摘要
通过在g-C_(3)N_(4)/生物炭(BC)材料表面还原沉积纳米零价铁(nZVI)制备了g-C_(3)N_(4)/BC/nZVI复合催化剂.利用SEM、TEM、XPS、XRD、UV-Vis DRS、光电流等对所制备的催化剂进行了物化性质和光电性能的表征,考察了g-C_(3)N_(4)/BC/nZVI在可见光照下对水中硝酸盐(NO_(3)^(-))的还原性能.结果表明,中性水体的最佳反应条件为g-C_(3)N_(4)/BC与nZVI的质量比为1:0.6,g-C_(3)N_(4)/BC/nZVI的投加量为2g/L,NO_(3)^(-)的初始浓度为20mg/L.与nZVI,BC/nZVI,g-C_(3)N_(4)/nZVI相比,g-C_(3)N_(4)/BC/nZVI表现出最快的NO_(3)^(-)还原速率(k=10.6×10^(-2)min^(-1))以及较高的脱氮性能(71.6%).实验进一步考察了g-C_(3)N_(4)/BC/nZVI还原NO_(3)^(-)过程中氮的变化规律.推测还原机理为:可见光照下,光生电子通过BC转移到n ZVI表面,提高了nZVI的反应活性和稳定性,同时,BC材料抑制光生空穴对nZVI的氧化作用;nZVI表面的活性电子将NO_(3)^(-)还原为N2和NH4+,而光生空穴则进一步将部分NH4+氧化为N2和其他气态产物.
A g-C_(3)N_(4)/biochar(BC)/nanoscale zero-valent iron(nZVI)composite catalyst with deposited nZVI on the surface of g-C_(3)N_(4)/BC material was prepared.The physical and chemical properties,as well as the photoelectric performance of the prepared catalyst,were characterized using SEM,TEM,XPS,XRD,UV-Vis DRS,photocurrent test,etc.The nitrate(NO_(3)^(-))reduction performance of g-C_(3)N_(4)/BC/nZVI under visible light irradiation was investigated.The results showed that the optimal reaction conditions in neutral water were a mass ratio of g-C_(3)N_(4)/BC to nZVI of 1:0.6,an addition amount of g-C_(3)N_(4)/BC/nZVI of 2g/L and the initial NO_(3)^(-)concentration of 20mg/L.Compared with nZVI,BC/nZVI and g-C_(3)N_(4)/nZVI,g-C_(3)N_(4)/BC/nZVI exhibited the fastest NO_(3)^(-)reduction rate(k=10.6×10^(-2)min^(-1))and higher denitrification efficiency(71.6%).The study further investigated the variation of nitrogen during the NO_(3)^(-)reduction by g-C_(3)N_(4)/BC/nZVI.The reduction mechanism is proposed that:Under visible light irradiation,photogenerated electrons transferred via BC to the surface of nZVI,which enhanced the reactivity and stability of nZVI,while BC material inhibited the oxidation of nZVI by photogenerated holes.The active electrons on the surface of nZVI reduced NO_(3)^(-)to N2 and NH4+,while the photogenerated holes further oxidized some NH4+to N2 and other gaseous products.
作者
李厚芬
魏谦
郭阳
刘鹏霄
李瑞
周爱娟
岳秀萍
LI Hou-fen;WEI Qian;GUO Yang;LIU Peng-xiao;LI Rui;ZHOU Ai-juan;YUE Xiu-ping(College of Environmental Science and Engineering,Taiyuan University of Technology,Jinzhong 030600,China;School of Environment and Safety Engineering,North University of China,Taiyuan 030024,China;Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering,Taiyuan 030024,China)
出处
《中国环境科学》
EI
CAS
CSCD
北大核心
2024年第3期1357-1365,共9页
China Environmental Science
基金
山西省应用基础研究计划项目(202303021211030)
山西浙大新材料与化工研究院研发项目(2022SXTD006)。
