Chemical forms of cobalt and nickel extracted by M1, M3 and CaCl2 DTPA

Mehlich 1(M1), mehlich 3(M3) and CaCl₂ DTPA have been used to predict the available micronutrient in soil. However, the forms of micronutrient extractable by these extractants are not known. In the present study, ten soils, collected from five provinces and the capital of China, representing a wide range of chemical and physical properties, were analyzed by sequential extraction to isolate five forms of cobalt and nickel, they are exchangeable, carbonate bound, Fe Mn oxide bound, organically bound and residual forms. The chemical forms extracted by M1, M3 and CaCl₂ DTPA were also investigated. The results show strong correlation between the carbonate bound or organically bound forms of Co or Ni and the amounts of extractable by any of the above three extractants. The main forms extracted by these extractants are carbonate and organically bound forms. The ranking of these three extractants for extraction of Co and Ni are M1>M3=CaCl₂ DTPA and M1=M3>CaCl₂ DTPA, respectively.     

Metabolism of N-phenyl-2-naphthylamine andN-phenyl-1-naphthylamine by rat hepaticmicrosomes and hepatocytes

The carcinogenic antioxidants,N-phenyl-1-naphthylamine (P1NA)and N-phenyl-2-naphthylamine (P2NA) were examined in vitro for biotransformation by rat hepatic microsomes and in freshly isolated hepatocytes. HPLC-analysis of hepatocyte incubations with revealed that phenols were the major metabolites in both cases. P1NA formed one phenolic metabolite only, while incubation with P2NA yielded two phenols identified as 6-hydroxy-P2NA and 4'-hydroxy-P2NA by cochromatography with authentic samples. β-naphthylamine, a metabolite indicating dephenylation of P2NA was not detectable.Metabolism studies with microsomes revealed that the phenols were formed by cytochrome P-450 dependent monooxygenases. Pretreatment of animals with phenobarbital and 3-methylcholanthrene both increased the rate of microsomal metabolism of P1NA and P2NA, indicating that more than one P-450 enzyme mediate the oxygenation reaction. Animal pretreatment with single and repeated doses of P1NA and P2NA did not markedly stimulate metabolism, b     

Chemical speciation of pollutants in waters of Dexing Copper Mine area by using chemical equilibrium modeI-MINTEQA2

The MINTEQ program is used on the speciation of pollulants in waters of Dexing Copper Mine area．Four kinds of waters are encountered．The results show that all pollutants are dissolved phase in typical acid mine drainage，with pH increasing，the iron，aluminum and copper would be precipitated at different pH values．After receiving alkaline wastewater，pH value of the Dawu River water goes higher，resulting in increasing amount of pollutants bounded in solid phase．For the mixed water，the speciation results show that at mixing ratio(alkaline water to acid water)of 8 to 9，neutral water will be gained and different pollutants will precipitate completely at different mixing ratios．     

Photocatalytic remediation of γ-HCH contaminated soil induced by α-Fe2O3 and TiO2

Heterogeneous photocatalytic degradation of γ-HCH on soil surfaces was carried out to evaluate the photocatalytic effectiveness of α-Fe2O3 and TiO2 toward degrading γ-HCH on soil surfaces. After being spiked with γ-HCH, soil samples were loaded with α-Fe2O3 or TiO2 and exposed to UV-light irradiation. Different catalyst loads(0%, 2%, 5%, 7%, and 10% (wt). α-Fe2O3; 0%, 0.5%, 1%, 2% wt. TiO2) were tested for up to 7 d irradiation. The effects of soil thickness, acidity, and humic substances were also investigated. The obtained results indicated that the γ-HCH photodegradation follows the pseudo-first-order kinetics. The addition of α-Fe2O3 or TiO2 accelerates the photodegradation of γ-HCH, while the photodegradation rate decreases when the content of α-Fe2O3 exceeds 7%(wt.). The degradation rate increases with the soil pH value. Humic substances inhibit the photocatalytic degradation of γ-HCH. Pentachlorocyclohexene, tetrachlorocyclohexene, and trichlorobenzene are detected as photodegradation intermediates, which are gradually degraded with the photodegradation evolution.     

