Removal of Coomassie Brilliant Blue R-250 Using Iron Oxide-Graphene Oxide Composite via Fenton-like Reaction

The presence of organic dyes in the environment greatly affects the photosynthetic capabilities of underwater organisms as these compounds block sunlight and reduce the amount of available oxygen. Moreover, the structural diversity of dyes makes them highly resistant to light, heat, and oxidizing agents; thus, new approaches for dye remediation are continuously being developed. The use of iron oxide-graphene oxide composite (IOGOC) with persulfate oxidant via a Fentonlike reaction for the removal of Coomassie Brilliant Blue (CBB) R-250 in aqueous solutions was investigated. The IOGOC adsorbent was synthesized and then characterized using FTIR (Fouriertransform infrared spectrophotometry), SEM (scanning electron microscope), and XRD (X-ray powder diffraction). Adsorption isotherm and kinetic studies revealed that the adsorption of the dye on IOGOC was best described by Langmuir isotherm with a maximum adsorption capacity of 14.31 ± 0.65 mg CBB R-250/ g IOGOC and followed the pseudo-second-order kinetic model. Batch adsorption studies were done to determine the effect of dye concentration, adsorbent loading, oxidant concentration, and pH on dye removal. Results showed that the parameters for the dye degradation that afforded a significantly higher degree of dye removal were 10 mg/L adsorbate amount at pH 3.0 with 7 mg adsorbent loading and 3 mM persulfate solution for 270 min contact time. End product analyses indicate that the treated water sample contains 1.84 ± 0.30 mg dissolved iron/ L solution, which is within the limits based on Department of Environment and Natural Resources’ (DENR) Water Quality Guidelines and General Effluent Standards of 2016 and a 73 ± 19% chemical oxygen demand (COD) removal. Recyclability studies show that the synthesized composite can be used for four times without a significant decrease in the dye removal efficiency.