Enhanced UV/H2O2 process by expanded graphite: an effective method for rhodamine B dye decolorization

摘要

In the present work, the decolorization of rhodamine B (RhB) dye was studied using a UV/H2O2 process enhanced by expanded graphite (EG). The effects of initial solution pH, EG/H2O2 dosage, and reaction temperature on decolorization were investigated. The decolorization effectiveness increased with increasing EG and H2O2 doses but reached optima with 1.0 g/L and 1.0 mL/L, respectively. The UV/H2O2 process enhanced by EG for RhB dye decolorization followed the pseudo-first-order kinetics model and exhibited an enhancement effect with the rate constant (k) of 0.05268 min(-1) (k = 0.01972 min(-1) for the UV/H2O2 process). The improved decolorization efficiency of RhB may be ascribed to the cooperation effect in the UV/H2O2 process enhanced by EG. Furthermore, the possible mechanism of RhB decolorization was discussed. EG not only acts as an absorbent of RhB dye and H2O2 molecules, but also acts as a catalyst to decompose H2O2.