【作者】 孙俊杰；

【导师】 沈学优；

【作者基本信息】 浙江大学 ， 环境科学， 2005， 硕士

【摘要】 本文评述了有机物在水/气界面挥发速率的研究进展。介绍了有机物挥发的四种模式:双膜理论、改进的双膜理论、Mackay理论、Chiou理论。同时介绍了表面活性剂的增溶特性和混合表面活性剂的性能,总结了表面活性剂对有机物亨利系数（H）的变化规律。 研究了表面活性剂对萘和苯系物在水/气界面挥发速率的影响,重点探讨了混合表面活性剂对萘和苯系物在静水面挥发的影响规律和机理,初步探索了表面活性剂对萘在扰动水体中挥发速率的影响。得到以下主要结论: （1）表面活性剂在静水面抑制苯系物挥发速率的主要机理为表面活性剂的存在使苯系物的液膜阻力（r_L）增加,即在液膜中的交换系数（K_L）减小,导致液相中的整个质量传质系数（K_L）相应减小,促使挥发速率常数（K_v）减小,从而对苯系物的挥发起到了抑制作用。随着表面活性剂浓度的增加,液膜阻力也相应增加,抑制作用也越明显;其液膜阻力增加的能力与苯系物的lgK_ow呈正相关。 （2）混合表面活性剂对萘和苯系物的挥发有协同抑制作用。其对苯系物的液膜阻力增加能力强于相应的单一表面活性剂,对苯系物的挥发具有更强的抑制作用。SDS混合体系对萘的协同抑制作用强于SDBS混合体系,协同抑制量与协同增溶量呈较好的正相关性。 （3）扰动促进萘的挥发,溶液中不含SDS时,扰动状态（搅拌速率为51rpm/min）萘的挥发速率常数K_v约为静水面萘的挥发速率常数K_v⁰的5.63倍;在静水面时,含SDS浓度为2500mg/L的溶液中萘的挥发速率常数K_v约为不含SDS的溶液中萘的挥发速率常数K_v⁰的0.59倍。SDS浓度越高,挥发速率常数减少倍数越大;搅拌速率越大,挥发速率常数增加的倍数越大。低搅拌速率对挥发速率常数增加的贡献最大,即从静水面到低速搅拌过程对挥发速率常数增加的作用最明显。 （4）SDS对萘挥发的抑制量不仅随浓度的增大而增加,而且随搅拌速率的增更多还原

【Abstract】 This work was devoted to the study of the volatilization rates of organic pollutants in Air-water Interface. Four volatilization models were summarized: two-film theory,reviewed two-film theory, D.Mackay’s volatilization rate model, and the volatilization rate model advanced by C.T.Chiou.Otherwise, the paper introduced the solubilization of organic pollutants enhanced by surfactants, and special performance of mixed-surfactants.The influence rule of surfactants on Henry’s law constants of organic pollutants was also involved.Based on the multimedia environment with complex pollution, the study discussed the influence of surfactants on volatilization rates of volatile organic compounds（VOCs） in the interface of water/gas.In chief,It studied the effects of mixed-surfactant on the volatilization rates of naphthalene and BTEX from the static water and the corresponding mechanisms.Compared to phenomena in static state, the influence of surfactant on the volatilization rate of naphthalene in stirred water was investigated primarily.The main conclusions of this work were drawn as follows:（1） The main reason for the decrease of volatilization rate of BTEX from static water was that the presence of surfactant increased the resistance constant（r_L） in liquid film.That is, the transfer constant（k_L） became smaller,which lead to the mass transfer constant（K_L） in the liquid and then the volatilization rate（ K_v） diminished.Thereby,the volatilization of BTEX was inhibited.It was concluded that with the increase of surfactant concentration,the resistance of liquid film increased accordingly,and the inhibition was more obvious. In addition, the positive relation was found between the restraining ability of a surfactant and lgK_ow of BTEX.（2） Mix-surfactants inhibited the volatilization rates of naphthalene and BTEX synergistically.Compared to the single-surfactant solution,mixed-surfactants inhibited the volatilization more efficiently.It was attributed to that the restraining ability of mixed-surfactant was stronger than that of single-surfactant.In the study,the inhibition caused by Mixed-surfactant solutions containing SDS was stronger than that by solutions containing SDBS. Data analysis showed that the evaporative loss weakening caused by mixed-surfactant synergistically was positively correlated to the degree ofsolubility enhancement.（3） The volatilization of naphthalene was enhanced by agitation. In solutions without SDS,when the rate of agitation was 51rpm/min,the volatilization rate K_v was5.63 times as K_v^o in static state;while K_v of naphthalene from static water in the presence of 2500mg/L SDS was 0.59 times as K_v^o .The volatilization rate decreasedwith either the increase of concentration of SDS or the increase of agitation rate.Agitation at low rates had the biggest contribution to the volatilization rate.In the other hand,the increase of volatilization rate was most obvious in the process from static water turn to the state with low rate of agitation.（4） In solutions containing SDS,the decrement of naphathalene’s volatilization rate increased with the increase not only of SDS’s concentration but also of agitation rate.It could be explained that the solution was mixed more completely with stirring.That made the molecule of naphathalene transfer to the interface more easily,and reinforced the decrease of naphathalene in liquid film caused by volatilization process.In the result,the mass transfer resistance in liquid diminished greatly,and then,the volatilization rate increased. Simultaneously,agitation enhanced combiness of naphthalene with SDS micelle, which astricted the molecule of naphthalene.And thus,the volatilization was inhibited.As described in this paper,effects of surfactants on the volatilization of organic matter from static water and the corresponding mechanisms have been beat out in the main,while rules that surfactants effect on the volatilization in the stirred state have been understood primarily.These support for the studies theoretically,which concerned to the fate o更多还原