Humic acid-induced formation of tobermorite upon hydrothermal treatment with municipal solid waste incineration bottom ash and its application for efficient removal of Cu(II) ions

In this study, conversion of municipal solid waste incineration bottom ash (IBA) into highly efficient sorbents for Cu(II) removal was reported. The formation of tobermorite induced by humic acid (HA) and IBA under hydrothermal condition was explored and its potential application for efficient removal of Cu(II) ions was further investigated. After hydrothermal treatment, the morphology and microstructure of IBA remarkably changed from sheet-like to particle-like, thereby resulting in substantial increases of sorption capacity. The synthesized tobermorite exhibited a strongly enhanced sorption performance toward Cu(II), which was 270.3 mg g-1 and higher than other reported sorbents. The adsorption behaviors were subsequently examined by isotherm and kinetic studies. Langmuir model was found to describe the adsorption process well, suggesting that the adsorption was chemisorption in nature. Therefore, the hydrothermally synthesized tobermorite may be used as sorbents to remove Cu(II). Conversion of IBA into valuable minerals recovers waste into potential resources and alleviates the needs for ash disposal.