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VOL. 10, ISSUE 2 (2026)
Removal of heavy metals from pharmaceutical effluents using (Activated Charcoal) rice husk
Authors
Moronkola Bridget Adekemi, Alegbe Monday John, Alege Justinah Racheal, Asimi Awonike Julianah, Dosunmu Olufemi Michael
Abstract
Pharmaceutical effluents
are significant sources of environmental pollution, due to their complex
composition and toxic heavy metal content, which threaten the aquatic ecosystems
and human health. The aim of the study was to remove zinc (Zn), chromium (Cr),
and iron (Fe) from pharmaceutical effluents, using activated rice husk charcoal
derived from Oryza glaberrima as a low-cost and sustainable adsorbent.
The rice husk charcoal was chemically activated and characterised using Fourier
Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD),
Thermogravimetric analysis (TGA), Brunauer-Emmett-Teller (BET), Scanning
Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The
results for FTIR of the rice husk ash before adsorption showed the spectrum at
3227.88 cm⁻¹ (O-H stretching), 2877.51 cm⁻¹ (C-H stretch), 2072 cm⁻¹ (C≡C
stretch) or (C≡ N), 1591 cm⁻¹ (N − H bending), 1379.35 cm⁻¹ (C − H bending),
1017.52 cm⁻¹ (c − O stretching), or (Si − O stretching). X-ray diffraction
(XRD) identified a mineral composition of Silicon dioxide 86.9%, Osmilite
10.41%, Graphite 2.63%, and Hanksite 0.09% for the rice husk ash sample. The
Brunauer-Emmett-Teller (BET) for the pore size of the rice husk ash indicates
an average pore of 7 diameter of 2.647 nm, which classifies the material as
mesoporous, its cumulative surface area is 7.805 m²/g-which is relatively
moderate for materials with mesopores, and the pore volume of 0.953 cm³/g
suggests that the material has a significant amount of internal space for
storing gas or liquid. In the thermogravimetric analysis (TGA), it was
discovered that the rice maintains its stability, up to 250°C before
significant degradation occurs. The batch adsorption experiments were conducted
to assess removal efficiency under varying operational parameters, including
adsorbent dosage, contact time, and pH. Heavy metal concentrations were
determined using Atomic Absorption Spectroscopy (AAS). Removal efficiency
increased with higher adsorbent dosage, with an optimum of 1.0 g per 50 mL.
Maximum adsorption occurred at 60 minutes. Optimal pH values were 2.0 for Zn
and Fe, and 4 for Cr, indicating pH-dependent adsorption. The removal
demonstrates that activated rice husk charcoal is an effective, economical, and
environmentally-sustainable material for heavy metal removal from
pharmaceutical wastewater, while also promoting agricultural waste
valorisation.
Pages:17-23
How to cite this article:
Moronkola Bridget Adekemi, Alegbe Monday John, Alege Justinah Racheal, Asimi Awonike Julianah, Dosunmu Olufemi Michael "Removal of heavy metals from pharmaceutical effluents using (Activated Charcoal) rice husk". International Journal of Chemical Science, Vol 10, Issue 2, 2026, Pages 17-23
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