超(近)临界水氧化法降解炸药废水的工艺优化与动力学研究

炸药工业排放废水中含TNT、RDX、HMX等多种剧毒物质,一般难以生物降解甚至不可生物降解,处理非常困难.并且炸药废水的COD很大,对水体污染严重.文中采用超(近)临界水氧化技术,对TNT, RDX和HMX模拟炸药废水进行正交实验及反应动力学研究,在降解TNT, RDX和HMX同时降低废水的COD值.得到最佳氧化降解工艺条件为:反应温度648 K,反应时间5 min,模拟炸药废水:氧化剂(H_2O_2) (体积比)= 10:1,处理后废水的COD=38 mg·L~(-1),COD降解率为98.65%.动力学研究结果表明,在573 K、603 K、623 K、653 K时的表观速度常数k分别为:0.01030、0.02069、0.03709和0.04699.TNT、RDX、HMX氧化反应的活化能、指前因子和平均反应级数分别为:61.31 kJ·mol~(-1),4251,1.56.

The Technology Optimization and Reaction Dynamics of Simulated Explosive Industrial Wastewater Degradation by Super(Sub)critical Water Oxidation Method

Wastewater of explosive industry contains TNT, RDX, HMX and other toxic substances which are difficult to be degraded by biodegradation or by other traditional wastewater treating methods. The COD value of the explosive industrial wastewater is commonly as high as several thousand mg·L~(-1) and is very difficult to be decreased. In this paper, the super(sub)critical water oxidation technology was adopted to degrade the TNT, RDX, HMX in the simulated explosive industrial wastewater, and so as its COD value was decreased at the same time. Through orthogonal experiments, the technology optimization and reaction dynamics of TNT, RDX, HMX degradation in super(sub)critical water were studied, and the optimum degradation conditions were found as follows: reaction temperature T = 648 K, reaction time t = 5 min and the volume ratio of wastewater to H_2O_2=10:1. After degradation under above conditions, the COD degradation ratio of the degraded wastewater reaches 98.65% and the COD value in it can be reduced to 38 mg·L~(-1). The study results of the degradation dynamics show that the velocity constants for the reactions at 573 K, 603 K, 623 K and 653 K are 0.01030, 0.02069, 0.03709 and 0.04699, respectively;and for the oxidizing degradation reaction studied, the active energy, pre-exponential factor and average reaction kinetics order are 61.31 kJ·mol~(-1), 4251, 1.56, respectively.