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381.
382.
Soybean wastewater was used to generate biomass resource by use of purple non-sulfur bacteria(PNSB). This study investigated the enhancement of PNSB cell accumulation in wastewater by Mg2+under the light-anaerobic condition. Results showed that with the optimal Mg2+dosage of 10 mg/L, biomass production was improved by 70% to 3630 mg/L,and biomass yield also was improved by 60%. Chemical Oxygen Demand(COD) removal reached above 86% and hydraulic retention time was shortened from 96 to 72 hr. The mechanism analysis indicated that Mg2+could promote the content of bacteriochlorophyll in photosynthesis because Mg2+is the bacteriochlorophyll active center, and thus improved adenosine triphosphate(ATP) production. An increase of ATP production enhanced the conversion of organic matter in wastewater into PNSB cell materials(biomass yield) and COD removal, leading to more biomass production. With 10 mg/L Mg2+, bacteriochlorophyll content and ATP production were improved by 60% and 33% respectively. 相似文献
383.
潘佳俊 《安全．健康和环境》2012,12(4):43-45
针对化工企业大检修期间的危险性及救援难点进行了分析,总结了在历次大修期间的消防安保经验,提出了消防队在大检修期间应发挥的作用。 相似文献
384.
随着城市的发展,大量抽取地下水,海水入侵灾害已成为制约沿海地区社会经济可持续发展的突出因素.论文以六股河地段为例,针对海水入侵灾害现状,建立了地下水流数值模拟模型,探讨通过地下水人工调蓄来防治海水入侵灾害的途径. 相似文献
385.
Low-density polyethylene(LDPE) has been widely used as a sorbent for passive sampling of hydrophobic organic contaminants(HOCs) in aquatic environments.However,it has seen only limited application in passive sampling for measurement of freely dissolved concentrations of parent and substituted PAHs(SPAHs),which are known to be toxic,mutagenic and carcinogenic.Here,the 16 priority PAHs and some typical PAHs were selected as target compounds and were simultaneously determined by gas chromatography–... 相似文献
386.
Chemical forms, reactivities and transformation of iron fractions in marshy waters were investigated with cross-flow filtration technique to study the iron environmental behavior. Iron fractions were divided into four parts: acid-labile iron (pre-acidification of unfiltered marshy water samples, 0.7 μm), high-molecular-weight iron (0.7-0.05 μm), medium-molecular-weight iron (0.05-0.01 μm), and low-molecular-weight iron ( 0.01 μm). The cross-flow filtration suggested that iron primarily exist in both the 0.7 μm and 0.01 μm size fractions in marshy waters. Rainfall is the key for rain-fed wetland to determine fate of iron by changing the aquatic biochemical conditions. By monitoring the variation of iron concentrations and fractions over three years, it was found that dissolved iron and acid-labile iron concentrations exhibit a large variation extent under different annual rainfalls from 2006 to 2008. The seasonal variation for iron species proved that the surface temperature could control some conversion reactions of iron in marshy waters. Low- molecular-weight iron would convert to acid-labile iron gradually with temperature decreasing. The photochemical reactions of iron fractions, especially low-molecular-weight iron had occurred under solar irradiation. The relative proportion of low-molecular-weight in total dissolved iron ranging from 28.3% to 43.2% were found during the day time, which proved that the observed decreasing concentration of acid lability iron was caused by its degradation to low molecular weight iron. 相似文献
387.
城市脱水污泥常见的处置方式是焚烧、燃烧发电、堆肥后土地化利用和填埋等。无论采用哪种无害化、资源化处置方法,输送环节都是必不可少的。城市污泥管道输送技术是以管道输送设备为核心,融合城市污泥的预处理和处置工艺的集成化系统。通过对城市污泥的流变特性和输送特性实验测试,其流变方程符合幂定律关系式;通过环管实验拟合出了污泥在管道中的阻力损失与输送距离和输送流量之间的关系,经验证,其理论计算和实际测定基本相符,证明管道输送方式能够成功地应用于城市污泥的远距离输送,为城市污泥管道输送系统的优化设计提供了理论依据。 相似文献
388.
