Fenton技术中残余组分对COD测定的干扰和消除研究

Interference and Elimination of Residual Components on the Standard COD Test in Fenton Technology

Fenton试剂与水样中难降解有机物反应后,残余组分会对后续水样COD测定产生干扰。实验表明,Fenton试剂残余组分中H_2O_2对COD测定产生的干扰较大,其对水样COD测定产生的影响值与H_2O_2浓度成良好的线性关系,而残余组分Fe^(2+)对COD测定产生的干扰与H_2O_2相比,影响值较小,可忽略其影响。通过对比分析掩蔽剂法、催化分解法对H_2O_2干扰消除试验得出,掩蔽剂Na_2SO_3能够迅速的与H_2O_2发生反应,消除H_2O_2的干扰,但掩蔽剂Na_2SO_3也会对水样COD产生一定的干扰,测量结果偏差较大;MnO_2催化分解H_2O_2的效率较高,很好的消除H_2O_2的干扰,但MnO_2分解后水样COD测定值需乘以折减系数0.89,满足试验精度的要求;过氧化氢酶可以将H_2O_2完全分解,分解效率较高,干扰消除效果较好。

After the reaction between Fenton reagent and refractory organic reaction in water samples, the residual components will interfere with the COD test of subsequent water samples. Experimental results show that H2O2 in the residual fraction of Fenton reagent is the maximum interference factor, the impact value of which on standard COD test is a linear relationship with the concentration of H2O2; the impact of Fe^2＋ in the residual fraction on standard COD test is less than that of H2O2, and it can be neglected. The masking agent method and catalytic decomposition method for H2O2 interference elimination were comparatively analyzed. The results show that masking agent Na2SO3 can quickly react with H2O2 and eliminate the interference of H2O2, but the masking agent Na2SO3 will also bring certain interference to the standard COD test in water samples, which will cause larger test result; MnO2 is high efficient for catalyzing and decomposing H/O2,so it has good effect on eliminating the influence of H2O2, but after decomposition of the water by MnO2, COD test values should be multiplied by the discount factor of 0.89 to meet the accuracy requirements; Catalase can decompose H2O2 completely, the decomposition efficiency is very high, and the interference elimination effect is better.