NH_3-H_2O_2气雾对氰化氢气体的消毒

Decontamination of HCN gas by NH_3-H_2O_2 vapor

采用NH_3-H_2O_2气雾对1 m3密闭试验舱内氰化氢气体进行消毒,采用单因素试验研究H_2O_2和NH_3质量浓度对消毒率和消毒反应速率的影响规律。结果表明,NH_3-H_2O_2气雾对HCN的消毒符合一级反应动力学特征,NH_3质量浓度对消毒反应速率有一定影响,但当NH_3质量浓度增加至20 mg/m3以上时,对反应速率几乎没有影响; H_2O_2质量浓度对消毒反应速率有显著影响,反应速率随H_2O_2质量浓度的提高明显增大。NH_3-H_2O_2气雾消毒剂的最佳配方为H_2O_2的质量浓度为120 mg/m3、NH_3的质量浓度为20 mg/m3,在此条件下对HCN进行消毒,在28 min时HCN的残余质量浓度为0. 92 mg/m3,可以达到GBZ 2. 1—2007《工作场所有害因素职业接触限值第1部分:化学有害因素》中有关HCN最高容许质量浓度MAC值(1 mg/m3)的规定。分析消毒机理为H_2O_2首先将HCN氧化为氰酸(HCNO),氰酸不稳定,在NH_3和水的作用下可以水解成碳酸铵,也可以进一步被氧化形成CO2和N2。

The paper is inclined to use NH3-H2O2 vapor to decontaminate HCN gas in an airtight testing chamber with a capacity of 1 m^3.For this purpose,we have made efforts to generate HCN gas by adding sulfuric acid to KCN powder in the chamber and make the mass concentration of HCN stabilized within 35 min.As a matter of fact,NH3-H2O2 vapor can be efficiently used to decontaminate such chemical warfare agents,such as sarin,sulfur mustard,soman and VX,in the enclosed space.NH3 is introduced into the chamber by a standard cylinder gas.At the same time,H2O2 vapor generator can also be switched on to start up the decontamination process.What is more,a HCN gas sensor can still be adopted to monitor the mass concentration online.Besides,it is also necessary to investigate the impacts of the mass concentrations of H2O2 and NH3 on the decontamination efficiency and the reaction kinetics.Thus,as a result,the decontamination reaction of HCN with NH3-H2O2 vapor can be found following the first order reaction,whereas the mass concentration of NH3 may also have some extent of effects on the decontamination reaction rate.However,the reaction rate constant tends to keep almost unchanged when the mass concentration of NH3 increases to over 20 mg/m^3.Or rather,the mass concentration of H2O2 can have a considerable positive effect on the reaction rate.And,in correspondence with the experimental results,an optimal formulation of NH3-H2O2 vapor can be screened out,so as to make the massc oncentrations of H2O2 and NH3 equal to 120 mg/m^3 and 20 mg/m^3,respectively.And,if possible,in the optimalized condition,the residual mass concentration of HCN would like to get reduced to 0.92 mg/m^3 just for 28 min,which can meet the maximum allowable concentration(MAC)rate of 1 mg/m^3,as prescribed in the“Occupational exposure limits for the hazardous agents in the workplace Part 1:chemical hazardous agents”(GBZ 2.1-2007)in China national standard of the occupational health.Based on the products detection and literature reports,the decontamination mechanism has been stated as follows:HCN is oxidized by H2O2 to HCNO firstly.But HCNO is so instable that it can be hydrolyzed to ammonium carbonate with the participation of NH3 and H2O,either or further oxidized to CO2 and N2.