Portland pozzolana cement in India with respect to total chromium and hexavalent chromium content

2011 ◽  
Vol 23 (3) ◽  
pp. 145-149 ◽  
Author(s):  
Rina S. Vaity ◽  
Jayant K. Verma
Keyword(s):  
Hexavalent Chromium ◽  
Chromium Content ◽  
Total Chromium ◽  
Portland Pozzolana Cement

Total chromium and hexavalent chromium occurrence analysis

2013 ◽  
Vol 105 (6) ◽  
pp. E310-E319 ◽  
Author(s):  
Chad J. Seidel ◽  
Christopher J. Corwin
Keyword(s):  
Hexavalent Chromium ◽  
Total Chromium

Interference of Sb(III) in the Determination of Hexavalent Chromium in Thermoplastic Matrices

2011 ◽  
Vol 2011 (1) ◽  
pp. 000345-000351
Author(s):  
Sophia S. Lau ◽  
Joe P. Kuczynski
Keyword(s):  
Hexavalent Chromium ◽  
Flame Retardants ◽  
Test Method ◽  
Polymer Matrices ◽  
Antimony Trioxide ◽  
False Negatives ◽  
Total Chromium ◽  
Adverse Health Effects ◽  
The Eu

Due to the adverse health effects of hexavalent chromium, Cr(VI), pigments and other materials containing Cr(VI) were largely banned for use in electrotechnical products under the EU RoHS Directive [1]. While there are several effective methods to determine the presence of total chromium in electrotechnical plastic matrices, a validated compliance test method that is capable of discerning Cr(VI) from the non-regulated forms of Cr(III) is not yet available. One of the challenges in developing a standardized compliance test for Cr(VI) is the low recovery of Cr(VI) compounds from polymer matrices This study identified antimony trioxide (ATO), a common synergist added to enhance the ignition resistance of brominated flame retardants (BFRs), as a source of matrix interference in the quantitative determination of hexavalent chromium extracted from polymer matrices. ATO reduces hexavalent chromium to trivalent chromium prior to complexation of Cr(VI) with diphenylcarbazide (DPC) leading to false negatives. EDTA was found to be an efficient reagent for Sb(III) complexation, thereby suppressing the reduction of Cr(VI) and enabling quantitative Cr(VI) determination in the presence of ATO.

Optimization for Reduction/Precipitation Treatment of Hexavalent Chromium

1994 ◽  
Vol 29 (9) ◽  
pp. 275-284 ◽  
Author(s):  
J. W. Patterson ◽  
E. Gasca ◽  
Y. Wang
Keyword(s):  
Wastewater Treatment ◽  
Hexavalent Chromium ◽  
Treatment Plant ◽  
Kinetic Studies ◽  
Critical Parameters ◽  
Sodium Metabisulfite ◽  
Treatment Optimization ◽  
Total Chromium ◽  
Manufacturing Operations ◽  
Treatment Train

This paper describes wastewater treatment optimization studies performed on an industrial wastewater generated in Boston, Massachusetts, USA. The manufacturing plant generates hexavalent chromium [Cr(VI)] wastewater as a result of chromating brass, bronze and copper parts produced in the manufacturing operations. The facility utilizes a continuous flow treatment train, involving segregated Cr(VI) reduction with sodium metabisulfite (Na2S2O5) under acidic conditions, followed by combined wastestream two-stage pH adjustment, metals precipitation, and clarification before discharge to the municipal sewer. The objectives of the studies were to define and evaluate critical parameters, such as pH and oxidation reduction potential (ORP) for hexavalent and total chromium control and to perform treatability studies to optimize the performance of the wastewater treatment plant (WWTP). The treatability studies included Cr(VI) reduction versus Na2S2O5 dosage evaluations and corresponding chromium reduction kinetic studies, and trivalent chromium hydroxide precipitation. The Cr(VI) reduction experiments and chromic hydroxide precipitation studies were performed for three different wastewaters collected from within the manufacturing process; a high, typical, and dilute strength wastewater.

scholarly journals Survey of Total and Bioavailable Chromium in Grain and Cereal Products by Atomic Absorption Spectrophotometry

1990 ◽  
Vol 73 (5) ◽  
pp. 798-800 ◽  
Author(s):  
Maria Plessi ◽  
Agar Monzani
Keyword(s):  
Atomic Absorption ◽  
Dietary Supplements ◽  
Chromium Content ◽  
Atomic Absorption Spectrophotometry ◽  
Total Chromium ◽  
Cereal Products ◽  
Oil Seeds ◽  
Absorption Spectrophotometry ◽  
Different Types

Abstract The chromium content of samples of cereals, legumes, oil seeds, and alimentary pastes (In the latter, bioavailable chromium as well) was determined by atomic absorption spectrophotometry. The chromium content in whole cereals differs substantially and Is mostly concentrated In pericarps. Variations occur not only among different types of cereals, but also among cereals of the same type, depending on the areas of origin. Concentration varies substantially even In samples of legumes and oil seeds. The content of bioavailable chromium (ethanol-extractable) Is, In most cases, more than 50% of the total chromium amount. This makes these products particularly Interesting as dietary supplements

Hexavalent chromium content in stainless steel welding fumes is dependent on the welding process and shield gas type

2009 ◽  
Vol 11 (2) ◽  
pp. 418-424 ◽  
Author(s):  
Michael Keane ◽  
Samuel Stone ◽  
Bean Chen ◽  
James Slaven ◽  
Diane Schwegler-Berry ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Hexavalent Chromium ◽  
Chromium Content ◽  
Welding Process ◽  
Welding Fumes ◽  
Stainless Steel Welding

scholarly journals Appraisal of Chromium Contents from Different Tanneries and Drains of Sialkot

2020 ◽  
Vol 63 (2) ◽  
pp. 112-117
Author(s):  
Amin Riaz ◽  
Abid Zia
Keyword(s):  
Hexavalent Chromium ◽  
Oxygen Demand ◽  
Absorption Spectrometry ◽  
Total Dissolved Solids ◽  
Biological Oxygen Demand ◽  
Pollution Level ◽  
Total Chromium ◽  
Industrial City ◽  
Uv Visible ◽  
Tanning Industry

The tanning industry is the major chromium consuming industry. Tanning industries are present throughout Pakistan, but their presence is more concentrated in small industrial city Sialkot. The samples of wastewater were collected from different tanneries and Nullah Aik which are situated in Sialkot and analyzed for the measurement of pollution level. The effluents sample demonstrated high values of temperature (32-42°C), pH (5.1-10.9), biological oxygen demand (335-5818 mg/L), chemical oxygen demand (740-14546 mg/L), total solids (2265-19314 mg/L), total dissolved solids (1313-17467 mg/L), hexavalent chromium (1.8-9.8 mg/L), and total chromium (3.75-16.7 mg/L). The total chromium analyzed by atomic absorption spectrometry and hexavalent chromium determined by UV-Visible Spectrophotometer with DCP. The study focused on the level of pollution in tannery wastewater to estimate the impairment caused by them.    

TOTAL CHROMIUM AND HEXAVALENT CHROMIUM IN AIR FROM SOLID TANNERY WASTES AND HEALTH RISKS FOR SLUM POPULATION IN BANGLADESH

2016 ◽  
Author(s):  
Mohammad Alauddin ◽  
◽  
Rabije Cekovic ◽  
Sarah Alauddin ◽  
Sandra Minchala ◽  
...  
Keyword(s):  
Hexavalent Chromium ◽  
Health Risks ◽  
Total Chromium ◽  
Tannery Wastes ◽  
Slum Population
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