中心组合设计优化S-Cr-TiO2催化剂光降解工艺条件

在确定的温度和光照条件下,采用中心组合设计法研究了固相反应法合成的硫与铬共掺杂二氧化钛(S-Cr-TiO2)光催化剂与水溶苯胺蓝(ANB)可见光降解过程中的三个作用因子:催化剂的浓度、水溶苯胺蓝水溶液的pH值及其初始浓度之间的相互作用关系,得到了影响因子与降解速率之间的回归方程及因素之间相互作用的响应面图.结果表明,S...     

Beyond hypoxia：Occurrence and characteristics of black blooms due to the decomposition of the submerged plant Potamogeton crispus in a shallow lake

Organic matter-induced black blooms(hypoxia and an offensive odor) are a serious ecosystem disasters that have occurred in some large eutrophic shallow lakes in China. In this study, we investigated two separate black blooms that were induced by Potamogeton crispus in Lake Taihu, China. The main physical and chemical characteristics, including color- and odor-related substances, of the black blooms were analyzed. The black blooms were characterized by low dissolved oxygen concentration(close to 0 mg/L), low oxidation-reduction potential, and relatively low pH of overlying water. Notably higher Fe2+and∑S2-were found in the black-bloom waters than in waters not affected by black blooms. The black color of the water may be attributable to the high concentration of these elements, as black FeS was considered to be the main substance causing the black color of blooms in freshwater lakes. Volatile organic sulfur compounds, including dimethyl sulfide, dimethyl disulfide, and dimethyl trisulfide, were very abundant in the black-bloom waters. The massive anoxic degradation of dead Potamogeton crispus plants released dimethyl sulfide, dimethyl disulfide, and dimethyl trisulfide, which were the main odor-causing compounds in the black blooms. The black blooms also induced an increase in ammonium nitrogen and soluble reactive phosphorus levels in the overlying waters. This extreme phenomenon not only heavily influenced the original lake ecosystem but also greatly changed the cycling of Fe, S, and nutrients in the water column.     

Compositions and sources of organic acids in fine particles (PM2.5) over the Pearl River Delta region, south China

Organic acids as important constituents of organic aerosols not only influence the aerosols' hygroscopic property, but also enhance the formation of new particles and secondary organic aerosols. This study reported organic acids including C14–C32fatty acids, C4–C9dicarboxylic acids and aromatic acids in PM2.5collected during winter 2009 at six typical urban, suburban and rural sites in the Pearl River Delta region. Averaged concentrations of C14–C32fatty acids, aromatic acids and C4– C9 dicarboxylic acids were 157, 72.5 and 50.7 ng/m3, respectively. They totally accounted for 1.7% of measured organic carbon. C20–C32fatty acids mainly deriving from higher plant wax showed the highest concentration at the upwind rural site with more vegetation around, while C14–C18fatty acids were more abundant at urban and suburban sites, and dicarboxylic acids and aromatic acids except 1,4-phthalic acid peaked at the downwind rural site. Succinic and azelaic acid were the most abundant among C4–C9dicarboxylic acids, and 1,2-phthalic and 1,4-phthalic acid were dominant aromatic acids. Dicarboxylic acids and aromatic acids exhibited significant mutual correlations except for 1,4-phthalic acid, which was probably primarily emitted from combustion of solid wastes containing polyethylene terephthalate plastics. Spatial patterns and correlations with typical source tracers suggested that C14–C32fatty acids were mainly primary while dicarboxylic and aromatic acids were largely secondary. Principal component analysis resolved six sources including biomass burning, natural higher plant wax, two mixed anthropogenic and two secondary sources; further multiple linear regression revealed their contributions to individual organic acids. It turned out that more than 70% of C14–C18fatty acids were attributed to anthropogenic sources, about 50%–85% of the C20–C32fatty acids were attributed to natural sources, 80%–95% of dicarboxylic acids and 1,2-phthalic acid were secondary in contrast with that 81% of 1,4-phthalic acid was primary.     

冬季东海、南黄海中DMS和DMSP浓度分布及影响因素研究

于2011年12月~2012年1月现场测定了东海、南黄海表层海水中二甲基硫(DMS)及其前体物质二甲巯基丙酸内盐(DMSP分为溶解态DMSPd和颗粒态DMSPp)的含量,研究了它们的浓度分布规律及其影响因素,并对DMSPp的粒级分布和DMS的海-气通量进行了探讨.结果表明,表层海水中DMS、DMSPd和DMSPp的浓度分别在0.58~4.14、0.37~7.86和4.29~25.76 nmol·L-1之间,平均值分别为(2.20±0.82)、(2.12±1.66)和(11.98±6.23)nmol·L-1.DMS、DMSPp与叶绿素a(Chl-a)呈现明显的正相关关系,并且它们的周日变化趋势基本一致,说明浮游植物生物量是影响研究海域内DMS和DMSP生产分布的关键因素.另外,DMSPd浓度和总细菌丰度表现出一定的负相关,这可能是在细菌释放的DMSP裂解酶的作用下DMSPd会发生裂解生成DMS.研究发现,5~20μm的微型浮游植物是海区内Chl-a和DMSPp的主要贡献者.此外,冬季东海、南黄海表层海水DMS的海-气通量在0.61~25.52μmol·(m2·d)-1之间,平均值为(8.30±5.92)μmol·(m2·d)-1.     

