a decrease in the maximum adsorption capacity of ball clay for each ion in the multi-component heavy metal ion solutions.However,the total amount of adsorption increased greatly in the ball clay,indicating the better adsorption capacity for the multi-metal ions and the synergistic effect among heavy metals.Therefore,the ball clay can be expected to serve as the greater adsorption for the heavy metal ions.This finding can provide the theoretical basis and data support to the ball clay as an adsorbent,The treatment efficiency of industrial wastewater can be improved to reduce the secondary pollution to rivers and agricultural products,particularly with the great practical significance.
作者
陈榕
王彪
郝冬雪
高晋宁
王伟卓
高宇聪
CHEN Rong;WANG Biao;HAO Dongxue;GAO Jinning;WANG Weizhuo;GAO Yucong(Institute of Geotechnical Engineering,Northeast Electric Power University,Jilin 132012,China;Key Lab of Electric Power Infrastructure Safety Assessment and Disaster Prevention of Jilin Province,Northeast Electric Power University,Jilin 132012,China)
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2024年第4期245-253,共9页
Transactions of the Chinese Society of Agricultural Engineering
基金
国家自然科学基金项目(52078108)
吉林省科技厅中青年科技创新领军人才及团队项目(20210509058RQ)。
关键词
重金属
等温线
动力学
球黏土
单组分吸附
多组分吸附
heavy metal
isotherms
kinetics
ball clay
mono-component adsorption
multi-component adsorption
