Birch bark modified with potassium permanganate for lead and cadmium adsorption from simulated WEEE solution
Wang, Jiru (2026)
Diplomityö
2026
School of Engineering Science, Kemiantekniikka
Kaikki oikeudet pidätetään.
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi-fe20260621100704
https://urn.fi/URN:NBN:fi-fe20260621100704
Tiivistelmä
Hydrometallurgical recycling of metals from waste electrical and electronic equipment (WEEE) generates strongly acidic leachates with multi-metals. Due to the complexity of real WEEE leachates, simulated acidic single-metal solutions were used in this study. Birch bark, a forestry by-product, was modified using potassium permanganate (KMnO₄) to produce a green and affordable adsorbent for lead (Pb) and cadmium (Cd) removal. The optimized adsorption conditions were determined using response surface methodology (RSM) with Box-Behnken design (BBD).
Under the optimized conditions, the adsorption kinetics of both Pb and Cd were better fitted by the pseudo-second order (PSO) model, while the Freundlich model offered the best fit among the three isotherm models (the Langmuir, Freundlich, and Sips model). The maximum adsorption capacities of Pb and Cd were 140.7 mg g-1 and 39.9 mg g-1 fitted by the Sips model, showing the potential of modified birch bark as an adsorbent. Characterization analyses, including Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR), the pH point of charge (pHpzc), and Scanning Electron Microscopy coupled with Energy-Dispersive Spectroscopy (SEM-EDS), indicated the adsorption mechanisms involved the electrostatic interactions and ion exchange.
Under the optimized conditions, the adsorption kinetics of both Pb and Cd were better fitted by the pseudo-second order (PSO) model, while the Freundlich model offered the best fit among the three isotherm models (the Langmuir, Freundlich, and Sips model). The maximum adsorption capacities of Pb and Cd were 140.7 mg g-1 and 39.9 mg g-1 fitted by the Sips model, showing the potential of modified birch bark as an adsorbent. Characterization analyses, including Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR), the pH point of charge (pHpzc), and Scanning Electron Microscopy coupled with Energy-Dispersive Spectroscopy (SEM-EDS), indicated the adsorption mechanisms involved the electrostatic interactions and ion exchange.