Efficient separation, adsorption, and recovery of Samarium(III) ions using novel ligand-based composite adsorbent

The novel organic compound of ammonium (4-chlro-2-mercaptophenyl)carbamodithioate (ACMPC) was prepared and then subsequently grafted onto the mesoporous silica by direct approach for the preparation of composite adsorbent (CPA). The lanthanide (Ln(III)) intra-series separation behavior was measured using CPA and then the samarium (Sm(III)) ion was selected according to the high adsorption ability by CPA for effective separation, adsorption, and recovery in the solid-liquid approach. The mesoporous silica and CPA were characterized systematically for the evaluation of affecting experimental criterion. The solution acidity played an important factor as the alkaline pH area was avoided due to the hydroxide precipitation probability and pH 5.0 was selected for selective and effective Sm(III) ion separation and recovery. The data clarified that CPA exhibited high kinetic performances with high adsorption ability. The Sm(III) adsorption was highly fitted with the Langmuir adsorption isotherm model with monolayer coverage and the maximum adsorption capacity was determined as 155.13 mg/g. In addition, the diverse foreign ions were not reduced the Sm(III) ion adsorption significantly, and the CPA has approximately no adsorption capacity for other ions at this pH. The Sm(III) ion was strongly coordinated with the ACMPC and the expected highly stable complexation mechanism with the soft donor of N- and S- atoms. The elution of Sm(III) ions from the saturated CPA was desorbed successfully with 0.30 M HNO3. The regenerated CPA that remained maintained the high selectivity to Sm(III) ions and exhibited almost the same adsorption capacity as that of the original CPA. Therefore, the proposed CPA offered a costeffective material and may be considered a viable alternative for effectively Sm(III) ion separation and recovery from waste samples as potential materials.