1：Experimental Design and Method Selection:

The study involved synthesizing TiO2 nanoparticles via a sol-gel process and depositing them on electrospun polyacrylonitrile nanofibers. Photocatalytic degradation of methylene blue dye was assessed using immersion and cross-flow filtration methods under UV irradiation, with efficiency calculated using Langmuir-Hinshelwood pseudo-first order kinetics.

2：Sample Selection and Data Sources:

Methylene blue dye solutions at various concentrations (e.g., 40 μM) and pH levels were prepared. Filter samples included polyacrylonitrile nanofibers with and without TiO2 nanoparticles on a polyurethane-carbon substrate.

3：List of Experimental Equipment and Materials:

Equipment included a UV lamp (Philips, 254 nm wavelength, 0.085 W radiant power), spectrophotometer (Shimadzu UV mini-1240), FESEM (HITACHI S.4160), XRD (Philips X'pert-MPD), FTIR (Bomem MB100), electric mixer, oven, and cross-flow filtration setup. Materials included polyacrylonitrile polymer (PolyAcryl Company, Mw=105 g/mol), DMF solvent (Merck), titanium isopropoxide (Merck), 2-isopropanol (Merck), triethylamine (Merck), hydrochloric acid (Merck), methylene blue dye (Yuhao Company), and polyurethane-carbon non-woven fabric (Milad Industry Company).

4：085 W radiant power), spectrophotometer (Shimadzu UV mini-1240), FESEM (HITACHI S.4160), XRD (Philips X'pert-MPD), FTIR (Bomem MB100), electric mixer, oven, and cross-flow filtration setup. Materials included polyacrylonitrile polymer (PolyAcryl Company, Mw=105 g/mol), DMF solvent (Merck), titanium isopropoxide (Merck), 2-isopropanol (Merck), triethylamine (Merck), hydrochloric acid (Merck), methylene blue dye (Yuhao Company), and polyurethane-carbon non-woven fabric (Milad Industry Company). Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: TiO2 nanoparticles were synthesized via sol-gel, deposited on nanofibers by wet impregnation, and heat-treated. Dye solutions were prepared and filtered using immersion (beakers with samples under UV) or cross-flow (recirculation system with pressure control) methods. UV irradiation was applied, and samples were collected at intervals for absorbance measurement using spectrophotometry.

5：Data Analysis Methods:

Dye concentration was determined using Beer-Lambert law from absorbance measurements. Filtration efficiency and reaction rate constants were calculated using Langmuir-Hinshelwood equations. Statistical analysis (ANOVA and LSD tests) was performed using SPSS software to assess significance of differences.