碳氮比对废水好氧脱氮中含氮气态产物的影响

针对目前人们对好氧脱氮中气态产物认识不清的问题,采用SBR反应器,以人工配制的NO3--N废水为处理对象,对影响好氧脱氮的COD/N进行了深入研究,测定了三种主要含氮气态产物(NO、NO2、N2O),揭示了好氧状态下生物脱氮的途径和机理。通过对COD/N分别为9、12、15、18的系统氮元素的全程跟踪测定,得到系统内各含氮化合物的变化规律。结果表明,三种气体的产生同COD/N有着密切的关系,低C/N会导致NO、NO2和N2O的积累,最多达总脱氮量的9%。研究结果还表明当进水COD/N为15时,既保证了良好的脱氮效果且抑制了NO、NO2、N2O三种有害气体的大量产生。     

STAC有机膨润土的表征及其处理垃圾渗滤液的研究

文章以钙基蒙脱石为原料,经钠化后与十八烷基三甲基氯化铵(又称1831,简称STAC)进行离子交换反应,合成有机膨润土,通过XRD、IR 、SEM等测试仪,对有机膨润土的结构进行了分析,同时利用改性后的STAC有机膨润土对某垃圾填埋场中的渗滤液进行处理,用GC/MS对处理前后垃圾渗滤液中主要有机组分进行了分析,结果表明,...     

不同进水条件对SBR工艺脱氮除磷效能的影响

采用人工配水,研究进水在不同pH值,碳源类型,碳氮比条件下,厌氧/好氧/缺氧(A/O/A)sBR工艺对生物法脱氮除磷效能的影响.结果表明:不同的进水条件对反应器的影响较大,当pH值为7.5,乙酸钠为碳源,碳氮比为1.4时,反应器运行效果最佳,系统对PO43--P,NH4+-N的去除率分别达到97.28%,99.5%.N...     

土壤pH、Eh对土壤-苦丁茶树系统中铅分布的影响

以苫丁茶冬青(Ilex kudingcha C.J.Tseng)扦插苗(15个月生)进行盆栽实验,通过土施H2SO4、Ca(OH)2和复合肥,改变土壤pH和氧化还原电位(Eh),研究土壤pH、Eh条件对土壤-苦丁茶树系统中铅分布的影响.结果表明:在所研究的土壤pH范围内,从酸性到碱性变化,铅在土壤中含量分布趋于减少,在...     

垃圾焚烧飞灰中二噁英削减技术研究

二噁英(PCDD/Fs)是多氯代二苯并二噁英和多氯代二苯并呋喃的总称,因具有生物蓄积性、高毒性、难降解等特点而备受关注。垃圾焚烧是二噁英的重要来源,而其中超过50%的二噁英以飞灰形式排出。文章综述了热分解法、光降解法、机械化学法、生物降解法等飞灰二噁英毒性削减技术的国内外研究进展,并在此基础上对飞灰二噁英削减技术研究和管理提出了建议。     

供碳源载体及其在低碳氮比污水处理中的应用研究

为解决低C/N污水的脱氮问题,本实验自行研制开发了一种新型碳聚合物载体.对该载体进行低C/N污水的生物膜脱氮研究,考察了HRT、pH、DO、温度等因素对系统同步硝化反硝化脱氮效果的影响.结果表明:在C/N比为4、pH=8、DO=1 mg/L、HRT=6 h,T=24℃的条件下,氨氮及总氮的去除率分别可以达到90%和70...     

用GC/MS分析火灾后苯板产生固体废物中的有机物

采用GC/MS方法对某苯板厂火灾后产生的固体废弃物进行检测分析.结果表明,在苯板火灾后产生的固体废弃物中检测出61种化合物,其中被美国EPA列入优先污染物的苯系物、萘和蒽等占总有机物12.2％.     

快速高效去除微囊藻的GO/QPEI复合纳米材料

本研究合成了一种新型高效的去除铜绿微囊藻(Microcystis aeruginosa)的氧化石墨烯/季铵盐聚乙烯亚胺(GO/QPEI)纳米复合材料.GO/QPEI在pH为4~10的条件下都具有高效去除M.aeruginosa的能力,其去除能力在2 min内可达96%以上.GO/QPEI对微囊藻的吸附更符合Freundlich方程,最大吸附量为5.58×1011cells·mg-1.吸附动力学表明GO/QPEI的假二级吸附反应.GO纳米片和QPEI的协同效应是其高效去除微囊藻的主要机制.     

Effects of metal and acidic sites on the reaction by-products of butyl acetate oxidation over palladium-based catalysts

Catalytic oxidation is widely used in pollution control technology to remove volatile organic compounds. In this study, Pd/ZSM-5 catalysts with different Pd contents and acidic sites were prepared via the impregnation method. All the catalysts were characterized by means of N2 adsorption- desorption, X-ray fluorescence （XRF）, HE temperature programmed reduction （H2-TPR）, and NH3 temperature programmed desorption （NH3-TPD）. Their catalytic performance was investigated in the oxidation of butyl acetate experiments. The by-products of the reaction were collected in thermal desorption tubes and identified by gas chromatography/mass spectrometry. It was found that the increase of Pd content slightly changed the catalytic activity of butyl acetate oxidation according to the yield of CO2 achieved at 90%, but decreased the cracking by-products, whereas the enhancement of strong acidity over Pd-based catalysts enriched the by-product species. The butyl acetate oxidation process involves a series of reaction steps including protolysis, dehydrogenation, dehydration, cracking, and isomerization. Generally, butyl acetate was cracked to acetic acid and 2- methylpropene and the latter was an intermediate of the other by-products, and the oxidation routes of typical by-products were proposed. Trace amounts of 3-methylpentane, hexane, 2-methylpentane, pentane, and 2-methylbutane originated from iso4merization and protolysis reactions.     

Pd/activated carbon sorbents for mid-temperature capture of mercury from coal-derived fuel gas

Higher concentrations of Hg can be emitted from coal pyrolysis or gasification than from coal combustion, especially elemental Hg. Highly efficient Hg removal technology from coal-derived fuel gas is thus of great importance. Based on the very excellent Hg removal ability of Pd and the high adsorption abilities of activated carbon（AC） for H2 S and Hg, a series of Pd/AC sorbents was prepared by using pore volume impregnation, and their performance in capturing Hg and H2 S from coal-derived fuel gas was investigated using a laboratory-scale fixed-bed reactor. The effects of loading amount, reaction temperature and reaction atmosphere on Hg removal from coal-derived fuel gas were studied. The sorbents were characterized by N2 adsorption, X-ray diffraction（XRD） and X-ray photoelectron spectroscopy（XPS）. The results indicated that the efficiency of Hg removal increased with the increasing of Pd loading amount, but the effective utilization rate of the active component Pd decreased significantly at the same time. High temperature had a negative influence on the Hg removal. The efficiency of Hg removal in the N2-H2S-H2-CO-Hg atmosphere（simulated coal gas） was higher than that in N2-H2S-Hg and N2-Hg atmospheres, which showed that H2 and CO, with their reducing capacity, could benefit promote the removal of Hg. The XPS results suggested that there were two different ways of capturing Hg over sorbents in N2-H2S-Hg and N2-Hg atmospheres.