High-strength and low-swelling chitosan/cellulose microspheres as a high-efficiency adsorbent for dye removal

Dye contamination of water supplies has a serious threat to human health, prompting the development of highly effective and eco-friendly adsorbents. In this work, polyelectrolyte microspheres derived from positively charged chitosan and negatively charged cellulose were constructed in alkali/urea solvent by a simple water/oil emulsification. The obtained chitosan/cellulose microspheres (CCM) were further used for the removal of reactive black 5. By using alkali/urea solution as the solvent, a homogeneous chitosan/cellulose solution was achieved, which avoided the easy occurrence of agglomeration between oppositely charged polymers. More importantly, CCM showed significantly improved mechanical strength and anti-swelling properties compared with pure chitosan microspheres (CM). Adsorption experiments demonstrated that CCM can effectively remove reactive black 5 with high adsorption capacity of 214.36 mg/g, fast adsorption kinetic that reached 76% of the equilibrium adsorption amount within only 20 min, and good reusability that maintained 75% efficiency even after five times of adsorption/desorption cycle, indicating a great potential for the application of dye removal.