电极生物膜法去除地下水中的硝酸盐

地下水硝酸盐污染日益严重,为了克服传统生物处理工艺的脱氮效果不甚理想、容易造成二次污染等缺点,对操作简单、脱氮效率高、不需后续处理的新型的电极生物膜法工艺进行研究。采用电极生物膜法处理含硝酸盐污染的地下水。自行设计了一套电极生物膜反应器,对停留时间、电流、温度、碳氮比、等主要影响因素进行了研究,得出了最佳工艺条件:停留时间3小时,电流40mA,温度30°C,碳氮比为1。     

含氮废水处理工艺研究进展

随着人们进一步认识到含氮废水的危害,脱氮已成为水质处理必不可少的部分。传统的脱氮方法主要是生物法、物化法等。新的生物脱氮技术新型生物脱氮工艺主要有同时硝化反硝化技术、厌氧氨氧化技术、短程硝化反硝化技术。综述了含氮废水的来源和危害,分析了传统脱氮工艺和新型脱氮工艺的优缺点及适用的废水类型。     

低浓度氨氮废水处理技术进展

综述目前各种低浓度氨氮废水的脱除技术,包括物化脱氮法和生物脱氮法。其中,物化脱氮包括折点氯化法、离子交换法、吸附法、电化学氧化法;生物脱氮包括固定化细胞技术、膜-生物反应器工艺(MBR工艺)、序批式生物膜法(SBBR)、厌氧氨氧化技术。简单阐述各个方法的原理及优缺点,并指出今后研究工作中需要解决的问题。     

垃圾填埋场渗滤液中的氨氮脱除技术

处理渗滤液,不仅考虑工艺方法处理渗滤液的效果,而且要考虑工艺对水量、水质变化的适应性。处理渗滤液的方法包括物理化学法和生物处理法。垃圾填埋场渗滤液尤其是老龄填埋场渗滤液中的氨氮含量普遍较高。对渗滤液氨氮的脱除技术-吹脱法、生物脱氮技术值得研究,对生物脱氮新技术的原理进行分析,并对在垃圾渗滤液脱氮中的应用进行了深度的探讨。     

制革废水中氨氮脱除方法的研究进展

综述了制革废水中氨氮处理的主要方法,阐述了物理化学法、生物法和新型生物脱氮法氨氮的去除原理和应用研究进展.分析了制革废水氨氮处理工艺中存在的主要问题,提出了相关的解决方法.     

pH冲击对同步厌氧生物脱氮除硫反应器性能的影响

研究了pH冲击对同步厌氧生物脱氮除硫反应器性能的影响。同步厌氧生物脱氮除硫体系的酸碱缓冲容量不大,反应液pH值对进水pH冲击的响应较为灵敏。实际响应曲线不同于单纯水力停留时间分布所致的理论响应曲线,反应液pH值变化是水力传递等物理作用、基质解离等化学作用以及细菌代谢等生物作用的综合效应。pH值冲击对硫化物氧化过程有一定的影响,但可恢复。反应液pH值较高时,出水硫酸盐质量浓度较低,高pH值可抑制硫化物向硫酸盐的完全氧化。硝酸盐还原对pH冲击较为敏感,但出水硝酸盐质量浓度对pH冲击的响应曲线具有滞后性,可能与硝酸盐运输至细胞体内的运输方式有关。     

南极磷虾酶解液氯化钙法脱氟工艺的研究

为解决南极磷虾酶解液氟含量过高问题,以脱氟率为指标,利用响应面法对南极磷虾酶解液氯化钙法脱氟工艺进行优化。优化结果表明,在氯化钙添加量1.38%,初始pH9.0,反应温度20℃时,脱氟率达到89.43%。而且,氯化钙法脱氟过程对酶解液氨基氮、总氮的影响都不显著,是一种较为理想的脱氟方法。     

污水生物脱氮除磷改良技术

随着科技的发展,节能降耗的改良的脱氮除磷技术在国内外迅速发展。文章阐述了污水生物脱氮除磷的改良的技术,介绍了UCT技术、同步硝化反硝化、短程硝化反硝化、SBR改良工艺及CASS工艺等脱氮除磷技术,这些工艺运行灵活、费用低,解决因碳源不足、含NO2-或NO3-污泥回流等问题而影响脱氮除磷效果的新型技术,是今后污水脱氮除磷发展的方向。     

生物脱氮工艺的发展综述

回顾传统生物脱氮工艺的基本原理和工艺发展,针对传统生物脱氮技术在工业废水等高氮低碳废水处理的不足,介绍新型生物脱氮技术的基本理论和工艺。     

生物脱氮技术

本文论述了生物脱氮技术的发展历程，生物脱氮工艺，以及对生物脱氮的影响因素。     

Indirect photolysis promoted by natural and engineered wetland water constituents: processes leading to alachlor degradation

