Microwave-assisted synthesis of magnetic Pb(II)-imprinted-poly(schiff base-co-MAA) for selective recognition and extraction of Pb(II) from industrial wastewater

Abstract

Microwave-assisted magnetic Pb(II)-imprinted-poly(schiff base-co-Methacrylic acid) (MA/Fe₃O₄@Pb(II)-IIP) was prepared by inverse emulsion-suspension polymerization using lead ion as template ion, methacrylic acid and salicylaldehyde schiff base as bifunctional monomers, ethylene glycol dimethacrylate and azodiisobutyronitrile as cross linker and initiator, respectively. The influence of various single factor on the adsorption effect was analyzed. MA/Fe₃O₄@Pb(II)-IIP had the best adsorption capacity at 60 mg·L⁻¹, pH 6, 303 K and 60 min, and the maximum value was 107.75 mg·g⁻¹. The adsorption mechanism of MA/Fe₃O₄@Pb(II)-IIP was evaluated by kinetic model and adsorption isotherm. The experimental process could be better fitted by pseudo-second-order kinetics, intra-particle diffusion model and Langmuir adsorption isotherm. Under the optimum SPE conditions of pH 6, 10 ug·L⁻¹ Pb(II) solution and 5 mL, 0.5 M eluent, the extraction rates of MA/Fe₃O₄@Pb(II)-IIP for Pb²⁺, Cu²⁺, Cd²⁺ and Zn²⁺ were 92.32%, 41.86%, 31.39% and 30.57%, respectively, indicating that it had good reusability and specific recognition. The regeneration and reuse studies revealed that the MA/Fe₃O₄@Pb(II)-IIP showed no significant decrease in 5 cycles. All these adsorption performance suggested that the proposed polymer had specific recognition ability, high selectivity and high stability. It can be a promising candidate for selective recognition of lead(II) in industrial wastewater.

Graphical Abstract

Highlights

• MA/Fe₃O₄@Pb(II)-IIP was synthesized using inverse emulsion-suspension polymerization method.

• MA/Fe₃O₄@Pb(II)-IIP used schiff base and methacrylic acid as functional monomers.

• Microwave-assisted technology can catalyze the thermal reaction, increasing the temperature rapidly.

• Solid-phase extraction was developed to extract and determine lead(II) from wastewater.

Keywords:

• Pb(II)-imprinted-poly(schiff base-co-methacrylic acid)
• salicylaldehyde schiff base
• microwave-assisted
• inverse emulsion-suspension
• solid-phase extraction

Additional information

Funding

This article was supported by the National Natural Science Foundation of China (No. 21276174) and Natural Science Foundation of Shanxi province (No. 201801D121267 and 2013011040-1).