Since the last few years, the growing interest in the use of natural and synthetic antioxidants as functional food ingredients and dietary supplements, is observed. The imbalance between the number of antioxidants and free radicals is the cause of oxidative damages of proteins, lipids, and DNA. The aim of the study was the review of recent developments in antioxidants. One of the crucial issues in food technology, medicine, and biotechnology is the excess free radicals reduction to obtain healthy food. The major problem is receiving more effective antioxidants. The study aimed to analyze the properties of efficient antioxidants and a better understanding of the molecular mechanism of antioxidant processes. Our researches and sparing literature data prove that the ligand antioxidant properties complexed by selected metals may significantly affect the free radical neutralization. According to our preliminary observation, this efficiency is improved mainly by the metals of high ion potential, e.g., Fe(III), Cr(III), Ln(III), Y(III). The complexes of delocalized electronic charge are better antioxidants. Experimental literature results of antioxidant assays, such as diphenylpicrylhydrazyl (DPPH) and ferric reducing activity power assay (FRAP), were compared to thermodynamic parameters obtained with computational methods. The mechanisms of free radicals creation were described based on the experimental literature data. Changes in HOMO energy distribution in phenolic acids with an increasing number of hydroxyl groups were observed. The antioxidant properties of flavonoids are strongly dependent on the hydroxyl group position and the catechol moiety. The number of methoxy groups in the phenolic acid molecules influences antioxidant activity. The use of synchrotron techniques in the antioxidants electronic structure analysis was proposed.

The presence of antibiotic-resistant bacteria in our environment is a matter of growing concern. Consumption of contaminated drinking water or contaminated fruit or vegetables can provoke ailments and even diseases, mainly in the digestive system. In this work, we present the latest data on the ability to remove bacteria from potable water and wastewater. The article discusses the mechanisms of the antibacterial activity of polymers, consisting of the electrostatic interaction between bacterial cells and the surface of natural and synthetic polymers functionalized with metal cations (polydopamine modified with silver nanoparticles, starch modified with quaternary ammonium or halogenated benzene). The synergistic effect of polymers (N-alkylaminated chitosan, silver doped polyoxometalate, modified poly(aspartic acid)) with antibiotics has also been described, allowing for precise targeting of drugs to infected cells as a preventive measure against the excessive spread of antibiotics, leading to drug resistance among bacteria. Cationic polymers, polymers obtained from essential oils (EOs), or natural polymers modified with organic acids are promising materials in the removal of harmful bacteria. Antimicrobial polymers are successfully used as biocides due to their acceptable toxicity, low production costs, chemical stability, and high adsorption capacity thanks to multi-point attachment to microorganisms. New achievements in the field of polymer surface modification in order to impart antimicrobial properties were summarized.

The following article discusses the antioxidant properties of mandelic acid and its hydroxy and methoxy derivatives. The antioxidant capacity of these compounds is determined by DPPH, FRAP, CUPRAC and ABTS. The mechanisms underlying the antioxidant properties are described by BDE, IP, PDE, ETE and PA calculation method values and referenced to experimental data. Thermochemistry, HOMO/LUMO energies, dipole moments, charge distribution, IR, RAMAN, NMR frequencies, binding lengths and angles were calculated using the B3LYP method and the 6-311++G(d,p) basis set. The structure of mandelic acid and its derivatives was determined experimentally using IR and RAMAN spectroscopy.

The aim of this work was the characterization of polymer microspheres obtained by the suspension polymerization of divinylbenzene (DVB) and glycidyl methacrylate (GMA), depending on the pore-forming diluents and molar ratio of monomers. The assessed properties included the chemical and porous structure, thermal stability, and sorption capacity of the obtained polymers towards methylene blue. The abovementioned characteristic was carried out for two series of copolymers with molar ratios of monomers of 1:2, 1:1 and 2:1, synthetized with toluene and a mixture of decanol and benzyl alcohol. The structure of the polymers was confirmed by FTIR and elemental analysis. The results of TGA demonstrated the main influence on thermal stability was the composition of polymers, whereas the impact of porogens was negligible. The S_BET varied in the range of 12–534 m²g⁻¹ for polymers obtained with toluene and 0–396 m²g⁻¹ with the mixture of alcohols. Toluene enhanced the formation of micro- and mesopores, while the mixture of alcohols enhanced the creation of meso- and macropores. For the polymers prepared with toluene, their effectiveness in water purification decreases in the following order: DVB-GMA 2:1 > DVB-GMA 1:1 > DVB-GMA 1:2, according to the decreasing values of porous structure parameters. In the case of a series obtained with a mixture of alcohols, such correlation was not observed.

In this work development of structural and chemical properties of four nanoporous hybrid carbons has been presented. The carbons were synthesized by direct carbonization at 450, 600, 750 and 900 °C of the terpolymeric hybrid precursor composed of methacrylamide, divinylbenzene and trimethoxyvinylsilane and impregnated with sulfanilic acid (SA) as the surface modifier. The conditions of the carbonization process were set on the basis of the thermogravimetric analysis combined with FTIR analysis of the evolved gases (TGA-EGA). The use of SA contributed to the reduction of the carbonization temperature by about 100 °C and resulted in carbons with very uniform and bimodal porosity with the width range of about 1 and 14–28 nm. Spectral (ATR, Raman, XPS) and X-ray diffraction methods used to characterize the resulting carbon products allowed to define the gradual changes taking place in the morphological and chemical structure of the prepared materials. Cyclic and symmetrical structures of silicates species were gradually replaced by amorphous arrangements. At the same time, the increase in the sp2/sp3 carbon ratio from 1 to 65% proved progressive ordering and aromatization of the carbonized polymeric hybrid precursor. Some functional groups (e.g., N-containing) were built into carbon clusters forming pyridinic, pyrrolic and N-graphitic like structures, while others (e.g., carbonyls) were removed from the surface.

Activated carbons are usually prepared from natural precursors (e.g., fruit stones or nutshells) by carbonization and activation processes carried out at 400–1000 °C. They exhibit well-developed porosity, and chemical activation introduces hydrophilic functional groups on their surface, providing excellent sorption properties. However, the high temperatures required during thermal treatment increase production costs. In this work, cost-reducing methods for preparing carbon sorbents are proposed. Carbonization of H₃PO₄ activated waste pistachio nutshells was performed using classical pyrolysis (500 or 550 °C, 30 min, N₂ atmosphere) and microwave treatment (power 1000 W, 20 min). The properties of the synthesized carbons were characterized using thermogravimetry and spectroscopic techniques including infrared (ATR), Raman, photoelectron (XPS) spectroscopies, and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS). Porous structure parameters were determined using nitrogen adsorption experiments. The efficiency of Pb²⁺ removal from spiked ultrapure, tap and river water was evaluated by batch sorption experiments and inductively coupled plasma–mass spectrometry. The most porous carbons were those prepared at 500 and 550 °C, with specific surface areas of 910 and 256 m²/g, respectively. Surface phosphates increased the Pb²⁺ sorption efficiency to 99% from ultrapure water, at an initial concentration of 300 µg Pb²⁺/L. The material obtained with the microwave method was not fully carbonized and remained nonporous, but it also exhibited 99% Pb²⁺ uptake from ultrapure water due to the presence of oxygen-containing surface groups. The Pb²⁺ removal from spiked tap and river water reached up to 84% and 94%, respectively, at the spiking level of 300 µg Pb²⁺/L.