Preparation of Chitosan Modified Cu-Metal-Organic Framework Antibacterial Microspheres and Their Application in Adsorption of Cr(VI) from Aqueous Solution

Metal-organic frameworks (MOFs) are ideal adsorbents for wastewater treatment and excellent antibacterial agents. In this study, Cu-NH2-MOF chitosan composite microspheres were prepared by the in situ method, and the synthesized microspheres solved the disadvantages of poor recoverability of powder adsorbent and complex operation process. Cr(VI) was removed by adsorption, and the microspheres had a good bacteriostatic effect. The synthesized MOF chitosan composite microspheres were systematically characterized. The adsorption kinetics, isotherms, and thermodynamic properties were appraised, and influences of adsorption conditions toward Cr(VI) adsorption were studied. The kinetic study demonstrated that the adsorption of Cr(VI) by CS@Cu-MOF-M conformed to the pseudo-second-order model. The adsorption isotherms fit the Sips model, and the maximum adsorption capacity of CS@Cu-MOF-M for Cr(VI) was 159.25 mg/g under optimal conditions. The thermodynamic result showed that the removal of Cr(VI) was a spontaneous endothermic process. The adsorption rate of CS@Cu-MOF-M was still more than 80% of that of the first one after four cycles of regeneration experiments. The antibacterial activity results showed that MOF chitosan composite microspheres had good antibacterial properties with MIC value of 0.2 mg/mL and MBC value of 1 mg/mL. These results demonstrated that the synthesized CS@Cu-MOF-M had a great potential to treat wastewater containing Cr(VI) and bacterial contamination.