TiO_2/改性硅藻土对LAS废水COD_(Cr)的降解性能

Degradation performance of COD_(Cr) in LAS wastewater by TiO_2/modified diatomite

采用Sol-gel法制备了纳米TiO_2/改性硅藻土复合材料,并用于处理直链烷基苯磺酸钠(LAS)废水,以COD_(Cr)为评价指标,考察了催化剂的投加量、水温、催化时间、废水初始pH值和初始浓度等因素对降解性能的影响,分析了催化降解的动力学。结果表明,初始COD_(Cr)为425.9mg/L的LAS废水,当调节废水pH=5.0,催化剂投加量为4.0g/L时,10W紫外光催化反应6h废水中COD_(Cr)降解率达到84.46%;水温升高不利于降解率的提高,废水初始浓度的降低或稀释后COD_(Cr)降解率明显提高,在酸性条件下催化效果要优于中性和碱性;添加1mL 30%H_2O_2,COD_(Cr)降解率可提高10%~15%;LAS废水降解COD_(Cr)的反应符合Langmuir-Hinshelwood动力学模型。

Nano TiO2/modified diatomite composite photocatalyst was prepared by sol-gel method, with CODer as the evaluation index,LAS wastewater was treated by photocatalysis. The effects of dosage, temperature, reaction time, ini- tial pH value of wastewater and the initial concentration of catalyst etc. on the degradation performance of photocatalyst were investigated,and the kinetics of catalytic degradation was analyzed. The results showed that the initial CODcr was 425.9mg/L of LAS wastewater, and pH= 5.0, the catalyst dosage was 4.0g/L, under the 10W UV light conditon, the degradation rate of CODcr was 84.6% when reaction time was 6h. The water temperature was not conducive to increase the degradation rate, CODer degradation rate increased significantly with initial wastewater concentration reduced or diluted, the catalytic effect under acidic condition was better than neutral and alkaline. With addingl mL 30 G H2O2 ,CODer degradation rate can be increased 10%-15%. CODcr photocatalytic degradation of LAS wastewater was consistent with the kinetic model of Langmuir- Hinshelwood.