Preparation and characterization of porous chitosan microspheres and adsorption performance for hexavalent chromium

• Published in: International journal of biological macromolecules Vol. 135; pp. 898 - 906
• Main Authors: Ren, Lili, Xu, Jian, Zhang, Yuchen, Zhou, Jiang, Chen, Donghui, Chang, Zhiyong
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15.08.2019
• Subjects: Adsorption; Chitosan; Chitosan - chemistry; Chromium; Chromium - chemistry; Chromium - isolation & purification; Fourier transform infrared spectroscopy; freeze drying; freezing; freezing point; hydrogels; Hydrogen-Ion Concentration; Kinetics; microparticles; Microspheres; moieties; Porosity; Porous microsphere; scanning electron microscopy; Waste Water - chemistry; Water Pollutants, Chemical - chemistry; Water Pollutants, Chemical - isolation & purification; Water Purification - methods; Chromium; Chitosan; Adsorption; Porous microsphere
• ISSN: 0141-8130; 1879-0003; 1879-0003
• DOI: 10.1016/j.ijbiomac.2019.06.007

Porous chitosan microspheres were successfully developed by the simple procedure of freezing chitosan hydrogel beads and subsequently lyophilizing the frozen structure in present study. The characterization of porous chitosan microspheres was subjected to detailed analysis of scanning electron microscopy (SEM), porosity and Fourier transform infrared spectra (FTIR), and their adsorption performance for hexavalent chromium (Cr(VI)) was investigated. Results showed that when the chitosan solution concentration ranged from 2.5% to 3.5% (w/v), porous spherical structures with uniform size distribution and good sphericity formed, and the pore size and porosity could decrease significantly by increasing the concentration of chitosan solution or reducing the freezing temperature. The porous chitosan microsphere prepared with 3% chitosan solution at −40 °C for 200 min experienced the highest Cr(VI) adsorption due to its higher porosity. FTIR result suggested that porous chitosan microspheres provided adsorption sites of the amino and hydroxyl groups for the removal of Cr(VI). [Display omitted] •Porous chitosan microspheres were successfully prepared by freeze-drying methods.•Pore size and porosity decreased with the increase of chitosan solution concentration.•A lower freezing temperature resulted in smaller pore diameters and tighter network structure.•Microspheres prepared with 3% chitosan solution possessed enhanced Cr(VI) adsorption capacity.•High adsorption capacity was due to morphological structure with large porosity and surface area.