Nanocellulose-chitosan-metal organic framework composites for arsenic removal

Abstract

In this work, a new composite sponge of chitosan, nanocellulose, and MIL-53(Fe) metal-organic-framework were synthesized and applied for As(III) and As(V) removal. Nanocellulose with an average size of 433.5 ± 41.0 nm were prepared and used. The octahedron crystalline MIL-53(Fe) was successfully synthesized. The nanocellulose was mixed with chitosan and MIL-53(Fe) before crosslinking and freeze-drying. The obtained materials were characterized by Fourier transform infrared spectroscopy, nitrogen adsorption, scanning electron microscope, and energy dispersive x-ray spectroscopy. The results showed that the composite sponge was successfully fabricated with a suitable weight ratio of 2CS: 1NC: 1.5MIL-53(Fe). The CS-NC-MIL-53(Fe) composite exhibited a highly porous structure with the surface area of 8.70 m2/g. The composite was further used to adsorb As(III) and As(V) in solutions. The effect of the solution pH, contact time, initial concentration of arsenic, and interfering ions were investigated. The composite could remove As(III) and As(V) from solutions in the pH range of 9-11 and 3-11, respectively. The suitable contact time for arsenic removal was 6 h. The kinetics of As(III) and As(V) adsorption followed pseudo-second order and the adsorption isotherm fit well to the Langmuir model. The maximum adsorption capacities were 8.53 mg/g and 36.76 mg/g for As(III) and As(V), respectively. The potential interfering ions included phosphate and sulfate ions. Furthermore, the composite showed good mechanical property and stability in water. Their application to remove arsenic in wastewater samples from a petroleum refining industry was demonstrated.