摘要
向污染土壤中施用螯合剂可增加土壤溶液金属离子的浓度,有利于金属离子到根部而被植物吸收。选用人为污染土壤为供试样品,在土样中加入壳聚糖,通过等温吸附试验研究了壳聚糖对污染土壤中吸附态Cd的提取效果。结果表明,壳聚糖能提高土壤中吸附态Cd的解吸效率,增加解吸溶液中Cd2+的浓度。壳聚糖对污染土壤中Cd2+的吸附作用随着壳聚糖加入量的增大而增大。用质量浓度为0.4 g/L的90%脱乙酰度壳聚糖做提取液,提取液pH值为6,提取平衡时间为20 h,对Cd2+质量比为200 mg/kg的土壤,Cd2+提取率为31.8%。该吸附过程遵从一级动力学模型。研究结果可为Cd在环境中的迁移转化和治理技术等方面的实际应用提供有价值的参考。
The paper is aimed at introducing its authors＇ report on the enhanced extraction of chitosan for cadmium（Ⅱ） from the contaminated soil.As is known in the farming practice,with the increase of contamination of the soil by heavy metals,it has become an urgent demand for remediation for and control of the level of such contaminants.Although non-metallic mineral ingredients have been used widely as soil amender,there are still few reports on the remedy for the contaminated soil caused by heavy metals,especially,for soil by contaminated cadmium（Ⅱ）,which is a kind of integrated new soil remediation and control technology to promote the ordinary plant concentrating on the heavy metals in the absorption soil.It is also reported that the chelating agent can be used to purify and alleviate the polluted soil and increase the concentration of the metallic ions in the soil by strengthening the plant absorption of the pollutants and offering the plant roots the beneficial metallic ions.In hoping to heighten the adsorption effect,we have conducted isotherm experiments so as to determine the effect of chitosan in removing Cd2＋ from the artificially contaminated soil by enhancing the additives of the Cd（Ⅱ） extraction.From the experiments we know that the removing rate of Cd^2＋ from the soil sample of 200 mg/kg of Cd^2＋ proves to reach 31.8% of Cd^2＋ at pH of 6,90% of the degree of deacetylation at 0.4 g/L chitosan,with the adsorption equilibrium time being about 20 h.It is also found that the adsorption of isotherm followed the first dynamic equation.Thus,the results of our study are expected to provide valuable references for the environmental migration and lowering of cadmium and soil pollution and enhanced extraction of chitosan for cadmium.
出处
《安全与环境学报》
CAS
CSCD
2008年第5期51-54,共4页
Journal of Safety and Environment
基金
青岛市科技发展计划项目(05-1-NS-58)
关键词
环境工程
土壤重金属污染
土壤修复
壳聚糖
镉离子
environmental engineering, soil heavy metal pollution, soil remediation, chitosan, cadmium（Ⅱ）