Biosorption of Cu^2＋ and Zn^2＋ by raw and autoclaved Rocella phycopsis

The behavior of Cu2+ and Zn2+ biosorption onto raw and modified Roccella phycopsis from aqueous solutions was studied. Modification process was applied by autoclavation at 121°C for 30 min. The effcts of pH, initial metal concentration and biosorbent dosage were investigated. The maximum Cu2+ biosorption was achieved at pH 5.0 and the maximum biosorption capacities of 31.5 and 37.8 mg/g were recorded for raw and modified biosorbent, respectively. In the case of Zn2+ biosorption, maximum biosorption capacities were obtained at pH 4.0 as 29.1 and 35.3 mg/g for raw and modified biosorbent, respectively. Biosorption of Zn2+ and Cu2+ on all form of R. phycopsis increased much quickly with increasing initial metal concentrations from 10 to 100 mg/L. After modification process, probable changes in the surface polarity of raw and modified R. phycopsis were investigated by contact angle measurements. As expected, R. phycopsis has a polar surface and shows a highest contact angle with water, while after autoclavation water contact angle of R. phycopsis was significantly decreased from 47.5° to 34.4°.     

The effect of freezing on the composition of supercooled droplets—I. Retention of HCl,HNO3, NH3 and H2O2

Experiments were done to check on the possibility that cloud droplets might, during freezing, lose acidity by evolution of HCl or HNO₃, lose NH₃ or lose dissolved H₂O₂. A spray of droplets with average diameter 39μm was produced by an ultrasonic transducer. The droplets acquired a temperature between −8 and −12°C and fell onto an ice surface, where they froze. Appropriate analytical techniques were applied to compare the composition of the frozen droplets with that of the sprayed liquid. It was found that the four chemical species studied were totally retained in the ice after freezing.     

Chemical fixation of toxic metals in stainless steel pickling residue by Na2S∙xH2O, FeSO4∙6H2O and phosphoric acid for beneficial uses

The leaching concentrations of different metals in stainless steel pickling residue(SSPR)were determined and the toxic metals were treated using Na_2 S·xH_2 O,FeSO_4·6 H_2 O,and phosphoric acid.A modified European Community Bureau of Reference(BCR) sequential extraction was used to identify the speciation of the concerned metals.Results showed that SSPR contains a large amount of Ca(58.41%),Fe(29.44%),Cr(3.83%),Ni(2.94%),Mn(2.82%) and some of Al,Cu,Mg,Zn.Among them,Cr and Ni were the most toxic metals in SSPR,thus the raw SSPR falls into hazardous waste category due to the leaching amount of Cr.In addition,the leached Cr was identified as Cr6+(MgCr04) in the waste.BCR test revealed that risk assessment code(RAC) of Cr and Ni were 33.29% and 61.7%,indicating they posed "high" and "very high" risk to the environment,respectively.After fixing by Na_2 S·xH_2 O and FeSO_4·6 H_2 O,the leaching concentrations of Cr and Ni were less than 1.5 and 0.5 mg/L,respectively.After fixing by Na_2 S·xH_2 O and FeSO_4·6 H_2 O the tre ated SSPR can be safely reused as roadbed materials,concrete and cement aggregates.This study provides a useful implication in treatment and beneficial reuse of heavy metal-containing hazardous wastes.     

Reduction of NO by CO using Pd–CeTb and Pd–CeZr catalysts supported on SiO_2 and La_2O_3–Al_2O_3

The catalytic activity of Pd catalysts supported on Ce0.73Tb0.27 O x/Si O2, Ce0.6Zr0.4O x/Si O2,Ce0.73Tb0.27 O x/La2O3–Al2O3and Ce0.6Zr0.4O x/La2O3–Al2O3was studied using the reduction of NO by CO. The catalysts were characterized by X-ray fluorescence, surface area, X-ray diffraction, temperature-programmed reduction, CO chemisorption and oxygen storage capacity. Temperature-programmed reduction results indicated that Tb or Zr incorporation improves the reducibility and oxygen storage capacity. CO chemisorption data suggested the presence of large Pd O particles due to the low CO/Pd ratio. No significant differences were obtained in light off temperatures(T Light off) for all Pd catalysts and the most active was1.5%Pd/Ce0.6Zr0.4O x/Si O2.     

