Boronate affinity imprinted Janus nanosheets for macroscopic assemblies: From amphiphilic surfactants to porous sorbents for catechol adsorption

Abstract

Abstract The fabrication of macroscopic assemblies from Janus-like nanosheets to porous sorbents, that can be used for highly efficient pollutant uptake in waters is a very meaningful work. Here, Janus nanosheets (NS-1) with amino groups on one side and Cl initiators on the other side are firstly prepared by interfacial sol-gel process from anisotropic emulsion droplets. Amphiphilic NS-1 can spontaneously assemble at the water/oil interface of high internal phase emulsions (HIPEs) to reduce the interfacial tension, and can also be firmly immobilized onto porous foam substance (NS-1-HIPEs) by initiating the continuous phase. Boronate affinity imprinted Janus nanosheets for macroscopic assemblies (NS-1-MIPs) can be obtained via selectively grafting imprinted polymers onto one side of Janus nanosheets, which can be applied for sorptive extraction of cis-diol-containing catechol. Under the conditions of 308\xa0K, 298\xa0K (pH\xa0=\xa08.5), the saturated adsorption capacity of NS-1-MIPs is 128.1\xa0μmol\xa0g−1 and 99.6\xa0μmol\xa0g−1, respectively, and the Langmuir model can well describe the equilibrium performance. In addition, NS-1-MIPs possess quick rebinding kinetics in 40\xa0min, and the pseudo-second-order model fits well with the adsorption process, and the adsorption rate is controlled by the chemical adsorption. After 7 cycles of regeneration, adsorption capacity of NS-1-MIPs remains 95.57% of the initial value. This work opens a new pathway to prepare MIPs composite sorbents by the interfacial assembly strategy, and provides for a strategy to overcome the bottleneck of engineering nanoparticles for pollutant uptake.