宏量和微量元素在炉内喷钙脱硫过程中的作用

研究添加粉煤灰对脱硫过程的作用,实验在滴管炉上进行,温度为１２００℃,结果表明,一些宏量元素的金属氧化物对脱硫过程具有催化作用,但这种催化作用随Ｆｅ２Ｏ３掺加量的改变而变化,先升高后降低,有一个最佳值;一些微量元素的金属氧化物对脱硫过程更强的催化氧化作用,当ＭｎＯ２的掺加量为３％时,充效率提高近１倍。     

环境空气监测中NO_x、SO_2空白值的研究

本文研究了惠州市市区环境空气监测中氮氧化物、二氧化硫的现场空白值与室内空白值的差异,得出了二氧化硫测定的两种空白值相差无几,氮氧化物测定的两种空白值相差较显著的结论。提出了在计算环境空气氮氧化物浓度时,扣除现场空白值是消除分析误差的一个不可忽视的环节。讨论了现场空白值受环境条件（气温、光照强度等）影响的情况     

NiB2O4 (B = Mn or Co) catalysts for NH3-SCR of NOx at low-temperature in microwave field

● Microwave-assisted catalytic NH₃-SCR reaction over spinel oxides is carried out. ● SCR reaction temperature is tremendously lowered in microwave field. ● NO conversion of NiMn₂O₄ is highly up to 90.6% at 70°C under microwave heating. Microwave-assisted selective catalytic reduction of nitrogen oxides (NO_x) was investigated over Ni-based metal oxides. The NiMn₂O₄ and NiCo₂O₄ catalysts were synthesized by the co-precipitation method and their activities were evaluated as potential candidate catalysts for low-temperature NH₃-SCR in a microwave field. The physicochemical properties and structures of the catalysts were characterized by X-ray diffraction (XRD), Scanning electron microscope (SEM), N₂-physisorption, NO adsorption-desorption in the microwave field, H₂-temperature programmed reduction (H₂-TPR) and NH₃-temperature programmed desorption (NH₃-TPD). The results verified that microwave radiation reduced the reaction temperature required for NH₃-SCR compared to conventional heating, which needed less energy. For the NiMn₂O₄ catalyst, the catalytic efficiency exceeded 90% at 70 °C and reached 96.8% at 110 °C in the microwave field. Meanwhile, the NiMn₂O₄ also exhibited excellent low-temperature NH₃-SCR reaction performance under conventional heating conditions, which is due to the high BET specific surface area, more suitable redox property, good NO adsorption-desorption in the microwave field and rich acidic sites.     

脱硫类水滑石衍生复合氧化物不同方法的制备与表征

采用尿素水解法和共沉淀法制备了MgAl类水滑石,高温焙烧获得衍生复合氧化物.采用X射线衍射(XRD)、热重分析(TG-DTG)、扫描电镜(SEM)、N2-吸附/脱附和CO2程序升温脱附(CO2-TPD)等手段对所制备的复合氧化物结构特征进行表征,并研究其对SO2脱除性能的差异.结果表明,共沉淀法制备的MgAlO复合氧化物比尿素法具有更大的比表面积(148.1m2·g-1)和更多碱性位,这些特点可能促使该方法制备的复合氧化物具有更高的SO2储存容量和反应速率.采用尿素法和共沉淀法制备的MgAl水滑石复合氧化物在700℃温度下SO2吸附容量分别可达0.55g·g-1和0.79 g·g-1.     

铁-镧系合金氧化物污水除磷及再生简

采用共沉淀法制备了系列铁-镧系合金氧化物并研究其除磷能力。结果表明：以铁、镧摩尔比为0.08的吸附剂除磷能力最强，吸附曲线适合Langmuir等温线方程。该吸附剂的吸附量受pH影响显著，pH在4.0~7.0之间时吸附量较大。进行了抗共存阴离子能力测试，结果表明CO₃^2-对磷吸附量影响较大，给出了共存阴离子对吸附量的影响顺序。对该吸附剂进行了真空高温再生，再生率最高可达62.27%。     

Catalytic oxidation of o-chlorophenol over Co2XAl (X= Co,Mg, Ca,Ni) hydrotalcite-derived mixed oxide catalysts

• Superior catalytic activity observed for o-chlorophenol oxidation on Co₂MgAlO. • The reducibility, oxygen species and basicity influenced catalytic activity. • The organic by-products were generated in o-chlorophenol catalytic oxidation. A cobalt-based hydrotalcite-like compound was prepared using a constant-pH coprecipitation method. Cobalt-transition metal oxides (Co₂XAlO, X= Co, Mg, Ca and Ni) were investigated for the deep catalytic oxidation of o-chlorophenol as a typical heteroatom contaminant containing chlorine atoms. The partial substitution of Co by Mg, Ca or Ni in the mixed oxide can promote the catalytic oxidation of o-chlorophenol. The Co₂MgAlO catalyst presented the best catalytic activity, and could maintain 90% o-chlorophenol conversion at 167.1°C, compared only 27% conversion for the Co₃AlO catalyst. The results demonstrated that the high activity could be attributed to its increased low-temperature reducibility, rich active oxygen species and excellent oxygen mobility. In the existence of acid and base sites, catalysts with strong basicity also showed preferred activity. The organic by-products generated during the o-chlorophenol catalytic oxidation over Co₂MgAlO catalyst included carbon tetrachloride, trichloroethylene, 2,4-dichlorophenol, and 2,6-dichloro-p-benzoquinon, et al. This work provides a facile method for the preparation of Co-based composite oxide catalysts, which represent promising candidates for typical chlorinated and oxygenated volatile organic compounds.     

