【作者】 吴东海；

【导师】 尤宏；

【作者基本信息】 哈尔滨工业大学 ， 环境科学与工程， 2007， 硕士

【摘要】 硝基苯类化合物是常用的有机化学工业原料,在染料、医药、农药、橡胶、香料等行业都要用到这类化合物,但是,若要进入水体,将成为有毒有害的污染物。硝基苯是高毒性物质,其毒性一般为其它化合物的20-30倍,且具有弱致突变性。长期接触,对人体及动物危害极大。目前,国内各大江河由于工业发展过程产生结构性污染问题,致使水环境有机物污染日益严重,并且国内外已将硝基苯类污染物列入水中优先控制污染物名单。所以本文在实验室的条件下,就硝基苯在结冰过程中在冰、水中的分配规律,以及冰中和水中硝基苯光降解规律,光降解影响因素进行了研究,并且对水中硝基苯光降解的中间产物和生物综合毒性进行了初步分析。本文建立了水样中硝基苯的检测方法。水样中硝基苯的检测采用液相色谱法,实验结果表明硝基苯浓度在1.0¹000μg/L时,峰面积与硝基苯浓度成很好的线性相关性,其结果令人满意。本文通过模拟自然水体结冰实验考察了结冰过程中硝基苯在水中与冰中的分配规律,结果表明硝基苯水溶液在结冰过程中,硝基苯在水中与冰中重新分配,绝大部分（96%⁹8%）硝基苯留在水中,冰中硝基苯浓度较小（2%⁴%）。通过不同光源下硝基苯光降解实验考察了硝基苯的光降解规律以及相关影响因素的作用,实验结果表明紫外光可以有效地降解冰中和水中的硝基苯,反应速率可以按一级反应解释。在20W低压紫外汞灯（中心波长254nm）辐射下,冰中硝基苯表观反应速率常数为0.268h^-1,降解半衰期约2.59h。水中硝基苯降解反应表观速率常数平均值为k=0.00585min^-1,半衰期平均为118.5min。在2³月份太阳辐射强度下,冰中硝基苯降解反应表观速率常数0.045h^-1 ,半衰期为13.6h ,水中硝基苯反应速率常数为0.042⁰.059h^-1,江面30⁴0mm厚的表层水中硝基苯光降解的半衰期约为2天。紫外光在冰中和水中光强衰减符合Lambert定律,随冰层厚度的增加光解反应迅速下降,厚度大于30mm以后光解反应可以忽略。酸性条件下水中硝基苯反应速率有所提高,碱性条件下反应速率基本无变化。江水中含有的腐殖质和各种杂质对光降解冰中和水中硝基苯有促进作用。通过液质联机分析不同光降解阶段的硝基苯溶液,研究表明硝基苯溶液光降解过程中有新物质产生,其质核比为108.04,经分析为硝基苯酚。用DeltaTOX毒性分析仪检测不同光降解阶段的硝基苯溶液,检测指标为发光细菌光损失率,结果表明起始阶段综合毒性略有上升,而随着反应的进行,毒性又有所下降,低于原始水样。更多还原

【Abstract】 The nitrobenzene and its ramification are commonly used as the organic chemistry raw material for the industries of dye, medicine, agricultural chemicals, rubber and spice. However, if they enter the waters, they will become the virulent harmful pollutants. Nitrobenzene is toxious, and its toxicity is generally 20-30 times higher than that of other compounds, and it is weakly mutagenic. The long-term contact with it is deleterious for the human and the animals. At the present, the industry developing process brings structural pollution to the domestic big rivers, causing the organic pollution in the water environment becomes more and more serious, and the nitrobenzene pollutants have be listed as the pollutants which we should give priority to control home and abroad. So in laboratory conditions, we do research about the distribution of nitrobenzene in ice and water at icing processes, and about photodegradation of nitrobenzene in ice and water, the factors influencing photodegradation. And the intermediate products and synthetic biological toxicity of the photodegradation of nitrobenzene in water are preliminarily studied in this paper.In the paper we establish the method to test nitrobenzene in the water. We test nitrobenzene in the water sample by means of liquid chromatography, and the test results show that when the nitrobenzene concentration is between 1.0 and 1000μg·L^-1, the peak area correlates linearly with the nitrobenzene concentration well, so the result is satisfactory.We investigate the distribution of nitrobenzene in ice and water at icing processes through simulation of nature water’s icing experiments, the result shows that in the course of nitrobenzene aqueous solution ice accretion, nitrobenzene reapportion in water and ice. Most of the nitrobenzene（96%⁹8%） in water, the concentration of nitrobenzene in ice is less（2%⁴%）.With different irradiation sources, the photochemical degradation of NB was studied. And the influence of different illumination intensity, pH Value and soluble matter in river water on the photodegradation of NB was investigated. Nitrobenzene could be degraded remarkably under ultraviolet radiation, and the photodegradation of NB is first-order reaction. The rate constants（k） of the photodegradation of nitrobenzene in ice under ultraviolet radiation is 0.268h^-1, the half-life is 2.59h. The rate constants（k） of the photodegradation of nitrobenzene in water under ultraviolet radiation is 0.00585min^-1, the half-life is 118.5min. Exposed to intensity of solar radiation in February and march , The rate constants（k） of the photodegradation of nitrobenzene in ice is 0.045h^-1, the half-life is 13.6h, the rate constants（k） of the photodegradation of nitrobenzene in water under ultraviolet radiation is 0.042⁰.059h^-1, the half-life of photodegradation of NB in river water which below the river surface about 30⁴0mm is about two days. The attenuation regularity of ultraviolet light intensity in ice or water follows an exponentially attenuation law. The rate constants（k） of the photodegradation of nitrobenzene decreases with the increase of the ice layer thickness.when layer thickness more than 30mm, it can be neglected. Under the acidic condition the reaction rate increased while unchanged under alkalinity condition. And the photodegradation rate of NB has been stimulated when there were humic substance and various impurities in river water.LC-MS analysis on nitrobenzene aqueous solution of different photodegradation stages showed that some new material were produced in the process, whose cytoplasma/nucleus ratio.is 108.04, was thought as nitrophenol.Nitrobenzene aqueous solution in different stages of photodegradation was analyzed by DeltaTOX toxic analysor. The detection index is photogenic bacteria loss ratio. The result shows that at the initial stage the comprehensive toxicity is slightly increased, whereas with the prolonging of reaction time the comprehensive toxicity decreased, lower than original sample.更多还原