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Search Results: 1 - 10 of 21206 matches for " Potassium Dichromate Method "
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A Modified Method for the Accurate Determination of Chemical Oxygen Demand (COD) in High Chloride Oilfield Wastewater  [PDF]
Shanhui Zhang, Wu Chen, Yang Liu, Pengfei Luo, Huiwen Gu
Open Journal of Yangtze Oil and Gas (OJOGas) , 2018, DOI: 10.4236/ojogas.2018.34023
Abstract: In this work, in order to find a method for the accurate determination of chemical oxygen demand (CODCr) in high chloride oilfield wastewater, the interferences of chloridion (Cl-) on CODCr determination were first studied based on the Chinese national standard GB 11914-89. The results showed that the CODCr values and deviations determined by the classical potassium dichromate (K2Cr2O7) method increased gradually with the increase of Cl- mass concentration in water samples. Then, theoretical and experimental studies on reducing interferences of Cl- on CODCr determination were carried out. The results showed that different concentrations of K2Cr2O7 exhibited different oxidation capacities on Cl-, while having little effects on the oxidation of organic compounds. More specifically, when the concentration of K2Cr2O7 was 0.025 mol·L-1 and the mass ratio of HgSO4:Cl- was 10:1, the interferences of Cl- on CODCr determination were the slightest. Finally, a low concentration oxidant method was proposed for the accurate determination of CODCr in high chloride oilfield wastewaters. The performances of the proposed method were verified by the simulated and actual high chloride oilfield wastewater. The results showed that when Cl- ≤ 20,000 mg·L-1 and COD < 100 mg·L-1, the relative prediction errors of CODCr provided by the proposed method were acceptable, which revealed that the low concentration oxidant method is feasible and reliable for the determination of CODCr in high chloride oilfield wastewater.
重铬酸钾法测定铁矿石中全铁
Potassium Dichromate Method of Total Iron in Iron Ore
 [PDF]

陈占生, 罗学辉, 聂凤莲, 谢璐
Advances in Analytical Chemistry (AAC) , 2013, DOI: 10.12677/AAC.2013.31001
Abstract: 本文简述了测定铁矿石中全铁三种测试方法并进行了比对,选择了三氯化钛–重铬酸钾–中性红指示剂法,实验研究了温度、溶样酸、介质酸、指示剂的选择及共存离子的消除,避免了汞带来的危害,取标样分析结果非常满意。
Three methods for determination total iron in iron ore were described and compared in this paper. The tita-nium trichloride, potassium dichromate and neutral red were selected as indicator. At the same time, the temperature, solution acid, medium acid, the selection for indictor and elimination of coexisting were all studied in this experiment, while the hazards posed by mercury was also avoid. At last, the results for analysis standard samples were very satis-factory.
Levaduras autóctonas con capacidad fermentativa en la producción de etanol a partir de pulpa de excedentes de plátano Musa (AAB Simmonds) en el departamento de Córdoba, Colombia
Oviedo Zumaqué,Luis; Lara Mantilla,Cecilia; Mizger Pantoja,Mauricio;
Revista Colombiana de Biotecnología , 2009,
