Adsorption and removal of rhodamine B from aqueous solution by tannic acid functionalized graphene

• Tannic acid functionalized graphene (TA-G) was synthesized.
• TA-G exhibited fine adsorption performance for RB.
• Theoretical maximum adsorption capacity of RB on TA-G achieved 201 mg g−1.

A facile and green method was employed to synthesize the tannic acid functionalized graphene nanocomposite (TA-G) using tannic acid as reducing as well as capping reagent which could alter graphene surface physicochemical properties to improve the adsorption efficiency. Then the as-prepared TA-G was used as adsorbent to investigate the adsorption behavior for rhodamine B (RB). Due to the intensive π–π stacking interaction and electrostatic attraction, TA-G exhibited fine adsorption performance for RB. The adsorption isotherm fitted Langmuir model well and the theoretical maximum of adsorption capacity calculated by Langmuir model was 201 mg g−1 which was approximately in a close agreement with the experimental measured data. The kinetics of adsorption was consistent with the pseudo-second-order model perfectly and chemisorption was the speed limit step. Therefore, the as-prepared TA-G nanocomposite would be an ideal adsorbent for the removal of RB in aqueous solution and opened a new door to broaden the potential applications of graphene in environmental research.

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