二氧化钛/多壁碳纳米管的制备及其对乐果光催化降解的影响

采用溶胶-凝胶法制备了二氧化钛/多壁碳纳米管(TiO2/MWCNTs)复合材料,其m(TiO2)∶m(MWCNTs)=3∶4、表面平均孔径为5.724 nm。选用该复合材料对乐果进行光催化降解试验,探讨不同光源及光照时间、乐果初始浓度、复合材料添加量、温度等对其光催化降解能力的影响。结果表明:乐果在25℃、紫外光照30 min、初始质量浓度为5 mg/L和TiO2/MWCNTs复合材料添加量为0.25 g/L条件下的降解率为80.7%,TiO2/MWCNTs复合材料的最大吸附量为16.15 mg/g;在其他条件相同,仅将紫外光改为自然光条件下,乐果的催化降解率为79.2%,与紫外光下的催化降解率相差不大;而同等条件下,Ti O2对乐果在紫外光下的催化降解率比TiO2/MWCNTs低33.1%。因此,可以用自然光代替紫外光用于吸附试验,自然条件下采取该工艺可有效降解环境中乐果污染。

Preparation of TiO2/MWCNTs and evaluation of its influence on the photocatalytic degradation of dimethoate

Titanium dioxide/multi-walled carbon nanotubes(TiO2/MWCNTs ) was prepared by sol-gel method, with the quality ratio of 3:4 and the surface average pore size of 5.724 nm. This composite materials were then applied in the photocatalytic degradation of dimethoate. A series of affecting factors were studied, including the difference of light sources, the illumination time, the initial concentration of dimethoate, the adding quantity of composite materials, the solution temperature, etc. The results showed that the degradation rate of dimethoate was 80.7% under the conditions of the solution temperature at 25 ℃, the illumination time of ultraviolet light for 30 min, the initial mass concentration of 5 mg/L, the composite additive amount of 0.25 g/L and ultraviolet light and the maximum adsorption capacity of TiO2/MWCNTs is 16.15 mg/g. Under the same conditions, but using natural light instead of ultraviolet light, the catalytic degradation rate was 79.2%, which had little difference compared with the rate using ultraviolet light. However, under the same conditions, the catalytic degradation of dimethoate using TiO2 under ultraviolet light is lower than TiO2/MWCNTs by 33.1%. Therefore, natural light can be used in the adsorption experiments instead of ultraviolet light, and employing this technology under natural conditions can effectively degrade the environment pollution of dimethoate.