Preparation and application of porous activated carbon using phenolic distillation residue

Porous carbons (PCs) have been prepared by using the heavy fraction of phenolic distillation residue as raw materials, and it used a carbonize-activated one-step method combining with KOH activation and different templates (CaCO3, Al2O3, MgO). The PCs were characterized by X-ray diffraction, Raman spectrum, scanning electron microscope and nitrogen adsorption–desorption analysis. Results show that the PCs prepared with Al2O3 and MgO templates possessed much higher specific surface area (1493 m2/g and 1553 m2/g, respectively) and abundant pores. The organic vapor (p-xylene) had also been used to test the adsorption of PCs to the VOCs gas. Results show that PCAl2O3 had the highest adsorption amount of p-xylene of 16.315 mmol/g, while PCMgO had the higher mass transfer coefficients for VOCs adsorption, κ = 0.29. In addition to the adsorption of VOCs, the adsorption of phenol from aqueous solution on the PCs had been comprehensively tested. It was found that all adsorption isotherms of PCs were consistent with Langmuir model, and the adsorption processes of PCs were fitted well into pseudo-second-order model. PCAl2O3 had the highest adsorption amount of phenol of 238 mg/g and the fastest adsorption rate 0.000538 g/(min⋅mg). Due to the presence of cross-linked micropores and mesopores, which formed from the site-occupying effect of Al2O3 template and the catalytic effects of Al2O3, PCAl2O3 had the highest absorption capacity to p-xylene gas and phenol, showing the potential application in treating VOCs and wastewater.