Chitosan-Graft-Poly(N-Tert-Butylacrylamide) Copolymer: Synthesis, Characterization and Optimization of Tetracycline Removal Using RSM

Abstract In present study, graft copolymer was synthesized by free radical method using N-tertiary butylacrylamide monomer on chitosan which is an environment friendly polymer. The chemical structure and the surface morphology of the newly synthesized graft copolymer were determined by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and X-ray diffraction (XRD). Thermal behavior was analyzed by thermogravimetric analysis (TGA). To investigate the applicability of chitosan-graft-poly(N‑tert‑butylacrylamide) graft copolymer, it was used as an adsorbent for rapidly removal of tetracycline from aqueous solution. Response surface methodology (RSM) was employed for the optimization of the study conditions such as adsorbent dosage (0.01–0.04 g), reaction time (10–90 minutes), and initial tetracycline concentration (10–100 mg 100 mL− 1). The effects of these conditions on tetracycline uptake capacity were examined by RSM and the results were statistically analyzed. The RSM results showed that maximum tetracycline uptake capacity (104.81 mg g− 1) was achieved at the adsorbent dose of 0.03 mg 100 mL− 1, reaction time of 51.12 minutes, and initial tetracycline concentration of 97.99 mg L− 1. ANOVA analysis based on central composite design combined with RSM showed good agreement between experimental values and quadratic model estimates, thus resulting in 0.9118 R2 for tetracycline uptake. The findings demonstrated chitosan-graft-poly(N‑tert‑butylacrylamide) copolymer is an effective adsorbent for pharmaceutical wastewater treatment.