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摘 要:Fenton类氧化技术处理有机废水是新兴的高级氧化技术,但Fe3+还原成Fe2+的反应速率较低,限制了Fenton反应的应用,改良的Fenton反应却只能应用紫外光,而太阳光谱中紫外光(λ<400 nm)不到5%,大部分为波长为400~700 nm的可见光,可利用可见光降解染料废水。为了更有效地利用可见光,并降解无色的难降解污染物,研究并开发可见光-类Fenton体系的技术势在必行。本研究针对传统Fenton体系的缺陷,以TaCl5为前驱体,通过溶胶凝胶法和氮化反应制备氮(氧)化钽,并应用于可见光-类Fenton反应。对不同条件下制备的氮(氧)化钽进行Fe3+还原实验及模拟阿特拉津废水降解,结果表明:制备的氮(氧)化钽在可见光照射下,能够有效地还原Fe3+为Fe2+;在本论文制备条件下,阿特拉津降解效果与氮(氧)化钽制备条件----氮化时间、氮化温度、氨气流量因素有关。氨气流量0.3 L•min-1、700℃氮化时间6 h制备出的氮(氧)化钽在可见光下还原Fe3+的能力最佳,阿特拉津降解效果最好。 关键词:可见光;类Fenton;氮(氧)化钽;Fe3+还原;阿特拉津
Abstract:Fenton oxidation technics that treat wiith organic waste water is a rising advanced oxidation technic. In general fenton reactions, the speed of reducing Fe3+ to Fe2+ is slow, which limits the Fenton recation. For speeding up iron cycling, a method can be used in ultraviolet radiation(λ<400 nm)called UV-Fenton wss improved that however, natural UV ccupies onlyless than 5% of solar spectrum and large quantities of electrical power is visible light(400<λ<700 nm). In Fenton system, it was also found that visible light irradiation can only accelerate greatly discoloration and mineralization of dyes wastewater,.To make better use of the visible light and degrade colorless organic pollutants, the study of photo-fenton –like system is imperative under the situation. Concidering the problem of the system of Fenton ,a new kind of photocatalyst tantalum (oxy)nitrides this study was introduced into Fenton-like system under visible light . tantalum (oxy)nitrides was synthesized with TaCl5 by gas-solid reaction under high temperature. I do experiments of Fe3+ deoxidiation and simulate the atrazine waste water in different conditions.The result indicates that Fe3+ can be deoxidized effectually in the irradiation of tantalum (oxy)nitrides. In this study, the effect of atrazine degradation and the preparation of tantalum (oxy)nitrides are related to nitridation time ,the nitridation temperature, and ammonia flow rate. The sample prepared at 700℃ under ammonia flow rate of 0.3 L•min-1、for six hours, showed the hightest level of photocatalytic activity for Fe3+ reduction and atrazine degradation. Key words:visible light; Fenton-like system; tantalum (oxy)nitrides; Fe3+reduction; atrazine |