The purpose of the presented study was to explore the photocatalytic activity of Cu₂O-supported anion exchangers and to explain the mechanism of their action in water purification processes. The functionality of this type of material was studied in the process of As(III) removal from water. As a result of the reactivity of cuprous oxide and functional groups of the polymer, the obtained composite exhibited complex activity towards arsenic(III) species. The adsorption studies were conducted under various conditions: dark, UV-VIS irradiation, VIS irradiation, under aerobic and anoxic conditions. The results from chemical analyses were supported by instrumental analyses - X-ray photoelectron spectroscopy, and FTIR and Raman spectroscopy. These studies showed that the mechanism of As(III) oxidative adsorption is based on the coupling of several reaction pathways: 1) photocatalytic oxidation involving Cu₂O as a photocatalyst, and photogenerated holes and ROS as oxidative agents, 2) chemical oxidation on the surface of CuO (being a result of the ageing process) with a re-oxidation of the produced Cu₂O to CuO by ROS and oxygen present in water, and 3) photochemical oxidation of As(III) in solution under UV light irradiation and subsequent adsorption of arsenates in the functional groups of the polymer.

Hybrid ion exchangers (HIX) containing manganese(IV) oxide (MnO₂) based on macroporous and gel-type carboxylic cation exchangers as supporting materials were obtained. The hybrid materials were characterized using scanning electron microscopy with energy dispersive spectrometry (SEM/EDS), Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD) and nitrogen adsorption isotherms at 77 K and mercury porosimetry. HIX with introduced MnO₂ (20.0–32.8 wt% Mn) were tested for removal of dissolved sulfides from anoxic aqueous solutions with 100–500 mg S²⁻/dm³ concentrations. The process proceeded effortlessly at pH 10–13 despite unfavorable electrostatic interactions of the reactants. The highest exhibited sorption capacity was 144.3 ± 7.1 mg S²⁻/g. Approximately 65% of dissolved sulfides were oxidized to S₂O₃²⁻ ions and repelled from HIX structure. On average, 13% of sulfide removal products were adsorbed by the MnO₂ surface. The impact of MnO₂ load and the ionic form of HIX functional groups on removal of sulfides and resulting products was examined. The mechanism of the process is suggested.

In this study, we aimed to investigate the potential of utilizing red grape pomace as a source of polyphenolic compounds in the growing, fragmented winemaking sector in Poland. For polyphenol extraction, we compared two methods: conventional extraction using water and alcohol solutions, and the supercritical CO₂ technique with ethanol as a cosolvent. The conventional method yielded at least 30% more polyphenols compared to the advanced SC-CO₂ technique. Experimentally chosen conditions, including a solvent composition of ethanol–water (1:1; v/v) containing 3% HCl, a liquid-to-solid ratio of 25:1 mL/g, and 2 min of ultrasound pretreatment and conventional extraction at a temperature of 30 °C over 4.5 h, enabled an extraction efficiency of 101 mg of total polyphenols per 1 g of raw material used, with an antioxidant capacity equivalent to 600 µmol of Trolox. According to HPLC analyses, the main components of the investigated biomass were epicatechin, anthocyanins and p-coumaric acid. The extract was encapsulated in liposomes, revealing no negative effect on their stability or aggregation under the conditions tested (21 days). The study suggests that conventional water–ethanol extraction can be a relatively safe and effective method for managing winemaking residuals, increasing the competitiveness of small producers through the production of high-value antioxidant additives.