低浓度含磷水体除磷填料的选择研究

通过对不同填料进行初筛，选择红瓦、环保砖和水泥砖作为研究对象，对低浓度含磷水体进行磷吸附能力试验研究.结果表明，Langmuir 和Freundlich方程均能合理地描述低浓度含磷水体中各填料的等温吸附特性，Langmuir方程中3种填料对磷的理论饱和吸附量由大到小依次为：红瓦（38.13 mg·kg^-1）>环保砖（25.79 mg·kg^-1）>水泥砖（8.85 mg·kg^-1），Freundlich方程中反应吸附能力的K值由大到小的规律同Langmuir方程的饱和吸附量一致.一级动力学方程、Elovich方程和双常数速率方程均能很好地描述填料对磷素的吸附动力学特征，从可决系数来看，Elovich型方程的拟合效果最好.从磷释放及其安全性分析，3种填料没有向水体释放磷，释放的重金属元素非常低，不会对水体造成二次污染.各填料出水均偏碱性，因此，选择湿地植物时必须具有较强的耐碱性.综合考察得出，红瓦和环保砖可作为处理低浓度含磷水体的除磷填料.

Substrate screening for phosphorus removal in low concentration phosphorus-containing water body

According to the preliminary test, red tiles, green bricks and cement bricks were chosen to study their phosphorus adsorption capacity in wastewater with low concentration of phosphorus. Results demonstrated that the biosorption processes for substrates corresponded well with both Langmuir and Freundlich model. The theoretical saturated adsorption quantity of red tiles in Langmuir model was the highest (38.13 mg·kg^-1), followed by green bricks (25.79 mg·kg^-1) and cement bricks (8.85 mg·kg^-1); meanwhile, parameter K which represents the adsorption capacity in Freundlich model changed in the same sequence as the theoretical saturated adsorption quantity. The first order kinetics equation, Elovich equations and the two-constant rate equation all fit to describe the absorption characteristics of the three substrates. Among them, the Elovich equations exhibited the best correlation. According to the analysis of phosphorus release and water safety, three substrates did not release phosphorus into water body and their release of heavy metals was pretty low, indicating no secondary pollution of water bodies. However, the selected wetland plants must have strong alkali resistance since the effluent of all three substrates was alkaline. In summary, the red tiles and green bricks were good substrates for the treatment of low phosphorus concentration water body.