Water, being essential for life, necessitates urgent protective measures, particularly in treating existing polluted water to safeguard public health and ecosystems. In Lebanon, water resources are suffering from urban and industrial pollution. Thus, the objectives of this work are to investigate the efficacy of a biochar-based filter (prepared from a mixture of Lebanese organic waste and pyrolyzed at 400 °C) in the adsorption of organic dyes such as methyl orange (MO) and methylene blue (MB). The biochar-based filter prototype is composed of three consecutive layers: sand–biochar–sand. The effects of the initial concentrations of MO and MB and contact time are studied and tested in batch experiment tests.
Therefore, different concentrations of methyl orange (MO) and methylene blue (MB) ranging between 2.5 mg/L and 12.5 mg/L and 1 h contact time are tested. The obtained results show varying rates of MO removal, reaching up to 37.9% at 15 ppm, while consistently high MB removal rates range between 99.2% and 99.8%. The addition of biochar notably improves efficiency when compared to a filter composed only of sand.
The variation in contact time reveals its impact on MO adsorption, with optimal adsorption after 24 h, contrasting with rapid MB adsorption occurring within two hours. The biofilter’s superior performance over sand alone underscores the effect of biochar.
The experimental results are fitted with the Langmuir and Freundlich isotherm to predict the mechanisms of adsorption. The results show that the Freundlich model fits the MO adsorption data better, indicating multilayer adsorption, whereas the Langmuir model accurately describes MB adsorption, implying monolayer adsorption.
Our results highlight the complex nature of adsorption processes influenced by different parameters: dye concentration, contact time and adsorbent properties. This study gives valuable insights into biochar-enhanced biofilters for effective water treatment, emphasizing the importance of tailored approaches based on specific dye characteristics and environmental conditions.
Author Contributions
Conceptualization, G.K. and M.I.; methodology, G.K.; software, M.B.; validation, M.B., A.H. and M.I.; formal analysis, G.K.; investigation, G.K.; resources, M.B.; data curation, G.K.; writing—original draft preparation, G.K.; writing—review and editing, M.I.; visualization, M.B.; supervision, A.H.; project administration, A.H.; funding acquisition, M.B. All authors have read and agreed to the published version of the manuscript.
Funding
This project received support and funding from the Lebanese University, along with a grant provided by the French Embassy in Lebanon.
Institutional Review Board Statement
Not applicable.
Informed Consent Statement
Not applicable.
Data Availability Statement
Data sharing not applicable. No new data were created or analyzed in this study. Data sharing is not applicable to this article.
Conflicts of Interest
The authors declare no conflict of interest.
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