Surface-bound humic acid increased rhodamine B adsorption on nanosized hydroxyapatite |
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| Authors: | Gang Wang Jingjing Qi Shuangyan Wang Zhenggui Wei Shiyin Li Jing Cui |
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| Institution: | 1. Jiangsu Provincial Key Laboratory of Materials Cycling and Pollution Control, School of the Environment, Nanjing Normal University, Nanjing, China;2. Key Laboratory of Virtual Geographic Environment (Nanjing Normal University), Ministry of Education, Nanjing, China;3. State Key Laboratory Cultivation Base of Geographical Environment Evolution (Jiangsu Province), Nanjing, China;4. Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing, China |
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| Abstract: | In this study, humic acid-bound nanosized hydroxyapatite (HA-nHAP) was developed as a novel adsorbent, and the potential of using HA-nHAP for the adsorption of rhodamine B (RhB) from aqueous solution as functions of pH, adsorbent dosage, contact time, ionic strength, and temperature was investigated. The results indicated that the HA binding significantly increased the adsorption of RhB due to the introduction of abundant negatively charged functional groups. The adsorption capacity of HA-nHAP for RhB was found to be pH-dependent, and the optimal pH value was found to be 6.0. The adsorption equilibrium data obeyed Sips and Freundlich isotherms and the kinetic data were well described by the Elovich kinetic model. According to the Sips equation, the maximum adsorption capacity for RhB was 24.12 mg/g. The temperature and ionic strength experiment showed that they both had an effect on the adsorption capacity of HA-nHAP. Thermodynamic study confirmed that the adsorption was a spontaneous, endothermic, and more random arrangement process. The present investigation showed that HA-nHAP is a promising adsorbent for the removal of RhB from aqueous solution. |
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| Keywords: | Adsorption humic acid hydroxyapatite rhodamine B surface modification |
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