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

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 K, 298 K (pH = 8.5), the saturated adsorption capacity of NS-1-MIPs is 128.1 mu mol g(-1) and 99.6 mu mol g(-1), respectively, and the Langmuir model can well describe the equilibrium performance. In addition, NS-1-MIPs possess quick rebinding kinetics in 40 min, 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.

Automated summary

The research presents a new method to prepare efficient sorbents for pollutant uptake in water using Janus nanosheets. By selectively grafting imprinted polymers onto one side of Janus nanosheets, the efficient sorptive extraction of catechol can be achieved. NS-1-MIPs show excellent adsorption performance and regeneration capability.