A novel material poly(N-acryloyl-L-serine)-brush grafted kaolin for efficient elimination of malachite green dye from aqueous environments

Abstract

In the present work, poly(N-acryloyl-L-serine) grafted-kaolin (PNALS@K) synthesized with the surface-initiated reversible addition fragmentation chain transfer (SI-RAFT) polymerization method is reported for the efficient removal of malachite green (MG) dye from aqueous environments. The characterization of PNALS@K was carried out by scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), energy dispersive x-ray spectroscopy (EDX), and contact angle measurements. The surface characterization analysis indicates there is a thin layer of PNALS on the kaolin surface. Four parameters (starting pH, starting MG concentration (Co), adsorbent dosage (m), and contact time (t)) were evaluated using response surface methodology (RSM) combined with central composite design (CCD) for the removal of MG by PNALS@K. The optimum adsorption conditions for the removal of MG using PNALS@K were determined as starting pH = 8.92, Co = 23.49 mg/L, m = 17.44 mg, and t = 72.2 min. The results indicated that PNALS@K has maximum adsorption decolorization performance of 98.90% for MG% removal at the optimal points. Moreover, adsorption data obeyed the Weber-Morris, liquid film diffusion and pseudo-second-order kinetic models. According to the isotherm results, it was also observed that Freundlich isotherm model presented a better fit.