Phenolic acids modified cellulose microspheres for selective capture of Bi(III): Batch, column and mechanism investigation

Abstract

Bismuth (Bi) is a strategic metal, and its recovery is of great significance for environmental protection and resource recycling. In this work, three polyhydroxyl monomers (gallic acid (GA), protocatechuic acid (PC) and shikimic acid (SA)) functionalized cellulose microspheres (MCGA, MCPC and MCSA) were fabricated by radiation technology, and employed for Bi(III) uptake. The effect of the number and type of hydroxyl groups on the adsorption performance was evaluated by batch and column experiments. The adsorption capacity of phenolic acid modified MCGA (Qm = 155.28 mg/g) and MCPC (Qm = 93.46 mg/g) was found to be significantly higher than that of non-phenolic acid modified MCSA (Qm = 3.90 mg/g) in the batch experiment. DFT calculation manifested that the phenolic hydroxyl groups could more easily coordinate with Bi(III) than the alcoholic hydroxyl groups. The higher number of phenolic hydroxyl groups, the more favorable the coordination. Notably, the column experiments demonstrated that MCGA and MCPC can selectively capture and recover Bi(III) using 0.5 M HNO3. Finally, the MCGA and MCPC could remove trace Bi(III) from actual environmental water samples, indicating that MCGA and MCPC would be promising candidates in environmental remediation and water purification.