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71.
Reduction of viable airborne Staphylococcus epidermidis and Aspergillus niger spore concentrations using two types of photocatalytic fluorescent lamps under controlled environmental conditions (25 vs. 35 °C and 55 vs. 75% relative humidity) were investigated. Visible white-light and UVA black light were in-house spray-coated with TiO2 and then compared with a commercially coated visible white-light for microbial concentration reduction. The white-light photocatalytic lamps reduced the concentration of culturable S. epidermidis up to 92% independent of temperature or humidity change, while the black light photocatalytic lamps completely inactivated the culturable bacteria at 25 °C, 55% relative humidity. Humidity seemed to alleviate UVA damage since better bacteria survival was found. For A. niger spores, rising humidity or temperature could lower their concentration or drop their culturabilities so that a difference between the natural decay and photocatalytic disinfection could not be distinguished. Reductions of total bacteria and total fungi concentrations using these lamps were also examined under uncontrolled environmental conditions in an office and a waste-storage room. It was found that photocatalytic lamps could reduce total culturable bacteria concentration from 9 to 97% and total culturable fungi concentration from 3 to 95% within irradiation time of 30-480 min, respectively. Insignificant difference in concentration reduction among these photocatalytic lamps was pronounced. 相似文献
72.
建立了以w(C2H5OH)=95 %乙醇直接提取,高效液相色谱仪在波长280 nm和254 nm处连续测定饲料中维生素A、维生素D3和维生素E的方法.色谱柱为大连依利特Hypersil ODS C18(25 cm×4.6 mm×5 μm),流动相为甲醇-水,流速为1.2 mL/min.维生素A、维生素D3、维生素E的质量浓度分别在1.0 mg/L~20.0 mg/L、0.5 mg/L~15.0 mg/L 、2.5 mg/L~50.0 mg/L范围内与峰面积呈良好的线性关系,检测限分别为0.3×10-6 μg、0.04×10-6 μg、5.0×10-6 μg,相对标准偏差分别为1.6 %、2.7 %、2.4 %,平均回收率分别为99 %、102 %、98 %. 相似文献
73.
Da Chen Bixian Mai Jie Song Eddy Y. Zeng 《Environmental pollution (Barking, Essex : 1987)》2009,157(7):2023-2029
Little data are available on organochlorine contamination in Chinese terrestrial birds of prey. This study examined the presence of PCBs, DDTs and other organochlorine pesticides in various raptors from northern China. DDE exhibited the highest concentrations among targeted compounds. Greatest levels (23.5-1020 mg/kg lipid weight) were observed in Eurasian sparrowhawks. This may be due to their stopover in southeastern China, where high DDT and dicofol applications have been documented. Residential kestrels exhibited much lower DDE, but similar PCB and HCH concentrations. ΣTEQs and PCB-126/-77 concentration ratios exhibited significant positive correlations with ΣPCB concentrations, respectively. Similar results were also demonstrated by a meta-analysis of previously published data across avian species. Possible hepatic sequestration of coplanar PCB-77, -126, -169 and -118 was observed as liver TEQs increased in Eurasian sparrowhawks. These observations may indicate an induction of CYP1A enzymes, as a result of elevated contamination in some species. 相似文献
74.
通过正交试验,得到了DAT-IAT工艺和A/DAT-IAT工艺处理城市污水的常规指标去除和生态毒理指标削减的最优运行条件。结果表明,在正交试验的同一工艺中,COD去除最优运行条件的出水COD值优于生态毒性削减最优运行条件的出水COD值,但前者出水的生态毒性较大。由于厌氧池的水解酸化作用,A/DAT-IAT工艺对COD和生态毒性的处理效果均优于DAT-IAT工艺,并且回流总能耗低于DAT-IAT工艺,但是出水COD仍不达标。为了降低进入工艺的COD的总量,以絮凝沉淀做为预处理工艺,并采用Al残留量最小的絮凝剂投药量以降低出水中残留Al带来的生态风险。结果表明,在COD去除最优运行条件下,具有絮凝预处理的工艺对COD的去除效果优于没有絮凝预处理的工艺。絮凝-A/DAT-IAT工艺在COD去除最优运行条件下出水COD为104.46 mg/L,满足排放标准。在毒性削减最优运行条件下,具有絮凝预处理的工艺的出水生态毒性有所上升,但是污染物的总量得到了大幅削减。絮凝-A/DAT-IAT工艺与DAT-IAT工艺相比,在污染物去除效率得到大幅增加的同时,生态毒性得到有效控制,生态安全得到了有效的保障。 相似文献
75.
