Preparation of efficient ion-imprinted polymers for selectively removing and detecting As(iii) from the aqueous phase

Abstract

In this study, an As(III)-imprinted polymer (As(III)-IIP) was synthesized via a one-pot method using 1,4-dithioerythritol and 3-mercaptopropyltrimethoxysilane as bifunctional monomers and the As(III) ion as the template ion, which was eluted by nitric acid; this ion can be oxidized from trivalent arsenic to pentavalent arsenic, which benefits the elution of the As(III) target ion from As(III)-IIP. The synthesized As(III)-IIP showed a good spherical structure and a rough surface with a large specific surface area of 779.80 m² g⁻¹ and a uniform mesoporous size of 2.08 nm in N₂ adsorption–desorption experiments. Moreover, As(III)-IIP revealed good adsorption capacity and specificity for As(III) ions, with the saturated adsorption capacity and imprinting factor reaching 17.11 mg g⁻¹ and 1.35, respectively. The adsorption isotherms and kinetics results showed that the adsorption isotherms of As(III)-IIP were more consistent with the Langmuir model (R² = 0.991) and that the adsorption kinetics were well fitted by a pseudo-second-order model (R² = 0.963), which indicated a monolith homogeneous adsorption process with chemical interaction between As(III)-IIP and As(III) ions. Additionally, the As(III)-IIP demonstrated highly selective adsorption toward As(III) ions compared with other interfering ions, and also exhibited good regeneration properties, retaining more than 90% of its initial adsorption capacity after five adsorption–desorption cycles. In the treatment of actual water samples, As(III)-IIP also showed excellent performance with a recovery rate of 95.00–105.0% and an RSD of 1.54–8.34%, and the limit of detection (LOD) was as low as 1.60 μg L⁻¹ with a good linear relationship (R² = 0.997) in the range of 2.50–20 μg L⁻¹. In conclusion, the synthesized As(III)-IIP with good adsorption capacity, selectivity and regeneration properties would be a great alternative material for the detection, adsorption and removal of As(III) ions from real water samples.