环境修复中锰氧化物与变价重金属交互作用的研究进展

氧化-还原过程是影响重金属环境行为的重要过程.锰氧化物作为重要的天然氧化剂,通过对变价重金属的氧化还原和吸附作用,影响着其在环境中的形态、生物有效性乃至归趋,具有很高的环境修复潜力和应用价值.近年来对锰氧化物和变价重金属元素的研究主要集中在以下几个方面:生物氧化锰的形成与多铜氧化酶体系的关系;锰氧化物与变价重金属的交互作用的机制及其影响因素,尤其锰氧化物的空间结构和作用位点的影响.目前,锰氧化物在环境修复中的应用主要集中在水环境修复方面,土壤体系及土壤微界面还很鲜见.同时土壤体系中影响锰氧化物与重金属交互作用的因素更多,其过程也更为复杂.本文通过总结锰氧化物与变价重金属交互作用的研究进展,对比不同重金属种类之间反应机制的差别,为更好的理解锰氧化物的环境作用提供基础,也期望能够进一步拓展其在污染环境的修复中的应用范围.     

宁夏水泥行业氮氧化物减排现状及对策建议

介绍了2012年底宁夏水泥行业生产规模现状及氮氧化物减排现状,分析了宁夏水泥行业氮氧化物减排工作进展及存在的主要问题,并提出了相应的对策建议。     

磷酸盐对铁锰复合氧化膜去除地表水中氨氮的影响

利用中试实验系统,研究磷酸盐对石英砂滤料表面负载的铁锰复合氧化膜去除地表水中氨氮的影响.结果表明,当水温为17.2~21.9℃时,随着运行时间的推移,未投加磷酸盐滤柱的氨氮去除效果有所下降;而投加5~15μg·L~(-1)磷酸盐滤柱的氨氮去除效果稳定,且去除率大于95.3%.当水温低于10.5℃时,滤柱出水氨氮浓度超标,此时通过提高磷酸盐投加量至30μg·L~(-1)或增加滤层厚度均可实现出水氨氮浓度达标.但随着系统持续运行,仅增加滤层厚度的滤柱出水氨氮浓度会再次超标.水温在6.5~10.5℃之间,投加30μg·L~(-1)磷酸盐的条件下,120 cm和80 cm活性滤层的最大安全进水氨氮浓度分别为2.34 mg·L~(-1)和1.95 mg·L~(-1).滤柱中生物灭活实验表明活性氧化膜对氨氮的去除同时包括催化氧化作用和生物作用;投加磷酸盐条件下,活性氧化膜的总活性和催化氧化活性分别是未投加磷酸盐条件的1.36倍和1.79倍,这表明磷酸盐促进了活性氧化膜的催化氧化活性.     

Reduction behaviors of permanganate by microbial cells and concomitant accumulation of divalent cations of Mg2+, Zn2+, and Co2+

Permanganate treatment is widely used for disinfection of bacteria in surface-contaminated water. In this paper, the fate of the dissolved permanganate in aqueous solution after contact with cells of Pseudomonas fluorescens was studied. Concomitant accumulation of divalent cations of Mg~(2+), Zn~(2+), and Co~(2+) during precipitation of Mn oxides was also studied. The time course of the Mn concentration in solution showed an abrupt decrease after contact of Mn(VII) with microbial cells, followed by an increase after ～ 24 hr.XRD analysis of the precipitated Mn oxides, called biomass Mn oxides, showed the formation of low-crystalline birnessite. Visible spectroscopy and X-ray absorption near edge structure(XANES) analyses indicated that dissolved Mn(VII) was reduced to form biomass Mn oxides involving Mn(IV) and Mn(III), followed by reduction to soluble Mn(II).The numbers of electron transferred from microbial cells to permanganate and to biomass Mn oxides for 24 hr after the contact indicated that the numbers of electron transfer from microbial cell was approximately 50 times higher to dissolved permanganate than to the biomass Mn oxides in present experimental conditions. The 24 hr accumulation of divalent cations during formation of biomass Mn oxides was in the order of Co~(2+) Zn~(2+) Mg~(2+).XANES analysis of Co showed that oxidation of Co~(2+) to Co~(3+) resulted in higher accumulation of Co than Zn and Mg. Thus, treatment of surface water by KMnO_4 solution is effective not only for disinfection of microorganisms, but also for the elimination of metal cations from surface water.