酸-碘改性壳聚糖-膨润土脱除单质汞特性及机理分析

为探明烟气中酸性气体(SO2,NO,HCl)和H2O对酸-碘改性壳聚糖-膨润土吸附剂脱除单质汞(Hg0)的影响和脱除机理,在小型固定床试验台架上开展了Hg0脱除的实验研究.结果表明:由于SO2与Hg0在吸附剂表面活性位上存在竞争吸附,SO2抑制吸附剂对Hg0的脱除.H2O和较高浓度(1000μg/m3)的NO对脱汞具有明显地促进作用.由于低温下HCl与Hg0较高的反应能垒,HCl对脱汞没有影响.与单一烟气成分影响相比,在SO2、NO、HCl和H2O的联合作用下,吸附剂的长时间脱汞性能得到大幅提高.机理分析表明壳聚糖首先被酸中的H+质子化,之后再吸附酸与KI反应生成的I2,进而有效地吸附Hg0.量子化学计算表明壳聚糖在酸性条件下对I2具有良好的吸附特性,改性壳聚糖吸附剂对Hg0具有较好的吸附能力,其吸附能约为127kJ/mol.     

厌氧/好氧运行方式对颗粒污泥形成的影响

序批式反应器(SBR)饱食-饥饿的运行方式对颗粒污泥的形成具有一定的促进作用,为考察该作用的大小,采用小试SBR装置,按照厌氧/好氧(An/O)交替的方式运行,考察了强化饱食-饥饿效应对颗粒污泥形成的影响.研究发现,An/O方式运行的第7d,反应器内即有微颗粒出现,30d后该颗粒污泥系统趋于稳定.通过对典型周期内厌氧和好氧末期污泥中胞外聚合物(EPS)的测定分析,发现厌氧末期的胞外多糖(PS)由最初的13mg/g-VSS逐渐上升到后期的55mg/g-VSS,且厌氧饱食阶段的PS含量一直高于好氧饥饿段.在颗粒形成初期,好氧饥饿阶段胞外蛋白质(PN)的平均含量为10mg/g-VSS,大于厌氧饱食段的6mg/g-VSS;而在颗粒成熟阶段,好氧末期PN为13mg/g-VSS,厌氧末段为20mg/g-VSS.在整个颗粒污泥的形成过程中,PS含量一直高于PN.由此可见,PS所具有的黏性作用在颗粒的形成中起到了比较重要的作用. An/O交替的运行方式会对SBR所特有饱食/饥饿效应起到强化作用,刺激微生物分泌大量的EPS,同时筛选出具有厌氧储存有机物能力的微生物,从而促进了颗粒污泥的形成.     

Investigation of naphthalene contamination in olive oil from Greece

Abstract

Incidents of using naphthalene in olive orchards as a repellent of olive fly (Bactrocera oleae) have recently been recorded. Naphthalene, the primary ingredient of mothballs, is described to be diluted in plastic bottles and hanged on the trees releasing its characteristic odor which is supposed to repel olive fly. Since naphthalene has been characterized as possibly carcinogenic to humans and animals, it was considered essential to monitor olive oils regarding their potential contamination with this specific pollutant. To this goal, a simple, sensitive and reliable analytical method for the determination of naphthalene in olive oil has been developed. The method involves extraction with ethyl acetate: acetonitrile (1:1) and determination of naphthalene using gas chromatography triple quadrupole mass spectrometry. The method was validated in four fortification levels, 0.005, 0.01, 0.05, and 0.1?mg/kg in accordance with the EU requirements. The obtained results were acceptable as far as validation criteria are concerned, given recoveries between 71% and 87% and RSDs between 5% and 24%. The limit of determination for naphthalene was set at 0.005?mg/kg based on the lowest concentration level being validated with acceptable accuracy. The analytical technique was successfully applied to 75 olive oil samples collected from oil mills in Greece and no positive results of naphthalene were detected.     

Occupational exposures,delivered doses and exposure limits for chromium and nickel†

The interaction of HCH (50 mg/kg) and dietary protein levels on microsomal drug metabolizing enzymes system and liver lipids were studied in the rats for 90 days. The results indicated that rats fed a lower protein diet and HCH has a higher rate of mortality, lower rate of growth and an increased liver weight. A significant induction in the hepatic microsomal aminopyrine‐N‐demethylase, p‐nitroanisole‐O‐dealkylase, benzo(a)pyrene hydroxylase and glutathione‐S‐transferase activity was observed in pesticide treated animals as compared to control animals. The pathological changes observed in liver of HCH treated animals consisted mainly of necrosis and fatty degeneration of hepatocytes. HCH also induced the significant accumulation of cholesterol, triglycerides, phospholipid and total lipid in liver in low protein diet animals. Protein accelerates the metabolism of HCH, resulting in a decrease of HCH concentration with the increase of dietary protein level. A close correlation existed between lipid accumulation, induction of drug metabolizing enzyme system and deposition of HCH in liver.     

