PDA/PMMA Blend Membrane Utilized for the Selective Adsorption and Separation of Heavy Metal Ions

The detrimental effects of heavy metal aqueous pollution are attracting people's attention increasingly. Membrane separation technology plays a pivotal role in the treatment of aqueous pollution due to its low energy consumption and excellent separation effect. Inspired by the strong adhesion of heavy metal ions by the dopamine in mussel protein, we have fabricated the 5 %, 10 %, 20 % and 30 % proportion of polydopamine (PDA)/Polymethyl methacrylate (PMMA) blend membranes with dopamine structure by solvent-induced phase conversion. I-V current, UV titration and transmission tests examined the membrane's selective adsorption and retention capabilities for Fe³⁺, Cu²⁺ and Cr³⁺. These experiments indicated the different selectivity for Fe³⁺ of four blend membranes with varying PDA/PMMA fractions. Based on Langmuir's adsorption theory, the 10 % blend membranes exhibited the most outstanding selective adsorption for Fe³⁺ with an LOD of 4.724×10^-9 M. Moreover, the ability to retain Fe³⁺ is still close to 100 % after 48 h of transmission. This study manifested that the PDA/PMMA blend membrane is capable of adsorbing trace amounts of Fe³⁺ from water, thereby contributing to aqueous purification.