A highly active ZrOx/ZnO catalyst for microwave-assisted photocatalytic (MW/PC) degradation of endocrine disruptor dimethylphthalate (DMP) has been prepared via cetyltrimethylammonium assisted hydrothermal method. The ZrOx/ZnO was characterized byXPS, XRD, UV-Vis, BET and SEM techniques. The XPS result showed that Zr oxides with different valences (+2, +3, +4) co-existedin ZrOx/ZnO. By using the ZrOx/ZnO (0.1 g), the TOC removal efficiency of DMP (100 mL of 50 mg/L) was 88% after 30 min reaction,which was about 15% higher than P25 TiO2. It was found that the removal process of DMP by MW/PC followed pseudo first-orderkinetics in all cases, and ZrOx/ZnO significantly accelerated the degradation of DMP. The degradation half-life time of DMP wasshortened 45% compared with P25 TiO2. A possible catalytic mechanism was proposed based on microwave response and interfacialcharge transfer. ZrOx/ZnO could be reused for six times without obvious decrease in catalytic activity. The study offers new insightsinto designing highly efficient catalysts for MW/PC process and is applicable for MW/PC environmental remediation. 相似文献
389.
Yan Zhang Meng Wang Shunyu Kang Tingting Pan Hua Deng Wenpo Shan Hong He 《环境科学学报(英文版)》2021,33(6):17-26
The control of ethyl acetate emissions from fermentation and extraction processes in the pharmaceutical industry is of great importance to the environment. We have developed three Mn2O3 catalysts by using different Mn precursors (MnCl2, Mn(CH3COO)2, MnSO4), named as Mn2O3-Cl, -Ac, -SO4. The tested catalytic activity results showed a sequence with Mn precursors as: Mn2O3-Cl > Mn2O3-Ac > Mn2O3-SO4. The Mn2O3-Cl catalyst reached a complete ethyl acetate conversion at 212℃ (75℃ lower than that of Mn2O3-SO4), and this high activity 100% could be maintained high at 212℃ for at least 100 hr. The characterization data about the physical properties of catalysts did not show an obvious correlation between the structure and morphology of Mn2O3 catalysts and catalytic performance, neither was the surface area the determining factor for catalytic activity in the ethyl acetate oxidation. Here we firstly found there is a close linear relationship between the catalytic activity and the amount of lattice oxygen species in the ethyl acetate oxidation, indicating that lattice oxygen species were essential for excellent catalytic activity. Through H2 temperature-programmed reduction (H2-TPR) results, we found that the lowest initial reduction temperature over the Mn2O3-Cl had stronger oxygen mobility, thus more oxygen species participated in the oxidation reaction, resulting in the highest catalytic performance. With convenient preparation, high efficiency, and stability, Mn2O3 prepared with MnCl2 will be a promising catalyst for removing ethyl acetate in practical application. 相似文献
390.
Xiaoyong Liu Mingshi Wang Xiaole Pan Xiyue Wang Xiaolong Yue Donghui Zhang Zhigang M Yu Tian Hang Liu Shandong Lei Yuting Zhang Qi Liao Baozhu Ge Dawei Wang Jie Li Yele Sun Pingqing Fu Zifa Wang Hong He 《环境科学学报(英文版)》2021,33(5):20-32
The region along the Taihang Mountains in the North China Plain (NCP) is characterized by serious fine particle pollution. To clarify the formation mechanism and controlling factors, an observational study was conducted to investigate the physical and chemical properties of the fine particulate matter in Jiaozuo city, China. Mass concentrations of the water-soluble ions (WSIs) in PM2.5 and gaseous pollutant precursors were measured on an hourly basis from December 1, 2017, to February 27, 2018. The positive matrix factorization (PMF) method and the FLEXible PARTicle (FLEXPART) model were employed to identify the sources of PM2.5. The results showed that the average mass concentration of PM2.5 was 111 μg/m3 during the observation period. Among the major WSIs, sulfate, nitrate, and ammonium (SNA) constituted 62% of the total PM2.5 mass, and NO3? ranked the highest with an average contribution of 24.6%. NH4+ was abundant in most cases in Jiaozuo. According to chemical balance analysis, SO42?, NO3?, and Cl? might be present in the form of (NH4)2SO4, NH4NO3, NH4Cl, and KCl. The liquid-phase oxidation of SO2 and NO2 was severe during the haze period. The relative humidity and pH were the key factors influencing SO42- formation. We found that NO3? mainly stemmed from homogeneous gas-phase reactions in the daytime and originated from the hydrolysis of N2O5 in the nighttime, which was inconsistent with previous studies. The PMF model identified five sources of PM2.5: secondary origin (37.8%), vehicular emissions (34.7%), biomass burning (11.5%), coal combustion (9.4%), and crustal dust (6.6%). 相似文献