Adsorption of uranium from aqueous solution as well as seawater conditions by nitrogen-enriched nanoporous polytriazine

Abstract

Efficient removal of uranium from both aqueous and simulated seawater conditions using a nitrogen enriched nanoporous polytriazine (NENP-1), is reported. A maximum adsorption capacity of 489 mg g?1 with 97.8% adsorption efficiency was estimated at 25 °C and pH of 7, when 10 mg of NENP-1 was introduced to 10 mL of 500 mg L?1 aqueous uranium solution. Both linear and non-linear regression analyses have been performed. The adsorption follows a pseudo second order kinetics and fitted well with the Langmuir adsorption isotherm model. The negative values of ?S (?52.08 J mol?1 K?1), ?H (?24.37 kJ mol?1) and ?G indicate that the uranium adsorption is a spontaneous exothermic process with a reduced entropy. Retention of 93% activity even after five consecutive cycles, achieving (0.012 mg L?1) the permissible limits of the WHO (0.015 mg L?1) and USEPA (0.03 mg L?1) and adsorption of uranium (50 mg g?1) from simulated seawater have made this a potential adsorbent for industrial applications. © 2019 Elsevier B.V.