Hydrothermally synthesized porous materials from municipal solid waste incineration bottom ash and their interfacial interactions with chloroaromatic compounds

To prolong the lifespan of landfills and to recover waste into resources, it is of great interest to develop environment-friendly and sustainable routes for municipal solid waste (MSW) incineration bottom ash (IBA) recycling and utilization. In this study, mesoporous materials were hydrothermally synthesized from incineration bottom ash. The properties of converted materials were characterized and interfacial interactions between the hydrothermally treated incineration bottom ash and chloroaromatic compounds were investigated through a multi-technique approach. Results show that the morphology of incineration bottom ash changed significantly from dense particles to porous aggregation of fine crystals of gehlenite and katoite after hydrothermal treatment, resulting in substantial increases of total and meso porosities, N₂ sorption capacity and specific surface area. Atomic force microscopy measurements revealed greater adhesion energy between the treated incineration bottom ash and chloroaromatic compounds (3-chloroaniline and triclosan) due to enhanced electrostatic forces evidenced by the increased zeta potential of incineration bottom ash after hydrothermal treatment, which led to improved sorption performance of incineration bottom ash toward organic pollutants. Hydrothermal reactions provide an effective means to stabilize heavy metals in incineration bottom ash and greatly reduced leaching of heavy metals. Thus, the hydrothermally treated incineration bottom ash may be used as sorbents for wastewater treatment to remove organic pollutants with no significant toxicity risk.