Development of a Three-Step Approach to Repurpose Nickel-Laterite Mining Waste into Magnetite Adsorbents for As(Iii) and As(V) Removal: Synthesis, Characterization and Adsorption Studies
2022; RELX Group (Netherlands); Linguagem: Inglês
10.2139/ssrn.4130056
ISSN1556-5068
AutoresEinstine M. Opiso, Carlito Baltazar Tabelin, Leonard Marc Ramos, Leonar Jun R. Gabiana, Marybeth Hope T. Banda, Jet Ryan Y. Delfinado, Aileen H. Orbecido, Joshua B. Zoleta, Ilhwan Park, Takahiko Arima, Mylah Villacorte-Tabelin,
Tópico(s)Adsorption and biosorption for pollutant removal
ResumoNickel (Ni)-laterite mining is a major industry in the Philippines but is generating large amounts of Ni-laterite mining waste (NMW) that threatens surrounding water bodies due to siltation. To repurpose this waste as magnetic iron (Fe)-based adsorbent, a three-step extraction-reduction-coprecipitation approach was developed, and the adsorption properties of synthesized product for arsenate (As(V)) and arsenite (As(III)) was investigated. The three-step approach extracted >90% Fe from NMW and produced fine (<4 μm), high-purity magnetite based on XRD, FTIR and SEM-EDS. The kinetic and isotherm adsorption results at pH 5 showed that NMW-derived magnetite has high maximum adsorption capacity ( q max ) for As(V) and As(III) estimated at 141 mg/g and 19.4 mg/g, respectively. The good fit of pseudo-second-order rate law to the kinetic results implies that chemisorption is a dominant removal mechanism for both As(V) and As(III), a deduction supported by geochemical modelling and ToF-SIMS. In addition to direct adsorption via chemisorption, ToF-SIMS identified two more pathways—As(III) oxidation As(V) followed by adsorption, and reduction of As(III) to As(I) followed by adsorption—and could explain the high As(III) adsorption capacity of NMW-derived magnetite. These results demonstrate the potential of NMW as raw material for magnetic adsorbent synthesis for environmental applications.
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