Pore size control of polymer-derived carbon adsorbent and its application for dye removal

Abstract

Adsorption using porous carbon is an effective method to remove dyes from wastewater. The performance of the adsorbent depends on the pore structures; hence, selecting an optimal structural parameter for removal of a specific dye is required. This work studies the effect of pore structures on the methylene blue adsorption. Porous carbons featuring a similar surface area, but different pore characters, were synthesized, and the influences of their pore structure on the removal of the dye were assessed. The porous carbon was produced by pyrolysis of phenolic resin at 850 °C. To produce nanoporous carbon with different pore structures, the composition of resin precursors (resorcinol, phenol, ethylene glycol and formaldehyde) was altered. The pore- and microstructures of material were characterized by N2-sorption analysis, scanning electron microscopy and thermogravimetric analysis. An equal specific surface area of 1300 m2 g−1 was demonstrated, but it results in different pore properties (micropores or mesopores). Application performance of porous carbon was investigated for adsorption of methylene blue under ambient conditions. The experimental data (equilibrium and adsorption kinetic) were successfully described by Langmuir model and the pseudo-first order of adsorption rate. The adsorption parameters showed that carbon with mesoporous network is more beneficial.