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The removal of a non-steroidal anti-inflammatory drug (NSAID) diclofenac sodium salt (DCF, C14H10Cl2NNaO2) from water in two hybrid systems coupling photolysis or photocatalysis with direct contact membrane distillation (DCMD) is presented. A UV-C germicidal lamp was used as a source of irradiation. The initial concentration of DCF was in the range of 0.005-0.15 mmol/dm3 and the TiO2 Aeroxide® P25 loading (hybrid photocatalysis-DCMD) ranged from 0.05 to 0.4 g/dm3. Regardless of the applied hybrid system and the initial concentration of DCF, the model drug was completely decomposed within 4h of irradiation or less. Mineralization was less efficient than photodecomposition. In case of the hybrid photolysis-DCMD process the efficiency of TOC degradation after 5h of irradiation ranged from 27.3-48.7% depending on the DCF initial concentration. The addition of TiO2 allowed to improve the efficiency of TOC removal. The highest degradation rate was obtained at 0.3 gTiO2/dm3. During the process conducted with the lowest DCF initial concentrations (0.005-0.025 mmol/dm3) a complete mineralization was obtained. However, when higher initial amounts of DCF were used (0.05-0.15 mmol/dm3), the efficiency of TOC degradation was in the range of 82.5-85%. The quality of distillate was high regardless of the system: DCF was not detected, TOC concentration did not exceeded 0.7 mg/dm3 (1.9 mg/dm3 in permeate) and conductivity was lower than 1.6 μS/cm.

Porous carbons obtained from poly(ethylene terephtalate) contained in a mixture with either MgCO3 or Mg(OH)2 were examined as adsorbents for removal of humic acid from water. Adsorption of the model contaminants is discussed in relation to the textural parameters of the obtained carbon materials. Pore structure parameters of the carbonaceous materials were strongly influenced by preparation conditions including temperature and relative amounts of the inorganics used during preparations as template. Porous carbons prepared revealed a potential to purify water from the model contaminant of high molecular weight. The results presented confirmed a key role of mesoporosity in the adsorption of humic acid. Fluorescence spectroscopy was confirmed to be an useful method to evaluate concentration of humic acid in water.

Photocatalytic mineralisation of humic acids using TiO2 modified by tungsten dioxide/ hydrogen peroxide TiO2 of anatase structure was modified by tungsten dioxide and H2O2 in order to obtain WO3-TiO2 photocatalyst with enhanced photocatalytic activity under both, UV and artificial solar light irradiations. WO2 was dissolved in 30% H2O2 and mixed with TiO2 in a vacuum evaporator at 70°C. Such modified TiO2 was dried and then calcinated at 400 and 600°C. The prepared samples and unmodified TiO2 were used for the photocatalytic decomposition of humic acids (Leonardite standard IHSS) in the aqueous solution under irradiations of both, UV and artificial solar light. Modification of TiO2 with tungsten dioxide and H2O2 improved separation of free carriers in TiO2 which resulted in the increase of OH radicals formation. Calcination caused an increase of anatase crystals and higher yield in OH radicals. The uncalcined samples showed high abilities for the adsorption of HA. Combination of adsorption abilities and photocatalytic activity of photocatalyst caused that the uncalcined TiO2 modified with WO2/H2O2 showed the shortest time of HA mineralisation. The mineralisation of HA under the artificial solar light was much lower than under the UV. It was proved that, although OH radicals are powerful in the decomposition of HA, adsorption can facilitate the contact of the adsorbed molecules with the photocatalyst surface and accelerate their photocatalytic decomposition.

New photocatalyst for decomposition of humic acids in photocatalysis and photo-Fenton processes Humic acid Leonardite IHSS standard was decomposed on TiO2 and TiO2 modified by FeC2O4 via the photocatalysis and photo-Fenton processes under UV irradiation. Humic acid (HA) were favorable adsorbed on TiO2 surface and followed decomposition during UV irradiation faster on TiO2 than on the modified samples. However, when H2O2 was added to the solution, the photo-Fenton process occurred on the prepared TiO2 samples, contained iron together with photocatalysis and high acceleration of HA decomposition was observed. In this case the mineralization degree was much higher than in the applied photocatalysis only, around 75% HA (with concentration of 18 mg/L) was mineralized after 3 h of adsorption and 5 h of UV irradiation in the presence of H2O2 and modified TiO2 whereas on TiO2 mineralisation of HA occurred in around 45% only. The measured fluorescence spectra of HA solutions showed that in the presence of H2O2 polycyclic aromatics were rapidly oxidized to the lower size products such as alcohols, aldehydes, ketones and carboxylic acids, what accelerated the process of HA decomposition.

