TITLE:
Discarded Carbon-Zinc Batteries as Source of an Efficient Heterogeneous Fenton-Like Catalyst Employed to Degrade Organic Molecules in an Aqueous Medium
AUTHORS:
A. Valadares, S. F. Resende, I. M. F. de Oliveira, R. Augusti
KEYWORDS:
Electronic Waste, Zinc-Carbon Batteries, ZnMn2O4, Fenton-Like Degradation, Indigo Carmine, Direct Infusion Electrospray Ionization High Resolution Mass Spectrometry, By-Products Identification
JOURNAL NAME:
Green and Sustainable Chemistry,
Vol.9 No.3,
August
22,
2019
ABSTRACT: The present work evaluates the feasibility of using the raw material
collected from discarded zinc-carbon batteries as heterogeneous catalyst to
degrade the dye Indigo Carmine in an aqueous solution. Besides the evident
environmental application, this work also presents an economic alternative for
the production of new catalysts used to remediate polluted waters. For this,
discarded carbon-zinc batteries were gathered, disassembled and their anodic
paste collected. After acidic treatment and calcination at 500°C,
characterization measurements, i.e. flame atomic absorption spectroscopy (FAAS), nitrogen sorption, X-ray
diffraction (XRD) and scanning electron microscopy (SEM), revealed that the
so-obtained material consisted mainly of ZnMn2O4. This
material acts as a heterogeneous catalyst in a Fenton-like process that degrades
the dye Indigo Carmine in water. That is probably due to the presence of
Mn(III) (manganese in the +3 oxidation state) in this material that triggers
the decomposition of hydrogen peroxide (H2O2) to yield
hydroxyl radicals (HO·). Moreover,
direct infusion electrospray ionization coupled to high resolution mass
spectrometry (ESI-HRMS) was employed to characterize the main by-products
resulting from such degradation process. These initial results thus indicate
that raw materials from waste batteries can therefore be potentially employed
as efficient Fenton-like catalysts to degrade organic pollutants in an aqueous
solution.