Reduction in Graphene Oxide by Sodium Borohydride for Enhanced BR13 Dye and Cu2+ Adsorption

In this study, reduced graphene oxide (RGO) with good water dispersibility and excellent adsorption performance was successfully prepared using sodium borohydride (NaBH 4 ) as reductant, and their characterization and adsorption performance for Basic Red13 (BR13) and Cu 2+ were analyzed. The results showed that RGO had an obvious graphene-like structure with the C/O ratio of 3.19, while the C/O ratio of graphene oxide (GO) was only 1.81. The reason for the good water dispersibility of RGO was the retention of partial oxygen-containing groups, especially carboxyl groups. The adsorption of RGO for BR13 and Cu 2+ was typical monolayer physisorption, which could be well-described by pseudo-first-order and Langmuir isotherm models. The maximum adsorption capacities of RGO were 1674.01 mg/g for BR13 at pH = 13 and 164.72 mg/g for Cu 2+ at pH = 6, which much higher than the corresponding values of 1258.65 mg/g and 123.14 mg/g for GO. In particular, the adsorption capacity of RGO for BR13 was the highest value reported so far. Moreover, no significant loss of adsorption performance was observed even after five cycles. This work suggested that reduced graphene oxide was an efficient adsorbent for the removal of organic dyes and heavy metal ions from water, which had great potential in pollution control applications.