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661.
硝基苯属于典型的难降解有机化合物,通过雾化-多相协同臭氧氧化技术对硝基苯废水的处理效果进行了分析研究.通过对实验中的主要影响因素进行分析,结果表明,液滴粒径对硝基苯降解速率常数具有负相关性;紫外灯功率、活性炭投加量和水温对硝基苯降解速率常数具有正相关性;pH值和臭氧投加量对硝基苯降解速率常数具有最佳值.雾化-多相协同臭氧氧化技术对硝基苯的降解过程遵从一级化学反应动力学方程.经验动力学方程为:C=C0exp(-4.54×10-6Q0.50G0.31W0.11t). 相似文献
662.
石墨炉原子吸收分光光度法测定土壤中总铬 总被引:1,自引:0,他引:1
建立了土壤中总铬测定的石墨炉原子吸收分光光度法;以塞曼效应扣除背景,优化了石墨炉灰化、原子化温度、停留时间及基体改进剂用量。结果表明:当原子化温度为2 700℃,灰化温度为700℃,原子化时间2 s,灰化时间为9 s;基体改进剂用量为3~5μL时,仪器可以达到最佳工作状态。该方法铬元素浓度在0~32μg/L内呈良好的线性关系,相关系数r=0.999 9,检出限为0.3 mg/kg;对土壤标样GSS-1和ESS-1的铬测定精密度均小于5%,相对误差在-4.8%~-0.7%之间,方法的灵敏度和准确度均符合要求。因此,石墨炉原子吸收分光光度法测定土壤中总铬具有原子化温度高、干扰少、灵敏度高等特点可适用土壤中总铬的测定。 相似文献
663.
陕西地震现场应急技术系统在汶川地震中的应用 总被引:1,自引:0,他引:1
"十五"期间,国家在31个省(直辖市、自治区)建立了全国一体化的地震应急与救援指挥技术体系,其中包括地震现场应急技术系统.在四川汶川8.0级大地震中,陕西省地震局现场应急技术系统重点完成现场通信保障、协助现场考察等工作任务.通过对现场工作的总结分析,旨在把汶川8.0级地震现场工作中应急技术系统一些好的做法继续发扬,对在实际工作中发现的问题,提出一些改进参考建议,以便日后现场应急系统能更好地为大震现场工作服务. 相似文献
664.
Many studies on methane emissions from animal manure have revealed that animal manure is a major source of methane emissions
to the atmosphere that can have negative consequences for people, animals and environment. In general, the release of methane can
be influenced by the type of feed taken by animals, temperature, manure characteristics and so on. This study aimed at quantifying
and comparing methane release from dairy manure with di erent piling treatments. Four treatments were designed including manure
piling height 30, 45, 60 cm and adding 6 cm manure every day until the piling height was 60 cm. Static chamber method and gas
chromatography were adopted to measure the methane emissions from April to June in 2009. Methane emission rates of all four
manure treatments were low in the first week and then increased sharply until reaching the peak values. Subsequently, all the methane
emission rates decreased and fluctuated within the steady range till the end of the experiment. Wilcoxon nonparametric tests analysis
indicated that methane emission rate was greatly influenced by manure piling height and manner. There were no significant relationships
between methane emission rates and the temperatures of ambience and heap. However, regression analysis showed that the quadratic
equations were found between emission rates of all treatments and the gas temperature in the barrels. 相似文献
665.
Yang Li Junfeng Niu Lifeng Yin Wenlong Wang Yueping Bao Jing Chen Yanpei Duan 《环境科学学报(英文版)》2011,23(11):1911-1918
Pentachlorophenol could be photocatalytically reduced with superoxide radicals in aqueous solution under simulated sunlight irradiation. 相似文献
666.
