Activated carbon-chitosan based adsorbent for the efficient removal of the emerging contaminant diclofenac: Synthesis, characterization and phytotoxicity studies.

The rise in pharmaceutical pollutants due to their unregulated discharge in pharmaceutical wastewater has landed them as emerging contaminants that would gradually affect the aquatic ecosystem and human life. The current study emphasizes the adsorptive elimination of one such emerging pharmaceutical pollutant, i.e., Diclofenac (DIF), using a synthesized adsorbent vis. Activated carbon-chitosan beads (ACCB). The morphological and physicochemical properties of the prepared adsorbent, ACCB and its interaction with the DIF species were investigated. Process parameters influencing the adsorptive interactions between ACCB and DIF were optimised. DIF was efficiently adsorbed at optimised initial DIF pH of 6.0 and ACCB dosage of 1.5 mg/mL at an incubation temperature of 40 °C. Freundlich isotherm model showed the best fit (R2 = 0.98) with the experimental data to conclude that the adsorbent surface is heterogenous, promoting multilayer adsorption. As depicted from the Langmuir isotherm model, the maximum theoretical adsorption capacity was 99.29 mg/g. The seed toxicity assay confirmed the efficacy of ACCB in the adsorptive removal of DIF species from aqueous setups, making the post-treated solution fit enough for seed germination.