Rapid removal of Cr(VI) from aqueous solution using polycationic/Di-metallic adsorbent synthesized using Fe3+/Al3+ recovered from real acid mine drainage
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Date
Authors
Muedi, Khathutshelo Lilith
Masindi, Vhahangwele
Maree, Johannes Philippus
Brink, Hendrik Gideon
Journal Title
Journal ISSN
Volume Title
Publisher
MDPI
Abstract
The mining of valuable minerals from wastewater streams is attractive as it promotes a
circular economy, wastewater beneficiation, and valorisation. To this end, the current study evaluated
the rapid removal of aqueous Cr(VI) by polycationic/di-metallic Fe/Al (PDFe/Al) adsorbent
recovered from real acid mine drainage (AMD). Optimal conditions for Cr(VI) removal were 50 mg/L
initial Cr(VI), 3 g PDFe/Al, initial pH = 3, 180 min equilibration time and temperature = 45 C.
Optimal conditions resulted in 95% removal of Cr(VI), and a maximum adsorption capacity of
Q = 6.90 mg/g. Adsorption kinetics followed a two-phase pseudo-first-order behaviour, i.e., a fast
initial Cr(VI) removal (likely due to fast initial adsorption) followed by a slower secondary Cr(VI)
removal (likely from Cr(VI) to Cr(III) reduction on the surface). More than 90% of adsorbed Cr(VI)
could be recovered after five adsorption–desorption cycles. A reaction mechanism involving a rapid
adsorption onto at least two distinct surfaces followed by slower in situ Cr(VI) reduction, as well
as adsorption-induced internal surface strains and consequent internal surface area magnification,
was proposed. This study demonstrated a rapid, effective, and economical application of PDFe/Al
recovered from bona fide AMD to treat Cr(VI)-contaminated wastewater.
Description
DATA AVAILABILTY : The data presented in this study are openly available in the University of Pretoria Research Data Repository at https://doi.org/10.25403/UPresearchdata.21342765.
Keywords
Chromium removal, Acid mine drainage, Wastewater streams, Circular economy, Wastewater beneficiation, Polycationic/di-metallic adsorbent (nanocomposite)
Sustainable Development Goals
Citation
Muedi, K.L.; Masindi, V.;
Maree, J.P.; Brink, H.G. Rapid
Removal of Cr(VI) from Aqueous
Solution Using Polycationic/
Di-Metallic Adsorbent Synthesized
Using Fe3+/Al3+ Recovered from
Real Acid Mine Drainage. Minerals
2022, 12, 1318. https://DOI.org/10.3390/min12101318.