微曝气Fenton氧化法处理模拟双酚A废水的效果及其生物验证 总被引:2,自引:1,他引:1
研究了微曝气Fenton氧化法关键工艺参数对模拟双酚A(BPA)废水处理效果的影响,并从活性污泥性质和污染物去除率两方面,采用膜生物反应器(membrane bioreactor, MBR)对微曝气Fenton氧化法的处理效果进行了实验验证,为实现BPA废水的生物处理奠定基础。结果表明,初始pH值、反应时间、H2O2/COD(质量浓度比)、H2O2/Fe2+ (摩尔浓度比)、反应温度及曝气量均对预处理效果有较大影响,在最佳条件下,COD去除率可达70%,BOD/COD值则由原废水的0.02提高到0.50以上。MBR处理上述出水的结果表明,经微曝气Fenton氧化处理BPA的废水,可较好地适应后续的生化处理。 相似文献
76.
77.
Biosorption of nickel(II) from aqueous solution by Aspergillus niger: Response surface methodology and isotherm study 总被引:1,自引:0,他引:1
In the present study, the effects of biosorbent Aspergillus niger dosage, initial solution pH and initial Ni(II) concentration on the uptake of Ni(II) by NaOH pretreated biomass of A. niger from aqueous solution were investigated. Batch experiments were carried out in order to model and optimize the biosorption process. The influence of three parameters on the uptake of Ni(II) was described using a response surface methodology (RSM) as well as Langmuir and Freundlich isotherm models. Optimum Ni(II) uptake of 4.82 mg Ni(II) g−1 biomass (70.30%) was achieved at pH 6.25, biomass dosage of 2.98 g L−1 and initial Ni(II) concentration of 30.00 mg L−1 Ni(II). Langmuir and Freundlich were able to describe the biosorption isotherm fairly well. However, prediction of Ni(II) biosorption using Langmuir and Freundlich isotherms was relatively poor in comparison with RSM approaches. The biosorption mechanism was also investigated by using Fourier transfer infrared (FT-IR) analysis of untreated, NaOH pretreated, and Ni(II) loaded A. niger biomass. 相似文献
78.
79.
双酚A及其类似物对斑马鱼胚胎及幼鱼的毒性效应 总被引:1,自引:0,他引:1
为探讨双酚A及其类似物对鱼类早期生长发育的毒性效应,研究了双酚A及其7种类似物对斑马鱼胚胎及仔鱼的毒性效应。通过对胚胎的孵化率、心率、仔鱼体长等指标进行测定分析,结果显示:(1)双酚A及其7种类似物都可使斑马鱼胚胎出现心包水肿、卵黄囊肿、脊柱弯曲和尾部弯曲等症状。(2)综合考虑斑马鱼78 hpf胚胎心率、120 hpf胚胎孵化率及7 dpf仔鱼体长抑制率等指标,8种受试物中双酚P(BPP)的毒性最大,其次是双酚AP(BPAP)、双酚AF(BPAF)、双酚Z(BPZ),然后是双酚A(BPA)、双酚B(BPB)、双酚F(BPF),双酚S(BPS)的毒性最小,每种受试物的浓度与受精卵的孵化率、仔鱼心率呈明显负相关关系,与体长抑制率呈明显正相关关系。8种受试物毒性与辛醇-水分配系数(log K_(OW))呈正相关关系,log K_(OW)越大毒性则越大。 相似文献
80.
Sapna Johnson Dipankar Patra P. Dureja 《Journal of environmental science and health. Part. B》2013,48(4):491-501
Abstract Azadirachtin‐A on exposure to UV‐light (254 nm) as a thin film on glass surface gave a isomerised (Z)‐2‐ methylbut‐2‐enoate product. Half‐life of azadirachtin‐A as thin film under UV light was found to be 48 min. Azadirachtin ‐A was irradiated along with saturated and unsaturated fatty acids, and fatty oils under ultra‐violet light as thin film. Saturated fatty acid increased the rate of photodegradation of azadirachtin‐A, whereas unsaturated fatty acids such as oleic, linoleic and elaidic acid reduced the rate of degradation. Castor, linseed and olive oil accelerated the rate of degradation, whereas neem oil showed no or little change in the rate of degradation of azadirachtin‐A. None of these fatty acids and fatty oils were effective in controlling the rate of degradation of azadirachtin‐A under UV‐light as thin film. 相似文献