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11.
1 IntroductionAseveryoneknown ,chelatingresincontainingheteroatomsuchassulfur,nitrogen ,andoxygenpossessexcellentadsorptionandselectivitypropertiesformetalions,especiallyfornoblemetallicions.Therefore ,manyeffortshavebeendonetopreparetheabove mentionedre…  相似文献   
12.
利用气-固相固定床反应装置考察了Rh交换的Al-MCM-41在高气体空速条件下对贫燃NOx的选择性催化还原活性,考察了氧含量对其的影响。结果表明,在200000h~(-1)的气体空速、O_2/C_3H_6=20、603K时,NO转化率为74.3%。利用原位FTIR技术研究了该催化剂的表面吸附物种及表面程序升温反应行为,并结合实验观察探讨了贫燃条件下Rh-Al-MCM-41催化剂上NO的选择性催化还原机理。  相似文献   
13.
以黑曲霉菌丝体作为吸附剂,通过静态吸附实验研究了各种因素对其吸附去除废水中Pb2+的影响。结果表明:当Pb2+初始浓度为50 mg/L,吸附剂用量为1.0 g/L,吸附时间为45 min,pH为5.0时,吸附效果最佳。此时吸附量为44.1 mg/g,去除率为90.86%。使用准二阶动力学方程可较好的拟合黑曲霉对Pb2+的吸附,表明该吸附过程以化学吸附为主。等温吸附过程可用Freundlich方程描述,说明该吸附为多分子层吸附。傅立叶红外光谱分析表明,黑曲霉吸附剂表面的酯羰基(-COO-)、羧基(-COOH )和羟基(-OH )在吸附Pb2+的过程中发挥主要作用。  相似文献   
14.
利用长光路傅立叶变换红外光谱技术(LP-FTIR),用相对速率方法研究大气中氯氟烃替代物HFC152a(CHF2CH3)和HCFC22(CHClF2)与OH自由基反应速率常数,用紫外光照射O3和H2O的方法产生OH自由基。实验测定了700Tor大气压力和常温(298±2k)下的反应速率常数值:k(HFCl52a+OH)=(2.90±0.09)×10-14cm3·molecule-1.S-1,k(HCFC22+OH)=(3.80±0.24)×10-15cm3.Molecule-1.S-1,统计误差为2σ  相似文献   
15.
Polyethylene terephthalate bottles containing natural spring water were used to study the leaching effect of carbonyl compounds after one year storage under real conditions of exposure. Ultraviolet-B and ultraviolet-A spectra of direct sunlight were acquired during the experiment. Leaching of acetone, acetaldehyde, and formaldehyde reached steady state after 210 days of outdoor storage, with the following concentrations: 434 ± 22, 345 ± 18, and 94 ± 5 µg/L, respectively. The increase due to sunlight exposure in comparison with laboratory storage in the dark was around 10%, 16%, and 36%. The leaching process of all three carbonyl compounds was found to follow the first-order kinetics. Photo-degradation of Polyethylene terephthalate bottles and the appearance of carboxyl end-groups were followed by attenuated total reflectance infrared spectra. After 313 days of storage under direct sunlight, new peaks appeared in the regions of 1770–1920 cm?1 and 1685–1490 cm?1. Cations, anions, total dissolved solids, pH, and conductivity were also measured during the storage period. Additionally, microbiological measurements as well as statistical analyses were also carefully discussed.  相似文献   
16.
Green source Ep was extracted from marine alga waste. The molecule model structure of Ep was studied and constructed. PAC-Ep coagulation system improves the efficiency of removal efficiency. Synergistic effects between NPs and HA make a big difference to enhance efficiency. Mechanism is charge neutralization, hydrogen bonding and adsorbing-complexing Enteromorpha polysaccharide (Ep) extracted from alga a novel green coagulant aid for nanoparticles (NPs) and heavy metal ions removal and the structure of EP was intensively studied in this study. The integration of Ep with polyaluminum chloride (PAC-Ep) coagulants exhibited higher coagulation performance than that of the polyaluminum chloride (PAC) because of the negatively charged NPs suspension and humic aid (HA) solution. Significant high removal efficiencies of dissolved organic matter (94.1%), turbidity (99.3%) and Zn ions (69.3%) were achieved by the PAC-Ep coagulants. The dual-coagulation properties of PAC-Ep for different pollutants was based on multiple mechanisms, including (i) Al3+ charge neutralization; (ii) hydroxy aluminum hydroxyl bridging formed polynuclearhydroxy complexes bridge and sweep colloidal particles; (iii) adsorption and bridging of Ep chain for the NPs and heavy metal ions. Results indicated that the destabilization of colloid was induced by the coexisting HA and higher removal was achieved as ions adsorption was enhance in the presence of HA complexation. On the basis of that, the extraction of polysaccharide is a promising candidate for its high coagulation performance in water treatment.  相似文献   
17.
