Surface Chemistry Enhancements of Activated Carbons Enabled Tunable Efficiency and Capacity of Organics Adsorption

Abstract

The nature of activated carbons (AC) to possess large specific surface areas and highly developed internal channels, is beneficial to absorb a variety of organic pollutants. And this property is attractive for practical applications in widespread areas, such as odor removal, flue gas cleaning and water purification. However, a great amount of water vapor exists in multiple operating environments due to the high ambient humidity or evaporation of solvents. The domination of water affinity on AC could promote the adsorption to saturation in a short period, hindering the adsorptive performance on organics and reducing the service life severely. Thus, a simultaneous demonstration of the remarkable adsorptive property along with moisture resistance is of great significance. In this work, the superhydrophobic AC with selective adsorptive property were fabricated via the combination of pretreatment and superhydrophobic nanoparticles covering. The design scheme was verified by the theoretical calculation of density functional theory accompanied with surface grafting ratio, and the as-prepared AC presented favorable damp- and water-proof ability in the long term. Meanwhile, the self-desorption of adsorbed moisture occurred when they are transferred to the dry atmosphere. More importantly, superhydrophobic AC exhibited effective capture ability to organics for continuous adsorption under aqueous phase and humid condition. The pre-roughness of the pretreatment and effective grafting of propyl trimethoxysilane on superhydrophobic nanoparticles, makes it possible for the treated AC to display superior moisture resistance and selective adsorption against those in reported studies.

Keywords: Activated carbon, Superhydrophobic, high grafting, anti-moisture, Selective adsorption