## Materials and Methods
### Photocatalytic Films  
The photocatalyst was immobilized on the surface of a glass fiber mesh--i.e., a roving fabric made completely from glass fibers (density 480 g/m\({}^{2}\)) (Figure 1d). Support was cut into exact dimensions prior to photocatalysts immobilization: \(480\times 250\) mm. Immobilization was performed using the modified sol-gel procedure described previously in [48; 49; 50]. The TiO\({}_{2}\) (Evonik, Aeroxide(r), TiO\({}_{2}\) P25; with an elementary particle size of 30 nm, BET surface area of 56 m\({}^{2}\)/g and crystalline content of 75% anatase and 25% rutile); acetic acid (Kemiak); tetraetoxysilane (TEOS) (Aldrich Chemicals); ethanol p.a., 96%, deionized water; and 10M NaOH were used. The solution for immobilization of water, ethanol and TiO\({}_{2}\) with the use of acetic acid for adjusting pH value at 1.5 was mixed for 15 min. After mixing,  
Figure 1: (**a**) The flat-plate cascade reactor (FPCR) reactor; (**b**) the compound parabolic collector (CPC) reactor; (**c**) schematics of custom-made panel with linear fluorescent lamps; (**d**) the image of photocatalyst-TiO\({}_{2}\) photocatalytic film on glass fiber mesh (TiO\({}_{2}\)-GF). sonication of the solution was performed with the ultrasonic probe for 2 min (30 W, frequency 20 kHz). Furthermore, TEOS was added, and mixing at 50 \({}^{\circ}\)C continued for 1 h. Before the immobilization, glass fiber mesh supports were cleaned with the ethanol, treated with 10M NaOH for 5 min and washed with deionized water. Immobilization was performed through the dipping of supports in prepared solution and dried for 15 min on 70 \({}^{\circ}\)C, repeatedly 4 times. Films made of TiO\({}_{2}\) was marked as TiO\({}_{2}\)-GF. The image of immobilized photocatalysts (TiO\({}_{2}\)-GF) is given in Figure 1d. To study the intensification due to sensitization by carbon nanotubes (MWCNT, Sigma, 50-90 nm diameter, \(>\)95% carbon basis), another film series was made using TiO\({}_{2}\) and CNT (10:1, w:w), marked as TiO\({}_{2}\)/CNT-GF. The characterization was performed using different techniques. The Raman spectroscopy measurements were performed using a HORIBA Jobin Yvon T64000 spectrometer with a 532.5 nm solid-state laser excitation. The spectra were collected in micro-Raman mode with a multi-channel CCD detector, laser power of 20 mW at the sample and an objective with a 50\(\times\) magnification (Olympus) in a spectral range of 100-3000 cm\({}^{-1}\). The scanning electron microscopy (SEM) was performed with scanning electron microscopy (SEM) by an FEG SEM Quanta 250 FEI microscope operating at 20 kV and working distance set at 20 mm. The samples for SEM characterization were prepared by placing carriers on a sample holder covered with a piece of double-sided carbon conductive tape and then coated with the Au-Pt. The UV-VIS spectra of the prepared powder samples were obtained using diffuse reflectance spectroscopy (DRS) on a Perkin-Elmer Lambda 35 device equipped with an integrating sphere. The spectra were recorded at room temperature in the wavelength range of 200-800 nm. The BaSO\({}_{4}\) and Spectralon were used as a reference. The diffuse reflectance spectra were transformed by performing a Kubelka-Munk transformation of the measured reflectance according to: F(R) = (1 - R\({}^{2}\))/2R, where F(R) is proportional to the extinction coefficient (\(\alpha\)) and R is the reflectance of the \"infinitely thick\" layer of the solid. The bandgap energy, Eg, was estimated by plotting the modified Kubelka-Munk function, (F(R)hv)\({}^{n}\), vs. photon energy (hv), the Tauc plot, followed by extrapolation of the linear region of high slope region onto the energy axis. In the modified Kubelka-Munk function, h is Planck's constant and v is frequency; the exponent n is associated with electronic transition in the course of the optical absorption process. The exponent n is theoretically equal to 1/2 and 2 for indirect and direct allowed transitions, respectively.