Halloysite nanotubes-based antimicrobial nanocomposites for air filtration: Mechanism, challenges, and perspective

Airborne microbial contamination remains a pressing concern for public health, driving the need for advanced and sustainable air filtration solutions. Halloysite nanotubes (HNTs) are naturally occurring and hollow tubular and have a high surface area, biocompatibility, and tunable surface chemistry, which means they have strong potential as the support of antimicrobial agents required in antimicrobial air filtration among emerging materials. This review discusses the application of the HNTs in delivery of antimicrobial agents, the ability of the HNT-based antimicrobial nanocomposites (HANs) to overcome microbial threats, the ability of the HNTs to generate reactive oxygen species (ROS), and the physical engagement and disruption of microbial membranes by the HNTs. Recent development in alteration and integration of HNTs in fibrous filtration media has been reported with the focus on better antimicrobial activity and filtration effectiveness. Other major challenges that are discussed in the review include material durability, stability in operation under real world air conditions, and any probability of environmental and health hazards. In the future directions, scalable manufacturing, multifunctional filter system, and regulatory alignment opportunities have been identified. In general, this review gives a comprehensive outlook of the prospect and direction of HNT-based antimicrobial technologies towards next-generation air purification systems. • Integrates multifunctional antimicrobial mechanisms into a single HNT-based filter system. • Demonstrates > 99% pathogen removal with low pressure drop and recyclability. • Explores green synthesis strategies for sustainable HAN production and application. • Introduces smart responsive filters with real-time air quality adaptability. • Proposes multimodal HAN systems combining filtration, disinfection, and pollutant degradation