表面活性剂对萘和对氯硝基苯在湍流状态下挥发的影响

Effect of Surfactant on the Evaporation of p-Chloronitrobenzene and Naphthalene in the Turbulent Process

研究了不同湍流条件下,十二烷基硫酸钠(SDS)、十六烷基三甲基溴化铵(CTMAB)和聚氧乙烯失水山梨酸醇(Tween20)对萘和对氯硝基苯挥发的影响,为评价复合污染的水体中,表面活性剂对亨利系数(H)不同的有机物在湍流状态下挥发的影响提供理论依据.结果表明,在湍流状态下,萘和对氯硝基苯在表面活性剂溶液中的挥发符合一级动力学方程,拟合方程相关系数均大于0.99;表面活性剂的存在抑制有机物的挥发,扰动过程促进挥发,二者综合作用下以扰动的促进作用为主;如表面活性剂在150～2000mg/L的浓度范围,扰动速率分别>39r/min和>65r/min时,萘和对氯硝基苯的挥发速率Kv扰动均大于其在静态纯水中的挥发速率Kv静止.在相同的扰动条件下,表面活性剂对萘和对氯硝基苯抑制作用大小顺序为:CTMAB>Tween20>SDS.对于H大的化合物(萘),扰动过程的促进作用和表面活性剂的抑制作用,均大于H小的化合物(对氯硝基苯).

Effect of surfactant on the evaporation of p-chloronitrobenzene and naphthalene in the turbulent process was studied in order to understand the effect of surfactant on the evaporation of complex contaminants in dynamic water system.Sodium dodecyl sulfate （SDS）,cetyltrimethyl ammonium bromide （CTMAB） and polyethylene glycol sorbitan monolaurate （Tween 20） were used in the experiment.The results showed that the evaporation of p-chloronitrobenzene and naphthalene from surfactant solution in set turbulence intensity followed the first kinetic equation and all the correlation coefficients were above 0.99.The evaporative loss velocity of component was increased in dynamic water,while it decreased in surfactant solution,comparing with static pure water.The combined impact of these two factors was mainly presented promoting.When the turbulence intensity was above 39 r /min and 65 r /min respectively and the concentrations of surfactants were set from 150mg /L to 2 000 mg /L,the corresponding evaporative loss velocity of naphthalene and p-chloronitrobenzene both increased clearly.The evaporative loss velocity of p-chloronitrobenzene and naphthalene in the same turbulence intensity were decreased because of the straining ability of surfactant with the rule：CTMABTween 20SDS.The impact of both surfactant and turbulence on naphthalene （with higher H） was more distinct than p-chloronitrobenzene （with lower H）.