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991.
Ming Ge Changsheng Guo Xingwang Zhu Lili Ma Zhenan Han Wei Hu Yuqiu Wang 《Frontiers of Environmental Science & Engineering in China》2009,3(3):271-280
ZnO/TiO2 composites were synthesized by using the solvothermal method and ultrasonic precipitation followed by heat treatment in order
to investigate their photocatalytic degradation of methyl orange (MO) in aqueous suspension under UV irradiation. The composition
and surface structure of the catalyst were characterized by X-ray diffraction (XRD), field emission scanning electron microscope
(FE-SEM), and transmission electron microscopy (TEM). The degradation efficiencies of MO at various pH values were obtained.
The highest degradation efficiencies were obtained before 30 min and after 60 min at pH 11.0 and pH 2.0, respectively. A sample
analysis was conducted using liquid chromatography coupled with electrospray ionization ion-trap mass spectrometry. Six intermediates
were found during the photocatalytic degradation process of quinonoid MO. The degradation pathway of quinonoid MO was also
proposed. 相似文献
992.
993.
994.
稻壳焦炭导电特性的影响因素 总被引:2,自引:0,他引:2
为开发生物质焦炭电磁屏蔽材料,研究了各种因素对稻壳焦炭导电特性的影响规律.利用自制的高温炭化试验装置,考察了炭化终温、升温速率、终温下的保留时间、粒径大小、催化剂种类及配比等因素对焦炭电阻率的影响规律.研究结果表明:炭化终温对稻壳焦炭电阻率影响较大,特别是在1000℃以下,提高炭化终温可将焦炭电阻率从106 Ω·cm以上降低到2Ω·cm左右;而当炭化终温从1000℃提高到1400℃时,电阻率仅从2Ω·cm左右降低到1.5Ω·cm左右.提高升温速率会降低焦炭产率,但对电阻率的影响不大.延长炭化终温时间对降低电阻率有一定作用,但当物料粒径较小时其作用几乎可以忽略.Fe2O3和NiO可作为炭化催化剂降低焦炭电阻率,两者催化效果相当,稻壳与催化剂的最佳质量配比在50:1左右.当炭化终温>1000℃、升温速率为20℃·min-1、保留时间为30min、稻壳粒径为0.1~0.3mm、稻壳:催化剂=50:1时,所获焦炭电阻率为0.2~1.0Ω·cm. 相似文献
995.
BAF法处理高浓度含盐炼油污水 总被引:1,自引:0,他引:1
阐述了BAF法处理高浓度含盐炼油污水的原理和启动运行过程,分析了运行中出现的问题,并提出改进建议。 相似文献
996.
复合纳米Fe_3O_4的制备及其控磷效能的研究 总被引:1,自引:1,他引:0
采用氧化沉淀法在羧甲基纤维素(CMC)体系中制备了以纳米Fe3O4为核心,外包覆羧甲基纤维素的复合纳米Fe3O4.对比研究了复合纳米Fe3O4和微米Fe3O4对水中磷的吸附以及对土壤中磷的固化,并考察了添加纤维素酶在此过程中所起的作用.结果表明,在水中微米Fe3O4的平衡吸附量为3.2 mg/g,而复合纳米Fe3O4为2.1 mg/g.当将纤维素酶(用以降解包覆在氧化铁表面的羧甲基纤维素)添加到复合纳米Fe3O4吸附磷的溶液中,复合纳米Fe3O4的除磷效率(86%)接近于微米Fe3O4(90%),说明羧甲基纤维素的存在减弱了复合纳米Fe3O4的吸附能力.在土柱实验中,将2种Fe3O4悬浊液注入到10 cm高的土壤柱中,72%的复合纳米Fe3O4穿过土壤柱溢出,而微米Fe3O4完全滞留在土壤柱中没有溢出.原始土壤的固磷率为30%,注入复合纳米Fe3O4的土壤固磷率达到45%,而将纤维素酶和复合纳米Fe3O4一起注入土壤中固磷效率提高到74%. 相似文献
997.
998.
Xiaoyan Shi Kebin He Jie Zhang Yongliang Ma Yunshan Ge Jianwei Tan 《Frontiers of Environmental Science & Engineering in China》2010,4(1):30-34
Oxygenated fuels are known to reduce particulate matter (PM) emissions from diesel engines. In this study, 100% soy methyl
ester (SME) biodiesel fuel (B100) and a blend of 10% acetal denoted by A-diesel with diesel fuel were tested as oxygenated
fuels. Particle size and number distributions from a diesel engine fueled with oxygenated fuels and base diesel fuel were
measured using an Electrical Low Pressure Impactor (ELPI). Measurements were made at ten steady-state operational modes of
various loads at two engine speeds. It was found that the geometric mean diameters of particles from SME and Adiesel were
lower than that from base diesel fuel. Compared to diesel fuel, SME emitted more ultra-fine particles at rated speed while
emitting less ultra-fine particles at maximum speed. Ultra-fine particle number concentrations of A-diesel were much higher
than those of base diesel fuel at most test modes. 相似文献
999.
松花江及哈尔滨市饮用水雌激素活性的调查与分析 总被引:4,自引:1,他引:3
利用固相萃取/酵母双杂交法调查了哈尔滨市饮用水及周边松花江水的雌激素活性.结果表明,松花江哈尔滨段江水在夏秋两季的雌激素活性[以雌二醇当量(EEQs)计]为528~965 pg·L-1,其中上游水源地水雌激素活性水平较高.自来水厂对雌激素活性的去除率为34.6%~50.5%,整个水处理工艺并不能有效去除源水中的雌激素类物质,致使出厂水仍具有298~718 pg·L-1的雌激素活性;自来水厂所采用的3种净水工艺中以混凝沉淀工艺对雌激素活性的去除最为稳定,去除率为11.4%~26.1%,占总去除的32.9%~69.0%,而砂滤与氯消毒工艺出水不稳定,雌激素活性有时较进水有升高现象发生.此外,由于管网配送过程中产生了二次污染,致使管网水雌激素活性较出厂水最高可升高44.9%.7次取样测得哈尔滨市管网水的雌激素活性为347~1 362 pg·L-1,均值为738 pg·L-1. 相似文献
1000.
The UF membrane with molecular weight cuto (MWCO) ranging from 2 to 100 kDa and XAD-8 resin were employed to identify
the characteristic of molecular weight (MW) distribution of wastewater e uent organic matter (EfOM) in terms of TOC and UV254,
as well as the amounts of the hydrophilic/hydrophobic organic fractions in di erent MW ranges. Then, the nanofiltration (NF)
membrane fouling experiments were carried out using the above fractionated water to investigate the e ect of MW distribution and
hydrophilic/hydrophobic characteristics of EfOM on the membrane flux decline using the fractionated water samples. The experimental
results have shown that 45.61% of the total organics belongs to the low MW one, among which the percentage of the hydrophilic
organics with low MW (less than 2 kDa) was up to 28.07%, while that of the hydrophobic organics was 17.54%. In particular,
the hydrophilic fraction was found to be the most abundant fraction in the e uents. MW distribution has a significant e ect on the
membrane fouling. When the MWwas less than 30 kDa, the lower the MW, the larger was the specific flux decline, while in the case of
MW higher than 30 kDa, the higher the MW, the larger was the specific flux decline, and the decline degree of low MW organics was
larger than the high MW one. With the same MW distribution range, specific flux decline of the hydrophilic organic was considerably
slower than that of the hydrophobic organic, which indicated that the hydrophobic organic fractions dominantly contribute to the flux
decline. 相似文献