▎ 摘　　要

The interaction of Sr(II) on magnetic polyaniline/graphene oxide (PANI/GO) composites was elucidated by batch, EXAFS, and surface complexation modeling techniques. The batch experiments showed that decreased uptake of Sr(II) on magnetic PANI/GO composites was observed with increasing ionic strength at pH <5.0, whereas no effect of ionic strength on Sr(II) uptake was shown at pH >5.0. The maximum uptake capacity of magnetic PANI/GO composites derived from the Langmuir model at pH 3.0 and 293 K was 37.17 mg/g. The outer sphere surface complexation controlled the uptake of Sr(II) on magnetic PANI/GO composites at pH 3.0 due to the similarity to the EXAFS spectra of Sr2+ in aqueous solutions, but the Sr(II) uptake at pH 7.0 was inner sphere complexation owing to the occurrence of the Sr-C shell. According to the analysis of surface complexation modeling, uptake of Sr(II) on magnetic PANI/GO composites was well simulated using a diffuse layer model with an outer-sphere complex (SOHSr2+ species) and two inner sphere complexes (i.e., (SO)(2)Sr(OH)(-) and SOSr+ species). These findings are crucial for the potential application of magnetic nanomaterials as a promising candidate for the uptake of radionuclides for environmental remediation.