The discharge of inorganic pollutants like phosphate
and fluoride
is a cause of mounting concern to the world due to the substantial
environmental and human health risk. Adsorption is one of the most
common and affordable technologies widely utilized for removing inorganic
pollutants such as phosphate and fluoride anions. Investigating efficient
sorbents for the adsorption of these pollutants is extremely important
and challenging. This work aimed at studying the adsorption efficiency
of the Ce(III)-BDC metal–organic framework (MOF) for the removal
of these anions from an aqueous solution using a batch mode. Powder
X-ray diffraction (XRD), Fourier transform infrared (FTIR), thermogravimetric
analysis (TGA), Brunauer–Emmett–Teller (BET), and scanning
electron microscopy-energy dispersive X-ray analysis (SEM-EDX) techniques
evidenced the successful synthesis of Ce(III)-BDC MOF in water as
a solvent without any energy input within a short reaction time. The
outstanding removal efficiency of phosphate and fluoride was exhibited
at an optimized pH (3, 4), adsorbent dose (0.20, 0.35 g), contact
time (3, 6 h), agitation speed (120, 100 rpm), and concentration (10,
15 ppm) for each ion, respectively. The experiment on the effect of
coexisting ions demonstrated that SO4
2– and PO4
3– ions are the primary interfering
ions in phosphate and fluoride adsorption, respectively, while the
HCO3
– and Cl– ions
were found to have interfered less. Furthermore, the isotherm experiment
showed that the equilibrium data fitted well with the Langmuir isotherm
model and the kinetic data correlated well with the pseudo-second-order
model for both ions. The results of thermodynamic parameters such
as ΔH°, ΔG°,
and ΔS° evidenced an endothermic and spontaneous
process. The regeneration of the adsorbent made using water and NaOH
solution showed the easy regeneration of the sorbent Ce(III)-BDC MOF,
which can be reused four times, revealing its potential application
for the removal of these anions from aqueous environment.