紫外线消毒在污水处理中的应用

介绍了紫外线消毒的原理以及在污水处理中的优势和不足,阐述了紫外线消毒工艺的设计和维护方法,讨论了紫外消毒应用中的影响因素,并对紫外消毒在污水处理中的应用现状和前景进行了分析.     

上海地面紫外线辐射强度的监测

报道了上海地区１９９５－１９９６年地面紫外线辐射强度监测结果，紫外线辐射强度的最大值出现在７，８月份，总体上呈现出夏季－秋季－春季－冬季的趋势，一天中的紫外线辐射强度变化情况是在１２：００－１３：００时出现最高值。     

测定化学物对乙酰胆碱酯酶抑制毒性的微板吸光法研究

随着化学污染物种类与数量的日益增多,高通量测试方法显得越来越重要。基于乙酰胆碱酯酶(ACh E)抑制法原理,以多功能酶标仪为测试设备,96孔微板为暴露反应载体,建立了测定化学物对ACh E抑制毒性的微板吸光法。系统研究了ACh E浓度、碘化硫代乙酰胆碱(ATCI)浓度、二硫代二硝基苯甲酸(DTNB)浓度对显色吸光度、吸光度变化速率、化学物测试毒性的影响。结果表明,随着ACh E、DTNB、ATCI的浓度增加,吸光度均增加;吸光度变化速率与ACh E浓度呈正相关,与DTNB浓度基本无关,与ATCI浓度呈现先增后减的双相关系;随着ATCI浓度增加,灭多威剂量-效应曲线(DRC)向右移动。最终建立的优化测试条件为DTNB 0.2 g·L~(-1)、ATCI 0.2 g·L~(-1)、ACh E 0.04 U·m L~(-1)、p H 6.8、反应温度29℃及暴露时间15 min;并与国标方法进行了对比与验证,发现试剂加样顺序对毒性测定结果有显著影响。基于ACh E的微板毒性测试结果表明,灭多威的DRC呈现良好的S型曲线,可用Weibull函数有效表征,拟合决定系数R2大于0.97,空白变异控制在了±10%以内。此方法可用于化学污染物的高通量毒性检测。     

煅烧结合光辐照提高纳米AgI/TiO2的可见光响应

为提高AgI/TiO₂的可见光响应能力,采用煅烧结合光辐照的工艺对其进行改性.紫外-可见光吸收分析表明,改性AgI/TiO₂的敏感光谱范围覆盖了整个可见区,吸收边带从465 nm红移至800 nm,在500 nm处的吸光度提高了近3倍.X-射线衍射分析结果指出,煅烧提高了金红石型TiO₂的相对含量,导致禁带宽度从2.89 eV降到2.81 eV,氙灯辐照进一步增加了锐钛型TiO₂、金红石型TiO₂和AgI的相对含量,并生成了新的晶体AgCl,使其禁带宽度又降至1.55 eV左右.AgCl的产生、AgI和金红石型TiO₂相对含量的增加是降低改性材料禁带宽度和增强可见光响应能力的主要原因.研究还表明,只有煅烧后的AgI/TiO₂才能通过光辐照来拓宽可见光敏感范围,而且,光辐照中起作用的主要是紫外光,可见光的作用甚小.研究最后提出将2种或2种以上的卤化银负载在纳米TiO₂上,更能有效地增强TiO₂的可见光响应能力.     

紫外消毒系统的应用及其研究进展

介绍了紫外消毒系统的一般结构,综述了消毒反应器的发展及分类,讨论了国内外常用的消毒反应器结构,提出未采设计消毒系统的研究重点.     

