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Updated: Jan 28, 2026

Quantification of Humic and Fulvic Acids in Humate Ores, DOC, Humified Materials and Humic Substance-Containing Commercial Products
Published on: March 18, 2022
Enhanced removal of ciprofloxacin using humic acid modified hydrogel beads
Muhammad Zaheer Afzal1, Rengyu Yue2, Xue-Fei Sun2
1Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China; Department of Earth and Environmental Sciences, Bahria University, Islamabad 44000, Pakistan.
Abstract:
In this study, humic acid coated biochar (HA-BC) and chitosan were combined to prepare an adsorbent with enhanced reactivity for the removal of ciprofloxacin (CIP). With initial CIP concentrations of 250 mg/L, the maximum adsorbed amount was 154.89 mg/g. Removal rates reached equilibrium after 12 h, obeying the pseudo second-order kinetic model. Adsorption isotherm data was better fitted to the Langmuir isotherm model. The sorption capacity of humic acid-biochar/chitosan hydrogel beads (HBCB) decreased by 11.42%, 6.66%, 9.32%, and 23.92% in the presence of NaCl, NaNO3, Na2SO4, and Na3PO4, respectively. A complex mechanism was found to be responsible for the adsorptive removal of CIP including, hydrogen bonding, π-π electron donor-acceptor (EDA) interactions and hydrophobic interactions. After four regeneration steps, sorption capacity remained sufficient (61.23 mg/g). These removal results indicate that HBCB is durable and effective for long term CIP removal.
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