Wetland surface waters that received drainage from agricultural fields were probed for constituents that would promote the photodegradation of agriculture herbicides. Alachlor proved to be a good chemical probe for examining indirect photolysis due to its lack of reactivity by either direct photolysis or dark reaction pathways and its ubiquity as an agricultural herbicide. Water samples were taken from natural (Old Woman Creek) and engineered wetlands in Ohio that receive copious amounts of agricultural runoff. Possible photosensitizers including dissolved organic matter (DOM), iron, and nitrate were measured in the samples. In alkaline waters (pH > 7.8), the photochemical degradation of alachlor became important only in the presence of high nitrate levels (approximately equal to 1 mM). In pH-adjusted (approximately 4) samples, the observed degradation rate coefficient increased 3-18 times of that measured at the natural pH. Methanol quenching experiments and kinetics modeling suggest that hydroxyl radical is the principal reactant. The promotion of the reaction at the lower pH was apparently related to the activation of the photochemical pathways associated with the DOM and possibly iron-DOM complexes. The rate coefficients measured for the photodegradation of alachlor in reconstituted DOM isolates (cation-exchanged material with very low iron levels) were similar in magnitude to those measured in natural waters containing low amounts of nitrate and high amounts of DOM. Moreover, these reactions also exhibited a pH dependency. Thus, these results suggest that DOM plays a role in promoting an indirect photolytic mechanism that is highly pH dependent.     

Photostability of Cosmetic Materials

The basic principles of photochemistry and photochemical reactions applicable to the topic are briefly reviewed. A more detailed survey of the photochemical reactions of raw materials used in the formulation of cosmetics is treated, according to the principal chemical classification of the material. In each group the photochemical reactions of the substance are reported with the more apparent implications for the cosmetic industry highlighted. The effects of photochemical catalysts are discussed, including the sources of impurities which can catalyse photochemical spoilage of cosmetic products. The methods of retarding photochemical degradation are appraised, including precautions which could be adopted in manufacturing processes and the use of additives collectively known as antioxidants.
La stabilite a la lumiere des produits cosmetiques     

离子电极法快速测定榨菜中硝酸盐含量

建立一种采用离子电极快速测定榨菜中硝酸盐含量的方法。首先组建由硝酸根离子选择电极、参比电极、离子计和计算机构成的测试仪器,然后分析温度、离子强度调节剂及干扰离子对测试的影响,并建立标准曲线和校准方程,最后采用离子电极法测定榨菜成品液和榨菜脱盐液中的硝酸盐含量,并与紫外分光光度法进行比较。结果表明：温度、离子强度调节剂及干扰离子对榨菜中硝酸盐含量的测试影响较小;离子电极法测定结果与紫外分光光度法测定结果的总体平均相对误差为4.247%,相对标准偏差小于2.0%,且t检验的显著性水平大于0.05,2 种方法测试结果无明显差异,并且离子电极法测试时间小于15 s。本方法可代替紫外分光光度法作为榨菜中硝酸盐含量的快速测定方法。     

Photooxidation of atmospheric alcohols on laboratory proxies for mineral dust

We have used a novel photochemical Knudsen cell reactor to investigate the uptake and phototransformation of some atmospherically important trace organics on TiO(2) and TiO(2)-SiO(2) mixed films. Illumination of TiO(2) films led to an enhanced uptake of isopropanol and n-propanol and the concurrent production of gas-phase acetone and propionaldehyde, respectively, with high efficiency. Acetone production from isopropanol on illuminated TiO(2) films displayed a significant enhancement in the presence of cosorbed AgNO(3) or KNO(3). Uptake of cyclohexene by TiO(2) films required the presence of both nitrate anion and light. The wavelength and substrate (TiO(2) vs SiO(2)) dependence of the nitrate-induced enhancement in uptake indicates that it was not caused by direct photolysis of nitrate anion. We propose a 2-fold role for nitrate anion in the present experiments: first, as an electron trapping agent that activates the TiO(2) surface toward photooxidation; second, as suggested by our results for cyclohexene, as a source of reactive nitrate radical at the TiO(2) surface. These observations suggest that mineral dust containing photoactive components may catalyze the transformation of photochemically inactive organic compounds into species that absorb in the actinic region.     

