A new insight of recycling of spent Zn–Mn alkaline batteries: Synthesis of ZnxMn1−xO nanoparticles and solar light driven photocatalytic degradation of bisphenol A using them

Abstract

This work focuses on the synthesis of Zn0.1Mn0.9O, Zn0.3Mn0.7O, and Zn0.5Mn0.5O nanoparticles using Zn–Mn spent alkaline batteries (SABs) as raw materials and their applications for photocatalytic degradation of bisphenol A in water. Zn–Mn SABs were manually dismantled into scrap (including plastics, copper cap, zinc crust, and carbon rod) and powder. The mashed zinc crust and pretreated powder were successively added into H2SO4 and NH3⋅H2O, and the formed precipitates were characterized. The yield (wt) of synthesis of Zn0.5Mn0.5O (ZnMnO3) nanoparticles was 57.1%. The synthesized Zn0.5Mn0.5O nanoparticles were cylinder, with a length of 60nm. Afterwards, the removal efficiencies of bisphenol A (BPA) under solar light irradiation with the recovered ZnxMn1−xO nanoparticles were investigated: (1) the adsorption equilibrium of BPA on ZnxMn1−xO nanoparticles could be achieved after approximate 40min. The saturation absorbance of BPA was about 32.40±4.76mgg−1, 20.40±3.60mgg−1, and 14.50±4.55mgg−1 by Zn0.1Mn0.9O, Zn0.3Mn0.7O, and Zn0.5Mn0.5O nanoparticles, respectively; (2) compared with the 21.7±1.6% degradation of BPA (only solar light irradiation for 180min), the combination of solar light irradiation and Zn0.1Mn0.9O, Zn0.3Mn0.7O, and Zn0.5Mn0.5O nanoparticles could lead to 59.41±4.32%, 83.43±2.73%, and 71.22±4.79% decomposition yields of BPA, respectively. These findings have positive effects on solving the recycling of SABs, decreasing the cost of catalysts, and the problem of organic pollutant in water.