Effect of barium sulfate modification on the SO2 tolerance of V2O5 /TiO2 catalyst for NH3-SCR reaction

Sulfur poisoning of V_2O_5/BaSO_4–TiO_2(VBT),V_2O_5/WO_3–TiO_2(VWT) and V_2O_5/BaSO_4–WO_3–TiO_2(VBWT) catalysts was performed in wet air at 350℃ for 3 hr,and activities for the selective catalytic reduction of NO_x with NH_3 were evaluated for 200–500℃.The VBT catalyst showed higher NO_x conversions after sulfur poisoning than the other two catalysts.The introduction of barium sulfate contributed to strong acid sites for the as-received catalyst,and eliminated the redox cycle of active vanadium oxide to some extent,which resulted in a certain loss of activity.Readily decomposable sulfate species formed on VBT-S instead of inactive sulfates on VWT-S.These decomposable sulfates increased the number of strong acid sites significantly.Some sulfate species escaped during catalyst preparation and barium sulfate was reproduced during sulfur poisoning,which protects vanadia from sulfur oxide attachment to a great extent.Consequently,the VBT catalyst exhibited the best resistance to sulfur poisoning.     

基于环境质量管理的城市综合环境绩效评估研究

文章以26个省会城市2004~2013年的样本数据,从环境健康、生态保护、资源与能源利用、环境治理等4个方面开展研究,构建了包括4项二级指标、12项三级指标和26项四级指标在内的城市综合环境绩效指标体系。研究发现,大部分城市的综合环境绩效历年差异明显,东、中、西部的环境绩效有明显的差异。因此,文章认为应该进一步优化环境绩效指标体系,充分体现区域差异特点,通过实施城市综合环境绩效考核来提高城市环境质量管理水平。     

Modification of Ce02-ZrO2 catalyst by potassium for NOx-assisted soot oxidation

Potassium-modified ceria-zirconia catalyst was synthesized by wetness impregnation method. The ageing treatment was performed in static air at 800℃ for 20 hr to evaluate the thermal stability of the catalyst. The catalysts were characterized by X-ray diffraction,BET surface area, oxygen storage capacity, NOx-temperature programmed desorption and soot-temperature programmed oxidation measurements. By introduction of potassium, the maximum soot oxidation rate temperature (Tm) of the ceria-zirconia based catalyst decreased from 525 to 428℃ in the presence of NO under a loose contact mode. The shift of Tm of the K-modified catalyst after ageing is only 15℃. The enhanced activity of the aged catalyst mainly lies in the promotional effect of potassium on the NOx/oxygen storage cacity as well as the soot-catalyst contact.     

Remediating ethylbenzene-contaminated clayey soil by a surfactant-aided electrokinetic (SAEK) process

The objectives of this research are to investigate the remediation efficiency and electrokinetic behavior of ethylbenzene-contaminated clay by a surfactant-aided electrokinetic (SAEK) process under a potential gradient of 2 Vcm(-1). Experimental results indicated that the type of processing fluids played a key role in determining the removal performance of ethylbenzene from clay in the SAEK process. A mixed surfactant system consisted of 0.5% SDS and 2.0% PANNOX 110 showed the best performance of ethylbenzene removed in the SAEK system. The removal efficiency of ethylbenzene was determined to be 63-98% in SAEK system while only 40% was achieved in an electrokinetic system with tap water as processing fluid. It was found that ethylbenzene was accumulated in the vicinity of anode in an electrokinetic system with tap water as processing fluid. However, the concentration front of ethylbenzene was shifted toward cathode in the SAEK system. The electroosmotic permeability and power consumption were 0.17 x 10(-6)-3.01 x 10(-6) cm(2)V(-1)s(-1) and 52-123 kW h m(-3), respectively. The cost, including the expense of energy and surfactants, was estimated to be 5.15-12.65 USD m(-3) for SAEK systems, which was 2.0-4.9 times greater than that in the system of electrokinetic alone (2.6 USD m(-3)). Nevertheless, by taking the remediation efficiency of ethylbenzene and the energy expenditure into account for the overall process performance evaluation, the system SAEK was still a cost-effective alternative treatment method.     

