No abstract

Cu-modified immobilized nanoporous TiO 2 photocatalysts, prepared by electrochemical anodization of titanium foils, were obtained via four different synthesis methods: hydrothermal synthesis, anodization with Cu source, electrodeposition, and spin-coating, using two different copper sources, Cu(NO 3 ) 2 and Cu(acac) 2 . The objective of this research was to investigate how copper modifications can improve the photocatalytic activity of immobilized nanoporous TiO 2 under the UV/solar light irradiation. The best photocatalytic performances were obtained for Cu-modifications using spin-coating. Therefore, the effect of irradiated catalyst surface areas on the adsorption of model pollutants, methylene blue (MB) and 1H-benzotriazole (BT), was examined for samples with Cu-modification by the spin-coating technique. The mechanisms responsible for increased degradation of MB and BT at high Cu concentrations (0.25 M and 0.5 M) and decreased degradation at low Cu loadings (0.0625 M and 0.125 M) were explained. 1H-benzotriazole was used to study the photocatalytic activity of the given samples because it is highly toxic and present in most water systems. The characterization of the synthesized Cu-modified photocatalysts in terms of phase composition, crystal structure, and morphology were investigated using X-ray Diffraction, Raman Spectroscopy, Scanning Electron Microscopy, and Energy Dispersive X-ray spectroscopy.

The usage of old equipment (over 10-year-old diesel-fuelled waste collection vehicles, WCVs) for municipal solid waste (MSW) collection in Ludbreg for longer than a decade has had a negative environmental impact, which has been reduced by replacing an old diesel WCV with a new diesel WCV. This study aims to assess the share of air emissions of two old WCVs (FAP 1990 and MAN 2003) and one new (MAN 2015), expressed in CO emissions. In addition, these vehicles have been found easily to reach the limit of 100 dB, which can cause hearing damage in their surroundings. Furthermore, their average fuel consumption is more than 80 l per 100 km, which makes them ineffective in terms of fuel consumption. Generally, higher fuel consumption results in more emissions and for a more eco-friendly operation, the MAN 2003 from Ludbreg WCV fleet should be technically amended and adjusted, and the FAP 1990 should be retired. Although the MAN 2015 is diesel fuelled, the best solution for replacement, according to Maimoun et al. (Waste Management 33: 1079-1089, 2016), would be the use of hydraulic-hybrid vehicles, which provide the best environmental benefits over other alternatives. According to Maimoun et al., hybrid is better environmentally, diesel is the best environmental-economical option and landfill gas-sourced natural gas is the best alternative when accessible because it significantly (up to 80%) reduces emissions of hazardous gases as well as noise levels (50-98%).

Substantial quantities of toner cartridges are produced and used in photocopiers and printers every year. Spent toner cartridges are classified as hazardous waste because they contain toner powder with specific chemical composition, making a recovery of waste toner cartridges a very important issue from the aspect of waste management and environmental protection. Spent toner cartridges are mechanically processed to exploit valuable materials such as metals, plastics and magnets and to separate toner powder as a toxic waste. In this work, the use of waste toner powder as an additive in concrete was studied. The toner powder was mixed with calcium-based additive in ratio 50:50 immediately after the mechanical treatment. The resulting mixture (hereafter: WTP) was added to concrete at different percentages (1%, 3,%, 5% and 10%) as a replacement for fine aggregate. All processes were performed on industrial scale. The addition of 1% and 3% of WTP lead to a concrete with the optimal properties. The possible impact on the environment was studied by the means of leaching test using valid regulations for a landfill. The modified concrete with 1%, 3%, 5% WTP can be classified as inert waste.

