Hydrothermal carbonization synthesis of Al-pillared montmorillonite@ carbon composites as high performing toluene adsorbents

Clay-based composites coated with carbon are highly promising for volatile organic compounds (VOC) removal because of their unique and adjustable layered structures and good stability in high temperature regeneration. To develop such kind of cost-effective clay-based adsorbents, we synthesized a series of Al-pillared Montmorillonite@Carbon (Al-Mt@C) composites by a hydrothermal carbonization method on laboratory scale. The mass ratio of Al-pillared Montmorillonite (Al-Mt) to carbon precursor glucose was varied from 3/3, 3/5 to 3/7. The samples were extensively characterized by XRD, SEM, FTIR, N-2 adsorption/desorption and TG techniques. The adsorption/desorption performance for toluene, one of the typical VOC, was investigated by measuring the breakthrough curve under a dynamic condition. There were two forms of carbon formed in the AlMt@C composites: carbon microspheres and smaller carbon clusters. Both micropores and mesopores were formed by accumulation of the carbon clusters in the Mt. layers, which contributes to the enhanced adsorption capacity toward toluene in general. Among the Al-Mt@C samples, Al-Mt@C(3/5) showed the best adsorption and regeneration performance. The highest toluene adsorption capacity reached 39.9 mg/g. This research extends the possible use of the Al-Mt@C composites to the field of air pollutant control.