Sustainable recovery of rare earth elements from acidic media using recycled carton waste -derived cellulose functionalized with 1-amino-2-naphthol -4- sulphonic acid

Biopolymers have attracted increasing scientific interest because of their biodegradability, low toxicity and potential environmental benefits. Among these materials, cellulose has emerged as one of the most prominent biopolymers in recent years. This study aims to develop a sustainable cellulose-based adsorbent from recycled carton paper, providing a sustainable approach for rare earth recovery. The cellulose was sequentially treated under acidic and alkaline conditions, followed by grafting with amino naphthol sulfonic acid, leading to the formation of a novel composite referred to as cellulose amino naphthol sulfonic acid (CANS), which was specifically designed for the extraction of rare earth element (REE) from chloride-rich solutions. The CANS adsorbent was characterized using a range of physicochemical techniques and subsequently applied as an adsorbent for REE recovered from monazite ore. The ideal pH for the process of sorption at 30°C was determined to be 3, with equilibrium attained within 60 minutes. Several kinetic and isotherm models were employed to evaluate the sorption behaviour, illuminating a maximum capacity of 196.5 ± 3.1 mg g −1 . The sorption process was best described by a pseudo-second-order kinetic model. Desorption studies showed that approximately 98% of the adsorbed REE were successfully released using 0.5 M H 2 SO 4 . Further separation of the contaminant elements from desorbed REE was achieved using 10% oxalic acid at pH 1, yielding preferential REE concentrate. These findings indicate that the CANS sorbent is a promising material for the selective recovery of rare earth elements from acidic leachate.