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题名	洛克沙砷在水环境中的吸附与光降解行为
作者	周宁
学位类别	硕士
答辩日期	2013-05
授予单位	中国科学院研究生院
授予地点	北京
导师	彭先佳
关键词	洛克沙砷 吸附 光降解 迁移 转化 roxarsone sorption photodegradation migration transformation
其他题名	Sorption and photodegradation behavior of roxarsone in aquatic environment
学位专业	环境工程
中文摘要	洛克沙砷（3-硝基-4 羟基苯砷酸，简称ROX）是一种有机砷制剂，被广泛作为畜禽饲料添加剂应用于畜禽饲养，虽然其毒性小、且几乎以原形态随粪便排出，但其在环境中易降解生成有毒的As(V)、As(Ⅲ)、一甲基砷酸（MMA）和二甲基砷酸（DMA）。目前，对于洛克沙砷在禽类粪污及土壤中的形态转化过程有较多研究报道，但对于克沙砷由畜禽粪便流失进入水环境后，其迁移传输、形态转化等环境行为尚缺少足够的科学认识，尤其有机形态洛克沙砷向无机形态砷的转化过程、影响因素及转化机制等，目前缺少系统科学研究。本研究针对上述问题，开展了洛克沙砷在水悬浮颗粒典型成分粘土矿物上的吸附行为以及在水环境中光降解行为研究，得出如下主要结论： （1）洛克沙砷在高岭石、伊利石和蒙脱石上的吸附过程符合准二级动力学方程，吸附等温线符合Freundlich 方程。 （2）pH 对洛克沙砷的吸附影响明显，在高岭石、伊利石和蒙脱石的最大 吸附量分别发生在 pH= 9.0，5.0 和5.0；水环境中共存的金属阳离子对吸附有显著影响，Fe3+的存在能显著提高洛克沙砷在高岭石、伊利石和蒙脱石上的吸附量，而Ca2+和Mg2+的存在却对洛克沙砷的吸附有明显的抑制作用；洛克沙砷在三种粘土矿物上的吸附随温度升高而升高。 （3）分子态和完全解离态的洛克沙砷更容易发生紫外光降解。自然光下，同一季节，纬度越底，洛克沙砷最大理论降解速率越大；同一纬度下，洛克沙砷在夏季的最大理论降解速率最大，其次是春季，冬季最小。 （4）pH、NO3-和有机质的存在影响洛克沙砷在水环境中光降解速率，降 解速率有随pH 值的增大而增大，NO3-浓度越高越有利于洛克沙砷的光降解，腐殖酸、褐藻酸浓度越高，降解速率越大；洛克沙砷的降解符合一级动力学方程，降解产生的无机砷形态主要为As(V)。
英文摘要	Roxarsone(3-nitro-4-hydroxyphenylarsonic acid, ROX) is an organarsenic compound that is used extensively as a feed additive in the broiler poultry industry. Almost all the roxarsone in the feed is excreted unchanged in the manure. Although it is nontoxic, roxarsone is easy to be transformed to toxic As species, such as As(V),As(III), dimethylarsinic acid (DMA) and monomethylarsonic acid (MMA). Though the fate of roxarsone in pultry litter and soil has been extensively investigated, the environmental behavior of roxarsone, especially the process, influencing factors and mechanism for the conversion of roxarsone to inorganic arsenic after entering aquatic environment, is still unknown. To answer these questions, this investigation was aimed to study the sorption behavior of roxarsone on three representative clay minerals, which are typical compontent of suspended particulate matter in water, and the photodegradation behavior of roxarsone in aquatic environment. The results showed that: (1) The sorption of roxarsone on kaolinite, illite and montmorillonite were found to follow Freundlich isotherm and the the sorption process fits pseudo-second-order dynamic model well. (2) pH has an obvious effect on the sorption of roxarsone and the maximum soption occurs at pH about 9.0, 5.0 and 5.0 for kaolinite, illite and montmorillonite,respectively. The coexisting metal cations exert significant influence on the sorption. Ferric ion significantly promoted roxarsone sorption, while divalent calcium ion and divalent magnesium ions exhibit an inhibitory effect on roxarsone sorption. The sorption on all the three clay minerals increased with increasing temperature. (3) Roxarsone with molecular state and complete dissociation state of is more prone to photodegradation when exposed to UV-irradiation. Theoretical maximum photodegradation rate of roxarsone under the same season increases with the decrease in latitude. The theoretical maximum photodegradation rate occurs in summer followed by spring and that in winter is the smallest. (4) The pH value, NO3- concentration and organic matter concentration exert obvious effect on the photodegradation rate of roxarsone in aquatic environment. The photodegradation rate increases with the increase in pH value, NO3- concentration and organic matter concentration. First-order kinetics model fits photodegradation process of roxarsone in water well and As(V) was the dominant inorganic arsenic species produced by photodegradation
公开日期	2014-10-28
内容类型	学位论文
源URL	[http://ir.rcees.ac.cn/handle/311016/7710]
专题	生态环境研究中心_环境水质学国家重点实验室
推荐引用方式 GB/T 7714	周宁. 洛克沙砷在水环境中的吸附与光降解行为[D]. 北京. 中国科学院研究生院. 2013.

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