悬浮态TiO_2光催化降解腐殖酸的影响因素研究

Study on effect elements of TiO_2 aqueous suspensions with photocatalysis and degradation of HA

在悬浮态TiO2光催化体系中,探讨了光催化氧化降解腐殖酸的规律,考察了催化剂投加量、腐殖酸溶液初始浓度、初始pH值、光强、反应时间等因素对腐殖酸去除效果的影响。结果表明,光催化氧化法降解腐殖酸的效率比直接光解法有显著提高,腐殖酸的去除率从34.73%增加到65.61%(反应时间为3 h);TOC的去除率也大幅度提高,直接光解反应对TOC几乎无去除作用,而光催化氧化对TOC的去除率达37.5%;腐殖酸的初始浓度增加,初始pH值降低,光强增大,光照时间延长均能提高腐殖酸的降解率,其中pH值和光强的影响较为显著。另外,催化剂的投加量存在一个最佳值。

The rules of photocatalytic oxidation of HA were discussed in the photocatalytic system of TiO2 aqueous suspensions. The effects of the amount of catalyst, initial HA concentration,initial pH value of HA aqueous solution, the intensity of UV light and the reaction time on photocatalytic oxidation efficiencies were investigated. Experimental results showed that the system of photocatalytic oxidation had a higher removal rate of HA than the method of direct photolysis. The removal rate of HA was improved from 34.73% to 65.61% in three hours,and removal rate of TOC was also improved greatly. Direct photolysis had hardly any removal effect on TOC,but the photocatalytic oxidation had a removal efficiency of 37.5%. The increase of initial HA concentration ,the decrease of initial pH value of HA aqueous solution ,the strength of intensity of UV light and extension of irradiation time could all improve the degradation efficiency of HA, and the effects of pH value and the intensity of UV light were more obvious. In addition, there existed an optimum dose of catalyst.