热改性凹土钝化底泥对水体磷的吸附特征研究

基于前期选择的廉价热处理富钙凹土为依据,通过向底泥中添加不同比例的热处理富钙凹土,研究材料添加后底泥对磷的吸附及对底泥磷的转化特征.结果表明,添加材料后会显著增强底泥对磷的固持能力和吸附速率,其中5%~20%的材料添加会增加底泥的磷最大吸附量1.5~2.0倍,吸附速率增加1.7~3.7倍.材料添加后的底泥具有较强的抗干扰能力,其中pH值、NO₃^-以及HCO₃^-对磷吸附的干扰作用明显减弱,而SO₄^2-和SiO₃^2-依然会对添加材料底泥产生较大的影响.磷形态分析表明,材料添加可以将可移动磷转化为Al-P和Ca-P,增加了底泥中惰性磷的比例,由此会显著降低底泥磷向上覆水体的释放.以上研究结果表明,热处理富钙凹土是湖泊富营养化控制的一种有效材料,可以用于底泥磷释放的控制.

Phosphorus sorption from aqueous solution by the thermally-treated attapulgite amended sediment

In this study, the thermally-treated calcium-rich attapulgite was used as low-cost P sorbent amendments and which was added into lake sediment with different percentage. The P sorption on the material amended sediment and the sediment P fractionation were studied. The results indicated that the P sorption capacity and sorption rate were greatly enhanced with addition of the material. Specifically, the maximum P sorption capacity and sorption rate have been increased 1.5 to 2.0 times and 1.7 to 3.7times respectively with addition of 5% to 20% of material. In addition, material addition can increase the capacity of resisting disturbance of lake sediment. The interference of pH, NO₃^- and HCO₃^- on P sorption on the amended sediment has been attenuated. However, SO₄^2- and SiO₃^2- still exert great influence on P sorption on amended sediment. The results of P fractionation indicated that material addition can transform Al-P to Ca-P in sediment, increase the percentage of inert P and therefore low the P release into overlying from the sediment. All of the results suggested that the thermally-treated calcium-rich can be used as an effective material for lake eutrophication control.