混合酸浸提—原子吸收法测定土壤中铜

建立了混合酸浸提对土壤样品进行前处理,并运用空气-乙炔火焰原子吸收法(FAAS)分析土壤中铜的方法。结果表明:最佳前处理条件为混合酸HNO 3+HCl(1+1),浸提温度100℃,浸提时间120 min。该方法前处理简单,测定快速、结果准确,同时经多次进行加标试验验证,其结果样品测定相对标准偏差为2.2%,其回收率为95%~101%,方法可行,应用于土壤样品的微量元素分析。     

王水水浴消解-原子荧光法测定土壤中的砷和汞

采用王水水浴消解-原子荧光法测定土壤样品中砷和汞,探讨消解环境、载液特性、溶液基体和还原剂硼氢化钾等因素对土壤样品中砷和汞含量测定的影响,确定了最优分析条件:土壤样品敞开消解,时间2h,期间摇动3次,用盐酸溶液(5+95)定容,混匀静置过夜,砷和汞还原剂硼氢化钾的质量分数分别为2%和0.02%,载液均为盐酸溶液(5+95)。该方法将土壤环境监测样品中砷、汞元素同步消解前处理,简化了试验步骤,节约了分析测试时间,提高了分析效率,利于处理大批量土壤样品。选取部分GSS系列标准物质进行测试试验,试验结果的精密度和准确度均可满足土壤环境监测技术规范的要求,对2种未知土壤样品进行加标回收试验,土壤样品的加标回收率:砷为94.00%～100.40%,汞为86.40%～106.80%。     

水浴消解—原子荧光光度法测定土壤中的汞

介绍了用(1+1)王水在沸水浴中加热消解土壤样品,再利用氢化物发生-原子荧光光度法测定土壤中汞的方法,确定最佳氢化物反应条件。     

微波消解-GFAAS法测定土壤中的总铅

研究了微波消解-GFAAS法测定土壤样品中总铅的方法。土壤样品加入HNO3+HF,经微波消解体系消解后,在恒温加热器上赶酸并除硅,石墨炉原子吸收光谱法(GFAAS)测定土壤样品中的总铅。测定数据经过与国标(GB/T 17141-1997)消解方法的比对,以及对不同土壤及土壤标准物质的测试。结果表明,两者无显著性差异,且此法重复性好,试剂用量少,安全易控制,结果可靠。     

火焰原子吸收法测定土壤中铜和铅

本文建立了逆王水-高氯酸-氢氟酸分解法对土壤进行前处理,氘灯校正背景火焰原子吸收法分析土壤中铜和铅的方法.对逆王水-高氯酸-氢氟酸分解法和王水-高氯酸-氢氟酸分解法两种土壤前处理方法,对氘灯校正背景火焰原子吸收法和萃取火焰原子吸收法两种方法,进行了比较.应用于土壤标准样品及样品的测定,获得了满意的结果.     

RA-915~+型测汞仪快速测定土壤中的总汞

本文采用RA-915+型测汞仪建立了一种快速测定土壤中总汞的热解析冷原子吸收分光光度法。该方法使用土壤标准样品直接固体进样建立标准曲线,不需要任何样品前处理消解过程,可在几分钟内快速测量1个土壤样品中的总汞含量。采用该方法分析了ESS系列4个土壤标准样品和GSS系列15个土壤标准样品,并与原子荧光法比对分析了9个土壤实际样品,结果表明本方法具有快速、准确、简便和稳定性较高等优点。     

原子荧光法测定土壤中汞方法改进

采用(1+1)硝酸进行消解、原子荧光法测定土壤中汞,对ESS-2和ESS-3两个标准土壤样品进行测定,测定结果的相对标准偏差为0.3%~0.4%,加标回收率在85%~95%,同时空白样品测定的结果较低,表明该法满足实验要求。     

红外分光光度法测定土壤中石油烃总量的方法研究

时土壤中石油烃总量测定的方法进行了探讨,将适量土壤样品加入四氯化碳后静置过夜,再经热漫、脱水、过滤、振荡吸附后采用红外分光光度法测定土壤中石油烃.该方法简化了分析步骤,提高了工作效率,保证分析的准确度,具有可行性.     

酸浸法测定土壤中的铅

由于全量分解法（HCl-HNO3-HF-HC]O4）测定土壤中的铅具有操作复杂、耗时长、污染大等缺点,酸浸法测定土壤中的铅,通过对国家土壤标准样品的验证,证明该方法具有快速准确的优点.     

火焰原子吸收法与离子色谱法测定水中K+的方法比对

火焰原子吸收法与离子色谱法测定水中的K+、Na+均具有精密度高、准确度好的特点.用两种方法测定考核样的 6 个样品,考核结果全部合格.     

