High-efficient removal of U(VI) from aqueous solution by self-assembly pomelo peel/palygorskite composite

The efficient separation of low-concentration radionuclides by the eco-friendly adsorbent is a compelling requirement in the development of nuclear industry. Hence, a novel composite consisted of one-dimensional palygorskite (Pal) and three-dimensional pomelo peel (PP) is prepared by self-assembly approach (PP/Pal) and coupling agent approach (PP/KPal) for removing uranium (U(VI)) from aqueous solution. Moreover, the mass ratio (PP/Pal), adsorbent dosage, pH, contact time, temperature, and ionic strength are investigated. Two adsorption kinetic models and isotherm models are used to investigate the kinetic behaviors and adsorption capacity, respectively. The maximum adsorption capacities were 370.5 mg·g^-1 on PP/Pal and 357.3 mg·g^-1 on PP/KPal at pH 6.0, contact time 150 min and 25 °C. Meanwhile, the composite can be easily separated from water via a simple filtering. Furthermore, thermodynamic parameters indicate that adsorption is an endothermic and spontaneous process. And the surface complexation, ion exchange, and electrostatic attraction play a vital role. This work shows that the PP/Pal composite with high efficiency, low cost, and green has a further application in the treatment of wastewater containing U(VI).