Abstract: native yeasts' (cordoba, colombia) fermentation ability for producing ethanol from plantain (musa aab simmonds) surplus pulp was evaluated; the object was to find efficient yeasts. the microorganisms used here came from the kloeckera sp, candida guillliermondii (14ad), candida albicans and candida guillliermondii 13ad strains (native) and saccharomyces cerevisiae t73 (a commercial reference yeast). fermentation was carried out on different substrate concentrations, the 40% one giving the best result; ethanol production was evaluated by the potassium dichromate colorimetric method using a lambda 11 spectrophotometer. it was observed that the candida guilliermondii 14ad native yeast was the most efficient, having an average 3.45% v/v ethanol production after 72 hours' fermentation. there were no statistically significant differences compared to reference yeast strain ethanol production (3.59% v/v). these results suggest that native yeasts can be used in obtaining ethanol from residual plantain matter.
Levaduras autóctonas con capacidad fermentativa en la producción de etanol a partir de pulpa de excedentes de plátano Musa (AAB Simmonds) en el departamento de Córdoba, Colombia
Oviedo Zumaqué Luis,Lara Mantilla Cecilia,Mizger Pantoja Mauricio
Revista Colombiana de Biotecnología , 2009,
Abstract: Autoctonous yeasts having fermentation ability in producing ethanol from Musa (AAB Simmonds) plantain surplus pulp in the Córdoba department of Colombia Resumen: Se evaluó la capacidad fermentativa de levaduras nativas de la zona costanera del departamento de Córdoba, Colombia, para la obtención de etanol a partir de la pulpa de excedentes de plátano Musa (AAB Simmonds), con el objetivo de encontrar cepas eficientes. Los microorganismos utilizados correspondieron a las especies: Kloeckera sp, Candida guillliermondii 14AD, Candida albicans y Candida guillliermondii 13AD (nativas), y una cepa comercial de referencia, Saccharomyces cerevisiae T73. La fermentación se realizó a diferentes concentraciones de sustrato, siendo la concentración del 40% la mejor; se evaluó la producción de etanol mediante el método colorimétrico del dicromato de potasio utilizando un equipo espectrofotómetro Lambda 11. Se observó que la levadura Candida guilliermondii 14AD nativa fue la más eficiente con una producción promedio de 3,45% v/v de etanol a las 72 horas de fermentación; no se encontraron diferencias estadísticamente significativas con la producción de etanol a partir de la cepa de referencia, la cual produjo 3,59% v/v. Estos resultados sugieren la existencia de levaduras nativas con capacidad para ser utilizadas en la obtención de etanol a partir de material residuo de plátano. Palabras clave: etanol; fermentación; levaduras; método del dicromato de potasio. Abstract: Native yeastsa€ (Cordoba, Colombia) fermentation ability for producing ethanol from plantain (Musa AAB Simmonds) surplus pulp was evaluated; the object was to find efficient yeasts. The microorganisms used here came from the Kloeckera sp, Candida guillliermondii (14AD), Candida albicans and Candida guilllier-mondii 13AD strains (native) and Saccharomyces cerevisiae T73 (a commercial reference yeast). Fermentation was carried out on different substrate concentrations, the 40% one giving the best result; ethanol production was evaluated by the potassium dichromate colorimetric method using a Lambda 11 spectrophotometer. It was observed that the Candida guilliermondii 14AD native yeast was the most efficient, having an average 3.45% v/v ethanol production after 72 hoursa€ fermentation. There were no statistically significant differences compared to reference yeast strain ethanol production (3.59% v/v). These results suggest that native yeasts can be used in obtaining ethanol from residual plantain matter. Key words: ethanol; fermentation; yeast; potassium dichromate method.
Correlations between chlorine ion, COD and TOC in wastewaters from different sources
不同来源废水COD、TOC与Cl-的关系

