Preparation of chitosan/cellulose nanofibril composite aerogel and its adsorption performance for Cu(II)-MO binary pollutant.

Heavy metals and organic dyes commonly coexist in water, which pose a serious threat to human health. Herein, a functional aerogel for adsorption of Cu(II)-methyl orange binary-polluted system was prepared. Cellulose nanofibril (CNF) was prepared by 2,2,6,6-tetramethylpiperidinyloxy (TEMPO)-NaBr-NaClO system using abandoned pineapple leaves as the main raw material, and chitosan/cellulose nanofibril (CS/CNF) composite aerogel was constructed by sol-gel method combined with freeze-drying. The structure of composite aerogel was characterized by XRD, FTIR, TG and SEM. The fabricated aerogels were ultra-lightweight and exhibited a highly porous 3D network structure. The effects of adsorbent dosage, ionic strength, solution pH, adsorbent concentration, adsorption time, and temperature on the adsorption of Cu(II) and methyl orange (MO) by composite aerogel were studied. The adsorption of composite aerogel towards mono-polluted of Cu(II) and MO reached equilibrium after 100 min with a maximum adsorption capacity of 116.69 and 295.86 mg/g, respectively. The adsorption of Cu(II) and MO by CS/CNF aerogel was mainly achieved through electrostatic attraction, metal chelation and hydrogen bonding interactions. More importantly, the adsorption of Cu(II) by CS/CNF aerogel has an inhibitory effect on its adsorption of MO in Cu(II)-MO binary-polluted system.