水生植物生物质炭去除水体中氮磷性能

在富营养化水体的生物修复中,将产生大量的水生植物,如何进行合理的处置是需要解决的问题.本文采用水生植物制得生物质炭,并通过镁改性,提高了生物质炭对水体中氮磷的吸附性能.材料性质表征结果表明,镁改性不仅在生物质炭表面形成纳米MgO片层,增加比表面积,而且引入了羟基官能团促进对铵态氮的吸附.改性生物质炭对硝态氮和铵态氮的吸附过程均属于多层吸附,吸附等温线符合Freundlich模型.改性后生物质炭对磷的吸附机制由单层吸附变为多层扩散.改性生物质炭对硝态氮、铵态氮和磷的最大吸附量分别为5. 66、62. 53和90. 92 mg·g~(-1),其中对铵态氮的吸附量是未改性生物质炭的178倍.在磷、硝态氮和铵态氮共存时,改性生物质炭对其吸附量分别增加79. 1%、67. 5%和47. 1%.本文结果表明通过生物质炭制备可以实现水生植物资源化,并可回用于水体氮磷污染的修复,具有很好的应用前景.

Removal of Nitrogen and Phosphorus from Water by Biomass Carbon of Aquatic Plants

In the bioremediation of eutrophic water, a large number of aquatic plants will be produced. How to continue the reasonable disposition is the question that needs to be solved. In this paper, biomass carbon was prepared from aquatic plants, and the adsorption capacity of the biomass carbon on nitrogen and phosphorus in water was improved by magnesium modification. The characterization results of material properties showed that magnesium modification not only formed nanometer MgO sheets on the surface of biomass carbon to increase the specific surface area, but also introduced hydroxyl functional groups to promote the adsorption of ammonium nitrogen. The adsorption processes of modified biomass carbon on nitrates and ammonium nitrogen belonged to multi-layer adsorption, and the adsorption isotherms conformed to the Freundlich model. The adsorption mechanism of modified biomass carbon changed from single layer adsorption to multi-layer diffusion. The maximum adsorption capacity of the modified biomass carbon on nitrate nitrogen, ammonium nitrogen, and phosphorus were 5.66, 62.53, and 90.92 mg·g^-1, respectively. The adsorption capacity of the modified biomass carbon on ammonium nitrogen is 178 times that of unmodified biomass carbon. When phosphorus, nitrate nitrogen, and ammonium nitrogen coexist, the adsorption amounts of modified biomass carbon increase by 79.1%, 67.5%, and 47.1%, respectively. The results of this paper showed that the preparation of biomass carbon can realize the resource recovery of aquatic plants, and can be used for the removal of nitrogen and phosphorus pollution from water, which has good prospects for application.