Fabrication of Hydrotalcite-like Copper Hydroxyl Salts as a Photocatalyst and Adsorbent for Hexavalent Chromium Removal

Abstract

Cu-HyS-urea and Cu-HyS-NaOH, which are hydrotalcite-like copper hydroxyl salts, were prepared by two different methods, urea hydrolysis and precipitation, respectively. Both synthesis methods provided the successful formation of a copper hydroxyl salt, Cu2(OH)3NO3. From XRD and UV-DRS results, the product from the urea hydrolysis methods (Cu-HyS-urea) displayed higher crystallinity, small bandgap energy (Eg), and high light absorption ability because of some intercalated carbonate anions. For the Cr(VI) removal test, the Cu-HyS-NaOH showed superior adsorption of Cr(VI) than Cu-HyS-urea due to a higher specific surface area, confirmed by BET analysis. However, the Cu-HyS-urea presented higher photocatalytic Cr(VI) reduction under light irradiation than Cu-HyS-NaOH, owing to narrow Eg, less recombination, and a high transfer of the photogenerated charge carriers, proven by the results from photoluminescence, photocurrent density, and electrochemical impedance spectroscopy. Thus, this work provides a new function of the hydrotalcite-like copper hydroxyl salts (Cu-HyS-urea and Cu-HyS-NaOH) that can be utilized not only for adsorption of Cr(VI) but also as photocatalysts for Cr(VI) reduction under light irradiation.

Enhanced Photocatalytic Degradation of Rhodamine-B under Led Light Using CuZnAl Hydrotalcite Synthesized by Co-Precipitation Technique

“…It was proven that the H material modified by Cu 2+ ions had obtained a new material with excellent photocatalytic activity towards the Rh-B degradation under the investigation conditions. This finding is the first to show that the synthesized hydrotalcites can degrade the Rh-B at high concentrations using only the 30 W LED light, resulting in lower disposal costs as compared to the 400 W halogen and the 500 W Xenon lights [18,24]. As shown in Figure 8a, the catalytic activity of (1) the CuH−3.0 sample; (2) the combination of CuH−3.0 material sample and H2O2 30%; and (3) the blank confirmed the role of oxidizing precursor to the Rh−B degradation of the material.…”

Degradation of Lignin Pollutants by Persulfate Activated with a Graphene Oxide Loaded Cu2(OH)3NO3 Composite

“…[21] Many works have been focused on the synthetic methods of Cu 2 (OH) 3 NO 3 nano-materials with various morphologies which included monodispersed nanorods and nanobelts, [20] nanoribbons, [22] nanosheets [23] and nanoplates. [23][24] And Cu 2 (OH) 3 NO 3 could be used as an effective catalyst in the fields of photocatalysis [25] and catalytic wet oxidation for the degradation of organic pollutants. [26] However, rare work focused on the activation of PS by Cu 2 (OH) 3 NO 3 , especially, further improving the catalytic performance by loading the catalyst particles on carriers.…”