Designing PolyHIPE/CNC Nanocomposites for Application of Environmental Adsorption Processes

Cellulose nanocrystals (CNCs) are attracting specific interest in polymer nanocomposite preparation due to their contribution on physical and thermal properties, biocompatibility, and being a renewable feedstock. Surface modified CNCs have also remarkable potential in Pickering-emulsion preparation besides to developing of efficient adsorbent materials. In this work, polyHIPE/CNC nanocomposites from surface-modified CNC stabilized Pickering-HIPEs were designed and the Nile blue removal efficiency of CNC-based adsorbent from aqueous environment was reported. Surface modification of CNCs was achieved via grafting epoxy-terminated PEG on silylated CNCs. Highly stable Pickering-HIPEs were prepared according to experimental design matrix created based on varying four experimental parameters including nanoparticle loading, emulsifier amount, internal phase ratio, and stirring rate, for three distinctive levels. The main and interaction effects of experimental parameters on morphological and mechanical properties were expressed by mathematical model equations using statistical analysis. By using model equations, a polyHIPE/CNC nanocomposite was selected as adsorbent material, considering the main and interaction contribution of nanoparticle loading on cavity size, interconnected pore size, and specific surface area. The proposed adsorbent was tested in the adsorption of Nile blue from aqueous solutions and 87% of sorption efficiency was achieved. Moreover, kinetic mechanism of Nile blue adsorption was investigated and Freundlich isotherm was found to be as best fitted model consistent with pseudo second-order kinetic model. The designed polyHIPE/CNC nanocomposites have remarkable potential as efficient adsorbents which could be motivated for development of new CNC-based nanocomposites removal of different contaminants from wastewater.