Preparation of carbon black‐based porous carbon adsorbents and study of toluene adsorption properties

Abstract

AbstractBackgroundCarbon black, which has a low utilization rate, is a powdered carbon material produced by incomplete combustion or decomposition of hydrocarbons. Carbon black is used in rubber, coating and ink industries, the product quality will be affected due to its powder structure, and serious environmental pollution will be caused in the stacking process. However, carbon black used as the raw material for the preparation of porous carbon materials with high volatile organic compounds (VOCs) adsorption capacity, which can realize the resource utilization of carbon black and environmental protection.ResultsPorous carbon based adsorbents (PCBAs) were prepared by low‐temperature physical pore‐forming and high‐temperature chemical pore‐forming with waste carbon black as raw material and (NH4)2CO3 as pore‐forming agent. The high pore‐forming temperature was beneficial to the pore structure to be formed. The surface morphology of the prepared PCBAs was more wrinkled and loose, and the specific surface area, micropore ratio and graphitization degree showed a volcanic change trend with the increase of pore‐forming temperature. The micropore ratio reached the maximum (81.7%) and the graphitization degree reached the maximum (ID/IG = 1.15) at the pore‐forming temperature of 850 °C. When the pore‐forming temperature was 850 °C, the toluene saturated adsorption capacity of PCBA850 adsorbent was 298.9 mg/g. In addition, the kinetic fitting results show that the adsorption behavior of toluene molecules on the adsorbent is mainly affected by the pore diffusion.ConclusionAlthough increasing pore‐forming temperature did not change the surface chemical properties of PCBAs, high temperature pore‐forming could significantly increase the microporosity and surface area of PCBAs. The high microporous ratio and specific surface area can provide more active sites for toluene adsorption, thus improving the toluene adsorption performance of the porous carbon‐based adsorbent. In addition, the PCBA adsorbent prepared at 850 °C can restore the toluene adsorption performance at 120 °C, which provides a possibility for its practical application. © 2022 Society of Chemical Industry (SCI).