镧铁羟基氧化物修饰还原氧化石墨烯复合电极材料电吸附除磷效能及机理研究

污水处理厂尾水中低浓度PO43-的排放是水体中总磷的主要来源,是导致水体富营养化的重要原因之一,对其开展深度去除的应用基础性研究具有重要的理论意义和实践价值.复合金属氧化物材料表现出较好PO43-吸附能力,但仍然存在吸附速率较慢的问题.本研究采用溶剂热、复合薄膜压片法制备了镧铁羟基氧化物(LaFeOxHy)修饰还原氧化...

Efficiency and mechanism for electro-sorption of phosphate by LaFe (oxy)hydroxide-decorated reduced graphene oxide

The discharge of low concentration PO₄^3- in effluent from WWTP is the main source of total phosphorus in water and one of the important causes of eutrophication. It has great theoretical and practical significance for the research on deep PO₄^3- removal. Metal oxide composites exhibit excellent PO₄^3- adsorption capacity, but poor adsorption kinetics. In this work, a LaFe (oxy)hydroxide-decorated rGO (LaFe-rGO) was synthesized by solvothermal-film pressing method. The adsorption kinetics of PO₄^3- by the LaFe-rGO electrode was significantly improved. The equilibrium adsorption can be reached in 5 min and the maximum adsorption capacity of LaFe-rGO for phosphate was 108.69 mg·g^-1 (1.2 V). Mechanism study showed that the electro-promoted adsorption mechanism was due to active sites provided by lattice oxygen of LaFeO_xH_y and double-layer capacitance of LaFe-rGO:PO₄^3- was bonded with La/Fe through the formation inner-sphere surface complexation La/Fe-PO₄. Furthermore, the LaFeO_xH_y on rGO increases the capacitance of the electrode and improves its electrochemical activity, which promotes the PO^3- ₄ adsorption performance.