青岛4个海水浴场微塑料的分布特征   总被引:9,自引:7,他引:2  
微塑料(microplastics,MPs)作为有毒有害物质的载体,会随洋流作用传播、被生物摄入并影响其生长代谢,已经成为全球性的环境问题.为揭示青岛近岸MPs分布规律和影响因素,利用表层现场采样、密度悬浮法分离、光学显微镜和荧光显微镜结合观察的方法,研究了青岛近岸4个典型海水浴场海水和沉积物中MPs丰度分布,分析了各海水浴场MPs的粒径范围、形状和化学成分.结果表明,4个浴场海水中MPs含量范围为5.05×10~3~1.25×10~4个·m~(-3);沉积物中MPs含量范围为1.91×10~3~4.35×10~3个·m~(-2),海水中MPs含量高的站位相应沉积物中含量也高.4种粒径范围MPs在海水及沉积物中皆表现为粒径大小与其含量成负相关,例如,海水中MPs含量最高的为0.05~0.1 mm(4.10×10~3个·m~(-3)),最低为1~5 mm(2.05×10~3个·m~(-3)).纤维状MPs在海水中和沉积物中均占比最高,分别为48.73%和37.51%,其次为颗粒和碎片型.用ATR-FTIR从海水中检测出8种塑料类型,含量由高到低为:PETPPPSPEPVC≈SBPA≈PMA;沉积物中检测出6种MPs,同海水相比,没有PMA和PA,含量较高的4种MPs类型与海水相同.沉积物中的MPs在粒径、形状及成分上与海水具有相似性,说明青岛近岸海水浴场的海水及沉积物可能有相同的污染源:包装行业、服装纺织业、旅游业.研究结果为揭示沿海旅游型城市海水浴场MPs的分布及来源、开展海岸带MPs污染研究与监督工作提供了基础数据.  相似文献   
18.
研究鸟嘌呤与一系列卤代烃反应的加合产物 ,利用HPLC二极管阵列检测器得到的特征紫外光谱 (UV)对加合产物样品进行了鉴定 ,然后加合产物经薄层 (TLC)分离 ,再进一步做红外 (FTIR)鉴定 ,从而得到鸟嘌呤 卤代烃氧位和氮位加合物的红外光谱表征 .研究表明 ,鸟嘌呤卤代烃的氮位加合物异构体的紫外光谱吸收峰的波长在 240~250nm之间 ,氧位加合物UV波长在 260~270nm附近 .鸟嘌呤与本文涉及的各卤代烃的加合物的红外光谱之间差别不大 :其氮位加合物在 1700cm-1处 ,均有CO的特征吸收峰 ;其氧位加合物的红外光谱亦相近 .  相似文献   
19.
An optimized code for the near real-time retrieval of line of sight, temperature and volume-mixing ratio profiles of five key species (O3, H2O, HNO3, CH4 and N2O) from infrared limb spectra recorded by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) experiment on board the ENVISAT-1 satellite was developed as part of an ESA-supported study. In this code line of sight and temperature are retrieved simultaneously among themselves, but sequentially with respect to the volume-mixing ratio of the five key species. The sequential retrieval leaves unaccounted the mapping of line of sight and temperature errors in the retrieved volume-mixing ratio of the constituents. This paper illustrates an algorithm that provides the a-posteriori evaluation of temperature and line-of-sight-induced error on the retrieved volume-mixing ratio of the MIPAS key species. It is shown that in most cases temperature and line-of-sight-induced error provides a significant contribution to the total volume-mixing ratio error. The variability of this error as a function of latitude, season and atmospheric model is also analyzed.  相似文献   
20.
考察了在常温常压条件下,等离子体分别协同SiO2、Al2O3、NiO/Al2O3降解甲苯的性能,并从材料的介电常数、对甲苯的吸附性及臭氧分解能力等角度分析了不同活性表现的原因,同时,采用原位红外技术研究了甲苯降解过程中催化剂表面吸附物种的变化.结果表明,当甲苯浓度为100 ppm,气体流量为100 mL·min-1时,一定范围内,甲苯降解率随着能量密度、介电常数、吸附性及臭氧分解能力的提高而提高.甲苯在催化剂表面的吸附对其降解途径有十分重要的影响:在放电区域中加入SiO2,甲苯仍然在气相中完成降解;而存在Al2O3 及NiO/Al2O3时,甲苯氧化成苯甲酸的过程主要发生在催化剂表面,是甲苯催化降解的关键步骤,苯甲酸在活性位点的积累将降低催化剂的反应活性.  相似文献   
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