Bio‐Based Antimicrobial Ionic Materials Fully Composed of Natural Products for Elevated Air Purification

Abstract Air pollution, including particulate matter (PM) and microorganism aerosol, is a severe problem due to its high pathogenicity. In this study, bio‐based ionic polymers derived from alginate are prepared and employed as antimicrobial filter materials. Among them, fully bio‐based cholinium alginate material exhibits the optimal antimicrobial activity and PM removal performance (99.69% for PM_2.5 removal efficiency, 99.89% for PM₁₀ removal efficiency, pressure drop below 2 Pa, and 2.8882 for quality factor (QF)). The antimicrobial activity of cholinium alginate is dramatically promoted compared with that of the raw material sodium alginate. Density function theory (DFT) studies further confirm that cholinium can electrostatically bind with anionic components on Gram‐negative bacterial cell membranes to enable sterilization. Moreover, the performance of cholinium alginate material under practical condition outperforms commercial masks. This work will provide an effective approach to develop promising green antimicrobial materials for environmental decontamination.