摘要
以活性炭为载体,采用溶胶凝胶法制备负载型的催化剂(TiO_2/GAC),进行了有无紫外光降解和有无活性炭条件下的微囊藻毒素-LR(MCLR)降解试验。结果显示,在紫外光照射下,MCLR不会自身降解,且紫外光照对活性炭吸附性能无明显影响。此外,通过负载型催化剂对不同初始质量浓度的MCLH溶液的吸附和光催化降解试验,进行了Lagergren准二级模型和颗粒内部扩散模型拟合催化剂的吸附去除动力学研究,应用Langmuir-Hinshelwood和Freundlich-Hinshelwood模型拟合光催化降解过程。结果表明,Lagergren准二级模型和Langmuir-Hinshelwood模型均能较好地描述TiO_2/GAC对MCLR的吸附、光降解过程,Langmuir-Hinshelwood模型中吸附平衡常数K_L值基本保持不变,约(0.057 0±0.000 8)L/μg,降解速率常数k值随着初始质量浓度的增加有所下降。
This paper aimed to study the kinetic on photocatalytic ox- idation of microcystin-LR with TiO2-coated activated carbon. As a matter of fact, the chemical properties of microcystin is stable, posed a serious threat to the safety of drinking water, while simple biological oxidation or adsorption can not be removed the MCs effectively. In this study, granular activated carbon was selected as the TiO2 sup- porter, the immobilized catalyst activated carbon supported Ti02 （TiO2/GAC） was prepared by the sol-gel method, then the MCLR degradation experiments were investigated under the different experi- mental conditions whether the existence of UV or not, and whether the existence of activated carbon or not. The results indicated that MCLR won＇t self-degradation under the UV irradiation and won＇t be degraded by UV without activated carbon. After adding activated charcoal, about 50% of MCLR was adsorbed in 30 minutes, the ad- sorption equilibrium time was about 90min, and it was no effect on the adsorption properties of activated carbon under UV irradiation. Furthermore, the experiments of adsorption and oxidation on the re- moval of microcystin-LR were studied with this catalyst, then the pro- cess of adsorptive were fitted by the quasi second-order of Lagergren model and the intemal particles diffusion model, and the process of photocatalytic degradation was fitted by Langmuir-Hinshelwood model and Freundlich-Hinshelwood model. The results showed that the ad- sorption and oxidation processes were explained by quasi second-order of Lagergren and Langmuir-Hinshelwood models respectively. The correlation coefficient of quasi second-order of Lagergren model fitting was about 0.99, which was higher than the internal particles diffusion model＇s, so the chemical adsorption is the main factor to control the adsorption rate. In the process of Langmuir-Hinshelwoed model fitting for the different initial concentrations of MCLR, the adsorption equi- hbrium constant （KL） kept invariant （（0.057 0 ± 0.000 8） L/μg ）, while degradation rate constant would gradually dwindle with the in- crease of the initial concentration of MCLR.
出处
《安全与环境学报》
CAS
CSCD
北大核心
2011年第5期32-36,共5页
Journal of Safety and Environment
基金
上海市技术标准专项项目(10DZ0503900)
上海市自然科学基金项目(09ZR1426700)
关键词
环境工程学
微囊藻毒素-LR
活性炭
二氧化钛光催化
动力学
environmental engineering
microcystin-LR
activatedcarbon
titanium dioxide photocatalysis
kinetic.
