Modeling and optimization of indigo carmine adsorption from aqueous solutions using a novel polymer adsorbent: RSM-CCD

A novel adsorbent was prepared via the free radical copolymerization of 2-(dimethylamino) ethyl methacrylate (DMAEMA) and acrylonitrile (AN) using 2,2′-azobisizobutyronitrile (AIBN) as an initiator at 65 °C. Poly(DMAEMA-co-AN) was characterized by FT-IR, 1H-NMR, and SEM techniques. Its thermal properties were determined by TGA and DSC. The copolymer was used to remove indigo carmine (IC) from aqueous solutions. The optimum IC removal percentage was determined to be 99.53% with poly(DMAEMA-co-AN) of 0.10 g/100 mL, contact time of 31.37 min, 46.58 mg/L initial concentration of IC using a central composite design in response surface methodology. The high maximum adsorption capacity (196.07 mg/g) proved that poly(DMAEMA-co-AN) can be used as a promising adsorbent for the removal of IC from wastewaters.