Cu(Ⅱ)印迹[CTS/PVP]和[CTS/PVP/C]材料的制备及表征

以壳聚糖(CTS)、聚乙烯吡咯烷酮(PVP)、活性炭(C)为基材,Cu(Ⅱ)为印迹离子,制备了CTS/PVP共混印迹球[Cu(Ⅱ)-IICP]和CTS/PVP/C共混印迹球[Cu(Ⅱ)-IICPC].以Cu(Ⅱ)的吸附量作为评价指标,对两种共混印迹球的制备条件进行了优化.研究结果表明,当CTS/PVP的质量比为6∶4,活性炭质量分数为0.6%,Cu(Ⅱ)模板剂质量分数为0.05%,所制备的两种共混印迹球吸附性能较佳,且对Cu(Ⅱ)有较好的选择吸附性.物理吸附分析结果表明,与未印迹相比印迹材料的比表面积明显增大.FTIR谱图分析,Cu(Ⅱ)模板主要与CTS和PVP中的—NH2和—OH发生了配位作用.XRD谱图分析结果表明,CTS与PVP、C、Cu(Ⅱ)之间发生了相互作用,改变了CTS原有的晶体结构,使其结晶度降低.     

血清中二噁英测定方法的优化

以国内外文献及标准方法为基础,优化了血清中17种2、3、7、8位取代的PCDD/Fs的测定方法,建立了同位素内标稀释-索式萃取一段法层析柱净化-高分辨气质联用分析方法.实验结果表明,17种2、3、7、8位取代的PCDD/Fs的方法检出限范围为3.72—14.74 pg.基质加标实验中目标化合物回收率为94.61%—117.14%,标准参考物质SRM1958中PCDD/Fs的多数单体测定结果也在参考值范围内.实际样品同位素内标回收率为66.2%—95.2%,RSD是4.0%—9.0%.该分析方法准确可靠、灵敏、操作简便,适用于血清中二噁英的测定.     

2,3,7,8-TCDD代谢产物的液-质联用分析

采用肝微粒体体外温孵法,对2,3,7,8-TCDD在大鼠肝微粒体中进行体外代谢研究.利用实验中所建立的液相色谱串联质谱方法对其代谢产物进行直接分析,共鉴别出两类代谢产物,分别为2个单羟基化代谢产物(2-OH-1,3,7,8-TCDD和1-OH-2,3,7,8-TCDD)和双羟基化脱氯的代谢产物.     

碳氮比对厨余垃圾堆肥腐熟度的影响

以厨余垃圾和玉米秸秆作为堆肥原料,采用好氧堆肥的方法,探讨了不同C/N比对堆肥腐熟度的影响。结果表明:从温度、pH、电导率(EC)、腐植酸光学特性(E4/E6)、固相C/N和发芽率指数(GI)来看,只有C/N为21(T4)的处理没有达到无害化和腐熟的要求,其余3个处理均达到腐熟;建议采用C/N为17的方案,厨余垃圾和秸秆按照湿基质量9∶1的比例进行堆肥;如果秸秆资源比较丰富,可采用C/N为19的方案,此时厨余垃圾和秸秆湿基比例为5.7∶1。     

恩诺沙星和硫氰酸红霉素对铜绿微囊藻的毒性研究

研究了恩诺沙星、硫氰酸红霉素暴露对铜绿微囊藻生长和生理的影响.结果显示恩诺沙星、硫氰酸红霉素对铜绿微囊藻的生长有抑制作用,且96h-EC50分别为84.6,48.2mg/L;对铜绿微囊藻的叶绿素荧光和光合色素含量的影响一致,表现为浓度-效应关系;对可溶性蛋白含量的影响表现为低促高抑的现象;丙二醛含量随着抗生素浓度的增加显著增加.可见,恩诺沙星和硫氰酸红霉素能够阻碍铜绿微囊藻的光合作用,抑制可溶性蛋白的合成,从而影响铜绿微囊藻的正常生长.     

Trophic transfer of polybrominated diphenyl ethers and polychlorinated biphenyls in a tidal freshwater marsh

The John Heinz National Wildlife Refuge (NWR) at Tinicum Marsh contains one of the last remaining tidal freshwater marsh communities along the Pennsylvania side of the Delaware River Estuary. The marsh receives a significant load of nutrients and sediment-associated contaminants and is hypothesised to act as an effective trap for these chemicals. The goal of this study was to quantify the levels of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) at various trophic levels at two sites within Tinicum Marsh and assess the factors important in determining their bioaccumulation and trophic transfer. For both PCBs and PBDEs, lipid variation for all species was a large factor in determining contaminant body burden. Also, concentrations in biota increased with increasing trophic level as determined by nitrogen isotope analysis (δ¹⁵N values) at the downstream site within Tinicum Marsh. This trend was less apparent at the upstream site and may be due to differences in feeding behaviours among species between the two sites and/or differences in carbon and nitrogen sources and recycling. These data are valuable in assisting bioaccumulation/trophic transfer studies and serve as benchmarks to which future PCB and PBDE concentrations will be compared.