Design and preparation of FeNiCoCrY high-entropy alloy nanopowders with sustained, efficient and rapid degradation properties of CR and Cr(VI) wastewater

In this paper, magnetic nanopowders of Fe19.5Ni40Co19.5Cr19.5Y1.5 high-entropy alloy compositions were successfully prepared by the liquid phase reduction method, which represented a breakthrough from the traditional process of preparing high-entropy alloy nanopowders. The powders had a high specific surface area of 136.23 m2/g and exhibited sustained, efficient, and rapid degradation characteristics for high concentrations of CR and ultra-high concentrations of Cr(VI) wastewater. It was demonstrated that the removal rate of CR remained at 100 % after 100 cycles and 81 % of Cr after 8 cycles of the powder without changing the pH and room temperature. The powders also demonstrated good soft magnetic properties, which allowed them to be conveniently separated and recycled using magnetic field treatment, thus addressing the issue of recycling raw materials without causing secondary pollution in wastewater treatment. Furthermore, the analyzed powders also exhibited fast and efficient degradation effects. •High-entropy alloy nanopowders were used for the continuous, rapid, and efficient removal of CR and Cr(VI).•The degradation rate of CR remained at 100 % after 100 cycles under the original conditions.•The degradation of ultra-high concentrations of Cr reached 81 % after 8 cycles under the original conditions.•The powders were easily recovered and could be reused after being treated.