The future of water in Australia: The potential effects of climate change and ozone depletion on Australian water quality,quantity and treatability

Water is a resource that is essential for all life on Earth. An exponentially growing human population, in addition to unprecedented industrial and technological development, threaten the availability and quality of this resource. Climate change and ozone depletion are two major environmental problems facing mankind today. These problems have the potential to further strain currently available freshwater resources. Recent research has shown that climate change and ozone depletion are linked phenomena and their interaction exacerbates their impact. Changes in precipitation, surface runoff, solar UV radiation, temperatures, and evaporation are some of the predicted outcomes of climate change and ozone depletion. They influence the biogeochemical cycles and aquatic ecosystems in lakes and rivers, and alter the character of natural organic matter (NOM) and, consequently, they have the potential to affect the quality, quantity and treatability of our water resources. Given these uncertainties, and the need to mitigate the consequences of climate change and ozone depletion, the issues of changing water quality, quantity and treatability cannot be ignored by Australian governments and water utilities.     

Degradation of tert-butyl formate and its intermediates by an ozone/UV process

In this paper, the oxidation of tert-butyl formate (TBF) in aqueous solution by an ozone/UV process was described. The oxidation process was investigated experimentally in a semibatch reactor. The results of the study indicated that the ozone/UV process was very effective in oxidizing TBF. tert-Butyl alcohol (TBA), hydroxy-iso-butyraldehyde (HiBA), acetone, formaldehyde, and formic acid were identified as major primary intermediates during the oxidation of TBF. About 90% organic carbon balance was obtained indicating that most reaction intermediates have been identified and quantified. Some of the primary intermediates were also oxidized in the ozone/UV system. Accordingly, HiBA, acetone, formaldehyde, and formic acid were the primary intermediates of TBA oxidation. The oxidation of acetone in the ozone/UV system generated formaldehyde, pyruvaldehyde, acetic acid, formic acid as primary intermediates. It was also observed that the reaction intermediates formed during the oxidation of TBF react well in the ozone/UV system and complete mineralization could be achieved by the process.     

光反应器中UV/Fenton光降解湖水中微囊藻毒素的研究

在光催化反应器中,采用UV/Fenton光催化氧化技术,对湖水中微囊藻毒素的光催化降解过程中各影响因子分析表明:微囊藻毒素光催化氧化降解率受光照强度、氧化剂种类及浓度、溶液pH和不同光催化体系等多因素的影响.光促催化氧化体系对MC-LR藻毒素降解具有显著的作用,在紫外光与氧化剂的协同作用下,紫外光照强度越高,越易于促进MC-LR藻毒素快速降解,降解率可到达80%以上.     

光助Fenton氧化法降解水中六氯苯的研究

采用光助Fenton氧化法处理六氯苯模拟废水,考察了反应时间、Fe3 与H2O2摩尔比、Fenton试剂用量、初始pH、六氯苯初始浓度、光强对六氯苯降解效果的影响,并初步探讨了六氯苯的降解动力学规律.结果表明.光助Fenton法降解六氯苯的最佳工艺条件为:紫外灯功率为300 W、Fe3 投加量为1.0 mmol/L、H2O2投加量为5.0 mmol/L、反应时间为60 min、初始pH为3,在此条件下,浓度为500μg/L的HCB的去除率可达91.3%.UV辐射与Fenton氧化对HCB的降解具有协同效应.光助Fenton法对HCB的降解符合一级反应动力学方程,表观速率常数为0.04 min-1,与Fenton法相比,提高了近9倍.     

紫外分光光度法测定水中丁基黄原酸

根据丁基黄原酸具有在301 nm紫外波长段有最大吸收峰,pH＜2时1 min内能够完全被分解,同时该吸收峰消失的特性,采用紫外分光光度(UV)法测定待测水样中丁基黄原酸浓度,并用待测水样作为背景校正,可有效地消除干扰.该方法的检出限为0.006 mg/L、测定上限为12.00 mg/L,实际水样测定的相对标准偏差小于5.76%.利用不同方法对样品进行分析测试,无明显差异.该方法具有线性相关性好、线性范围宽、操作简单准确等特点.     

天津市秋季臭氧浓度影响因素及相关关系研究

选择天津市秋季典型重污染时期2005年11月2～7日近地面大气O3、NO、NO2、CO、紫外线(UV)强度和温度等观测数据,研究O3浓度的时间变化特征及其与相关前体物、气象条件的相关关系.结果表明,在观测期间O3浓度存在明显的日变化周期,在13:00～14:00时浓度最大,夜间变化平缓;O3浓度与NO、NO2、NOx和CO等前体物呈较好的负相关关系;温度和UV与O3浓度密切相关,昼间O3与UV呈相同变化趋势,相关系数达0.71,O3浓度变化滞后于UV变化,将O3浓度与前1小时的UV对比分析,相关系数提高到0.81.     

异丙草胺光解体系中溶解氧的增强效应

研究了异丙草胺光解过程中溶解氧的协同效应,在不同初始浓度溶解氧存在时异丙草胺在水中的光解规律.随着溶解氧初始浓度的增加,光解速率和效率均有提高,其中最高和最低光解效率相差30%.初始溶解氧浓度达到7.5mg/L后,光解速率和效率出现了平台效应,并且随着溶解氧浓度增加而有所下降.伴随异丙草胺的光解,溶解氧也有消耗,可以推测溶解氧也参与了光反应.通过对降解产物的分析,发现含高浓度溶解氧和缺氧条件下的光解产物基本一致,但部分光解产物生成量不同.通过光解体系做自旋捕捉实验,推测可能是通过单线态氧¹O₂机制进行光氧化.     

上海老港填埋垃圾场渗滤液COD与UVA的相互关系

本实验研究对象为上海老港填埋场1991年填埋单元渗滤液和各处理工艺出水渗滤液,水样经过不同孔径膜微滤和超滤后,比较了各自COD值和UVA值之间的相关性．结果表明,水样COD浓度愈低,与其对应的UVA相关性愈好．由于有机物的组成不同,对应的特征吸收范围存在差别,因此,不同渗滤液的UVA与COD的关系也不同．渗滤液中的胶体物质对COD值有贡献,微滤和超滤系统使渗滤液中的胶体物质被截留,COD值减小,测定得到对应的UVA值也相应减小．     

铁-草酸盐配合物光分解降解对硝基苯酚的研究

研究了铁(Ⅲ)-草酸盐配合物在可见光及太阳光照射下,对对硝基苯酚的光解降解作用。结果表明,在pH=4.0、Fe(Ⅲ)/H_2C_2O_4=0.080mmol/L/0.96mmol/L(分4次加入)、光照4h的条件下,20mg/L对硝基苯酚的降解率为89％。溶液pH值,铁与草酸盐浓度比和对硝基苯酚浓度均对降解效果产生影响。     

多环芳烃的光致毒效应

多环芳烃（ＰＡＨｓ）是一类常见的污染物,过去对其毒性的研究主要集中在生物体内代谢产物的毒效应上。但是近期研究表明紫外光的照射对多环芳烃的毒性具有显著影响,称为ＰＡＨｓ的光致毒效应。本文介绍了多环芳烃在紫外光照射下的急性光致毒作用,致毒作用发生机理及毒性预测的数学模型,同时探讨了ＰＡＨｓ对紫外光致癌性的影响。