The removal of four dissolved organic matter (DOM) fractions, non-acid hydrophobics, hydrophobic acids, hydrophilics and transphilics, was achieved by coagulation-UV/H2O2 oxidation in post-pharmaceutical wastewater (PhWW). Coagulation with Polyferric chloride (PFC), Polymeric ferric sulfate (PFS) and Polymeric aluminum ferric chloride (PAFC) was studied separately to evaluate the effects of the initial pH and coagulant dosage. The coagulation-UV/H2O2 oxidation method resulted in much higher reduction rates for dissolved organic carbon (DOC) (by 75%) and UV254 (by 92%) than coagulation or UV/H2O2 oxidation alone. The proportion of non-acid hydrophobics, hydrophobic acids, transphilics and hydrophilics removed by coagulation was 54%, 49%, 27% and 12 %, while the combined treatment removed 92%, 87%, 70% and 39%, respectively. Parallel factor analysis (PARAFAC) of fluorescence measurements revealed that the humic-like fluorescent component C4 showed the highest removal (by 44%) during the coagulation stage. After coagulation-UV/H2O2 treatment, the humic-like fluorescent component C3 had the highest removal (by 72%), whereas xenobiotic organic fluorescent components C1 and C4 remained recalcitrant to decomposition. Significant correlations (R2 > 0.8) between C1 and the hydrophobic acids and non-acid hydrophobics suggested the possibility of using fluorescence spectroscopy as an effective tool to assess variations in DOM fraction treatment efficacy in coagulation-UV/H2O2 systems. After the combined treatment, toxic inhibition of cellular activity by post PhWW decreased from 88% to 47% and biodegradability increased from 0.1 to 0.52. 相似文献
667.
Elevated arsenic (As) in groundwater poses a great threat to human health. Coagulation using mono- and poly-Fe salts is becoming one of the most cost-effective processes for groundwater As removal. However, a limitation comes from insufficient understanding of the As removal mechanism from groundwater matrices in the coagulation process, which is critical for groundwater treatment and residual solid disposal. Here, we overcame this hurdle by utilizing microscopic techniques to explore molecular As surface complexes on the freshly formed Fe flocs and compared ferric(III) sulfate (FS) and polyferric sulfate (PFS) performance, and finally provided a practical solution in As-geogenic areas. FS and PFS exhibited a similar As removal efficiency in coagulation and coagulation/filtration in a two-bucket system using 5 mg/L Ca(ClO)2. By using the two-bucket system combining coagulation and sand filtration, 500 L of As-safe water (< 10 μg/L) was achieved during five treatment cycles by washing the sand layer after each cycle. Fe k-edge X-ray absorption near-edge structure (XANES) and As k-edge extended X-ray absorption fine structure (EXAFS) analysis of the solid residue indicated that As formed a bidentate binuclear complex on ferrihydrite, with no observation of scorodite or poorly-crystalline ferric arsenate. Such a stable surface complex is beneficial for As immobilization in the solid residue, as confirmed by the achievement of much lower leachate As (0.9 μg/L–0.487 mg/L) than the US EPA regulatory limit (5 mg/L). Finally, PFS is superior to FS because of its lower dose, much lower solid residue, and lower cost for As-safe drinking water. 相似文献
668.
A two-phase anaerobic reactor fed with glucose substrate (3 g chemical oxygen demand (COD)/L) was used to investigate the effects of toxic metals on the degradation of organics and the soluble microbial product (SMP) formation. Low concentrations of Ni(II) (5 and 10 mg/L) promoted the acid phase, whereas high concentrations (15, 20, and 25 mg/L) exhibited an inhibitory effect on, but did not alter the fermentative method, which mainly involved the fermentation of propionic acid. The methanogenic microorganism exhibited a strong capability adapting constantly increased Ni(II) levels. The acid phase was an accumulation stage of SMP. In the absence of Ni(II), the high-molecular-weight material in the effluent SMP mainly contained polysaccharide, tryptophan, and casein. Methanogens metabolized most of the polysaccharide, the whole tryptophan content, and part of the casein, leading to the presence of humic acid and protein in effluent. After Ni(II) dosage, the protein and polysaccharide of the acid phase increased, and tryptophan changed, while casein remained stable. More protein than polysaccharide was produced, suggesting the prominent function of protein when addressing the negative effect of toxic metals. The analysis of DNA confirmed the change of bacterial activity. 相似文献
669.
670.
Niu Yayi Li Yuqiang Wang Mingming Wang Xuyang Chen Yun Duan Yulong 《Environmental science and pollution research international》2022,29(4):5295-5312
Environmental Science and Pollution Research - Sandy cropland ecosystems are major terrestrial ecosystems in semi-arid regions of northern China’s Horqin Sandy Land, where they play an... 相似文献