Tailorable Smart Attapulgite-Based Hybrid Material for Efficient Multifunctional Oil–Water Separation and Heavy Metal Removal

Abstract

We report a tailorable strategy of constructing pH-responsive multifunctional attapulgite (APT)-polymer hybrid material by precisely grafting polymer chains onto the surface of APT via surface-initiated activators regenerated by electron transfer atom transfer radical polymerization (SI-ARGET ATRP), enabling the fine-tuning of interfacial properties by molecular-level design and leading to a smart inorganic–organic system with integrated oil/water separation and heavy metal ion removal capabilities. The resulting attapulgite-poly(2-(dimethylamino)ethyl methacrylate) (APT-PDMAEMA) hybrid exhibits reversible pH-responsive wettability and strong environmental adaptability, achieving remarkable separation efficiencies (>99.9%) and flux (∼170 L·m–2·h–1) for various types of oil–water mixtures with excellent recyclability over 10 cycles, and allowing efficient demulsification of surfactant-stabilized emulsions (>99.5% separation efficiency), high-purity and stable water flux (∼150 L·m–2·h–1). Simultaneously, the material achieves high adsorption performance for a series of heavy metal ions with removal efficiencies up to 99% across a range of pH and concentration conditions. The strategy offers modularity, scalability, and compatibility for different environmental needs. The mechanisms underlying the pH-triggered wettability and adsorption behavior were systematically investigated, offering fundamental insights into the design of smart interfaces. Overall, this work presents a versatile and scalable strategy for the tailored design of hybrid materials, providing both theoretical significance and practical value for next-generation multifunctional wastewater treatment technologies.