Efficient adsorptive removal of diclofenac sodium by acidified MIL101(Cr): optimizing the content of phosphotungstic acid (PTA), Flow loop thin film slurry flat plate reactor, Kinetic, thermodynamic and recycling studies

Abstract The performance of Diclofenac sodium (DFs) adsorption by MIL101(Cr) and five different contents of PTA in PTA@MIL101(Cr) (encapsulated phosphotungstic acid (PTA) using one pot method) were investigated in a batch and a designed continuous flow loop thin film slurry flat plate reactor (TFSR). Excellent diclofenac sodium adsorption efficiency was achieved with 12 wt% PTA synthesized within the Metal Organic Framework (MOF) and using the Langmuir equation the maximum adsorption capacity of diclofenac sodium was 413.22 mg/g. The Langmuir model matched the isotherm adsorption data and the removal process was complemented with a pseudo–second–order kinetics model. According to the thermodynamic analyses, the process was found to be spontaneous and endothermic. In order to regenerate the MOF, 0.1 M HCl/EtOH (20/80 v/v) best performed as elution agent, regenerating the MOF to 88% of its originated maximum capacity after 5 times reusing. PTA (12 wt%) @MIL101 (Cr) showed to be a tremendous reusable adsorbent for removing DFs from aqueous media.