Efficiency of titanium dioxide-reduced graphene oxide in carbamazepine removal: A comparative study of adsorption, photocatalysis, and ultrafiltration techniques

Carbamazepine (CBZ) is known to be a persistent emerging contaminant which is highly resistant to biological degradation. In order to avoid its release into the receiving waterbodies, efficient tertiary treatment must be employed. In the present study, the removal of CBZ in three advanced water treatment technologies such as adsorption, photocatalysis, and ultrafiltration were investigated. The reduced graphene oxide (rGO) was used as an adsorbent and carrier for TiO2 photocatalyst. TiO2-rGO nanocomposite was characterized using SEM, TEM, FTIR, XRD, and UV- Vis spectrophotometer. The adsorption capacity of rGO was found to be 3.63 mg/g which contributed to 91.04 ± 1.5% removal of CBZ by adsorption alone. The adsorption process was found to be influenced by key parameters such as pollutant concentration, pH, ionic strength, and natural organic matter concentration. The use of TiO2-rGO nanocomposite as photocatalyst resulted in 95.32 ± 0.25% degradation of CBZ and the efficiency of photocatalysis majorly depended on the light source. Further, rGO was immobilized on an ultrafiltration membrane to enhance the removal of CBZ. The rGO-coated ultrafiltration treatment resulted in 39.80 ± 0.62% removal of CBZ. The study highlighted the applications of rGO in the removal of recalcitrant pharmaceuticals in advanced water treatment technologies.