以硝酸银、磷酸钠为原料,一步沉淀法制备了Ag_3PO_4可见光光催化剂,用硅溶胶将其负载于不锈钢丝网上,经干燥得到光催化电极。以此光催化电极和碳棒分别作为阴极、阳极,在阳极室加入负载生物产电菌的活性炭颗粒,建立光催化耦合微生物燃料电池反应器。以罗丹明B(RhB)为模型污染物,考察了光照、底物浓度、pH值等对污染物去除效率与电池产电性能的影响。结果显示:在100 W卤素灯光照下、外接500Ω电阻、pH=10、微生物量1.5倍,反应4 h可去除92%的(50 mg·L-1、200 m L)RhB;此时电池输出电压和功率密度分别为124 m V、34.9 mW·m-2。5次重复实验表明该负载型光催化电极具有很好的稳定性。
利用水热合成方法制备单斜晶型光催化剂Bi VO_4,首次将Bi VO_4引入MFC中,构建全新的PEC-MFC,EC-MFC耦合体系,并研究其对氨氮与染料废水的降解效果及能量消耗。PEC-MFC与EC-MFC耦合体系2 h内均能对Rh B达到95%以上的降解率;在中性偏酸条件下,可提高耦合体系对NH_4^+-N的降解效果,且O_2是耦合体系的主要决定因素;PEC-MFC和EC-MFC的单位电能消耗量为0.895和0 k Wh·m^(-3),在最优条件下,PEC-MFC最大输出电压为0.476 V,最大输出功率为755.25 m W·m^(-2)。研究了叔丁醇、KI对耦合体系的影响以探究耦合体系的主要氧化物种,阐述了光催化-微生物燃料电池的耦合机理。
An anodic TiO2/g-C3N4 hetero-junction and cathodic WO3/W were used to build a self-sustained catalytic fuel cell system for oxidizing rhodamine B or triclosan and reducing NO3^--N to N2 simultaneously.The WO3 nano-catalyst was formed in situ by heating and oxidizing a tungsten wire in air.Cyclic voltammetry and current-time curves were used to characterize the electrochemical properties of the electrodes and system.Aeration and activation of molecular oxygen by self-biased TiO2/g-C3N4 led to the formation of reactive oxidizing species in the fuel cell.The mechanism of simultaneous anodic oxidation of pollutants and cathodic reduction of nitrate was proposed.The spontaneously formed circuit and tiny current were used simultaneously in treating two kinds of wastewater in the reactor chambers,even without light illumination or an external applied voltage.This new catalytic pollution control route can lower energy consumption and degrade many other kinds of pollutants.
