槐糖脂生物表面活性剂增效重金属污染土壤电动修复研究

发布时间：2018-05-17 13:19

本文选题：重金属 + 槐糖脂　；参考：《中国海洋大学》2015年硕士论文

【摘要】：表面活性剂对土壤中重金属离子具有络合作用和增流作用,是增效重金属污染土壤电动修复的重要措施之一。槐糖脂生物表面活性剂分子结构中不仅具有羧基等多个对金属离子具有络合作用的活性基团,而且具有低毒、易于生物降解等特性,因而在强化重金属污染土壤电动修复中具有良好的应用潜力。然而,应用槐糖脂生物表面活性剂增效重金属污染土壤电动修复的相关研究尚未开展。本论文以评价和确定槐糖脂生物表面活性剂在强化重金属污染土壤电动修复中适用性为主要目的,首先确定槐糖脂生物表面活性剂与土壤中常见重金属离子铜(Cu2+)、铅(pb2+)、锌(Zn2+)、镉(Cd2+)的络合稳定常数及温度、pH、离子强度对其影响,然后考察了槐糖脂、铅、镉在土壤基质上的吸附解吸附行为,进而将槐糖脂应用于重金属污染土壤的电动修复中,优化其增效去除重金属离子的电动修复条件,并探讨强化污染土壤电动修复的机制。论文主要研究结果如下：(1)应用等摩尔系列法,测定了槐糖脂与土壤中常见重金属离子Pb2+、Cd2+、 Cu2+、Zn2+及土壤常量金属离子Ca2+、Mg2+的络合稳定常数。6种金属离子与槐糖脂的络稳定常数的大小顺序为：Cu2+Pb2+Cd2+Zn2+Ca2+Mg2+,表明槐糖脂优先络合4种重金属离子,因而可作为络合剂强化污染土壤电动修复,进一步研究表明,Pb2+、Cu2+、Zn2+与槐糖脂的络合常数随着离子强度的增加而减小,表明离子强度的增加不利于重金属与槐糖脂的络合反应的进行；Pb2+、Cd2+、Cu2+、Zn2+与槐糖脂的络合常数随溶液pH增大而显著增大,这主要是由于随pH增大,槐糖脂的电离度增大,对金属离子的络合点位增多在288-303K的温度范围内,Pb2+、Cd2+、Cu2+、Zn2+与槐糖脂的络合常数随温度变化无显著变化。(2)槐糖脂和不同类型的重金属在土壤基质上的吸附类型不同。其中,槐糖脂在土壤基质上的吸附等温曲线符合Langmuir形式,最大吸附量为11.228mg/g, Pb2+在土壤中的吸附等温线符合Langmuir形式,最大吸附量为5309.65mg/kg, Cd2+在土壤中的吸附等温线则符合Freundlich形式。增大pH对槐糖脂在土壤上的吸附量具有抑制作用,却促进了pb2+和Cd2+在土壤基质上的吸附,这是由土壤表面吸附位点上的正负电荷数量变化导致；离子强度的增加增大了槐糖脂在土壤基质上吸附,却阻碍了pb2+和Cd2+在土壤基质上吸附,这是由于Na+影响土壤颗粒表面吸附点位所致。应用在槐糖脂浓度为750mg/L时,槐糖脂对重金属离子pb2+和Cd2+淋洗去除率分别16%和21%；在槐糖脂浓度在100mg/L-1000mg/L范围内,两种金属的去除率都随着槐糖脂浓度的增加而增加；在pH在4-8范围内,pb2+和Cd2+淋洗去除速率随pH值增大而增大；在288-308K温度范围内,pb2+和Cd2+去除率随着温度的升高而降低；随洗脱剂离子强度的增大,pb2+的去除率增大而Cd2+去除率则下降。(3)通过添加槐糖脂生物表面活性剂增效电动修复过程,并考察处理时间、电压、有机质含量、阴极pH控制对去除效果的影响。结果表明,在15V下处理96h,添加750mg/L槐糖脂的电动修复体系pb2+和Cd2+去除率分别达到44.0%和38.9%,分别较未添加槐糖脂修复体系提高32.8%和20.3%,这是由于槐糖脂具有络合增溶作用,有利于重金属解吸和迁移。在2天到11天的修复时间,Cd2+的去除率随修复时间增长而增大,pb2+则在4天时去除率最高；在15-30V的电压下,Cd2+的去除率随电压增长而增大,pb2+则在15V时去除率最高,这可能是由于重金属离子形态在土壤中存在差异所致。综合考虑经济成本和Pb2+、Cd2+的总去除率,确定优化处理时间和电压分别为96h和15V。在1.348—2.695%浓度范围内,pb2+和Cd2+的去除率随有机质含量的增加而增加,这是由于有机质起到表面活性剂的作用,有利于重金属离子的去除。采用0.01M乙酸控制pH对pb2+和Cd2+的去除效果最佳,去除率分别达到52.2%和88.7%。综上,本实验所确定的pb2+和Cd2+污染土壤电动修复的优化条件为：添加槐糖脂750mg/L,电压为15V,0.01M乙酸控制pH,处理时间为96h。
[Abstract]:It is one of the important measures for the electrokinetic remediation of soil contaminated soil by surfactant, which is one of the most important measures for electrokinetic remediation of soil contaminated by heavy metals. The molecular structure of Sophora fat bioactive agent not only has many active groups such as carboxyl groups, but also has low toxicity and is easy to biodegrade. Therefore, the application of Sophora japonica bioactive agent to enhance the remediation of heavy metal contaminated soils has not been carried out. This paper is to evaluate and determine the biological surface active agent of Sophora japonica biologic surface active agent to strengthen the remediation of heavy metal contaminated soil The main purpose of this study is to determine the adsorption and adsorption behavior of Sophora fat bioactive agent and common metal ions copper (Cu2+), lead (pb2+), zinc (Zn2+) and cadmium (Cd2+) in soil, pH, and ionic strength, and then investigate the adsorption and adsorption behavior of sophoracacia, lead and cadmium on soil matrix, and then the Sophora fatty acid should be used. In the electric remediation of heavy metal contaminated soil, the electrokinetic remediation conditions for the removal of heavy metal ions are optimized and the mechanism for strengthening the remediation of contaminated soils is discussed. The main results are as follows: (1) the common heavy metal ions Pb2+, Cd2+, Cu2+, Zn2+ and soil in soil are measured by the equimolar series method. The amount of metal ions Ca2+, Mg2+ complexing constant constant.6 metal ions and Sophora Sophora fatty acid stability constant of the order is: Cu2+Pb2+Cd2+Zn2+Ca2+Mg2+, which indicates that Sophora gum first complexing 4 kinds of heavy metal ions, thus can be used as complexing agent to strengthen contaminated soil remediation. Further studies show that the complexation of Pb2+, Cu2+, Zn2+ and Sophora fatty acids The constant decreases