Hydroxyapatite synergistic polyamidoxime functionalized macroporous xerogels for fast removal of U (VI) in wastewater

Recovering uranium (VI) from wastewater is crucial for the sustainable development of nuclear energy industry and ecological environment health. Polyamidoxime (PAO) based 3D hydrophilic adsorbents are regarded as ideal materials for their high selectivity and adsorption capabilities. However, constructing efficient 3D hydrophilic adsorbents from inorganic and PAO composites remains a challenge. This study exploited high internal phase emulsions (HIPEs) as template to fabricate hydroxyapatite (HAP)-PAO hydrophilic xerogels for U(VI) extraction. The oil-in-water HIPEs were constructed using sodium dodecyl sulfonate (SDS) modified HAP particles as stabilizers and acrylamide (AAm) with dissolved PAO as continuous phase. After the polymerization of AAm, macroporous xerogels were prepared by removing the water and oil phases. Xerogels exhibited the removal efficiency of 99.9 % for U(VI) within 3 h with a maximum adsorption capacity of 223 mg.g(-1). The outstanding removal performance was ascribed to the specific structure of HAP and PAO which can effectively integrate with U(VI) ions in the presence of a hydrophilic network. This work provided a new approach to fabricate the complex adsorbents of inorganic particles with PAO for the rapid clean-up of U(VI) in wastewater.