Adsorption of Hg(II) Ions from Aqueous Solution Using Doum Palm Shell: Desorption and Effluent Treatment

1Alkali, M. I. and 2Kyari, A.U.

1Department of Chemistry, Kashim Ibrahim University, Maiduguri, Borno State, Nigeria
2Department of Geography, Kashim Ibrahim University, Maiduguri, Borno State, Nigeria

*Corresponding author’s Email: ibrambnanabe@gmail.com, doi.org/10.55639/607.020100114


ABSTRACT

The contamination of water bodies by heavy metals, particularly mercury (Hg²⁺), poses significant environmental and public health challenges due to their toxicity, persistence, and bioaccumulative nature. This research investigates the potential of carbonized Doum palm shell (DPS) (Hyphaene thebaica) as a low-cost for the adsorption of Hg(II) ions from aqueous solutions and real industrial effluent. The adsorbent was prepared via pyrolysis under controlled conditions and characterized using physicochemical and advanced analytical techniques such as FTIR, XRD, SEM-EDX, and BET surface area analysis. Batch adsorption experiments were conducted to evaluate the effects of operational parameters including initial metal ion concentration, pH, contact time, temperature and adsorbent dosage. The results revealed that adsorption efficiency was highly dependent on pH 7 with optimal Hg(II) ions removal. The maximum adsorption capacity observed was 254.63 mg/g at 45 mg/L. The BET analysis showed a high surface area 960.650 m²/g, confirming the mesoporous nature of the material, while SEM analysis revealed a well-developed porous structure suitable for adsorption. Application of the adsorbent to real textile effluent demonstrated an outstanding removal efficiency of 99.68 %, reducing mercury concentration close to permissible limits. Desorption studies using dilute acids (HCl and HNO₃) indicated that the adsorbent could be regenerated and reused, with HCl showing superior desorption efficiency. The adsorption mechanism was predominantly governed by ion-exchange processes. The findings demonstrate that Doum palm shell derived activated carbon is effective, eco-friendly, and economically viable material for mercury removal from contaminated water, offering promising potential for wastewater treatment applications in developing regions.

KEYWORDS
Adsorption,
Activated carbon,
Doum palm,
Effluent.