不同材料对河岸带土壤吸附除磷的强化能力及机制

IMPROVEMENT OF THREE MATERIALS ON PHOSPHORUS REMOVAL BY RIPARIAN SOIL,AND THE MECHANISM

以北京潮白河的河岸带土壤为研究对象进行室内试验,研究赤泥、白云石和硅灰石的添加对除磷吸附的强化作用。结果表明:3种材料对磷的吸附能力顺序为赤泥>硅灰石>白云石。3种材料对河岸带土壤的除磷能力均具有促进作用,且随着其投加量逐渐增加,对磷的去除效果均有明显上升趋势。在1%的添加量下,3种材料对磷去除的强化能力顺序为赤泥>硅灰石>白云石,去除率分别为63%、57.2%和56.4%,均显著高于对照组50.5%的去除率。赤泥添加量为2.5%和5%时,土壤pH值分别增加了约0.3和0.5,而白云石和硅灰石对土壤pH值没有影响,故可根据河岸带土壤酸碱度选择适合的除磷强化材料。3种材料对河岸带土壤强化后,均使土壤中无机磷形态发生了变化,特别是闭蓄态磷的含量百分比都显著增加,有助于河岸带对磷的截留。通过X射线衍射(XRD)分析可知:材料的强化能力与矿物组成有一定关系,赤泥对磷去除能力的促进主要与赤泥中的铁氧化物和铝氧化物有关。

The phosphorus removal ability of riparian soil were enhanced using red mud,dolomite,and wollastonite through indoor experiments. The results showed the adsorption abilities sequence of the three materials was red mud wallastonite dolomite. Moreover,the removal capacity of phosphorus could be improved with the amendment of the three materials. With increase of additive contents of the three materials,soil phosphorus adsorption capacity increased gradually. Amended with application ratio of 1%,the removal capacity for phosphorus of soil enhanced by red mud were the highest（63. 0%）,followed by the wollastonite groups and the dolomite groups with removal efficiencies of 57. 2%,56. 4%,respectively,which were all significantly higher than the control group（50. 5%）. The soil pH increased by about 0. 3 and 0. 5 with the red mud application rate of 2. 5% and 5%,and no significant influence was found using dolomite and wollastonite. Hence,the amendment for the phosphorus removal should be selected according to the riparian soil pH. The fractions of inorganic phosphorus in the soils showed that all the three materials promoted the percentage of occluded phosphorus. The mineral types of the amendments had some relationship with the enhancing capacity of the three amendments,and the improvement of phosphorus by red mud was probably due to the iron oxide and aluminum oxide.