The X-ray absorption fine structure method was applied for the quantitative analysis of hexavalent Cr in electronic products. The pre-edge peak intensity of the Cr K-edge increased according to the hexavalent Cr amount, and the hexavalent Cr ratio was calculated quantitatively by using the intensity. By combining with inductively coupled plasma atomic emission spectroscopy measurement results that gave the total Cr amount, the absolute amount of hexavalent Cr in chromate conversion coating and plastic samples could be evaluated. The results obtained by this method were in good agreement with those obtained by the chemical analysis method. This method can be successfully applied for the determination of hexavalent Cr amount in electronic products such as chromate conversion coating and plastic.
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http://dx.doi.org/10.1366/13-07014 | DOI Listing |
Molecules
June 2024
State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
Propane dehydrogenation (PDH) is a crucial approach for propylene production. However, commonly used CrO-based catalysts have issues including easy sintering at elevated reaction temperatures and relying on high acidity supports. In this work, we develop a strategy, to strongly anchor and isolate active sites against their commonly observed aggregation during reactions, by taking advantage of the net trap effect in chromate intercalated Zn-Cr layered hydroxides as precursors.
View Article and Find Full Text PDFChem Commun (Camb)
May 2024
State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, P. R. China.
Hydrogen production the photocatalytic water splitting reaction on semiconductors presents a promising avenue to directly achieve solar energy conversion and storage. Bismuth-based semiconductors with layered structures, a hierarchical arrangement of components stacked in the form of two-dimensional extended layers where the atoms within each layer are typically strongly bonded, while the interactions between the layers are relatively weak, have emerged as an important series of photocatalyst candidates. In this review, we focus on the new emerging layered bismuth-based semiconductors with structures in Sillén, Aurivillius, Sillén-Aurivillius and bismuth chromate systems primarily employed in the photocatalytic water splitting reaction.
View Article and Find Full Text PDFJ Hazard Mater
March 2024
Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China; National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, Institute of Eco-Chongming, Fudan University, Shanghai 200062, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China. Electronic address:
The reactive oxygen species (ROS) photochemically generated from natural iron minerals have gained significant attention. Amidst the previous studies on the impact of heavy metal ions on ROS generation, our study addresses the role of the anion Cr(VI), with its intrinsic photoactivity, in influencing ROS photochemical generation with the co-presence of minerals. We investigated the transformation of inorganic/organic pollutants (Cr(VI) and benzoic acid) at the ferrihydrite interface, considering sunlight-mediated conversion processes (300-1000 nm).
View Article and Find Full Text PDFBioresour Technol
February 2024
Microbiology Research Laboratory, Department of Biotechnology, Maulana Abul Kalam Azad University of Technology, W.B., Simhat, Haringhta, Nadia, West Bengal, India. Electronic address:
Environmental accumulation of hexavalent chromium [Cr(VI)] in the food chain can induce detrimental effects on plants and animals, which calls for effective remediation strategies using biological entities. The bacterium isolated from an iron mine in Odisha, India, is identified asSerratia marcescensAJRR-22. This multi-metal tolerant strain is capable of bio-converting up to 350 mg/L Cr(VI) within 72 h of incubation.
View Article and Find Full Text PDFSci Rep
August 2023
Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Pohang, Gyeongbuk, Republic of Korea.
We developed a facile method to produce a uniform chromate conversion (CC) coating on zinc alloy-plated steel substrates (ZS). When an acidic CC solution is applied to ZS (C-ZS), zinc is dissolved and chromium ions are reduced to form a chromate coating. In localized areas where zinc is excessively dissolved, zinc hydroxide particles are formed, which hinders the formation of a uniform chromate film, leaving the areas vulnerable to further corrosion (i.
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