Sub-100 nm Ti-MIL-125 Nanoparticles for Efficient Phosphate Removal From Water

NANOTR-20 20th Nanoscience and Nanotechnology Conference, İzmir, Türkiye, 26 - 28 Ağustos 2026, cilt.1, ss.38, (Özet Bildiri)

Anthropogenic industrial and agricultural activities have elevated aqueous phosphate, PO4

3-, concentrations in groundwater and wastewater,

inducing eutrophication and threatening ecological and public health. The performance and stability limitations of conventional water

treatment technologies, including chemical precipitation via coagulants [1-3] and adsorption using macroporous amorphous rocks [1-3],

microporous crystalline zeolites, or nanostructured materials [1-3], necessitate the development of advanced alternatives, such as metal organic

framework (MOF) particles [4, 5].

This study evaluates Ti-MIL-125, a titanium (Ti)-based MOF crystal featuring a high surface area-to-volume ratio, tunable porosity, and

enhanced stability, as a solution for water treatment. While Ti-MIL-125 is widely applicable in catalysis [6] and separation [6], this work

utilizes sub-100 nm Ti-MIL-125 nanoparticles synthesized via solvothermal method for pollutant removal. Batch adsorption experiments were

conducted using aqueous potassium dihydrogen phosphate (KH2PO4, ACS reagent grade) solutions at initial concentrations, Ci, of 7, 14, 21,

28, and 35 ppm with a fixed adsorbant dosage of 1 mg/mL across contact times of 1, 5, 10, 15, 30, 60, and 120 minutes. Residual phosphate

concentrations were quantified via UV-visible spectrophotometry to determine adsorption kinetics and performance of Ti-MIL-125

nanoparticles. Maximum adsorption conditions were obtained at 120 minutes for all initial concentrations. The phosphate removal efficiency,

η=(Ci-Cf)/Ci, of Ti-MIL-125 achieved with the 7 ppm solution was 92.3%. For higher phosphate concentrations, the efficiency, thus, the

amount of phosphate removed, reduced linearly according to the empirical correlation η=-0.6331Ci+96.5771, reaching a minimum of 74.6%

for the 35 ppm solution. Experimental data could be best modelled using the pseudo-second-order adsoption kinetics.

In conclusion, sub-100 nm Ti-MIL-125 nanoparticles offer an efficient, scalable approach for phosphate removal from contaminated water.

The reduced particle size enhances mass transfer and accelerates adsorption kinetics achieving significantly high removal efficiencies. These

findings support sustainable industrial process designs aligned environmental and advanced materials directives, applicable to both pollutant

remediation and critical chemical recovery.

Acknowledgment:

This study is supported by TUBITAK via 1001 research project no. 220M002 and 2209-A project no. 1919B012553670 and Hacettepe

University BAP via research projects FHD-2024-20812 and FYL-2026-22074.