Abstract High-alumina fly ash (FAHAl) is a typical industrial solid waste. The utilization of valuable aluminum and the environmental problems caused by stockpiling make the value-added use of FAHAl meaningful. In this work, leaching solution of FAHAl was used as the mother liquor to prepare layered boehmite in situ. Then, its characterization and adsorption capability were analyzed by XRD, SEM, FT-IR, BET, and adsorption experiments. Results showed that the leaching solution obtained from Na2CO3 roasting and HCl leaching of FAHAl is suitable for the in-situ conversion of layered boehmite, which can be ideally obtained when isopropanol solution is added. When the leaching solution without impurity removal is used as the mother liquor, sodium aluminosilicate, hydrogrossular, and zeolite from the impurity ions silicon and calcium in the leaching solution also generate in addition to boehmite, which affect the purity and adsorption performance of layered boehmite. After adsorption for 30?min, the removal rate of Congo red is lower than 30%. As purified leaching solution is used as the mother liquid, high-purity layered boehmite can be obtained by adjusting the pH value of the system with sodium hydroxide in the presence of isopropanol. When the pH value decreases from 12.5 to 11, the crystallinity of boehmite decreases slightly, layered boehmite with smaller crystal size and greater specific surface area is obtained. When pH is 11, the removal rate of Congo red reaches a maximum of 83.8%. This process not only achieves the extraction of aluminum and high-value utilization of FAHAl but also provides a new thought to prepare layered boehmite with adsorption properties.Graphical Abstract
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