Using a novel adsorbent macrocyclic compound cucurbit[8]uril for Pb removal from aqueous solution |
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Authors: | Xuzhuo Sun Bo Li Dongjin WanNing Wang |
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Institution: | School of Chemical and Chemical Engineering, Henan University of Technology, Zhengzhou 450001, China |
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Abstract: | In this study, cucurbit8]uril (CB8]) was utilized as a kind of new adsorbent to remove Pb2 + ions from aqueous solution. With the solution pH increased from 2 to 6, the removal efficiency of adsorption increased from 55.6% to 74.5%correspondingly. The uptake of Pb2 + increased rapidly in the initial 30 min, and then the adsorption rate became slower. The Pseudo-second order model could be used to interpret the adsorption kinetics satisfactorily; and the rate determining step in Pb2 + adsorption onto CB8] was the external mass transfer step. Equilibrium isotherm study reveals that the Langmuir model gave a better fitting result than Freundlich model. The maximum adsorption capacity calculated by the Langmuir model was 152.67 mg/g for 298 K, 149.70 mg/g for 313 K and 136.42 mg/g for 323 K, respectively. The adsorption is a spontaneous process of exothermic nature. The effect of the adsorbent dosage and the influences of solution pH and co-existing cations were also investigated. The CB8] was synthesized and characterized by 1H NMR, IR, ESI-MS spectra, SEM-EDAX, Zeta-potential and BET-analysis. The adsorption mechanism was due to the coordination between CB8] molecule and Pb2 + ions. |
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Keywords: | Cucurbit[8]uril Adsorption Kinetics Equilibrium Pb2 + |
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