Evaluation of phytoextracting cadmium and lead by sunflower, ricinus, alfalfa and mustard in hydroponic culture

Soil contaminated with heavy metals cadmium(Cd)and lead(Pb)is hard to be remediated.Phytoremediation may be a feasible method to remove toxic metals from soil,but there are few suitable plants which can hyperaccumulate metals.In this study,Cd and Pb accumulation by four plants including sunflower(Helianthus annuus L.),mustard(Brassica juncea L.),alfalfa(Medicago sativa L.), ricinus(Ricinus communis L.)in hydroponic cultures was compared.Results showed that these plants could phytocxtract heavy metals, the ability of accumulation differed with species,concentrations and categories of heavy metals.Values of BCF(bioconcentration factor)and TF(translocation factor)indicated that four species had dissimilar abilities of phytoextraction and transportation of heavy metals.Changes on the biomass of plants,pH and Eh at different treatments revealed that these four plants had distinct responses to Cd and Pb in cultures.Measurements should be taken to improve the phytoremediation of sites contaminated with heavy metals,such as pH and Eh regulations,and so forth.     

Oxidation of As(Ⅲ) by potassium permanganate

The oxidation of As(Ⅲ) with potassium permanganate was studied under conditions including pH, initial As(Ⅲ) concentration and dosage of Mn(Ⅶ). The results have shown that potassium permanganate was an effective agent for oxidizing of As(Ⅲ) in a wide pH range. The pH value of tested water was not a significant factor affecting the oxidation of As(Ⅲ) by Mn(Ⅶ). Although theoretical redox analyses suggest that Mn(Ⅶ) should have better performance in oxidization of As(Ⅲ) within lower pH ranges, the experimental results show that the oxidation efficiencies of As(Ⅲ) under basic and acidic conditions were similar, which may be due to the adsorption of As(Ⅲ) on the Mn(OH)2 and MnO2 resulting from the oxidation of As(Ⅲ).     

Distribution and ecological effect of mercury in Laogang landfill, Shanghai, China

Laogang landfill near Shanghai is the largest landfill in China, and receives about 10000 t of daily garbage per day, Samples of topsoil and plants were analyzed to evaluate mercury pollution from the landfill. For topsoil samples, there were significant correlations among total mercury （HgT）, combinative mercury （Hgc） and gaseous mercury （HgG）, and content of total organic carbon （TOC）, but, no significantly relationship was found between Hg content and filling time. Hg content changes in vertical profiles with time showed that the average Hgv of profiles 1992, 1996, and 2000 was similar, but their average HgG was quite different. HgT was significantly correlated with Hgc in profile 1992 and 2000, and Hgv was significantly correlated with Hg6 in profile 1996. HgG/Hgv ratio in profile samples decreased in the order of （HgG,/HgT）1992〉（HgG/HgT）1996〉〉（HgG/HgT）2000. A simple outline of Hg release in landfill could be drawn： with increasing of filling time, degradation undergoes different biodegradation, accordingly, gaseous mercury goes through small, more, and small proportion to total mercury. Distribution of Hg in plants was inhomogeneous, following the order of leaf〉root〉stem. The highest value of leaf may be associated with higher atmospheric Hg from landfill. Ligneous plants （e.g. Phyllostachys glanca, Prunus salicina and Ligustrum lucidum） are capable of enriching more Hg than herbaceous plants.     

EDTA-enhanced phytoremediation of lead contaminated soil by Bidens maximowicziana

Phytoremediation is a potential cleanup technology for the removal of heavy metals from contaminated soils.Bidens maximowicziana is a new Pb hyperaccumulator,which not only has remarkable tolerance to Pb but also extraordinary accumulation capacity for Pb.The maximum Pb concentration was 1509.3 mg/kg in roots and 2164.7 mg/kg in overground tissues.The Pb distribution order in the B. maximowicziana was:leaf>stem>root.The effect of amendments on phytoremediation was also studied.The mobility of soil Pb and the Pb concentrations in plants were both increased by EDTA application.Compared with CK(control check),EDTA application promoted translocation of Pb to overground parts of the plant.The Pb concentrations in overground parts of plants was increased from 24.23-680.56 mg/kg to 29.07-1905.57 mg/kg.This research demonstrated that B.maximowicziana appeared to be suitable for phytoremediation of Pb contaminated soil,especially,combination with EDTA.     

Decomposition of alachlor by ozonation and its mechanism

Decomposition and corresponding mechanism of alachlor, an endocrine disruptor in water by ozonation were investigated. Results showed that alachlor could not be completely mineralized by ozone alone. Many intermediates and final products were formed during the process, including aromatic compounds, aliphatic carboxylic acids, and inorganic ions. In evoluting these products, some of them with weak polarity were qualitatively identified by GC-MS. The information of inorganic ions suggested that the dechlorination was the first and the fastest step in the ozonation of alachlor.     

Enzymatic oxidation of aqueous pentachlorophenol

The influence of the nonionic surfactant Tween 80 on pentachlorophenol （PCP） oxidation catalyzed by horseradish peroxidase was studied. The surfactant was tested at concentrations below and above its critical micelle concentration （CMC）. Enhancement of PCP removal was observed at sub-CMCs. The presence of Tween 80 in the reaction mixture reduced enzyme inactivation which occurred through a combination of free radical attack and sorption by precipitated products. A simple first-order model was able to simulate time profiles for enzyme inactivation in the presence or absence of Tween 80. At supra-CMCs, the surfactant caused noticeable reductions in PCP removal, presumably through micelle partitioning of PCP which precluded the hydrophobic PCP molecule from interacting with the enzyme.     

