Treatment of water contaminated with petroleum hydrocarbons using a biochar derived from seagrass biomass as low-cost adsorbent: isotherm, kinetics and reusability studies

ABSTRACT

Petroleum hydrocarbons, including alkanes ranging from C₁₀ to C₃₂, have been recognized as priority organic water contaminants with a toxic impact on ecosystems. Therefore, the removal of these contaminants is of utmost importance to protect humans, plants and animals. In this work, biochar derived from the dead leaves of the widely-distributed seagrass Halodule uninervis (SGC) was prepared through biomass pyrolysis at 800°C and characterized using SEM, FTIR, TGA and surface area analysis. The prepared SGC was investigated for adsorptive removal of total petroleum hydrocarbons (TPHs) and individual alkane hydrocarbons (C₁₀ to C₃₂) from water contaminated with crude oil. The SGC displayed good removal efficiency, adsorption capacity and recyclability toward these hydrocarbons. Using the SGC, 98.8% of the TPHs were removed within 300 minutes with an adsorption capacity of 23.5 mg/g. The adsorption results were tested with the most commonly used isotherm and kinetics models. The hydrocarbon adsorption data for the SGC fit the Langmuir and Freundlich isotherms, which indicates non-uniformity of the adsorbent and a predominance of multilayer adsorption of the hydrocarbons onto the prepared SGC adsorbent. The performance and reusability of the prepared SGC adsorbent were promising, losing only 22% of its hydrocarbon removal efficiency after the 3rd cycle.

Graphical Abstract

KEYWORDS:

• Adsorption
• water treatment
• aliphatic hydrocarbons
• seagrass
• biomass

Acknowledgements

The authors would like to acknowledge and sincerely thank the Center for Environment and Marine Studies (CEMS) at King Fahd University of Petroleum and Minerals (KFUPM) for its support and funding of this research study.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data Availability

The related experimental data is presented in the manuscript.

Supplementary material

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Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.