Zhang Xiuxi,Qin Lijiao,Li Yuguo,Xu Nan,Li Xiuling,Zhao Chaocheng,
张秀霞
,秦丽姣,李玉国,徐娜娜,李秀玲,赵朝成

环境工程学报 , 2011,
Abstract: The wastewaters from different sources,such as high salinity chemical wastewater (A), tide-affected river water(B), municipal sewage (C) and oil production wastewater were monitored for a period of 15 days, COD, TOC and Cl- concentrations were determined and the relationship between them was investigated. The COD was measured by dichromate method, chlorine emendation method and potassium iodide alkaline permanganate method, respectively. The results showed that, there was a large difference among the Cl- concentrations of the samples, which was in order of A (21 749 mg/L)>D (7 013 mg/L)>B(1 807 mg/L)>C(977 mg/L). During the 15 days monitoring periods, the TOC values of high salinity chemical wastewater (A) fluctuated widely while the TOC of the other three kind wastewater remained stable, and there was no direct correlations between TOC and chloride ion concentration. The COD values of all four samples showed a significant positive relation with the Cl- concentration. It could be concluded that potassium iodide alkaline permanganate method was more suitable for determining COD in wastewater A and D, and chlorine emendation method was suitable for determining COD in wastewater C and D. As water in tidal river fluctuated widely, there was no significant difference among the COD values measured by three methods according to the Cl- concentration.TOC was more suitable for characterizing the organic pollution degree of water quality.
ESTANDARIZACION DEL BIOENSAYO DE TOXICIDAD AGUAD CON DIPLODON CHILENSIS USANDO UN TOXICO DE REFERENCIA
Silva,Jeannette; Fuentealba,Carmen; Bay-Schmith,Enrique; Larrain,Alberto;
Gayana (Concepción) , 2007, DOI: 10.4067/S0717-65382007000200001
Abstract: a wide range of species vulnerability to toxicans makes necessary to use a combination of different species in environmental toxicity assessment. species specific bioassays are standarized to minimize variations in successive measurements. the freshwater bivalve molluscs diplodon chilensis is a potential test species for toxicity bioassay based on its widespread and abundant populations in rivers and lakes of chile and its ecological significance in the plancktonic community as a powerful filter feeder. a standardized procedure with d. chilensis is herein described followed by the method's calibration. juveniles of this species were exposed to a concentration gradient of potassium dichromate (k2cr2o7) as reference toxicant for 96 h. the measured effect was mortality. after eight successive estimations of the median lethal concentration (lc50-96 h) a mean value ± sd of 20,4 ± 3,3 mg l-1 was found. intra laboratory precision, estimated by means of the variation coefficient (vc), was 16,2 % and the superior and inferior control limits for future lc50 values derived from the control chart were 27 and 17,1 mg l-1 respectively. this bivalve can then be used as test organism in ecotoxicity assessment increasing the diversity of species in environmental testing batteries, with the extra benefit of being a mollusc, zoological group poorly represented among freshwater testing animals in ecotoxicological bioassays.
Sensitivity of the amphipod Tiburonella viscana (Platyischnopidae) to K2CR2O7
Abessa, Denis M. S.;Sousa, Eduinetty C. P. M.;
Brazilian Archives of Biology and Technology , 2003, DOI: 10.1590/S1516-89132003000100009
Abstract: the sensitivity of tiburonella viscana to k2cr2o7 was evaluated from 18 water-only toxicity tests. the mean 48h-lc50 was estimated as 11.217 ± 3.768 mg/l, and the warning limits were calculated (mean lc50 ± 2 sd) as being between 3.68 and 18.75 mg/l. these results are baseline for the species and can be used for future comparisons in toxicity tests.
Sensitivity of the amphipod Tiburonella viscana (Platyischnopidae) to K2CR2O7
Abessa Denis M. S.,Sousa Eduinetty C. P. M.
Brazilian Archives of Biology and Technology , 2003,
Abstract:
Chloride Interference in the Determination of COD of Landfill Leachate
垃圾渗滤液COD检测方法中Cl-干扰问题的讨论

YANG Shi-ying,ZHANG Wen-yi,SHAN Liang,YANG Xin,WANG Ping,
杨世迎
,张文义,单良,杨鑫,王萍

环境科学 , 2010,
Abstract: Chemical oxidation demand (COD) is one of the most important determination indicators of landfill leachate. However, the presence of high concentration chloride in leachate generates interference, which hasn't caused enough concern. The objective of this paper is to compare anti-interference ability of chloride among potassium dichromate reflux method, rapid digestion-spectrophotometric method, basic potassium permanganate method and UV spectrophotometry method. For the traditional potassium dichromate reflux method, masking agent can't prevent the chloride interference completely when the concentration of chloride is more than 3550 mg·L-1.The same thing happens with rapid digestion-spectrophotometric method. Though basic potassium permanganate method can successfully obviate the interference from chloride, low oxidizing ability results in more errors in COD measurement, and the efficiency of potassium permanganate is only 60% of potassium dichromate. UV spectrophotometry can not only shorten the measure time and improve the efficiency, but also avoid the interference from chloride. The result indicates that when COD values is less than 150 mg·L-1, there is a prominent correlation between UV254 and COD, with a correlation coefficient of 0.9985. Furthermore, when COD values is less than 600 mg·L-1, the correlation between UV365 and COD is more prominent than UV254, with a correlation coefficient of 0.9996.
Effect of Garlic (Allium sativum) on Heavy Metal (Nickel II and ChromiumVI) Induced Alteration of Serum Lipid Profile in Male Albino Rats
Amrita Das Gupta,Swastika N. Das,Salim A. Dhundasi,Kusal K. Das
International Journal of Environmental Research and Public Health , 2008, DOI: 10.3390/ijerph5030147
Abstract: We have studied the effect of simultaneous oral treatment of aqueous garlic extract (Allium sativum) on heavy metal (nickel II and chromium VI) induced changes in serum lipid profile. Nickel sulfate and potassium dichromate treated rats showed a significant increase in serum low density lipoprotein-cholesterol (LDL-C), very low density lipoprotein-cholesterol (VLDL-C) and triglyceride (TG) level as well as decrease in serum high density lipoprotein-cholesterol (HDL-C) level. Simultaneous garlic administration with nickel sulfate showed improvement in serum LDL-C, HDL-C, VLDL-C and TG level. But in case of potassium dichromate, garlic administration did not show satisfactory improvement in lipid profile except VLDL-C and TG level. The results indicate that garlic (Allium sativum) has some beneficial effect in preventing heavy metal (nickel and chromium VI) induced alteration of lipid profile.
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