AccScience Publishing / AJWEP / Online First / DOI: 10.36922/AJWEP026140095
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ORIGINAL RESEARCH ARTICLE

Sustainable removal of Pb(II), Zn(II), and Ni(II) from aqueous solutions using date-pit-derived biochar: Performance evaluation under batch conditions

Marwa Y. Khudair1* ,  Rajaa N. Al-Yassein2 ,  Nawras A. Al-Faiz3
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1 Soil & Water Resources Department, College of Agriculture, University of Anbar, Ramadi, Iraq
2 Department of Pathological Analyses, College of Science, University of Basrah, Basrah, Iraq
3 Department of Natural Marine Science, College of Marine Sciences, University of Basrah, Basrah, Iraq
AJWEP, 026140095 https://doi.org/10.36922/AJWEP026140095
Received: 2 April 2026 | Revised: 3 May 2026 | Accepted: 11 May 2026 | Published online: 16 June 2026
© 2026 by the Author(s). This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution 4.0 International License ( https://creativecommons.org/licenses/by/4.0/ )
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Abstract

Heavy metal contamination in water remains a persistent environmental concern, particularly in regions where access to advanced treatment technologies is limited. In this study, biochar produced from date pits, an agricultural waste material, was investigated as a low-cost adsorbent for the removal of Pb(II), Zn(II), and Ni(II) from aqueous solutions. Batch experiments were conducted to evaluate the effects of contact time (5–120 min), solution pH (3–9), and initial metal concentration (5–50 mg L–1). The results showed that adsorption equilibrium was reached within 60 min for all metals. The maximum adsorption capacities were 39.6 mg g–1 for Pb(II), 23.5 mg g–1 for Zn(II), and 21.0 mg g–1 for Ni(II) at pH 7. Adsorption increased with increasing pH, and the affinity followed the order Pb(II) > Zn(II) > Ni(II), likely due to differences in hydration energy and interaction with surface functional groups. Kinetic analysis indicated that the adsorption process followed a pseudo-second-order model, while the equilibrium data were best described by the Langmuir isotherm model, suggesting monolayer adsorption behavior. Overall, the findings indicate that date-pit-derived biochar can serve as an effective and accessible material for removing divalent heavy metals from water, with potential application in simple and decentralized treatment systems.

Graphical abstract
Keywords
Biochar
Date pits
Heavy metals
Adsorption
Aqueous medium
Funding
None.
Conflict of interest
The authors declare that there are no conflicts of interest in competing financial or personal relationships that could have appeared to influence the work reported in this work.
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Asian Journal of Water, Environment and Pollution, Electronic ISSN: 1875-8568 Print ISSN: 0972-9860, Published by AccScience Publishing
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