One-pot layer casting-guided synthesis of nanospherical aluminosilica@organosilica@alumina core–shells wrapping colorant dendrites for environmental application

Abstract

A scalable one-pot method has been developed to control the fabrication of heterogeneous mesoporous aluminosilica@organosilica@alumina nanospheres via a layer casting-guided synthesis route. Uniformly spherical onion-like nanoparticle (NP) sizes (approximately 250–300 nm), well-dispersed and heterogeneous active sites throughout the interior core, and concentric double shells are the crucial features of this approach. Wrapping/decoration of dendritic colorant (spine or branch) aggregates into a 10 nm thin-layered crust around the second alumina shell and within the core–double shell cavities afforded a container-like vehicle tracking architecture (VTA) for detecting and recovering toxins (Bi³⁺, Zn²⁺, and Hg²⁺ ions) in environmental samples. The heterogeneous VTA design presents potential applicability in pH-dependent optical sensors/extractors for ultra-trace sensing and recovery of multiple toxins from water sources. The processing efficiency of VTA in terms of selective recognition, optical detection, and exclusive capture of the multiple contaminants by using a single VTA depends mainly on the pH. Experimental findings indicate that the resulting VTAs effectively remove >95% of toxins in a one-step process. The hierarchical-core–shell structures remained in the VTA after several reuse cycles. The VTA can potentially satisfy increasing needs for the purification of tap, well, and seawater sources from toxins in Saudi Arabia.