天然有机质-金属离子/氧化物-磷复合物的研究进展

Natural Organic Matter-Metal Ion/Oxide-Phosphorus Complexes in Environment: A Review

天然有机质-金属离子/氧化物-磷(NOM-Metal-P)复合物作为一种广泛存在于天然水体和土壤环境中的磷素形态,其环境行为对磷素在环境中迁移转化过程发挥着重要作用。鉴于此,在综述NOM-Metal-P复合物的结合方式、测定方法、分子质量大小、生物有效性和稳定性影响因素等相关研究进展的基础上,对NOM-Metal-P复合物研究做出展望。已有研究表明,NOM-Metal-P复合物形态磷可占土壤溶液或天然水体中磷总量的50%,有时甚至达80%;NOM-Metal-P复合物的结合方式主要为NOM和P以Metal作为键桥结合形成;目前多采用截留分子质量为500或1000Da的滤膜来分离游离磷酸盐和复合物形态磷;复合物形态磷能抑制磷的固定,增强磷在环境中的迁移能力,其作为磷肥的生物利用效率大于单一磷酸盐磷肥;复合物形态磷的稳定性受紫外光照、pH和共存离子等因素的影响。

Natural organic matter (NOM)-metal ion/oxide (Metal)-phosphorus (P) complexes as major P species widely exist in the aquatic and terrestrial environment. The behaviors of these complexes play an important role in the migration and transformation of P in the environment. The research progress of structure characteristics, determination methods, molecular weight identification, bioavailability and the influencing factors for the stability of NOM-Metal-P complexes at home and abroad are reviewed.The expectation to research on NOM-Metal-P complexes in the future are described. Previous studies indicate that NOM-Metal-P complexes account for more than 50%, whereas in some cases, more than 80% of P in natural water or soil solution. The metal ion/oxide could act as metal bridge which binds P to the surface of NOM. Currently, the high molecular mass fractions of NOM-Metal-P complexes were usually separated from free orthophosphate by 500 or 1 000 Da filters through ultrafiltration. In addition, it is found that NOM-Metal-P complexes can increase P migration in soil and it is also found that the bioavailability of P fertilizer containing NOM-Metal-P complexes is higher than those only containing single phosphate. Meanwhile, researchers also determined that the stability of NOM-Metal-P complexes were affected by ultraviolet light, pH and coexisting ions in both water and soils.