Application of response surface methodology for thorium adsorption on PVA/Fe3O4/SiO2/APTES nanohybrid adsorbent

• Response surface methodology was used for optimizing the conditions for Th(IV) adsorption.
• We observed physical adsorption mechanism and endothermic adsorption for Th(IV) ions.
• A novel nanohybrid adsorbent was characterized by FTIR, SEM and BET analyses.
• The structure of PVA/Fe3O4/SiO2/APTES nanohybrid was uniform and mesoporous.

A novel Fe3O4@SiO2@APTES/PVA nanohybrid adsorbent for Th(IV) adsorption in batch experiments was synthesized and characterized by FTIR, SEM and BET analyses. The effects of pH, initial concentration and adsorbent dosage were investigated using response surface methodology. The results showed that the maximum Th(IV) adsorption capacity (62.5 mg/g) was achieved under the following conditions: pH 5, adsorbent dosage 1.0 g/L and initial concentration 300 mg/L. Also, the effects of nanoparticles content, contact time and temperature were studied. The kinetic and isotherm data were accurately described by the double-exponential and Langmuir models. The reusability of adsorbent was determined after five adsorption–desorption cycles.