Chlorobenzenes in waterweeds from the Xijiang River （Guangdong section） of the Pearl River

The Xijiang River is the major source of water for about 4.5 millions of urban population and 28.7 millions of rural population. The water quality is very important for the health of the rural population. The concentration and distribution of chlorobenzenes (CBs) in both water and waterweeds collected from 4 stations in the Xijiang River (Gangdong section) of the Pearl River in April and November were determined. The result showed that nearly every congener of CBs was detected. The total contents of CBs (∑CBs) in the river water ranged from 111.1 to 360.0 ng/L in April and from 151.9 to 481.7 ng/L in November, respectively. The pollution level of CBs in the water in April was higher than that in November. The contents of ∑ CBs in waterweeds ranged from 13.53×102 μg/g to 38.27×102μg/g dry weight (dw). There was no significant difference between April and November in waterweeds. The distribution of CBs in roots, caulis, and leaves of Vallisneria spiralis L. showed different patterns. The leaves mainly contained low-molecular-weight CBs(DCBs), whereas the roots accumulated more PCBs and HCBs. The average lgBCFlip (bioconcentration factor) of CBs ranged from 0.64 to 3.57 in the waterweeds. The spatial distribution character of CBs in the Xijiang River was: Fengkai County ＜ Yunan County ＜Yun'an County ＜ Gaoyao County according to the ∑CBs, and the pollution deteriorated from the upstream to the downstream of the Xijiang River. Further analysis demonstrated that the discharge of waste containing CBs may be the main source of CBs pollution in the Xijiang River.     

Degradation of 2,4-dichlorophenol with a novel TiO2/Ti-Fe-graphite felt photoelectrocatalytic oxidation process

Degradation of 2,4-dichlorophenol(2,4-DCP)was studied in a novel three-electrode photoelectrocatalytic(PEC)integrative oxidation process,and the factors influencing the degradation rate,such as applied current,flow speed of O_2,pH,adscititious voltage and initial 2,4-DCP concentration were investigated and optimized.H_2O_2 was produced nearby cathode and Fe~(2 )continuously generated from Fe anode in solution when current and O_2 were applied,so,main reactions,H_2O_2-assisted TiO_2 PEC oxidation and E-Fenton reaction,occurred during degradation of 2,4-DCP in this integrative system.The degradation ratio of 2,4-DCP was 93% in this integrative oxidation process,while it was only 31% in E-Fenton process and 46% in H_2O_2-assisted TiO_2 PEC process.So,it revealed that the degradation of 2,4-DCP was improved greatly by photoelectrical cooperation effect.By the investigation of pH,it showed that this integrative process could work well in a wide pH range from pH 3 to pH 9.     

Effect of copper on the degradation of pesticides cypermethrin and cyhalothrin

The influence of coexisting copper (Cu) ion on the degradation of pesticides pyrethroid cypermethrin and cyhalothrin in soil and photodegradation in water system were studied.Serial concentrations of the pesticides with the addition of copper ion were spiked in the soil and incubated for a regular period of time,the analysis of the extracts from the soil was carried out using gas chromatography (GC).The photodegradation of pyrethroids in water system was conducted under UV irradiation.The effect of Cu~(2 ) on the pesticides degradation was measured with half life (t_(0.5)) of degradation.It was found that a negative correlation between the degradation of the pyrethroid pesticides in soil and Cu addition was observed.But Cu~(2 ) could accelerate photodegradation of the pyrethroids in water.The t_(0.5) for cyhalothrin extended from 6.7 to 6.8 d while for cypermethrin extended from 8.1 to 10.9 d with the presence of copper ion in soil.As for photodegradation,t_(0.5) for cyhalothrin reduced from 173.3 to 115.5 rain and for cypermethrin from 115.5 to 99.0 min.The results suggested that copper influenced the degradation of the pesticides in soil by affecting the activity of microorganisms.However, it had catalyst tendency for photodegradation in water system.The difference for the degradation efficiency of pyrethroid isomers in soil was also observed.Copper could obviously accelerate the degradation of some special isomers.     

基于综合水质标识指数和对应分析法的校园河道水质评价

以三峡大学的校园河道求索溪为研究对象,利用综合水质标识指数法确定求索溪水质类别,分析其水质时空变化规律,并利用对应分析法得出求索溪中不同监测点的主要污染因子.研究结果表明:求索溪整体的综合水质标识指数为7.423,整体水质为劣V类(地表水环境质量标准GB 3838-2002)且黑臭.从时间变化来看,求索溪4月份的水质最差,5月份次之,4、5月份所有监测点的水质都劣于V类且黑臭;8月份水质最好,水质为Ⅳ类;从空间分布来看,8个监测点综合水质标识指数均超过6.0,水质为劣V类,其中6号监测点的水质相对最好,监测点3号的水质相对最差;对应分析法得出求索溪的整体水体污染程度受总氮因子的影响最大,其次为总磷.该研究拟为求索溪及类似校园河道的水环境治理研究提供基础依据和参考.