Solar photocatalysis and its application for emerging contaminant removal from wastewater

Application of TiO2-Based Photocatalysts to Antibiotics Degradation: Cases of Sulfamethoxazole, Trimethoprim and Ciprofloxacin

“…Although individual antibiotics are always detected at quite low concentrations, ranging from ng/L to µg/L [10,17], the simultaneous presence of several antibiotics even at low concentrations might result in their much stronger cumulative effect [14,16]. Properties of antibiotics clearly demonstrate why their presence in natural aquatic environment is highly undesirable: antibiotics are, first of all, persistent, so that they are non-degradable and are able to withstand natural decomposition [1,6,18]. Secondly, they are highly mobile, bioaccumulative and toxic [1,2,19].…”

“…Easy to operate, highly efficient and environmentally friendly process [18,42,51] Fast recombination of photogenerated charge carriers decreases process efficiency [42] Performed under ambient temperature and pressure and utilizes atmospheric oxygen as oxidant [23,44] Limited visible light response [42] Complete mineralization of organic pollutants is possible, no waste generation [42,43] Laboratory scale [43] Efficient recovery and reuse of photocatalysts is possible [52,54] Not applicable to water with high concentrations of organic pollutants [42,51] Losses of photocatalyst under long-term operation [51] Toxicity of by-products should be considered [42] As follows from the information in Table 3, physical processes, such as adsorption and membrane filtration, have one significant limitation-the production of secondary waste. The problem is that pollutants are transferred from the liquid phase of wastewater to the solid phase of adsorbents in the case of adsorption process, or are collected on the membrane surface in the case of membrane filtration without any decomposition [44].…”

“…Photogenerated holes have high oxidizing ability: they degrade organic compounds directly or oxidize water, so that hydrogen ions (H + ) and hydroxyl radicals ( • OH) are generated (Equation ( 3)) [18,53].…”

“…It is known that UV light accounts for only 3-5% of the solar light, while visible light constitutes 45% of the solar spectrum [18,54]. It is very important that process is cost-effective and sustainable when implemented on an industrial scale.…”

“…It is very important that process is cost-effective and sustainable when implemented on an industrial scale. If heterogeneous photocatalysis over TiO 2 cannot be carried out under visible light, expensive UV light sources have to be used [18,44]. It is obvious that for successful TiO 2 employment under visible light, the wavelength adsorption of the photocatalyst should be extended into the visible region, thus making TiO 2 active in visible light [44,66].…”