Abstract:

The removal of excessive phosphorus in wastewater can slow down the eutrophication of water. Adsorption dephosphorization has attracted much attention due to its advantages of low energy consumption, large capacity and less pollution. On this basis, modified adsorbents can improve the targeting of dephosphorization, broaden the operating conditions and increase the adsorption capacity. This paper analyzed the modification methods and adsorption properties of four kinds of phosphorus removal adsorbents: modified silicates, modified metal oxides, modified solid wastes and polymers. Silicate adsorption materials and solid waste materials have poor phosphorus removal effect, but they have great attraction because of their rich sources and low price. Polymer adsorbents have high adsorption capacity and selectivity, but they are expensive. Metal (hydrogen) oxides have excellent phosphate adsorption performance, good selectivity and fast adsorption speed. These compounds have been incorporated into zeolite, mesoporous silica, biochar and other materials to further enhance their adsorption performance, and have made major breakthroughs in the application of engineering materials, mainly including magnetic adsorbents and particle adsorbents. The mechanism of four kinds of adsorbents can be summed up into two kinds: one is the coordination reaction between the metal on the adsorbent and the phosphate ion to form the precipitate; the other is the protonation of the hydroxyl group on the adsorbent under the acid condition, which makes the hydroxyl group positively charged, and the protonated hydroxyl group can remove the phosphorus through the electrostatic attraction. Through the comparative analysis of the adsorption characteristics of different types of adsorbents, it was proposed that the application of polymer technology in the preparation of adsorbents and the development of modified adsorbents with strong desorption capacity will become a new hotspot in the research of phosphorus removal adsorbents.

Key words: adsorbent, modification, phosphorus removal, adsorption mechanism, adsorptive capacity, desorption

摘要：

去除废水中过量的磷可以减缓水体富营养化。吸附除磷因具有能耗低、容量大、污染少等优点而备受关注，改性吸附剂则可在此基础上提高除磷的靶向性，拓宽操作条件，增大吸附容量。本文分析了改性硅酸盐类、改性金属氧化物类、改性固体废弃物类和聚合物类4类除磷吸附剂的改性方法和吸附性能。硅酸盐类吸附材料以及固体废弃物类材料除磷效果略差，但因来源丰富、价格低廉而具有极大的吸引力。聚合物类吸附剂具有高吸附容量、高选择性，但价格昂贵。金属（氢）氧化物具有出色的磷酸盐吸附性能，且选择性好、吸附速度快，这些化合物已被掺入到沸石、介孔二氧化硅和生物炭等材料中，进一步增强其吸附性能，并在工程材料应用中取得重大突破，主要包括磁性吸附剂和颗粒吸附剂。4类吸附剂的作用机理可归纳为两种：一种是吸附剂上的金属与磷酸盐离子发生配位反应，形成沉淀；另一种是酸性条件下吸附剂上的羟基质子化，使羟基带正电，质子化的羟基通过静电吸引使磷得以去除。通过对不同类别吸附剂的吸附特性进行对比分析，提出将高分子技术运用到吸附剂制备过程中，开发同时具有较强解吸能力的改性吸附剂将成为除磷吸附剂研究的新热点。

关键词: 吸附剂, 改性, 除磷, 吸附机理, 吸附容量, 解吸