Investigation on microstructure, magnetic and electronic structures of the mechanically alloyed (Co2Mn)100-xNix powders used as oxidizing agent for methylene blue

Abstract

• Nanocrystalline (Co 2 Mn) 100-x Ni x ( x = 0 , 20 , 40 , a n d 60 w t . % ) alloy powders were prepared by mechanical alloying. • The Ni addition to Co 2 Mn powders led to the formation of a highly disordered fcc solid solution with a soft magnetic character. • The powders were tested in the oxidation of methylene blue via a heterogeneous Fenton-like process. • (Co 2 Mn) 100-x Ni x powders are promising systems for the treatment of environmental pollution. Nanocrystalline (Co 2 Mn) 100-x Ni x ( x = 0 , 20 , 40 , a n d 60 w t . % ) alloy powders were prepared by mechanical alloying in a high-energy planetary ball mill. Morphology, structure, and microstructure have been analysed using scanning electron microscopy and X-ray diffractometry. Magnetic properties have been investigated employing magnetization measurement in 2 - 850 K range under an applied magnetic field up to 1 T. The Ni addition to Co 2 Mn powders led to the formation of a highly disordered face-centred-cubic solid solution (FCC-SS) with a soft magnetic character. The lattice parameter and the crystallite size are increased with Ni addition; while the microstrains’ variation is reduced. Electronic structure calculations have been performed in the framework of the self-consistent ab initio calculations, based on Korringa-Kohn-Rostocker (KKR) method combined with the Coherent Potential Approximation (CPA). The powders were tested in the oxidation of methylene blue via a heterogeneous Fenton-like process in which H 2 O 2 / • OH were produced in situ. Up to 97.13% of oxidation was achieved after 70 min with 30 mg of powders at 50 °C.