采用水热法分别在酸性和碱性条件下合成了α-MnO₂和δ-MnO₂催化剂，利用XRD、N₂-BET、Raman、H₂-TPR对合成样品进行表征。将合成的α-MnO₂和δ-MnO₂催化剂用于催化废水中尿素水解，在不同水解温度、水解时间和催化剂质量浓度下比较了2种催化剂的催化活性。结果表明，δ-MnO₂催化剂具有较高的催化活性。以δ-MnO₂为催化剂，得到了尿素水解的最佳工艺条件：水解温度为165℃，水解时间为60 min，催化剂质量浓度为50 g/L。在最佳水解工艺条件下，尿素的降解率可达99.9%以上，此时水解液中剩余尿素的质量浓度仅为7.2 mg/L，达到了10 mg/L以下的排放标准。

The α-MnO₂ and δ-MnO₂ catalysts are synthesized under acidic and alkaline conditions respectively by hydrothermal method.The synthesized samples are characterized by XRD,N₂-BET,Raman and H₂-TPR.These two catalysts are respectively used for catalytic hydrolysis of urea in wastewater.The catalytic activities of α-MnO₂ and δ-MnO₂ catalysts are compared under different hydrolysis temperatures,hydrolysis time and catalyst dosage,respectively.The results illustrate that the catalytic activity of δ-MnO₂ catalyst is higher than that of α-MnO₂ catalyst.With δ-MnO₂ as catalyst,the optimum process conditions for hydrolysis of urea are obtained that the temperature is 165℃,hydrolysis time is 60 min and catalyst dosage is 50 g·L^-1.At the optimum conditions,the degradation rate of urea can exceed 99.9%,and the remaining urea concentration in the hydrolysis solution is 7.2 mg·L^-1,which meets the 10 mg·L^-1 emission standard.

孙玉娟(1990-),女,硕士研究生,研究方向为环境化工,sunyj1990@sina.com