《生化制药学》本科生教学体会

本文主要从教学内容、教学方式、教学手段、实践教学、考试改革5方面介绍了教学体会与心得。     

Photoformation of low-molecular-weight organic acids from brown water dissolved organic matter

This work describes the effects of simulated solar UV light on the bulk properties of dissolved organic matter (DOM) of bog lake water and on the formation of low-molecular-weight organic acids (LMWOAs). By means of size-exclusion chromatography it was shown that the more hydrophilic moieties of the DOM were preferentially photodegraded while the more hydrophobic ones remained relatively unaffected or were even formed. The combined photochemical-biological degradation proved to be more important than the pure photochemical mineralization. Formic, acetic, pyruvic, oxalic, malonic, and succinic acids were identified as important degradation products. Their contribution to the dissolved organic carbon increased from 0.31% before to 6.4% after 24 h irradiation. About 33% of the bioavailable photoproducts of DOM were comprised of these LMWOAs. The influence of nitrate on the formation of carboxylic acids could not be observed in the investigated system. Kinetic experiments indicated that degradation of LMWOAs occurred simultaneously during irradiation experiments, alpha-oxygen-substituted LMWOAs being more amenable to these processes. Dissolved iron acted as a catalyst of DOM photodegradation and LMWOA photoformation. Copper played an antagonistic role in the irradiation experiments, reducing the formation of formic, acetic, and malonic acids while increasing the formation of oxalic acid.     

Conversion of fogwater and aerosol organic nitrogen to ammonium,nitrate, and NOx during exposure to simulated sunlight and ozone

Although organic nitrogen (ON) compounds are apparently ubiquitous in the troposphere, very little is known about their fate and transformations. As one step in addressing this issue, we have studied the transformations of bulk (uncharacterized) organic nitrogen in fogwaters and aerosol aqueous extracts during exposure to simulated sunlight and O3. Our results show that over the course of several hours of exposure a significant portion of condensed-phase organic nitrogen is transformed into ammonium, nitrite, nitrate, and NOx. For nitrite, there was both photochemical formation and destruction, resulting in a slow net loss. Ammonium and nitrate were formed at initial rates on the order of a few micromolar per hour in the bulk fogwaters, corresponding to formation rates of approximately 10 and 40 ng m(-3) h(-1), respectively, in ambient fog. The average initial formation rate (expressed as ng (m of air)(-3) h(-1)) of NH4+ in the aqueous extracts of fine particles (PM2.5) was approximately one-half of the corresponding fogwater value. Initial formation rates of NOx (i.e., NO + NO2) were equivalent to approximately 2-11 pptv h(-1) in the three fogwaters tested. Although the formation rates of ammonium and nitrate were relatively small as compared to their initial concentrations in fogwaters (approximately 200-2000 microM) and aerosol particles (approximately 400-1500 ng m(-3)), this photochemical mineralization and "renoxification" from condensed-phase organic N is a previously uncharacterized source of inorganic N in the atmosphere. This conversion also represents a new component in the biogeochemical cycle of nitrogen that might have significant influences on atmospheric composition, condensed-phase properties, and the ecological impacts of N deposition.     

海水提取硝酸钾新工艺过程中硝酸根的测定

目前用于测硝酸根的方法较多,但对于工业生产而言,快速、简便、而又比较准确的方法很少。为了满足海水提取硝酸钾新工艺的要求,文章选择了离子选择电极法来测定硝酸根离子,并对存在的相关问题进行讨论。     

Lack of influence of extracellular polymeric substances (EPS) level on hydroxyl radical mediated disinfection of Escherichia coli

Photolysis of nitrate, a prevalent constituent in agriculturally impacted waters, may influence pathogen attenuation in such systems through production of hydroxyl radical ((?)OH). This study focuses on the efficacy of (?)OH generated during nitrate photolysis in promoting E. coli die-off as a function of extracellular polymeric substances (EPS) coverage. EPS levels of four E. coli isolates were systematically altered through a sonication extraction method and photochemical batch experiments with a solar simulator examined isolate viability loss as a function of time in nitrate solutions. E. coli viability loss over time exhibited two regimes: an initial induction time, t(s), with little decay was followed by rapid exponential decay characterized by a first-order disinfection rate constant, k. Increasing steady-state (?)OH concentrations enhanced E. coli viability loss, increasing values of k and decreasing t(s) values, both of which were quantified with a multitarget bacterial disinfection model. Notably, at a given steady-state (?)OH concentration, values of t(s) and k were independent of EPS levels, nor did they vary among the different E. coli strains considered. Results herein show that while (?)OH generated via nitrate photolysis enhances rates of disinfection in surface water, the mechanism by which (?)OH kills E. coli is relatively insensitive to common bacterial variables.     

Sunscreens' photochemical behaviour: in vivo evaluation by the stripping method

This study shows the influence of a water-in-oil emulsion and an oil-in-water emulsion on the photochemical behaviour of four sunscreen preparations containing various amounts of three UV filters: octyl methoxycinnamate, butyl methoxydibenzoylmethane, and 4-methylbenzylidene camphor. With the stripping method in vivo, skin-product interactions were evaluated after topical application and ultra-violet exposure. Evaluations were also made under the same operating conditions as in determining sun protection factor in vivo. Results showed that each sunscreen preparation has a particular photochemical behaviour related to filter mixture and emulsion type. When developing a sunscreen preparation the choice of the emulsion type and filters is relevant for achieving optimum efficacy and spectral stability.