Preparation of Cellulose/Chitin Blend Materials and Influence of Their Properties on Sorption of Heavy Metals

A series of biodegradable cellulose/chitin materials (beads and membranes) were successfully prepared by mixing cellulose with chitin in an NaOH/thiourea–water system and coagulation in a H2SO4 solution. The effects of chitin content on the materials’ mechanical properties, morphology, structure, and sorption ability for heavy metal ions (Pb2+, Cd2+, and Cu2+) were studied by tensile tests, scanning electron micrographs, Fourier transform infrared spectroscopy, and atomic absorption spectrophotometry. The results revealed that the cellulose/chitin blends exhibited relatively good mechanical properties, a homogeneous, microporous mesh structure, and the existence of strong hydrogen bonds between molecules of cellulose and chitin when the chitin content was less than 30 wt%, which indicated a good compatibility of the cellulose/chitin materials. Furthermore, in the same chitin content range, Pb2+, Cd2+, and Cu2+ can be adsorbed efficiently onto the cellulose/chitin beads at pH0 = 5, and the sorption capacity of the beads is more than that of chitin flakes. This shows that the hydrophilicity and microporous mesh structure of the blends are favorable for the kinetics of sorption. Preparation of environmentally friendly cellulose/chitin blend materials provides a simple and economical way to remove and recover heavy metals, showing a potential application of chitin as a functional material.