Migration and Transformation of Phosphorus Forms in Field DitchSediments

摘要

A broad attention has been paid to the field ditches as the sewage interception channel for the agriculturalnonpoint source pollution, however, rare studies have involved in the phosphorus migration and transformation betweenthe ditch sediments and overlaying water, especially, from the ditch sediments to the water. The present paper aims toexplore with XPS binding energy data how pH, dissolved oxygen, sunlight affect the process of phosphorus migration andtransformation in ditch sediments to the water by methods of changing pH, aerating nitrogen and oxygen in water andchanging the sunlight; and hopes to provide a guidance on how to give full play to the ditch’s sewage interceptioncapacity and avoid ditch becoming pollution source reversely. The experimental results with XPS binding energy datashow that no electron transfer occurs insignificantly at different pH values in sediments, i.e. no electron transfer reactionoccurs on surface. This reveals that the phosphorus absorption form HPO42- in sediment substitutes OH- state on thesediment surface. The amount of phosphorus migration and transformation is the minimum under the neutral condition,and the maximum under the alkaline condition. Under aerobic atmosphere, the data of XPS binding energy shows thesurface charge of iron after oxygen aeration reduces, the surface charge of oxygen increases, i.e. Fe2+ is oxidized into Fe3+,the phosphorus is absorbed increasingly; the experimental results with XPS binding energy data disclose there existselectron transfer reaction significantly, that is the illumination affects the process of phosphorus migration andtransformation through dissolved oxygen (DO) and the pH impacted on the biological processes under the presence ofsunlight in sediments, indirectly. The influence of illumination on the sediment phosphorus migration and transformationis regular insignificantly. Conclusively, the amount of migration and transformation in sunlight-free group is greater thanthe sunlight group.