Construction of porous chitosan–xylan–TiO2 hybrid with highly efficient sorption capability on heavy metals

作者：Shuping Wu; Jiao Hu; Liuting Wei; Yumin Du; Xiaowen Shi; Hongbing Deng; Lina Zhang

来源：Journal of Environmental Chemical Engineering, 2014, 2(3): 1568-1577.

DOI：10.1016/j.jece.2014.07.001

• Chitosan
• Xylan
• TiO2 nanoparticles
• Schiff base
• Toxic heavy metal
• Adsorbent

A facile and environmentally benign method was developed to incorporate TiO2 into a chitosan–xylan polysaccharide network. The chitosan–xylan–TiO2 hybrid (CXTH) with highly porous structure was constructed via Schiff base linkages between the aldehyde groups on xylan chain and the amino groups on chitosan. The CXTH was characterized by FTIR, TGA, XRD, SEM and TEM. Moreover, the porous structure of CXTH could be controlled by employing nanoTiO2 particles as nanofillers. The results showed that the nanoTiO2 powders can significantly improve the porous structure of hybrid. The water absorption of CXTH reached 1507 wt% in purified water and 821 wt% in 0.9 wt% NaCl solution, respectively. The adsorption capabilities for heavy metals on CXTH was investigated as the function of pH, temperature, contact time and the initial concentration of metal ions. The maximum adsorption capacities of CXTH for Cu2+, Cr6+, Ni2+, Cd2+ and Hg2+ were 158.7, 97.1, 96.2, 78.1 and 76.3 mg g−1, respectively. Langmuir isotherm equation and the pseudo-second-order kinetic model illustrated that the adsorption was spontaneous and endothermic chemical adsorption. The regeneration experiments showed CXTH can be used effectively for numbers of adsorption–desorption cycles.