Efficient preparation of phosphazene chitosan derivatives and its applications for the adsorption of molybdenum from spent hydrodesulfurization catalyst

Abstract

In this study, the phosphazene chitosan derivative was manufactured and characterized. adsorption of molybdenum (Mo) from solutions using prepared working material as sorbent was examined. Nuclear magnetic resonance spectroscopy (¹HNMR), Carbon-13 (¹³CNMR) nuclear magnetic resonance, Gas Chromatography–Mass Spectrometry (GC–MS), Phosphorus-31 nuclear magnetic resonance (³¹P-NMR), scanning electron microscopy (SEM), Brunauer–Emmett–Teller analysis (BET surface area) and Fourier-transform infrared spectroscopy (FTIR) were used to characterize and confirm the prepared adsorbent. Many variables, including pH of the aqueous solution, the amount of adsorbent dosed, initial concentration of Mo(VI), contact time, and temperature were examined using the batch adsorption technique. When Mo(VI) is exposed to foreign ions, its desorption behavior changes. (Cr⁶⁺, Cl⁻, Co²⁺, Fe³⁺, and sulfate) were investigated. Cr⁶⁺ had a greater impact on the adsorption process in compared with other foreign ions. The maximum capability for Mo(VI) adsorption on the created adsorbent was 305.07 ± 2.36 mg/g, which was obtained at room temperature. The adsorption isotherms were best fitted with the Freundlich isotherm model. The kinetic data fitted well with the pseudo-second-order equation. The thermodynamic studies found that the adsorption was an exothermic and spontaneous process in nature.

Graphical Abstract

Keywords:

• Molybdenum
• adsorption
• phosphazene
• hydrodesulphurization catalyst
• chitosan

Acknowledgments

The authors extend their appreciation to the Deanship of Scientific Research at King Khalid University for supporting this work through research groups program under grant number R.G.P.2/120/42.