The usage of active pharmaceutical ingredients (API) has innovated the modern medical treatment and prevented human health from infectious diseases. On the other hand, API are usually discharged via hospital sewage or industrial wastewater into different aquatic environment.Their continuous input into environment has balanced transformation/elimination rate and renders API ‘pseudo-persistent’ contaminants. Antibiotics belong to the group of API and are detected extensively in raw water sources for drinking water. Concentration of pharmaceutical contaminants detected in wastewater ranges from ng/L to µg/L. Ciprofloxacin (CIP)has been detected at extremely high concentration (up to 31 mg/L) in sewage effluents, which is thousand times higher than levels toxic to some bacteria, and makes it the most abundant drug present in wastewater effluents.The growing concentration of antibiotics is the main reason of
antibiotic-resistant bacteria development, which cause a variety of antibiotic-resistant bacterial infections.Many pharmaceutical institutes were expected to develop new antibiotics in order to combat the antibiotic-resistant bacteria. However, many studies of new antibiotics are abandoned due to the expensive costs and lack of innovation. Thus, antibiotics and antibiotic-resistant bacteria are recalcitrant pollutants of great concern. Different conventional and modern techniques, such as ozonation, nanofiltration and biological methods have been used to eliminate pollutants.Nevertheless expensive infrastructures, complex systems and high demand of spaces and energy (electricity, gas) are required for the implementation of these techniques, which are also not effective in removing the contaminants present in trace amounts.Therefore, advanced oxidation processes (AOPs) are considered as an interesting solution. AOPsare
chemical treatments which can produce highly oxidizing species, such as hydroxyl radicals, in order to degrade pollutants in wastewater. Many studies have been carried out on the use of photocatalysis, which is one of the most important subsets of AOPs. The most popular photocatalysts such as semiconductors are
being widely used from twentieth century in wastewater treatment because of their high photocatalytic efficiency and lower cost. However, these photocatalysts have limitations. Titanium dioxide as the most used photocatalyst as well as large bandgap semiconductor has a bandgap of 3.0 eV in the rutile phase and 3.2 eV in the anatase phase. Therefore, it can be photoactivated mainly under UV irradiation ‒ which constitutes only 4-5% of solar light ‒ and requires the use of artificial UV light sources to obtain an efficient photodegradation. The requirement of external light sources is always coupled with a high
energy demand. The worldwide shortage of oil and natural gas have caused widespread concern about the energy supply with fears of a cold and dark winter, especially during the crucial situation of increasing global energy crisis. These concerns have attracted the focus on developing alternative, sustainable sources. The solution to all of these problems is to use solar energy. A flourishing research has been developing visible-driven photocatalytic systems. However, ultraviolet (UV) and visible light together account for only half of the photons of the solar spectrum. The remaining near-infrared (NIR) photons are still underexploited for energy conversion purposes. Developing practical strategies for harvesting solar NIR light portion is critical to increase the photocatalytic efficiency for
future industrial applications. The recovery and reuse of the particulate materials used represent another cumbersome step. As described in recent studies, the particle separation processes require higher cost and complicated systems. The immobilization of the particles onto a surface has been studied, which has shown drawbacks of limited surface area for adsorption and non-sufficient contact with contaminants or secondary pollutions caused by the particle leaching from the support materials. The aim of this thesis is to demonstrate a new approach to prepare efficient solar-driven Tm3+ UCNP-based photocatalysts consisting of relatively inexpensive precursors (poly(vinyl alcohol) (PVA), poly(acrylic acid) (PAA), poly(ether etherketone) (PEEK)) and trace amounts of lanthanide ions. The nanocomposite matrix is composed of PVA and hydroxylated sulfonated PEEK (SPOH), which were crosslinked with PAA-decorated UCNPs using PAA via a simple heating treatment at 170 °C, resulting in a UCNP non-leaching
porous material. The UCNPs embedded in the PVA/SPOH matrix were able to absorb NIR light and could transfer the upconverting excitation energy to the polymer matrix, resulting in the prodution of H2O2 (7.0·10‒8 mol·L-1*min-1
). This material proved to work even under solar irradiation. The as-prepared photocatalyst exhibited excellent adsorption (89%) and photocatalytic degradation (50%) in 4 hours.