Hygroscopicity measurement of sodium carbonate, β-alanine and internally mixed β-alanine/Na2CO3 particles by ATR-FTIR

Water-uptakes of pure sodium carbonate(Na_2CO_3),pure β-alanine and internally mixedβ-alanine/Na_2CO_3 aerosol particles with different mole ratios are first monitored using attenuated total reflectance Fourier transform infrared spectroscopy(ATR-FTIR) technique.For pure Na_2CO_3 aerosol particles,combining the absorptions at 877 and 1422 cm-1 with abrupt water loss shows the efflorescence relative humidity(ERH) of 62.9%–51.9%.Upon humidifying,solid Na_2CO_3 firstly absorbs water to from Na_2CO_3·H2 O crystal at 72.0% RH and then deliquesces at 84.5% RH(DRH).As for pure β-alanine particles,the crystallization takes place in the range of 42.4%–33.2% RH and becomes droplets at ～ 88.2% RH.When β-alanine is mixed with Na_2CO_3 at various mole ratios,it shows no efflorescence of Na_2CO_3 whenβ-alanine to Na_2CO_3 mole ratio(OIR) is 2:1.For 1:1 and 1:2 β-alanine/Na_2CO_3 aerosols,the ERHs of Na_2CO_3 are 51.8%–42.3% and 57.1%–42.3%,respectively.While β-alanine crystal appears from 62.7% RH for 2:1 and 59.4% RH for both 1:1 and 1:2 particles and lasts to driest state.On hydration,the DRH is 44.7%–75.2% for Na_2CO_3 with the OIR of 1:1 and 44.7%–69.0%for 1:2 mixture,and those of β-alanine are 74.8% for 2:1 mixture and 68.9% for two others.After the first dehumidification–humidification,all the water contents decrease despite of constituent fraction.And at ～ 92% RH,the remaining water contents are 92%,89% and 82%at ～ 92% RH,corresponding to OIR of 2:1,1:1 and 1:2 mixed system,respectively.     

Trisomy 2 due to a 3:1 segregation in an abortion studied by QF-PCR and CGH

Balanced reciprocal translocation is one of the known causes of recurrent spontaneous abortions. Cytogenetic studies of unbalanced miscarriages are difficult due to the growth failure of early loss and usually macerated abortions. We present a molecular study of an abortion in which the father carries a balanced reciprocal translocation t(2;17)(q32.1;q24.3) using QF-PCR and CGH techniques. DNA analysis showed the presence of a trisomy 2 due to a 3:1 interchange segregation. Recombinant events could also be investigated by comparing DNA samples from the family. We propose QF-PCR in addition to CGH as an efficient diagnostic method to improve our knowledge of unbalanced offspring in balanced translocation carriers. Copyright © 2005 John Wiley & Sons, Ltd.     

Seasonal variability of ambient NH3, NO, NO2 and SO2 over Delhi

We present the diurnal and seasonal variability of ambient NH3, NO, NO2 and SO2 over Delhi, India. Ambient NH3, NO and NO2 were measured continuously during winter, summer and autumn seasons using NH3- and NOx-analyzer, which operates by chemiluminescence method with a higher estimation e ciency (> 90%) than the chemical trap method (reproducibility 4.7%). Prominent diurnal, day-to-day and seasonal variations of ambient mixing ratio of NH3, NO, NO2 and SO2 were observed during the study period. Seasonal variation with higher mixing ratio in winter was observed for all measured trace gases except NO. Day-night variation of all measured trace gases observed was higher in winter in comparison with summer. Late morning increase in NO2 mixing ratio might be attributed to conversion of NO to NO2 with the interaction of O3.     

嗜吡啶红球菌GF3降解1-氨基蒽醌-2-磺酸的特性

从受溴氨酸污染的泥土中分离出1株蒽醌染料中间体1-氨基蒽醌-2-磺酸(简称ASA-2)降解菌株GF3.经形态学观察和16S r DNA序列分析,鉴定该菌株为嗜吡啶红球菌.研究了该菌对ASA-2脱色的特性,并利用液相-质谱联用仪初步分析了ASA-2降解终产物.研究结果表明,外加蛋白胨、酵母膏和水解酪蛋白均能促进ASA-2的生物脱色,其中蛋白胨促进作用最为明显.进一步的研究发现多种氨基酸可加速ASA-2的生物脱色过程,其中L-亮氨酸促进效果最好.ASA-2脱色的最适环境条件为p H 8.0、30℃和150 r·min~(-1).最适条件下,菌株GF3可使108 mg·L-1的ASA-2在30 h内脱色率达95%以上,TOC去除率为62%.紫外-可见波谱显示,当ASA-2水溶液由红色褪成无色时,ASA-2的特征吸收峰完全消失,并在340 nm产生了新峰.进一步分析发现,ASA-2降解终产物质荷比为260,初步推测产物为3-氨基-4-磺酸基邻苯二甲酸.此外,菌株GF3还可以降解溴氨酸、蒽醌-2-磺酸钠和蒽醌-2-羧酸.     

