Phosphate-functionalized magnetic calcium alginate for the engineering remediation of uranium-contaminated water and soil

The increasingly hazardous and radioactive environmental issues arising from the uranium-contaminated water and soil make it urgent to develop high-yield and efficient adsorbents and the green engineering remediation technology, as well as the engineering remediation evaluation. In this work, we successfully synthesis a phosphate-functionalized magnetic calcium alginate hydrogel (MPCA) in batches by using a simple in-situ coprecipitation method. MPCA keeps maximum adsorption proportion of uranium (˃ 60.01 %) in the mixed multi-nuclide solution, and high adsorption capacity in different natural simulated uranium-contaminated water systems. In the engineering remediation of natural uranium-contaminated soil, MPCA removes 83.9 % of uranium and 99.8 % of radium in muddy water, even removes 92.9 % of uranium in the soil leaching wastewater. This work also validates a promising green engineering linked soil remediation technology, which combines soil leaching and adsorption separation. The remediated soil meets international emission standards, 92.9 % of uranium in the leachate is removed, 93.2 % of adsorbed uranium is desorbed and enriched. In addition, the reuse of adsorbed leachate and desorbed MPCA also minimize the consumption of engineering water and the derived radioactive water pollution.