LAUSR

Abstract The disposal of manganese slag and chromium electroplating wastewater is a difficult problem worldwide. These wastes contain various transition metals, such as Mn, Cr, Fe, Ni and Cu. Thus, these wastes are also potential resources. In this work, a novel catalyst for selective catalytic reduction of nitric oxide was synthesized with the synergetic utilization of manganese slag and chromium wastewater for the first time. The catalyst was feathered by a multi-metal containing amorphous and crystal MnCr oxides. As a result, the manganese slag after ammonia activation increased the removal of nitric oxide from 25 to 61% at a temperature as low as 150 °C. The nitric oxide removal further increased to 97% after chromium wastewater precipitation. The enhanced efficiency lasted for more than 900 min. The results of X-ray diffraction, X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy revealed that chromium wastewater increased the amount of amorphous Mn4+, which coupled to Cr3+. Moreover, the Ni, Fe and Cu in Mn slag and Cr wastewater were incorporated into the coupling, further enhancing the amount of acid sites and low-temperature activity. This catalyst was even more active than a reagent-synthesized MnCr catalyst. Therefore, the present research developed a new strategy to recycle transition metal-containing wastes and to synthesize catalysts for sustainable development.