Research Articles (Chemistry)

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Browsing by Subject "Acid mine drainage"

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    Coal fly ash and acid mine drainage-based fe-bea catalysts for the friedel–crafts alkylation of benzene
    (Multidisciplinary Digital Publishing Institute (MDPI), 2025) Hlatywayo, Tapiwa; Petrik, Leslie; Louis, Benoit
    Coal fly ash and acid mine drainage are significant environmental issues in South Africa, causing storage constraints and impacting water quality. This study explores the use of coal fly ash and acid mine drainage in preparing zeolite HBEA-supported Fe catalysts. The Na-BEA parent catalysts were synthesised hydrothermally using coal fly ash as a feedstock. The Fe was loaded upon the H-BEA form zeolite using liquid-phase ion exchange or wet impregnation, using Fe-rich acid mine drainage as the metal precursor. The ion-exchanged Fe-BEA catalysts exhibited excellent activity, with the highest selectivity achieved over the 25 AHW after 0.5 h on stream. The study also found that when impregnation was used to load Fe onto the zeolite support, other metals present in the AMD affected the overall activity, with Mn, Ca, Mg, and Na decreasing conversion and selectivity, while Ni had a promoting effect. This study demonstrates that green solid acid catalysts with high catalytic activity can be prepared using two waste materials, coal fly ash and acid mine drainage. To the best of our knowledge, we are reporting for the first time the use of acid mine drainage as a metal precursor in Fe-BEA catalyst preparation.
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    Treatment of acid mine drainage with coal fly ash in a jet loop reactor pilot plant
    (Minerals Engineering, 2020) Kalombe, Rosicky Methode
    A 1500 L batch jet loop reactor pilot plant was designed, constructed, and evaluated for performance in the treatment of acid mine drainage (AMD) using coal fly ash with a view to optimize its operation and generate performance data. Results showed that concentration of major contaminants (sulfate, Al, Fe, Ca, Mg), and minor contaminants in the treated AMD can be significantly lowered (between one and four orders of magnitude) compared to the raw AMD. It was shown that the one-step treatment process recovered at least 66.6% (728.56 kg) of treated water depending on the degree of dewatering required for slurry pumping. The energy consumption of 2.655 kW used for pumping indicated that an oversized centrifugal pump (15 kW capacity) was used for the neutralization cycle, as only a small fraction of the pump capacity was utilized. The treated water met the target water quality range (TWQR) limit for agricultural irrigation in South Africa. The analysis of the solid residue shows its suitability for backfilling of mine voids or for making geopolymer such that AMD treatment with fly ash results in a zero discharge process. The treatment process offers a cradle-to-cradle solution to acid mine drainage and coal fly ash.