三硝基甲苯的γ-辐照降解实验研究

基于三硝基甲苯(TNT)溶液采用常规处理方法难以降解,采用60Co-γ射线对三硝基甲苯溶液进行辐照降解,研究了吸收剂量、初始浓度、溶液初始pH值、双氧水(H2O2)等因素对辐照降解效果的影响.实验结果表明,60Co-γ射线辐照能够有效地降解三硝基甲苯.三硝基甲苯溶液初始浓度为5—50 mg.L-1,当接受不超过15 kGy剂量时,三硝基甲苯的降解率可达100%,化学需氧量(COD)去除率可达55%;弱酸性和碱性环境更有利于三硝基甲苯的降解和COD的去除;加入少量H2O2时,三硝基甲苯降解率和COD去除速率均随之增加,但过高的H2O2加入量将会抑制三硝基甲苯的去除,并且加入H2O2的量愈大其抑制作用愈明显.     

Effect of dye auxiliaries on chemical oxygen demand and colour competitive removal from textile effluents using Posidonia oceanica

The use of an abundant and widely distributed seagrass species, Posidonia oceanica, as a biosorbent for the direct dye Yellow 44 was successfully shown. The studies were performed on the single dyestuff dissolved in water and in a dyebath containing agents commonly used in the textile industry, i.e. a surfactant (Lavotan TBU), a sequestring agent (Meropan DPE), a softening agent (Eurosoft CI10) and a salt (NaCl). The colour reduction results showed that P. oceanica was found to be more efficient for removal of Yellow 44 from an aqueous solution (162 mg g^?1) than from a dyebath solution (135 mg g^?1), according to the Langmuir isotherm model. For the single dyestuff sorption, Fourier transform infrared and X-ray photoelectron spectroscopy studies highlighted chemical sorption between the dye alcohol function and the sorbent acid function. The chemical oxygen demand removal percentages were found to be 54.9 and 76.6% for Yellow 44 dissolved in aqueous solution and in dyebath solution, respectively. This confirmed the both sorption of the chemical auxiliaries and the dye on P. oceanica.     

珠江口广州海域COD与DO的分布特征及影响因素

于2003-2007年2月(冬季)、5月(春季)、8月(夏季)、10月(秋季)调查了广州海域16个站位的COD、DO以及其它理化因子的时空分布特征.调查期间,COD质量浓度范围为0.76～9.12 mg·L~(-1),平均值为2.83 mg·L~(-1);溶解氧质量浓度范围为1.98～9.79 mg·L~(-1),平均值为5.27 mg·L~(-1).结果表明,COD与DO的时空分布特征主要受生活污水排放,陆源排污,降雨量以及水动力状况等因素的影响.COD质量浓度在冬季和秋季较高,春季和夏季较低,而DO质量浓度则是冬季和春季高于秋季和夏季.空间分布上,COD质量浓度从湾内向湾外逐步递减,而DO变化趋势则相反,湾内站位在夏季出现缺氧区.相关性分析中,COD质最浓度与氮营养盐及Chl-a显著正相关,而DO则与COD、Chl-a、Ph以及石油烃显著负相关.COD与DO分布特征对于河口地区的赤潮及碳循环研究有一定研究价值.     

外阻对污泥微生物燃料电池产电以及有机物降解的影响

重点考察了不同外阻（10、150和1 000Ω）对污泥微生物燃料电池（sludge microbial fuel cell,SMFC）产电性能及有机物去除速率的影响。结果表明,外阻对电池产电和有机物降解有显著影响,低电阻有利于电流产生及有机物消耗。当外阻为10Ω时,输出电流最高（4.2 mA）,且污泥溶解性化学需氧量（SCOD）去除速率最快（53 mg.d-1）。DGGE图谱显示,不同外阻导致阳极微生物菌落结构有明显差异;CV扫描发现外阻对生物膜氧化还原能力有显著影响,低电阻下运行的阳极生物膜氧化还原活性较强。本研究为理解外阻与阳极生物膜间的关系提供一条有益线索,也为MFC性能提高提供一条可操作性的途径。     

一株高效解磷细菌的紫外诱变选育及其在红壤稻田施用效果

红壤对磷有强大吸附固定力,磷肥易被土壤中活性铁、铝固定而使有效态磷转化为各种形态的非有效磷,从而大大降低磷肥的利用率。解磷菌能使土壤中难溶性或不溶性的磷转化为易于被植物吸收利用的磷。通过对江西鹰潭红壤分离筛选并经过紫外诱变获得一株性状稳定的高效解磷细菌Y8。经鉴定,菌株Y8为蜡状芽孢杆菌（Bacillus cereus）。通过与生产中应用的徐州华龙高效复合菌肥厂的解磷细菌X3相比,菌株Y8降解有机磷、溶解Ca3（PO4）2的能力均比较高,分别为155.3mg·L^-1和240.1mg·L^-1。研究各种理化因子对菌株Y8解磷能力的影响,确定了菌株Y8的最佳培养条件为葡萄糖20g·L^-1、NH4（SO4）21.5g·L^-1、pH7.0、温度为35℃,在该条件下菌株Y8溶解Ca3（PO4）2的量为295.6mg·L^-1。在江西鹰潭红壤稻田的施用试验表明,将菌株Y8制成微生物菌剂施用于水稻田可起到减施化肥的作用。     

Electrochemical hydride generation of tin(II) and its determination by electrothermal atomic absorption spectrometry with in situ trapping in the graphite tube atomizer

An electrolytic hydride generation system for the determination of tin(II) by means of batch electrochemical hydride generation-electrothermal atomic absorption spectrometry (EcHG-ETAAS) with in situ trapping in a graphite tube atomizer is described. The effects of four permanent chemical modifiers – palladium, tungsten, iridium, and platinum – for graphite tube treatment on analyte absorbance and the effects of four cathode materials, i.e., Pb, Sn, Pb–Sn alloy, and glassy carbon, are checked. Three electrolytes, i.e., nitric acid, sulfuric acid, and hydrochloric acid, are examined as catholyte solutions. The influence of several parameters on EcHG is investigated using multivariate and univariate methods. Interferences of some concomitant ions are evaluated. The calibration curve is linear from 1 to 200?µg?L^?1, with a detection limit of 0.8?µg?L^?1 and a relative standard deviation of 6.2% (n?=?3) for 100?µg?L^?1 Sn(II). The proposed method was successfully applied in the analysis of real environmental water samples and reference materials, and good spiked recoveries over the range of 93.1–115% were obtained. The proposed technique provides a means for developing hydride generation of other elements.