铅化学固定的效应分析
(1. 中南大学 资源加工与生物工程学院，长沙 410083；2. 湖南农业大学 资源环境学院，长沙 410128)
摘 要: 以赤泥废料制备含磷赤泥基颗粒作为铅污染土壤修复材料。通过栽种韭菜进行盆栽试验，于第1、5、10、20、30天取土样。通过五步法连续提取并测定土样中不同形态铅的含量。观测韭菜生长情况并测定生长30d韭菜中的铅含量。以残渣态铅含量增加和其他形态铅减少来确定修复效果，分析土壤中铅的化学形态转化的促进和固定效应以及对韭菜吸收铅的抑制影响。结果表明：含磷赤泥颗粒可缓解赤泥强碱性对土壤pH值的影响，添加5%含磷3.40%的赤泥颗粒时，在修复期内，土壤pH值与空白样品的pH值持平。同时赤泥对磷有固持作用，有利于减少可溶磷流失。随赤泥颗粒中磷含量增加，对铅的修复效果显著。施加5%含磷6.80%的赤泥颗粒时，残渣态铅增加达81.26%，有机结合态、铁锰氧化态和碳酸盐态铅分别减少78.74%、85.62%和73.46%。适量施用含磷1.70%的赤泥颗粒可在保证植株正常生长情况下有效抑制对土壤中铅的吸收，铝的吸收抑制率为68.05%。
关键字: 赤泥；土壤；铅锌；修复
（1. School of Resources Processing and Biological, Central South University, Changsha 410012, China;
2. College of Resources and Environment, Hunan Agricultural University, Changsha 410128, China）
Abstract:The red mud composite particles made up of red-mud (waste of alumina refinery) and phosphate were applied as remediation materials in Pb pollute soil. The leeks were planted for pot experiments and sampled at 1, 5, 10, 20 and 30d during the restoration. Through the five-step sequential extracting, the different phases of lead were extracted and determined. The growth of leeks was observed in 30 days and the content of lead in leeks were tested. The effect of remediation was evaluated by the increase of residue phase lead and the decrease of other phases. The promotion of chemical fixation and absorption inhibition were analyzed. The results show that the red mud-phosphate particles can relieve the increase of soil pH value caused by strong alkaline from red mud. After 5% particles containing 3.40% phosphorus are applied, the pH values of the soil samples remained unchanged to the control. And the particles have the effect of phosphate repository and the loss of water soluble phosphate is reduced. With phosphate content in particles increasing, the remediation effect of lead is significantly. When adding 5% composite particles containing 3.40phosphorus, the largest increase ratio of residual Pb is 81.26% and the decreases of carbonate phase, iron-manganese oxide phase and organic phase are 78.74%，85.62% and 73.46%, respectively. Using the composite particles containing 1.70% phosphorus, the absorption of lead is effectively inhibited as the rate is 68.05% in the base of better vegetating.
Key words: red mud; soil; lead; remediation
