Wettability Control on Chitosan-Wrapped Carbon Nanotube Surface Through Simple Octanal-treatment: Selective Removing Phenol from Water

Abstract

Chitosan-carbon nanotube membrane (Chit-CNTs) and octanal-modified Chit-CNTs (ocChit-CNT) membranes were obtained by chitosan-wrapping of individual carbon nanotube molecules, by self-assembly of chitosan shell-CNT core units, and by surface modification using octanal. Coexistence of diverse nano-pores (with BET pore size of about 2.0-5.3 nm and BET surface area of about 65.3-86.7 m2/g) and micro-pores (with porosity of average 10.9-12.2%) created between three-dimensionally interconnected Chit-CNT units within Chit-CNTs were observable in SEM images of Chit-CNT and ocChit-CNT membranes. As an application, they exhibit high selective affinity for phenol in aqueous medium. The sorption capacity (SC) (weight of phenol picked up by a given weight of sorbent) after draining was about 6 g/g and the sorption efficiency (SE) (weight of phenol picked up by a given weight of sorbent in water system) was >98%. Chit-CNT and ocChit-CNT membranes as a sorbent were reusable after centrifugation or washing with organic solvent such as acetone.