with the increase of ionic strength, indicating that the increase of ionic strength is not conducive to the complexation of heavy metals and Sophora fatty acids. The complex constants of Pb2+, Cd2+, Cu2+, Zn2+ and Sophora fatty acids increase significantly with the increase of pH in solution. This is mainly due to the increase of the degree of ionization of Sophora fatty acids with the increase of pH and the increasing of the complexing point of metal ions. In the temperature range of 288-303K, the complex constants of Pb2+, Cd2+, Cu2+, Zn2+ and Sophora fatty acids have no significant changes with the temperature. (2) the adsorption types of Sophora fat and different types of heavy metals on soil matrix are different. The adsorption isothermal curve of Sophora fat on soil matrix is in the form of Langmuir, and the maximum adsorption capacity is 11.228mg/g, Pb2+ The adsorption isotherm in the soil is in the form of Langmuir, the maximum adsorption amount is 5309.65mg/kg, and the adsorption isotherm of Cd2+ in the soil is in the form of Freundlich. Increasing pH can inhibit the adsorption of Sophora fat on soil, but promotes the adsorption of pb2+ and Cd2+ on soil matrix, which is the positive of the adsorption site on the soil surface. The increase of the amount of negative charge leads to the increase of the adsorption of Sophora Sophora on soil matrix, but it hinders the adsorption of pb2+ and Cd2+ on the soil matrix, which is due to the effect of Na+ on the surface adsorption point of soil particles. When the Sophora fat concentration is 750mg/L, the removal rate of heavy metal ions by pb2+ and Cd2+ is 16, respectively. % and 21%, in the range of 100mg/L-1000mg/L, the removal rate of two metals increased with the increase of the concentration of Sophora fat; in the range of 4-8, the leaching rate of pb2+ and Cd2+ increased with the increase of pH value; in the range of 288-308K temperature, the removal rate of pb2+ and Cd2+ decreased with the increase of temperature; with the eluant. The removal rate of pb2+ increased and the Cd2+ removal rate decreased. (3) the effect of treatment time, voltage, organic matter content, and cathode pH control on the removal efficiency was investigated by adding Sophora fatty acid surfactants. The results showed that the electrokinetic remediation system PB2 was added to 96h and 750mg/L Sophora fat under 15V. The removal rate of + and Cd2+ reached 44% and 38.9%, respectively, which increased by 32.8% and 20.3%, respectively, because of the complexation and solubilization of Sophora sophora, which was beneficial to the desorption and migration of heavy metals. The removal rate of Cd2+ increased with the longer repair time from 2 days to 11 days, and the highest removal rate of pb2+ at 4 days; at 1. Under the voltage of 5-30V, the removal rate of Cd2+ increases with the increase of voltage and the highest removal rate of pb2+ at 15V. This may be due to the difference in the form of heavy metal ions in the soil. Considering the economic cost and the total removal rate of Pb2+ and Cd2+, the optimal treatment time and the electrical pressure are within the concentration range of 1.348 to 2.695%, 96h and 15V., respectively, P. The removal rate of b2+ and Cd2+ increases with the increase of organic matter content, which is due to the effect of organic matter to the surface active agent, which is beneficial to the removal of heavy metal ions. The removal efficiency of pb2+ and Cd2+ by using 0.01M acetic acid is best, and the removal rate is 52.2% and 88.7%., respectively, and the pb2+ and Cd2+ contaminated soil is determined by this experiment. The optimum conditions for recovery were: adding 750mg/L, voltage 15V, 0.01M acetic acid controlling pH, and treating time 96h..
【学位授予单位】：中国海洋大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X53

【相似文献】