Oxidized lignin cross-linked O-carboxymethyl chitosan /aminosilane modified LDH for enhanced tetracycline removal

Alkyl-lignin and o-carboxymethyl chitosan (O-CMC) are biodegradable polymers, potentially applied as an antibiotic adsorbent. However, hydrogels prepared from these natural polymers have very low durability even in weak acids. For improving the stability, a novel dual-crosslinked nanocomposite hydrogel (DCNH; imine bond and nanoparticle crosslinking) was prepared by combination of aminosilane modified Mg-Al LDH (ALDH) , Oxidized alkyl-lignin (Oxi-Lignin) and O-CMC. Oxidation of lignin was performed with sodium periodate to prepare lignin dialdehyde (LD) and used as crosslinking agent. The FTIR peaks indicated the cross-linking reaction of the active aldehyde of LD and the amin groups of carboxymethyl chitosan (CMC) and of ALDH. The nanocomposite adsorbent shows a stable adsorption and resistance under acid. The nanocomposite adsorbent was stable under HCl 1 M. The thermos-stability of DCNH samples is also performed with of DTA-TGA. The DCNH adsorbent was stable up to 600°C. The hydrogel can be used as an adsorbent of tetracycline antibiotic (TC) in water. The optimum pH for adsorption of TC was reached at pH 5 with 98.3% efficiency and adsorption capacity of 65.51 mg/g.