A preliminary study on antifungal effect of TiO2-based paints in natural indoor light The antifungal activity of four commercial photocatalytic paints (KEIM Ecosil ME, Titanium FA, Photo Silicate and Silicate D) in natural indoor light was investigated. The paints contained TiO2 in rutile and anatase crystalline forms as evidenced by means of the X-ray diffraction analysis. In most cases the paints inhibited growth of fungi viz. Trichoderma viride, Aspergillus niger, Coonemeria crustacea, Eurotium herbariorum, and Dactylomyces sp. The KEIM Ecosil ME paint displayed the highest antifungal effect in the light, which could be explained with the highest anatase content. The paint antifungal activity and the fungal sensitivity to the TiO2-mediated photocatalytic reaction both decreased in the following orders: KEIM Ecosil ME > Titanium FA > Photo Silicate > Silicate D and T. viride > Dactylomyces sp. > A. niger > E. herbariorum.

TiO2 modified by ammonia as a long lifetime photocatalyst for dyes decomposition Ammonia-modified TiO2 (TiO2/N), prepared in a pressure reactor was used as the well- active and longlife photocatalyst for the azo dye (Reactive Red 198) decomposition. The effect of aeration and the different value of the pH of the reaction medium on the photocatalytic degradation of Reactive Red 198 in water has been investigated. It has been reported that the degradation is greatly influenced by the reaction pH and the faster decomposition of azo dye took place at pH 3.5. When the solution was acidic, a larger amount of azo dye on the positively charged surface of TiO2 photocatalysts was adsorbed. From the obtained results it can be seen that the effectiveness of the decolourisation of the solution was faster by using the nitrogen-modified TiO2.

Carbon modified TiO2 photocatalysts for water purification Carbon can form different structures with TiO2: carbon-doped TiO2, carbon coated TiO2 and composites of TiO2 and carbon. The presence of carbon layer on the surface of TiO2 as well as the presence of porous carbon in the composites with TiO2 can increase the concentration of organic pollutants on the surface of TiO2, facilitating the contact of the reactive species with the organic molecules. Carbon-doped TiO2 can extend the absorption of the light to the visible region by the narrowing of the band gap and makes the photocatalysts active under visible light irradiation. TiO2 loaded carbon can also work as a photocatalyst, on which the molecules are adsorbed in the pores of carbon and then they undergo the photocatalytic decomposition with UV irradiation. Enhanced photocatalytic activity for the destruction of some organic compounds in water was noticed on the carbon coated TiO2 and TiO2 loaded activated carbon, mostly because of the adsorptive role of carbon. However, in carbon-doped TiO2, the role of carbon is somewhat different, the replacement of carbon atom with Ti or oxygen and formation of oxygen vacancies are responsible for extending its photocatalytic activity towards the visible range.

Dye decomposition on P25 with enhanced adsorptivity The preparation method and the activity of the TiO2-P25/N doped photocatalyst based on commercial titanium dioxide (TiO2 Aeroxide® P-25 Degussa, Germany) are presented. For the TiO2-P25/N preparation TiO2-P25 and gaseous ammonia were kept in a pressure reactor (10 bars) for 4 hours at the temperature of 200°C. This modification process changed the chemical structure of the TiO2 surface. The formation of NH4 + groups was confirmed by the FTIR measurements. Two bands in the range of ca. 1430 - 1440 cm-1 attributed to bending vibrations of NH4 + could be observed on the FTIR spectra of the catalysts modified with ammonia and the band attributed to the hydroxyl groups at 3300 - 3500 cm-1, which were not reduced after N-doping. The photocatalytic activity of the photocatalysts was checked through the decomposition of two dyes under visible light irradiation. The modified TiO2 thus prepared samples were more active than TiO2-P25 for the decomposition of dyes under visible light irradiation.

Preparation of the TiO2 photocatalyst using pressurized ammonia The industrial hydrated amorphous titanium dioxide (TiO2ċ xH2O) was modified by treatment inside a chemical reactor under elevated pressure at low temperatures for 4 hours in an ammonia atmosphere. On the basis of the FTIR/DRS analysis the presence of nitrogen was confirmed. The XRD patterns of all of the catalysts exhibit mainly the diffraction lines of anatase phases. The photocatalytic activity of the modified photocatalysts was determined and compared to TiO2-P25 (Degussa, Germany). The high rate of phenol and dye degradation was obtained for the catalysts modified at 180°/15atm. TiO2-P25 showed similar activity in phenol decomposition like TiO2-15bar, whereas it was more active in dye decomposition.

Water purification using a novel reactor with the photoactive refill The aim of the presented work was the removal of organic dye, Acid Red 18, from water using a novel reactor with the photoactive refill. Titanium dioxide was immobilized on the base material as a thin layer from the alcoholic suspension followed by thermal stabilization. The prepared coating exhibits high stability in repeated cycles of water treatment. The complete removal of colour was achieved in a relatively short time of 14 hours. The proposed reactor with the photoactive refill solves the problem of the necessity of the replacement of the reactor or parts of the reactor when the photocatalysts activity decreases. In the case of activity drop of the photocatalyst, only the photoactivve refill can be easily replaced.