正辛烷替代甲苯用于降凝剂酯化物生产的研究

比较了多种溶剂替代甲苯,优选正辛烷替代甲苯用于降凝剂酯化物的生产。室内试验、工业生产和现场应用表明,试验正辛烷后,酯化物和降凝剂的质量没有影响,生产环境得到了改善。     

微生物燃料电池处理含S2-/NH4+废水的研究

以除硫硝化微生物燃料电池(Microbial Fuel Cell,MFC)处理含S~(2-)/NH_4~+的模拟无机废水,研究了不同进水S~(2-)浓度下MFC的产电性能、污染物去除效果和阳极室硫累积情况.结果表明,除硫硝化MFC可实现同步阳极除硫和阴极硝化,并通过非生物电化学作用和生物电化学作用共同产电.进水S~(2-)浓度为(60.8±2.9)、(131.7±2.4)、(161.7±4.5)和(198.1±3.1)mg·L~(-1)时,最佳阳极碳刷清洗周期分别为3、3、3、4个换水周期,前3个进水浓度下的换水周期可分别缩短为6、8和8 h.MFC阴极硝化完全,不受进水S~(2-)浓度影响,但氧从阴极向阳极的渗漏导致阳极库仑效率较低(40%).适当增加进水S~(2-)浓度可增强MFC的产电性能并提高S~(2-)去除负荷和颗粒硫累积比.除硫硝化MFC适宜的进水S~(2-)浓度为(161.7±4.5)mg·L~(-1),相应的最大功率密度为5.77 W·m~(-3),周期产电量为(141.0±5.2)C,S~(2-)去除负荷为(0.31±0.00)g·L~(-1)·d~(-1),颗粒硫累积比达58%.阳极碳纤维丝上沉积有粒径约100 nm的颗粒硫.阳极悬浮物与沉积物相比,悬浮物中S0含量比例较高,而S6+含量比例较低.     

活性污泥合成聚羟基烷酸酯代谢机制研究进展

聚羟基烷酸酯(PHAs)是生物制备型环境友好塑料,具有广阔的应用前景.活性污泥合成PHAs可降低生产成本,实现废水处理厂剩余污泥的减量化和资源化.研究微生物合成PHAs的代谢机制,有利于优化PHAs的工业化生产,目前其代谢研究多集中在以纯菌种合成PHAs,而以活性污泥合成PHAs的研究尚不成熟.资料表明,DO变化对活性污泥合成PHAs的代谢途径有显著影响,进而改变其PHAs产物的产量和单体组成.综述了活性污泥合成PHAs在厌氧/好氧工艺、微氧/好氧工艺、缺氧/好氧工艺、好氧动态底物投加工艺条件下的代谢机制,分析了现有PHAs合成代谢模型中存在的问题,展望了PHAs合成代谢机制研究的发展方向.     

大玉竹低聚糖硫酸酯抗HSV-2病毒活性的研究

从传统中药大玉竹中提取低聚糖Ｐｏｏｓ,用吡啶－氯磺酸法制备了它的硫酸酯衍生物Ｓ－Ｐｏｏｓ,产物经红外鉴定,证实Ｐｏｏｓ硫酸酯化后羟基连上硫酸基,硫含量为８．４７％,取代度（Ｄｓ）为０．６体外实验研究了Ｐｏｏｓ、Ｓ－Ｐｏｏｓ对非洲绿猴肾细胞（Ｖｅｒｏ）的细胞毒怀和抗单纯疱疹病毒２型（ＨＳＶ－２）活性。结果表明,Ｐｏｏｓ和Ｓ－Ｐｏｏｓ都无细胞毒性。Ｐｏｏｓ本身无抗病毒活性,对ＨＳＶ－２引起的细胞病变和     

阳离子聚丙烯酸酯对污泥脱水性能的影响

以比阻(SRF)、过滤时间(TTF)和泥饼含水率作为评价污泥脱水性能的指标,考察2种阳离子聚丙烯酸酯CPAL-1和CPAL-2对污泥脱水性能的影响,并与阳离子絮凝剂三氯化铁(FeCl3)、聚合氯化铝(PAC)、阳离子聚丙烯酰胺(CPAM)和阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)的作用效果进行比较.还测定了Zeta电位(ZP)和滤液中胞外聚合物(EPS)含量的变化来探讨CPAL的作用机理.实验结果表明,经CPAL-1调理的污泥脱水效果优于CPAM、PAC和FeCl3,明显优于CPAL-2和CTAB.当CPAL-1的投加剂量为0.200 g/g干基时,SRF、TTF和泥饼含水率降至最低,依次为5.37 ×1011m/kg、70 s和75.73％.CPAL主要通过电中和、吸附架桥作用和溶出EPS等来改善污泥的沉降脱水性能.     

煤气脱硫废料综合利用新工艺

针对煤气脱硫废料（简称废料）的成分（硫、碳、萘及少量其他有机物）,提出了一种处理废料的新工艺,先用乙酸乙酯提取废料中的萘和少量其他有机物,再用复合溶剂B加热溶解废料,热过滤得碳粉,最后将溶液冷却结晶分离出硫。实验结果表明：在乙酸乙酯与废料的质量比（R1）为3.75,提取温度为60℃,提取时间为4h的条件下,萘回收率为98%,纯度大于等于70%,在复合溶剂B与提取剩余物的质量比（R2）为2.69,过滤温度为100℃的条件下,硫回收率接近100%,纯度大于等于99%,碳回收率和纯度为100%。