Performance of mesoporous silicas (MCM-41 and SBA-15) and carbon (CMK-3) in the removal of gas-phase naphthalene: Adsorption capacity, rate and regenerability

Yingshu Liu, Ziyi Li*, Xiong Yang, Yi Xing, Chuen-Tinn Tsai, Quan Yang, Zhanying Wang, Ralph T. Yang

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

55 Scopus citations

Abstract

The adsorption isotherms of naphthalene on three typical mesoporous adsorbents, mesosilicas MCM-41 and SBA-15, and mesocarbon CMK-3 were determined by column tests at 125 °C, with feed concentrations ranging from 7.63 × 10-5 to 4.64 × 10-2 mol m-3 (1.88 to 1140 ppm). The Langmuir model and constant-pattern wave propagation model were found to well fit the isotherms and the breakthrough curves, respectively. Regenerabilities of the mesoporous samples and a benchmark activated carbon (AC) were characterized based on thermogravimetric analysis (TGA). The results show mesoporosity significantly reduced the internal mass-transfer resistance, contributing to facile desorption and to fast adsorption kinetics shown by high overall mass-transfer rate coefficient following the order of: CMK-3 > SBA-15 > MCM-41. Micropore-mesopore coexisting structures present in CMK-3 and SBA-15 facilitated the adsorption at very low concentrations due to micropore-filling, while greater surface hydrophobicity and micropore abundance on CMK-3 exhibited larger affinity for nonpolar naphthalene, rendering the highest adsorption capacity (1.014 mol m-3) among all sorbents including ACs. SBA-15 showed higher regenerability with a desorption temperature below 440 K, owing to the weaker binding and diffusion advantages contributed by the interconnectivity between primary mesopores.

Original languageEnglish
Pages (from-to)21193-21203
Number of pages11
JournalRSC Advances
Volume6
Issue number25
DOIs
StatePublished - 2016

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