玻璃弹簧负载TiO_2光催化降解甲醛的影响因素

Factors Influencing Formaldehyde Photocatalytic Degradation by Titanium Dioxide Deposited on Glass Springs

利用自制间歇式光催化气体反应器体系作为反应场所,以玻璃弹簧负载TiO2溶胶作催化剂,在紫外光照射下降解室内污染气体甲醛,探讨了催化剂的酸度、反应器内湿度、甲醛气体浓度和反应时间等因素对甲醛降解率的影响.结果表明:玻璃弹簧负载TiO2并经pH=5的蒸馏水酸浸后作催化剂对甲醛的降解效果最好,90 min内降解率达到57.26%;反应器内的湿度约为50%时甲醛降解率最高,反应90 min时达到82.20%;在0.46～8.10 mg/m3内,初始ρ(甲醛)为5.51 mg/m3时的降解率最高,150 min内达95.10%;延长反应时间,甲醛降解率上升幅度逐渐减小;通过计算降解后甲醛的残余量可知,TiO2光催化方法可以有效降解甲醛,并能使0.46 mg/m3以内的ρ(甲醛)在150 min内达到国家标准.

This paper studied a newly manufactured intermittent photocatalytic gas reactor system by which the photocatalytic degradation of formaldehyde gas occurs by TiO2 deposited on glass springs. The main controlling factors which affect the degradation rate of formaldehyde, such as the acidity of catalyst, the humidity in the reactor, the mass concentration of formaldehyde and the reactive time were discussed. The results showed that the degradation rate of formaldehyde could reach 57.26 % in 90 minutes when the glass springs depositing TiO2 were soaked in distilled water with pH = 5. The formaldehyde gas could reach the maximum degradation rate of 82.20 % in 90 minutes when the humidity in the reactor was about 50%. When initial formaldehyde mass concentration was in the range of 0.46-8.10 mg/m^3 ,5.51 mg/m^3 is the best mass concentration for formaldehyde degradation, with a degradation rate reaching 95.10% in 150 minutes. The rate of formaldehyde degradation gradually declined with the extending of reaction time. Through calculating the formaldehyde residue, it was determined that photocatalytic degradation of formaldehyde by TiO2 was effective and the concentration of formaldehyde could achieve the national standard in 150 minutes when its initial mass concentration was within 0.46 mg/m^3 .