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TiO2晶须在深度净化饮用水过程中失活原因分析 总被引:1,自引:0,他引:1
研究了TiO2晶须在光催化深度净化饮用水过程中失活的原因及相应的再生方法.对TiO2薄膜失活前后的AFM、XRD表征,以及对失活前后TiO2晶须酸洗液的ICP分析表明,TiO2晶须失活的主要原因是难溶性碳酸钙在催化剂表面的沉积.由于自来水中钙离子的存在以及有机物光催化降解过程中产生的二氧化碳,生成的难溶性碳酸钙覆盖在催化剂的表面,影响了紫外光的透光率,限制了光生电子和光生空穴的生成,导致催化剂的光催化能力逐渐下降直至失活;失活的催化剂通过1 mol/L的盐酸酸洗4 h后,光催化活性可以恢复到95%左右;多次失活/再生的催化剂的光催化活性保持较好的稳定性. 相似文献
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The herbicide paraquat belongs to the group of the bipyridylium salts. In California, it is used primarily for control of broad-leaved grasses in fruit orchards and plantations, as a cotton defoliant, and for inter-row control in many crop and non-crop areas. In plants, paraquat causes the formation of reactive radicals leading to cell membrane damage and ultimately rapid desiccation. Soil clay minerals have a greater influence on paraquat adsorption and inactivation compared with soil organic matter following an application. Degradation mechanisms include photolysis, chemical, and microbial degradation, but these processes are generally extremely slow. In California during 2000–2014, paraquat was used primarily for the cultivation of almonds, cotton, alfalfa, and grapes: median value for an application and annual mass applied statewide were 0.53 kg ion/ha and 280 Mg, respectively. Paraquat was undetected in groundwater as a non-point source pollutant. Detections in surface waters (0.42–3.6 μg/L) were <1%. In earthworms and other invertebrates there is limited paraquat accumulation as toxic effects are mitigated via soil inactivation. Paraquat is among the most embryotoxic contaminants for bird eggs, but not to adult; it causes toxic and teratogenic effects in amphibians, and toxic effects in honeybees, fish, and other aquatic species. 相似文献
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TiO2 nanotubes (TiNT) were prepared by a hydrothermal treatment and modified by three kinds of amines,namely ethylenediamine,polyetherimide and tetraethylenepentamine (TEPA),to study their CO2 adsorption properties from gas streams.The resultant samples were characterized by X-ray diffraction,transmission electron microscopy,and infrared spectroscopy,as well as low temperature N 2 adsorption.CO2 capture was investigated in a dynamic packed column at 30℃.TEPA-modified TiO2 nanotubes showed the highest adsorption capacity of 167.64 mg/g because it had the highest amino-group content among the three amines.CO2 fixation on TiNT impregnated by TEPA was investigated at 30,50,and 70℃,and the adsorption capacity increased slightly with temperature.Following the adsorption step,the sorbents were regenerated by temperature programmed desorption,and the TiNT-TEPA sample,as CO2 sorbent,was found to be readily regenerated and energy-efficient.The cycle test also revealed that the TiNT-TEPA adsorbent is fairly stable,with only a 5% drop in the adsorption capacity after 10 adsorption/desorption cycles.In addition,the CO2 adsorption behavior was investigated with the deactivation model,and which showed an excellent prediction for the TiNT-TEPA breakthrough curves. 相似文献
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在连续性反应器内以臭氧-光催化技术氧化硫化氢,证实了臭氧对光催化脱除硫化氢有促进作用,探讨了可能存在的主要基元反应和二氧化钛失活的原因,考察了反应温度、臭氧含量、硫化氢初始体积分数等因素对臭氧-光催化技术脱除硫化氢的影响。结果表明,臭氧在光催化作用下快速分解为活性氧离子或自由基,硫化氢在臭氧和光催化联合作用下快速氧化为二氧化硫,最终转化为硫酸;硫酸在二氧化钛表面的沉积使其催化活性降低,导致硫化氢和二氧化硫的转化率逐渐下降。研究还发现,当硫化氢的初始体积分数为100×10-6时,臭氧和硫化氢的最佳摩尔比约为2:1;臭氧-光催化脱除硫化氢的最佳温度为70℃左右;降低硫化氢的初始体积分数可大幅度降低二氧化硫的选择性。 相似文献
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宁南霉素对烟草花叶病毒的生物活性 总被引:6,自引:2,他引:6
研究了宁南霉素 (Ningnanmycin)对烟草花叶病毒 (tobaccomosaicvirus,TMV)的预防、治疗和钝化作用 .结果表明 ,宁南霉素喷施 5d后接种TMV ,对烟草花叶病毒的预防效果为 5 8.4 1% ;宁南霉素浓度为 15 0~ 2 0 0 μg/mL时 ,对烟草花叶病毒的治疗效果达 79.6 5 %~ 84 .96 % ,治疗效果最好为接种TMV 1d后喷施 2 0 0 μg/mL宁南霉素 ;宁南霉素对烟草花叶病毒的钝化效果为 76 .99%~ 83.19% ,混合 4 5min的TMV与宁南霉素等体积混合液效果更好 .试验证明 ,宁南霉素对烟草花叶病有很好的治疗作用 ,对烟草花叶病毒有显著的钝化效果 .图 1表 3参 15 相似文献
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