Polyoxometalates for photocatalytic degradation of aqueous dyestuff solutions and quantitative structure–property relationship study on photolysis rate constants

Polyoxometalate, K₆TiW₁₁O₃₉Sn·7H₂O (TiW₁₁Sn), was synthesized and characterized. TiW₁₁Sn and K₆ZrW₁₁O₃₉Sn·12H₂O (ZrW₁₁Sn) were evaluated for their photocatalytic degradation of triarylmethane (brilliant green and acid blue 9), bisazo (C.I. reactive black 5), and monoazo dyestuffs (C.I. reactive red 24, C.I. reactive red 194, and C.I. reactive orange 5) with natural sunlight in homogeneous aqueous solutions. TiW₁₁Sn and ZrW₁₁Sn effectively and photocatalytically decolorized the dyestuffs. The TiW₁₁Sn- and ZrW₁₁Sn-mediated photocatalytic degradation of the dyestuffs involved a pseudo-first-order reaction and was modeled by Langmuir–Hinshelwood-type kinetics. The observed pseudo-first-order rate constants (K^/) of triarylmethane dyestuffs were generally bigger than that of the azo dyestuffs. Quantitative structure–property relationship models of the K^/ of the dyestuffs were developed using partial least-square regression. The cumulative variance of the dependent variable explained by the partial least-square components was > 0.753 for each optimal model. This value indicated that the model had good predictive ability and robustness. The K^/ values of the dyestuffs were related to the energy of the lowest unoccupied molecular orbital, and the most positive net atomic charges on a sulfur atom of dyestuffs. The linear correlation coefficients between the predicted and experimental values were all > 0.9950.     

悬浮结晶法冷冻处理喹乙醇生产废液

采用悬浮结晶法处理喹乙醇生产废液,考察了成冰率(冰晶融化后的体积占原水总体积的百分比)对废液COD、氨氮、TN和电导率去除效果的影响。在一级冷冻成冰率45%的条件下,经过三级冷冻处理后,三级出水的COD、氨氮、TN和电导率的去除率分别为99.4%、98.7%、98.5%和98.2%,一级浓缩液的COD、氨氮和TN的浓缩比分别为1.6、1.5和1.5;在一级冷冻成冰率80%的条件下,每一级出水的各项指标的去除率均有所下降,三级出水的COD、氨氮、TN和电导率的去除率分别为98.6%、98.3%、97.1%和95.9%,但一级浓缩液的浓缩比明显提高,COD、氨氮和TN的浓缩比分别为2.7、2.2和2.4。成冰率为80%时一级浓缩液的热值为7 449 J/g,在焚烧过程中可以依靠自身热量维持燃烧,不需要添加辅助燃料,减少焚烧处理的成本。     

Wind energy and natural ventilation potential of a wind catcher in Yazd – Iran (a long-term measurement)

When designing energy efficient buildings it is useful to study existing climate—responsive building typologies. The wind towers or wind-catchers of Yazd city in Iran are typical examples of such a typology. Although many previous studies have investigated the performance of various types of wind catcher systems, studies based on a long-term real-life measurement can be rarely found. In this study a long-term whole year monitoring campaign on an existing full scale four sided wind catcher in Yazd was carried out in 2014–2015. Three prevailing wind directions were identified and the measured on-site wind speeds were used to estimate the wind induced natural ventilation potential of the tower. A shaft/tower airflow performance index was developed. The monitoring results were compared to the ASHRAE Standard 62:2001 ventilation rate requirement. Results show that the total ventilation rate of the wind tower surpasses the ASHRAE Standard requirements. Furthermore it shows that the shafts are exposed to the prevailing wind directions perform better. For more effective natural ventilation a wind tower with adaptable openings/shafts are proposed.     

环境污染的国际转移与城乡转移

从广义上考察了环境污染的国际转移与城乡转移,包括可见的和不可见的污染转移。分析了污染转移的不同途径,从环境质量需求和个人贴现率两个方面分析了污染转移的经济机制,以此为基础,探讨了防止污染转移的对策。     

人工污水对温室中秋茄苗光合速率的影响

用正常?5倍?10倍浓度的人工污水对温室中模拟的秋茄(Kandeliacandel)湿地系统持续灌污1a?在排污1周?3个月?11个月和结束后2个月对污水处理组及对照组植株秋茄幼苗的光合速率和温室中光通量密度?CO₂浓度?叶片温度进行同步测定?植株光合速率的实测值和计算值均显示,排污初期正常浓度组变化小,5倍?10倍浓度组稍下降;排污后期正常浓度组显著上升,较高浓度组回复正常;停止排污2个月,各组间无显著差异?结果提示秋茄苗对人工污水的耐受力和抗性较强,对高浓度污水有逐渐适应的过程?      

光合细菌处理淀粉废水的中试研究

利用光合细菌连续处理工艺,在适宜条件下进行淀粉废水处理的中试研究。中试系统日处理量为４ｍ３,ＣＯＤＣｒ最大容积负荷６．７１ｋｇ／（ｍ３·ｄ）,ＣＯＤ去除率为９５．７％。该法所得菌泥可作为饲料添加剂,具有较好的经济效益。     

慢速渗滤土地处理设计参数的研究

由于慢速渗滤土地处理系统对污水中的有机污染物有较高的去除能力,且城市污水的有机污染物浓度远低于系统的处理负荷量,故系统的设计参数受污水中氮浓度控制.试验表明,BOD_5负荷率高达3.57g/m~2·d仍不会影响系统的工艺性能,但氮负荷率一般不应超过0.6—0.7g/m~2·d.由氮极限值确定的水力负荷率为3—6m/a.在规定的负荷率下,投配水深采用<7cm,4—5天投配一次污水的投配频率是适宜的.     

聚乙烯醇生化矿化度及自然降解的研究

通过对聚乙烯醇(PVA)生化矿化度、PVA在目然水域及土壤中的自净能力以及PVA降解过程中结构变化的研究,探讨PVA的可生化性及降解进程中物质的转化规律.PVA的生化矿化度高达50-70％,表明PVA在微生物作用下可以高度降解.由自净能力和结构变化过程的研究表明,PVA首先由大分子转变为小分子,经相应时间后向无机物转化,说明PVA在自然水域和土壤中有较好的自净作用。     

蚕豆叶尖细胞及人淋巴细胞微核率对超声波诊断仪的监测

用蚕豆叶尖细胞微核率（MNR）及人淋巴细胞（MNR）对比观察超声波诊断工作人员与仪器的关系,本实验结果表明,从事本工作5年即已有很显著的MNR改变,时间愈长MNR愈高。用蚕豆叶尖细胞之MNR检测工作环境,距探头60cm为直径的范围内皆能引起MNR的显著性改变,8h较4h更为严重,此范围正是工作人员及患者躯干所在的位置,应该引起人们的重视。     

滇池生态动力学模型的改进

在分析滇池生态系统的基础上,从滇池浮游植物的优势种出发,根据各种藻大的生长特性．分别给予不同的温度限制因子,以此推求其增殖速率,并根据不同时期、不同地点优势藻种的构成比,加权出该时段浮游植物总的生长率。这一改进克服了以往模拟计算中把参数取为常数的缺陷．较好地模拟了浮游植物的生长过程和ＴＮ、ＴＰ等水质指标的年内变化情况。