Fenton-UV照射法对超高浓度聚乙烯醇有机废液的降解效能

采用Fenton-紫外照射（Fenton-UV）联用工艺对核电厂超高浓度聚乙烯醇（PVA）有机废液进行处理，研究了PVA转化率、平均分子量、溶液黏度等随时间的变化规律。结果表明：对于50 g/L的PVA溶液，H₂O₂投加质量浓度为15 g/L，FeSO₄·7H₂O投加质量浓度为0.050 g/L，初始pH值为3，经过2 h Fenton反应和2 h UV照射（3 mW/cm²）之后，PVA转化率达到100%，溶液平均分子量从60 000~80 000 Da降低到1 000 Da以下，黏度降低到1.1 mPa·s，但总有机碳和化学需氧量（COD）变化不大。Fenton-UV法可作为预处理方法，前期Fenton阶段提高PVA的溶解度，增加反应溶液中的PVA含量，并进行初步降解和氧化；后期UV法进一步降解溶液中的PVA，有效降低其分子量和黏度，为后续处理提供有利条件，最终形成经济可行的超高浓度PVA有机废液处理工艺。

Degradation Efficiency of Ultra-High-Concentration Polyvinyl Alcohol Organic Waste Liquid by Fenton-UV Irradiation

Fenton-ultraviolet irradiation(Fenton-UV) combined process was used to treat ultra-high-concentration polyvinyl alcohol(PVA) organic waste liquid of nuclear power plants, and the changes of PVA conversion rate, average molecular weight, solution viscosity, etc. over time were studied. The results show: for 50 g/L PVA solution, the concentration of H2O2 is 15 g/L, the concentration of FeSO₄·7H₂O is 0.050 g/L, the initial pH is 3, after 2 h Fenton reaction followed by 2 h UV irradiation(3 mW/cm2), the removal efficiency of PVA reaches 100%, and the average molecular weight in solution decreases from 60 000~80 000 Da to <1 000 Da. The viscosity decreases to 1.1 mPa·s, while only slight variations are observed for total organic carbon and COD. Fenton-UV method can be used as a pre-treatment. In the former Fenton stage, the solubility increases, and the concentration of PVA in solution can reach a very high level. A preliminary degradation and oxidation are also conducted in this stage. During the later UV stage, PVA can be further degraded, and the molecular weight and viscosity are significantly decreased. Fenton-UV treatment will be benefit to the further treatment, and it can be a cost-effective treatment method for ultra-high concentration PVA solution.