In this study, titanium dioxide nanotubes were prepared by electrochemical anodization technique and modified with an aqueous solution of FeCl3 using hydrothermal synthesis method to control the amount and distribution of iron compounds on the anatase TiO2 nanotubes. The objective was to synthesize immobilized FeOOH@TiO2 or Fe2O3@TiO2 photocatalysts designed for the flow-through reactor systems; to investigate thermal treatment effect on the photocatalytic efficiency; to determine appropriate Fe-compounds concentration for the maximum photocatalytic activity improvement, and to explain the mechanism responsible for the enhancement. The photocatalysts were tested for the degradation of 1H-benzotriazole in water under UV/solar light irradiation. Up to two times increase in the photocatalytic activity was obtained when TiO2 nanotubes were modified with 0.8 mM Fe. At higher Fe concentrations (8 mM and 80 mM), the photocatalytic activity of the given photocatalysts decreased. To confirm the formation of FeOOH or Fe2O3 species, and to clarify the mechanism of photoactivity, X-ray diffraction (XRD), Raman spectroscopy (RS), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray spectroscopy (EDS) and UV-Vis spectroscopy were used.

The immobilization of titanium dioxide, particularly commercial TiO2 P25, on the surface of recycled rubber tiles presents a solution for achieving passive air protection. A completely new purpose for tiles was obtained by addressing air pollution and related health issues. Modified rubber tiles were prepared using a sol–gel method with three different proportions of TiO2 (2, 4, and 10 g) in the solution. The nature of TiO2 nanoparticles and their respective binding on the tile surface was determined using scanning electron microscopy (SEM) equipped with electron dispersion X-ray spectrometry (EDS) and Fourier-transform infrared (FTIR) spectroscopy. The SEM-EDS results showed that the most successful immobilization was achieved with the lowest amount of TiO2 in the sol–gel solution. The FTIR results confirmed a band at 950 cm−1 that was attributed to the Ti-O-Si bond. The stability and environmental impact of the treated rubber substrates were investigated by a leaching test. Photocatalytic oxidation was confirmed by the oxidation of NH3 to N2. Based on the results obtained, rubber substrates with an addition of 2 g of TiO2 have demonstrated prospects for further tests of the photocatalytic degradation of airborne pollutants.

Antibiotics present common pollution in the environment, and they are often found in surface waters. Their presence or decomposition in water under natural sunlight can cause different unwanted consequences on the environment. In this paper, we report the application of 3D printed photocatalysts shaped as helix static mixers for tentative photocatalytic oxidation of antibiotic amoxicillin. The research was carried out in laboratory conditions in a semi-pilot-scale compound parabolic reactor (CPC) with static mixers made from PETG with TiO2 and MWCNT as fillers. The efficiency of 3D printed photocatalysts was evaluated in terms of amoxicillin decomposition kinetics using a pseudo-first-order kinetic model. The experimental results of amoxicillin decomposition and generated by-products were analyzed by using the Q-TOF LC/MS technique and presented using MassHunter Workstation.

The utilization of valuable properties of waste and their reuse as raw materials is an imperative of the circular economy. Waste electrical and electronic equipment (WEEE) is a significant source of valuable raw materials, certain metals, and rare earth elements that are the basis for highly sophisticated IT equipment production. It is estimated that the production of WEEE in Europe in 2019 was 16.20 kg/inhabitant, while quantities continue to grow at a rate of 3–4% per year. Waste liquid crystal displays used in televisions, laptops, desktops, and other devices represent a significant share of WEEE and contain 0.12–0.14% of liquid crystals whose main ingredient is indium—tin oxide. In order to investigate and determine the methods and conditions of indium recycling from waste LCDs, laboratory research was conducted. The influence of temperature, particle size, and retention time in different media with and without ultrasound treatment was monitored to provide the efficiency of indium leaching. The analysis of the results showed that 98% indium leaching was achieved with granulation samples of 10 × 10 mm at a temperature 40 °C/40 min in solution H2O:HCl: HNO3 = 6:2:1 under ultrasound conditions, while aqueous and alkaline media under the same conditions did not show significant efficiency. This study can be used as a practical reference for the recycling of indium from LCD panels.