Synthesis, characterization, and adsorption properties of collagen and attapulgite-filled copolymer biocomposites: Batch and column studies

Several biocomposites were synthesized by copolymerizing hydroxyethyl methacrylate (HEMA) and itaconic acid (IA) at varied molar ratios in the presence of different wt% of collagen (CLG) and attapulgite (APG) clay. The structure and properties of the biocomposite adsorbents were characterized by Fourier transform infrared apectroscopy, nuclear magnetic resonance, X-ray photo electron spectroscopy, X-ray diffraction, scanning electron microscope, transfer electron microscopy, energy-dispersive X-ray analysis, differential thermal analysis-thermogravimetric analysis, point zero charge analysis, mechanical properties, and pH reversibility tests. The synthesis variables were optimized with a central composite design of response surface methodology (RSM). The biocomposite prepared with an optimized composition of 1.5 wt% CLG, 1.7 wt% APG, and 5:1 molar ratio of HEMA:IA showed an adsorption capacity ([Q.sub.e], mg/g) of 674.4/602.4 for methylene blue (MB)/Rose Bengal (RB) dye from a feed containing 200 mg/L of MB + RB dye mixture in batch mode. In a fixed bed in column mode, the optimized biocomposite showed a removal% of 82.8/71.3 for 100 mg/L inlet concentration, 20 ml/min flow rate, and 20 mm bed height with a breakthrough time of 23/31 min and a mass transfer coefficient ([k.sub.mtc] * [10.sub.5] cm/s) of 8.36/7.67 for MB/RB as single dye solution. KEYWORDS batch and column adsorption, biocomposite adsorbent, collagen and attapulgite, copolymer, mass transfer coefficient, RSM
1 | INTRODUCTION Natural or semisynthetic polymers such as chitosan, starch, sodium alginate, or collagen (CLG) contain numerous functional groups such as hydroxyl (-OH), ketone (C=O), carboxyl (-COOH), or amines. [...]