研究目的
To develop and evaluate the UV/Sulfite/ZnO (USZ) process as a novel Advanced Oxidation/Reduction Process (AORP) for the degradation, dechlorination, and mineralization of 2,4,6-trichlorophenol (TCP) in wastewater, including investigating its efficiency, optimization, mechanisms, and effects of various factors.
研究成果
The USZ process is highly effective for TCP degradation, with efficiencies significantly higher than UV-only, UV/ZnO, and UV/sulfite processes. It achieves complete degradation within 15 min for lower concentrations, with optimal conditions at pH 7-11 and sulfite/ZnO/TCP molar ratio of 1:2:50. The process involves simultaneous generation of oxidative and reductive radicals, leading to dechlorination and partial mineralization. However, full mineralization requires longer times or coupling with secondary processes. The USZ process is energy-efficient compared to other methods and shows promise for treating halogenated organic compounds in wastewater.
研究不足
The process may have limitations in complete mineralization of TCP, as only 33.2% mineralization was achieved after 15 min. The presence of co-existing anions reduces degradation efficiency, and the short lifetime and penetration depth of reactive species may limit effectiveness in larger-scale applications. Optimization is needed for higher concentrations and longer reaction times.
1：Experimental Design and Method Selection:
The study used a lab-scale photoreactor in continuous-flow modes to evaluate the USZ process, employing UV radiation at 253.7 nm to activate sulfite and ZnO for generating oxidative and reductive radicals. Theoretical models included pseudo-first-order kinetics for degradation analysis.
2：7 nm to activate sulfite and ZnO for generating oxidative and reductive radicals. Theoretical models included pseudo-first-order kinetics for degradation analysis.
Sample Selection and Data Sources:
2. Sample Selection and Data Sources: TCP solutions with concentrations from 10 to 250 mg L-1 were prepared, with specific molar ratios of sulfite/ZnO/TCP. Data on degradation, dechlorination, and mineralization were collected through analytical methods.
3：List of Experimental Equipment and Materials:
Equipment included a tubular glass photoreactor (150 mL capacity), quartz sleeve, 11 W low-pressure mercury lamp (254 nm), UVC 512 light meter, peristaltic pump (Heidolph Co.), vacuum pump, high-performance liquid chromatograph (Phenomenex UK with Eclipse plus C18 column), UV-VIS detector, ion-chromatography for chloride measurement, and LC-MS for metabolite analysis. Materials included TCP, sodium sulfite, zinc oxide (ZnO), HCl, NaOH, methanol, 2-propanol, bicarbonate, chloride, carbon disulfide, carbon tetrachloride, nitrite, nitrate, and various anions for scavenger tests.
4：Experimental Procedures and Operational Workflow:
TCP solutions were injected into the photoreactor, pH was adjusted using HCl or NaOH, and oxygen was removed by vacuum and nitrogen purging. Reactions were conducted at different times (1-15 min), pH levels (3-11), and molar ratios. Samples were withdrawn, filtered, and analyzed for TCP concentration, COD, chloride ions, and metabolites using HPLC, ion-chromatography, and LC-MS.
5：Data Analysis Methods:
Data were analyzed using pseudo-first-order kinetic models to determine rate constants (kobs) and degradation rates (robs). Electrical energy consumption (EEO) was calculated using kinetic and figure-of-merit models. Statistical analysis included R2 values for model fitness.
独家科研数据包，助您复现前沿成果，加速创新突破
获取完整内容