菌株Cupriavidus sp. DT-1对液体和土壤中TCP的降解

采用液质联用（HPLC-MS）的方法检测菌株Cupriavidus sp.DT-1降解2-羟基吡啶（2-HP）的代谢产物.并用三亲结合、荧光定量PCR （q-PCR）方法评价降解菌对3,5,6-三氯-2-吡啶酚（TCP）污染土壤的修复效果.结果表明,菌株可以进一步降解2-HP,依次生成尼古丁蓝、马来酰胺酸和反丁烯二酸,直至转化成菌株DT-1生长的碳源.接种菌株DT-1对污染土壤中TCP的降解起到较大的促进作用,2组试验土壤中TCP （50mg/kg）降解率分别为94.4%和86.7%,未接种菌株的土壤中TCP降解率仅为20.4%和28.4%.带有绿色荧光蛋白基因gfp标记的菌株DT-1-gfp可在土壤中存活35d以上,并对TCP污染土壤的细菌群落丰度有显著的恢复作用.     

化学沉淀法除去废水中的氨氮及其反应的探讨

研究了化学沉淀法处理含氨氮废水，实验研究了不同操作条件，如溶液ｐＨ值、沉淀剂种类和配比、废水中的初始氨浓度等对氨的处理效率的影响，在适宜的操作条件下，可除去废水中的氨高达９９％，处理后残液中氨浓度小于１ｍｇ／Ｌ（１ｐｐｍ），探讨了化学沉淀反应过程的机理。     

Photocatalytic performance of TiO2 catalysts modified by H3PW12O40, ZrO2 and CeO2

The binary composite photo-catalysts CeO2/TiO2, ZrO2/TiO2 and the ternary composite photo-catalysts H3PW12O40-CeO2/TiO2,H2PW12O40-ZrO2/TiO2 were prepared by sol-gel method. The catalysts were characterized by thermogravimetric-differential thermal analysis (TG-DTA), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The photocatalyfic elimination of methanol was used as model reaction to evaluate the photocatalytic activity of the composite catalysts under ultraviolet light irradiation. The effects of doped content, activation temperature, time, initial concentration of methanol and gas flow rate on the catalytic activity were investigated. The results showed that after doping a certain amount of CeO2 and ZrO2, crystaniTation process of TiO2 was restrained, particles of catalysts are smaller and more uniform. Doping ZrO2 not only significantly improved the catalytic activity, but also increased thermal stability. Doping H3PW12O40 also enhanced the catalytic activity. The catalytic activities of binary and ternary composite photocatalysts were significantly higher than tin-doped TiO2. The dynamics law of photocatalytic reaction over the binary CeO2/TiO2 and ZrO2/TiO2 catalysts has been studied. The activation energy 15.627 and 15.631 kJ/mol and pre-exponential factors 0.5176 and 0.9899 s-1 over each corresponding catalyst were obtained. This reaction accords to the first order dynamics law.     

纳米四氧化三铁对2,4-D的降解研究

采用纳米Fe3O4降解溶液中的2,4-D,考察了2,4-D初始浓度、纳米Fe3O4的投加量、溶液pH对2,4-D降解效率的影响,并探讨了2,4-D的降解机理。实验结果表明,Fe3O4对2,4-D有明显的降解作用,纳米Fe3O4的降解效果优于微米级Fe3O4,降解过程中溶液中的氯离子浓度随着2,4-D的降解而升高,Fe3O4对2,4-D的降解机理是还原脱氯。当2,4-D初始浓度在0～10mg/L、纳米Fe3O4投加量0～300mg/L的范围内,2,4-D降解率随初始浓度和纳米Fe3O4投加量的增加而增大。在2,4-D初始浓度为10mg/L、pH3.0、纳米Fe3O4投加量300mg/L时降解效率最高,48h内2,4-D的降解率可达40%。