Palladium Nanoparticles Supported on Activated Carbon (C) for the Catalytic Hexavalent Chromium Reduction

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 identi ed 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 signi cant (> 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 [Cr 2 O 72− ], [Pd(0)@C], [HCOONa], [HCOOH]concentrations and temperature.

Critical Parameters and Mechanisms of Chromium Removal from Water by Copper-Based Nanoparticles

“…( 9) has been successfully applied to describe the chemical adsorption process and is appropriate for systems with heterogeneous adsorbing surfaces. It has been shown to cover a wide variety of slow adsorption rates [Gözeten and Tunç, 2022;Vaghetti et al, 2009].…”

“…This mechanism involves Cr(VI) sorption on the sorbent's surface and subsequent reduction to the less soluble and toxic Cr(III), as well as iron oxidation. Recently, various nanoparticles such as chitosan, inorganic NPs, and carbon nanotubes, have been used to sorb hexavalent chromium from groundwater [Abuzalat et al, 2020;Acharya et al, 2021;Bampaiti et al, 2013;Farooqi et al, 2021;Gözeten and Tunç, 2022;Kaprara et al, 2017;Simeonidis et al, 2015]. Copper nanoparticles (Cu-NPs) have also recently been implemented in environmental technology.…”

Reduction of hexavalent chromium using bacterial isolates and a microbial community enriched from tannery effluent

“…The remediation strategies involve physical methods such as adsorption, ion-exchange and electrodialysis, and chemical reduction by Fe(II) sulfate, sulfides, sulfites and sulfur dioxide 17 . Recently, palladium-based nanoparticles characterized by XPS, XRD, p-XRD, TEM, TEM–EDX and HR-TEM were used for the catalytic reduction of Cr(VI) 18 , 19 . A variety of other nanomaterials have also been applied to remove Cr(VI) from contaminated waters 20 and soils 21 .…”