Highly-porous and excellent-capacity zirconium-chitosan composite with superior Sb(III)/Sb(V) removal performance

A novel highly porous composite of zirconium-chitosan with excellent capacity for Sb(III) and Sb(V) adsorption has been successfully developed through a facile route. Due to the loss of H2O molecules coupled with Zr4+ after lyophilization, the as-prepared porous zirconium-chitosan (PZCS) composite possesses an open large-pore structure, which provides more adsorption sites for Sb(III) and Sb(V) removal. The adsorption experimental results illustrated that PZCS exhibited outstanding abilities in the removal of both Sb(III) and Sb(V), with the theoretical maximum adsorption capacities modeled by Langmuir isotherms of 408.3 and 635.1 mg g-1, respectively. Kinetic experimental data for both Sb(III) and Sb(V) followed a pseudo-second-order model due to the excellent correlation coefficient values (R2 greater than 0.996). With respect to the mechanism, the removal of Sb(III) involved a dehydration reaction between PZCS and Sb(III), while the removal of Sb(V) was closely related to electrostatic attraction between positive sites (Zr4+, -NH3+, -OH2+) and negatively charged ions (Sb (OH)6-) under acidic conditions. This study demonstrated that PZCS composites with environment-friendly, low-cost, and facile-preparation properties could have potential applications in water purification.

Automated summary

A highly porous composite of zirconium-chitosan with excellent adsorption capacity for Sb(III) and Sb(V) has been successfully developed. The composite possesses an open large-pore structure, providing more adsorption sites for Sb(III) and Sb(V) removal. The experimental results demonstrated the exceptional abilities of the composite in removing both Sb(III) and Sb(V). The removal of Sb(III) involved a dehydration reaction, while the removal of Sb(V) was attributed to electrostatic attraction. This study highlights the potential applications of the composite in water purification.