Adsorption of fluoride from aqueous solution by graphene

A batch adsorption system was applied to investigate the adsorption of fluoride from aqueous solution by graphene. The adsorption capacities and rates of fluoride onto graphene at different initial pH, contact time, and temperature were evaluated. The experimental results showed that graphene is an excellent fluoride adsorbent with an adsorption capacity of up to 17.65 mg/g at initial fluoride concentration of 25 mg/L and temperature of 298 K. The isotherm analysis indicated that the adsorption data can be well described by Langmuir isotherm model. Thermodynamic studies revealed that the adsorption reaction was a spontaneous and endothermic process.

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► Graphene was prepared by a facile liquid phase exfoliation of worm-like graphite.
► The maximum adsorption capacity of graphene took place at pH 7.0.
► The fluoride adsorption rate of graphene is very rapid.
► The adsorption is a spontaneous and endothermic process.