Adsorbents based on carbon microfibers and carbon nanofibers for the removal of phenol and lead from water

Abstract

This paper describes the production, characteristics, and efficacy of carbon microfibers and carbon nanofibers for the removal of phenol and Pb²⁺ from water by adsorption. The first adsorbent produced in the current investigation contained the ammonia (NH₃) functionalized micron-sized activated carbon fibers (ACF). Alternatively, the second adsorbent consisted of a multiscale web of ACF/CNF, which was prepared by growing carbon nanofibers (CNFs) on activated ACFs via catalytic chemical vapor deposition (CVD) and sonication, which was conducted to remove catalytic particles from the CNF tips and open the pores of the CNFs. The two adsorbents prepared in the present study, ACF and ACF/CNF, were characterized by several analytical techniques, including SEM-EDX and FT-IR. Moreover, the chemical composition, BET surface area, and pore-size distribution of the materials were determined. The hierarchal web of carbon microfibers and nanofibers displayed a greater adsorption capacity for Pb²⁺ than ACF. Interestingly, the adsorption capacity of ammonia (NH₃) functionalized ACFs for phenol was somewhat larger than that of the multiscale ACF/CNF web. Difference in the adsorption capacity of the adsorbents was attributed to differences in the size of the solutes and their reactivity towards ACF and ACF/CNF. The results indicated that ACF-based materials were efficient adsorbents for the removal of inorganic and organic solutes from wastewater.