Removal of fluorescence and ultraviolet absorbance of dissolved organic matter in reclaimed water by solar light

Storing reclaimed water in lakes is a widely used method of accommodating changes in the consumption of reclaimed water during wastewater reclamation and reuse. Solar light serves as an important function in degrading pollutants during storage, and its effect on dissolved organic matter(DOM) was investigated in this study. Solar light significantly decreased the UV_(254) absorbance and fluorescence(FLU) intensity of reclaimed water.However, its effect on the dissolved organic carbon(DOC) value of reclaimed water was very limited. The decrease in the UV_(254) absorbance intensity and FLU excitation–emission matrix regional integration volume(FLU volume) of reclaimed water during solar light irradiation was fit with pseudo-first order reaction kinetics. The decrease of UV_(254) absorbance was much slower than that of the FLU volume. Ultraviolet light in solar light had a key role in decreasing the UV_(254) absorbance and FLU intensity during solar light irradiation. The light fluence-based removal kinetic constants of the UV_(254) and FLU intensity were independent of light intensity. The peaks of the UV_(254) absorbance and FLU intensity with an apparent molecular weight(AMW) of 100 Da to 2000 Da decreased after solar irradiation, whereas the DOC value of the major peaks did not significantly change.     

Characterization of dissolved organic matter fractions from Lake Hongfeng, Southwestern China Plateau

With XAD-series and ion exchange resins, dissolved organic matter (DOM) from Lake Hongfeng in Southwestern China Plateau was isolated into 6 fractions, i.e., humic acid (HA), fulvic acid (FA), hydrophobic neutrals (HON), hydrophilic acids (HIA), hydrophilic bases (HIB) and hydrophilic neutrals (HIN). Those fractions were characterized by high performance size exclusion chromatography, fluorescence spectroscopy and UV absorbance. Among the 6 fractions, FA was predominant and accounted for 51% of the total DOM. The weight-average (M_w) and number-averaged (M_n) molecular weight of these fractions ranged from 1688 to 2355 Da and from 1338 to 1928 Da, respectively. A strong correlation was observed between specific UV absorbance at 280 nm, E₂/E₃ (absorbance at 250 nm to 365 nm), and the molecular weight for DOM fractions. UV-Vis fulvic-like fluorescence peaks were found in all fractions. Protein-like fluorescence peaks existed in HON may indicate that microbial activity was severely in Lake Hongfeng. There was a significant relationship between fluorescence intensities and specific UV absorbance at 254 nm for those DOM fractions, suggesting their similar luminescence characteristics. The values of fluorescence index (f_450/500) indicated that hydrophobic fractions may derive from terrestrial sources, and the hydrophilic fractions from microbial and terrestrial origins. Those results suggest that there were inter-relationships between molecular weight, fluorescence and absorbance characteristics, and also subtle consistencies between the hydrophilic and hydrophobic properties and the sources for these 6 fractions from Lake Hongfeng.     

模拟废水高温厌氧消化出水中SMP的特性研究

为考察废水高温厌氧消化出水中溶解性微生物产物(SMP)的特性,采用高温厌氧序批式反应器处理葡萄糖模拟废水,运用尺寸排除色谱(SEC)分离厌氧消化出水溶解性有机物(DOM),结合溶解性有机碳(DOC)、UV254吸光度和三维荧光光谱分析方法,对不同分离组分进行了定性和定量研究.结果表明,SMP在出水DOM(356mg/L,以DOC计)中占90.8%,其在高分子量(MW)(10k~100kDa)、中等MW(1k~10kDa)和低MW(<1kDa)内的含量分别为46.8%、45.4%和7.8%.高MW内的SMP比中等、低MW内的SMP有更高的芳香度.废水高温厌氧消化出水中SMP的荧光物质以高的酪氨酸类物质含量,低的富里酸和腐殖酸类物质含量为主要特征.低MW区域的SMP主要包括酪氨酸类物质,而富里酸和腐殖酸类物质主要集中于中等MW区域,色氨酸类和微生物副产物类物质在各MW区域内均有分布.高、中等MW区域(不含630Da相似文献   

焦化废水中难降解有机物去除的研究

研究了以UV(紫外线)照射、O₃氧化及厌氧酸化作为预处理方法来提高焦化废水生物降解性能的可行性和作用机理,并由此提出了一条新的工艺路线:A-A/O工艺。研究表明,以A-A/O工艺去除焦化废水中的难降解有机物效果显著,经济可行。