Date kernel biochar: A green approach to methylene blue removal from polluted water in Iraq

Abstract

This study investigated the potential use of biochar produced from Iraqi date kernels (Khestawi) as an adsorbent for methylene blue (MB) removal from polluted water. A full factorial design methodology was employed to examine the effects of heating rate, pyrolysis temperature and holding time on the performance of the produced biochar. The results showed that pyrolysis temperature and time had a strong effect on the biochar performance, while the heating rate had a weaker effect. The biochar produced at pyrolysis temperatures of 350°C and 550°C exhibited MB removal percentages (% R) of 48.9% and 30.9%, respectively. Similarly, biochar production through pyrolysis durations of 30 and 90 minutes resulted in MB removal rates of 47.5% and 30.3%, respectively. The adsorption experimental data was well-fitted by the Freundlich isotherm model, with a high value of the Freundlich constant (KF = 1.64), indicating a high adsorption capacity of the biochar. The activation of biochar using bio-oil (organic-1) led to a substantial enhancement in the adsorption capacity, with the activated biochar (ABC-1) exhibiting a higher adsorption capability and a higher value of the Freundlich constant (KF = 7.12). Overall, the results suggest that biochar produced from date kernels has the potential as an effective and sustainable adsorbent for MB removal from polluted water, with the potential for further enhancement through biochar activation.