Hydrochars produced via hydrothermal carbonization of rice husk were post-treated using three different acids and two bases. The post-treated hydrochars were characterized using different methods and evaluated for adsorption of dyes and antibiotics from aqueous solutions. The post-treated hydrochars had carbon and oxygen contents in the range of 37.4% to 44.7% and 29.9% to 38.6%, respectively, and their surfaces were rich in oxygen-containing functional groups and negative surface charges. Post-treatment remarkably influenced the physico-chemical properties of the hydrochars’ surfaces. All post-treated hydrochars could adsorb the model organics from aqueous solutions with the highest adsorption amount of 327, 353, 336, and 309 mg/g for Congo red, berberine hydrochloride, tetracycline, and acridine orange, respectively, at 0.3 mg/mL and 25 °C. The combined effects of functional groups, surface area, and negative surface charge of the hydrochars could assist in the adsorption of organics. The Langmuir-isotherm model provided a good fit for the adsorption of acridine orange, tetracycline, and berberine hydrochloride on the selected hydrochars, while the adsorption of Congo red generated linear isotherms indicating a partition-involved mechanism. The adsorption of the organics onto the hydrochars is a spontaneous and mainly physical adsorption process with a quite fast adsorption rate.
CITATION STYLE
Hagos, F. M., Qian, H., Di, J., Shan, S., Yang, R., Li, Y., & Gai, X. (2022). Rice Husk Hydrochars Prepared with Different Post-treatment Methods for the Adsorption of Dyes and Antibiotics. BioResources, 17(1), 725–749. https://doi.org/10.15376/biores.17.1.725-749
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