Morphology analysis of hexavalent chromium reduction to trivalent chromium with syrup under different pH conditions

Abstract Batch experiments were designed to ascertain the morphology and valence of chromium in the reduction of hexavalent chromium with syrup under different pH conditions. Results indicated that the syrup reduced hexavalent chromium to trivalent chromium, and the existing forms of Cr were mainly Cr(OH)3, CrOOH and CrOOH–Fe. The percentage of Fe–Mn oxide-bound state was 29.28%, 29.28%, 22.22% and 20.12%, respectively, and the percentage of organic binding state was 64.71%, 66.58%, 74.74% and 73.14%, respectively, in the reaction systems at different pH (2.0, 2.5, 3.0 5.6) conditions.

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Modeling Hexavalent Chromium Reduction in Groundwater in Field-Scale Transport and Laboratory Batch Experiments

Water Resources Research ◽

10.1029/95wr02104 ◽

1995 ◽

Vol 31 (11) ◽

pp. 2783-2794 ◽

Cited By ~ 26

Author(s):

J. C. Friedly ◽

J. A. Davis ◽

D. B. Kent

Keyword(s):

Hexavalent Chromium ◽

Batch Experiments ◽

Chromium Reduction ◽

Field Scale

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Palladium nanoparticles supported on activated carbon (C) for the catalytic hexavalent chromium reduction

10.21203/rs.3.rs-887515/v1 ◽

2021 ◽

Author(s):

İbrahim Gözeten ◽

Mehmet Tunç

Keyword(s):

Activated Carbon ◽

Formic Acid ◽

Acid Medium ◽

Hexavalent Chromium ◽

Catalytic Reduction ◽

Activation Parameters ◽

Trivalent Chromium ◽

Reducing Agent ◽

Chromium Reduction ◽

Mild Conditions

Abstract Hexavalent chromium is widely used in industry and causes human health and environmental problems due to its extremely toxic properties. On the contrary, trivalent chromium is necessary for living ecosystems. Therefore, it is best idea to detoxicate hexavalent chromium by reducing hexavalent chromium to trivalent chromium.. Pd(0)@C catalyst was prepared in solution under mild conditions by a simple impregnation-reduction method and was identified by XPS, XRD, TEM, TEM-EDX, HR-TEM, ICP-OES analyses. TEM results showed that very well dispersed Pd nanoparticles were formed on the C surface (mean particle sizes 3.98 ± 0.24 nm). The catalytic activity of Pd(0)NPs impregnated on C was tested in hexavalent chromium reduction in the reducing agent formic acid medium. The activated carbon supported Pd(0)@C nanoclusters were used as heterogeneous nanocatalysts in the catalytic reduction of Hexavalent chromium in formic acid medium, which is a good reducing agent under mild conditions. It was determined that the formed Pd(0) nanoclusters could successfully reduce Cr(VI) to Cr(III) by high selectivity (~ 97%). It was observed that the Pd(0)@C catalyst retained a significant (> 75%) initial activity even after the 5th use. In addition, for the kinetic data of the catalytic reduction reaction of Cr(VI) catalyzed by Pd(0)@C, the rate equation and activation parameters were derived depending on the [Cr2O72−], [Pd(0)@C], [HCOONa], [HCOOH]concentrations and temperature.

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