Remarkable removal of nanoplastics from water by amine-modified silica aerogels: Performance and mechanism

Abstract

Nanoplastics (NPs) have attracted global attention as emerging contaminants that potentially threaten aquatic ecosystems. The development of adsorbents for the effective elimination of NPs from water is urgent. Here, for the first time, amine-modified silica (SAA) aerogel was synthesized as a highly efficient and widely environmentally compatible adsorbent for removing NPs. Furthermore, the effects of various environmental parameters were examined regarding the adsorption behavior and mechanism. The doping of 3-aminopropyltriethoxysilanes (APTES) modulates the physicochemical properties of aerogels and imparts the adsorption capacity. The best-performing aerogel is 19 times more efficient at removing NPs (96.62%) than the unmodified aerogel. Within 15 min 83.15% of the target contaminants are extracted and equilibrium is reached in approximately 2 h. Notably, the maximum adsorption capacity is estimated to be 228.63 mg/g by the isotherm investigation, with NPs adsorbed into a homogeneous monolayer. As the point of zero charges (pHpzc) is 10.2, SAA supplies outstanding capability in a wide range of applications (acidic, neutral, or even alkaline circumstances). Characterization reveals that electrostatic interactions play a decisive role in adsorption. This study provides a superb and reliable adsorption approach for removing NPs and presents an in-depth study of the intricate adsorption mechanism.