热备用应急电源在化工企业中的应用

介绍了热备用应急电源(EPS)的分类、原理、选型、特点以及操作注意事项。随着智能化程度的提高、快速切换型离线技术的应用,具有抗晃电、稳频稳压、离线运行、快速切换、等功率拖动电机特性的应急电源产品,已不仅仅局限于变电所、厂区照明的应用,而且还用于安全设备、生产设备等。     

Enhanced CO2 adsorptive performance of PEI/SBA-15 adsorbent using phosphate ester based surfactants as additives

In this study,a series of polyetherimide/SBA-15: 2-D hexagonal P6 mm,Santa Barbara USA(PEI/SBA-15) adsorbents modified by phosphoric ester based surfactants(including tri(2-ethylhexyl)phosphate(TEP),bis(2-ethylhexyl) phosphate(BEP) and trimethyl phosphonoacetate(TMPA))were prepared for CO_2 adsorption.Experimental results indicated that the addition of TEP and BEP had positive effects on CO_2 adsorption capacity over PEI/SBA-15.In particular,the CO_2 adsorption amount could be improved by around 20% for 45PEI–5TEP/SBA-15 compared to the additive-free adsorbent.This could be attributed to the decrease of CO_2 diffusion resistance in the PEI bulk network due to the interactions between TEP and loaded PEI molecules,which was further confirmed by adsorption kinetics results.In addition,it was also found that the cyclic performance of the TEP-modified adsorbent was better than the surfactant-free one.This could be due to two main reasons,based on the results of in situ DRIFT and TG-DSC tests.First and more importantly,adsorbed CO_2 species could be desorbed more rapidly over TEP-modified adsorbent during the thermal desorption process.Furthermore,the enhanced thermal stability after TEP addition ensured lower degradation of amine groups during adsorption/desorption cycles.     

Effects of WOx modification on the activity, adsorption and redox properties of CeO2 catalyst for NOx reduction with ammonia

A series of WO₃/CeO₂ (WOx/CeO₂) catalysts were synthesized by wet impregnation of ammonium metatungstate on a CeO₂ support. The resulting solid acid catalysts were characterized by X-ray diffraction (XRD), UV-Vis spectroscopy (UV-Vis), Raman spectroscopy (Raman), in-situ Fourier transform infrared spectroscopy (in-situ FT-IR) of ammonia adsorption, NH₃-TPD, H₂ temperature-programmed reduction (H₂-TPR), NH₃/NO oxidation and activity measurements for NOx reduction by NH₃ (NH₃-SCR). The results show that polytungstate (WOx) species are the main species of tungsten oxide on the surface of ceria. The addition of tungsten oxide enhances the Brönsted acidity of ceria catalysts remarkably and decreases the amount of surface oxygen on ceria, with strong interaction between CeO₂ and WOx. As a result, the N₂ selectivity of NH₃ oxidation and NH₃-SCR at high temperatures (> 300℃) is enhanced. Therefore, a wide working temperature window in which NOx conversion exceeds 80% (NOx conversion > 80%) from 200 to 450℃, is achieved over 10 wt.% WOx/CeO₂ catalyst. A tentative model of the NH₃-SCR reaction route on WOx/CeO₂ catalysts is presented.     

我国钢铁工业节能环保工作现状与展望

分析了我国钢铁企业环保工作现状,指出了节能环保工作中存在的主要问题,提出了“十五”后期节能环保工作的主要目标和对策。     

单甲脒在水生生物中的积累和释放

本文朱生环境中对单甲脒在鱼和藻类中的积累释放及鱼体中的ＢＣＦ值进行了研究，结果表明，鱼体在３，５，６ｄ的ＢＣＦ值分别为３．５３，４．７３及５．２９，鱼体中单米积累为内脏〉锶〉肌肉，饲养７ｄ达积累最高量；藻类在６ｈ后达积累最高量；单甲脒在水藻和鱼（内脏）的富集比分别为１：３及１：１２。     

Predominance of clade D <Emphasis Type="Italic">Symbiodinium</Emphasis> in shallow-water reef-building corals off Kish and Larak Islands (Persian Gulf,Iran)

Scleractinian coral species harbour communities of photosynthetic taxa of the genus Symbiodinium. As many as eight genetic clades (A, B, C, D, E, F, G and H) of Symbiodinium have been discovered using molecular biology. These clades may differ from each other in their physiology, and thus influence the ecological distribution and resilience of their host corals to environmental stresses. Corals of the Persian Gulf are normally subject to extreme environmental conditions including high salinity and seasonal variation in temperature. This study is the first to use molecular techniques to identify the Symbiodinium of the Iranian coral reefs to the level of phylogenetic clades. Samples of eight coral species were collected at two different depths from the eastern part of Kish Island in the northern Persian Gulf, and Larak Island in the Strait of Hormuz. Partial 28S nuclear ribosomal (nr) DNA of Symbiodinium (D1/D2 domains) were amplified by polymerase chain reaction (PCR). PCR products were analyzed using single stranded conformational polymorphism and phylogenetic analyses of the LSU DNA sequences from a subset of the samples. The results showed that Symbiodinium populations were generally uniform among and within the populations of eight coral species studied, and there are at least two clades of Symbiodinium from Kish and Larak islands. Clade D was detected from eight of the coral species while clade C was found in two of species only (one species hosted two clades simultaneously). The dominance of clade D might be explained by high temperatures or the extreme temperature variation, typical of the Persian Gulf. Publication of this article was held up owing to technical problems. The publisher apologizes sincerely for this lengthy delay.