Titanium and its compounds are broadly used in both industrial and domestic products, including jet engines, missiles, prostheses, implants, pigments, cosmetics, food, and photocatalysts for environmental purification and solar energy conversion. Although titanium/titania-containing materials are usually safe for human, animals and environment, increasing concerns on their negative impacts have been postulated. Accordingly, this review covers current knowledge on the toxicity of titania and titanium, in which the behaviour, bioavailability, mechanisms of action, and environmental impacts have been discussed in detail, considering both light and dark conditions. Consequently, the following conclusions have been drawn: (i) titania photocatalysts rarely cause health and environmental problems; (ii) despite the lack of proof, the possible carcinogenicity of titania powders to humans is considered by some authorities; (iii) titanium alloys, commonly applied as implant materials, possess a relatively low health risk; (iv) titania microparticles are less toxic than nanoparticles, independent of the means of exposure; (v) excessive accumulation of titanium in the environment cannot be ignored; (vi) titanium/titania-containing products should be clearly marked with health warning labels, especially for pregnant women and young children; (vi) a key knowledge gap is the lack of comprehensive data about the environmental content and the influence of titania/titanium on biodiversity and the ecological functioning of terrestrial and aquatic ecosystems.

In this study, hexagonal boron nitride nanosheets enriched with hydroxyl groups (h-BN-OH) were successfully grafted on the surface of cellulose fibers after the simple and effective exfoliation and oxidation of bulk h-BN. OH groups of h-BN-OH and the ones presented on the surface of cellulose fibers interacted via hydrogen bonding. Both spectroscopic (FT-IR, XRD) and microscopic (TEM, SEM, and atomic force microscopy (AFM)) methods results proved the successful functionalization of the cellulose fibers with the nanomaterial. Modified cellulose fibers were used to prepare paper sheets samples with different concentrations of the nanomaterial (1 wt %, 2 wt %, and 3 wt %). All the samples were tested for the antibacterial properties via the colony forming unit method and exhibited good performance against both Gram-negative (E. coli) and Gram-positive (S. epidermidis) model bacteria. Additionally, the influence of the volume of working bacterial suspension on the antibacterial efficiency of the obtained materials was examined. The results showed significantly better antibacterial performance when the volume of bacterial suspension was reduced. Mechanical properties of the paper samples with and without nanofiller were also characterized. Tensile strength, tearing strength, and bursting strength of the paper samples containing only 2 wt % of the nanofiller were improved by 60%, 61%, and 118% in comparison to the control paper samples, respectively. Furthermore, the nanofiller improved the thermal properties of the composite paper—the heat release rate decreased by up to 11.6%. Therefore, the composite paper can be further explored in a wide range of antibacterial materials, such as packaging or paper coatings

One-hundred-nanometer films consisting of silver, copper, and gold nanocrystallites were prepared, and their antibacterial properties were quantitatively measured. The magnetron-sputtering method was used for the preparation of the metallic films over the glass plate. Single- and double-layer films were manufactured. The films were thoroughly characterized with the XRD, SEM, EDS, and XPS methods. The antibacterial activity of the samples was investigated. Gram-negative Escherichia coli, strain K12 ATCC 25922 (E. coli), and Gram-positive Staphylococcus epidermidis, ATCC 49461 (S. epidermidis), were used in the microbial tests. The crystallite size was about 30 nm in the cases of silver and gold and a few nanometers in the case of copper. Significant oxidation of the copper films was proven. The antibacterial efficacy of the tested samples followed the order: Ag/Cu > Au/Cu > Cu. It was concluded that such metallic surfaces may be applied as contact-killing materials for a more effective fight against bacteria and viruses.

This work presents the results ofa study which concerns the influence of rotating magnetic field (RMF) on the antibacterial performance of commercial pine essential oil. A suspension of essential oil in saline solution and Escherichia coli were exposed to the rotating magnetic Afield (the frequency of electrical current supplied by a RMF generator f = 1–50 Hz; the averaged values of magnetic induction in the cross-section of the RMF generator B = 13.13 to − 19.92 mT, time of exposure t = 160 min, temperature of incubation 37 °C). The chemical composition of pine (Pinus sylvestris L.) essential oil was determined by gas chromatography coupled with mass spectrometry (GC–MS). The main constituents were α-pinene (28.58%), β-pinene (17.79%), δ-3-carene (14.17%) and limonene (11.58%). The present study indicates the exposition to the RMF, as compared to the unexposed controls causing an increase in the efficacy of antibacterial properties of pine oil. We have shown that rotating magnetic fields (RMF) at a frequency, f, between 25 Hz to and 50 Hz increased the antimicrobial efficiency of oil a concentration lower than 50%.

Preparation of TiO₂ using the hydrothermal treatment in NH₄OH solution and subsequent thermal heating at 500–700 °C in Ar was performed in order to introduce some titania surface defects. The highest amount of oxygen vacancies and Ti³⁺ surface defects were observed for a sample heat-treated at 500 °C. The presence of these surface defects enhanced photocatalytic properties of titania towards the deactivation of two bacteria species, E. coli and S. epidermidis, under artificial solar lamp irradiation. Further modification of TiO₂ was targeted towards the doping of Cu species. Cu doping was realized through the impregnation of the titania surface by Cu species supplied from various copper salts in an aqueous solution and the subsequent heating at 500 °C in Ar. The following precursors were used as a source of Cu: CuSO₄, CuNO₃ or Cu(CH₃COO)₂. Cu doping was performed for raw TiO₂ after a hydrothermal process with and without NH₄OH addition. The obtained results indicate that Cu species were deposited on the titania surface defects in the case of reduced TiO₂, but on the TiO₂ without NH₄OH modification, Cu species were attached through the titania adsorbed hydroxyl groups. Cu doping on TiO₂ increased the absorption of light in the visible range. Rapid inactivation of E. coli within 30 min was obtained for the ammonia-reduced TiO₂ heated at 500 °C and TiO₂ doped with Cu from CuSO₄ solution. Photocatalytic deactivation of S. epidermidis was greatly enhanced through Cu doping on TiO₂. Impregnation of TiO₂ with CuSO₄ was the most effective for inactivation of both E. coli and S. epidermidis.

The paper presents the results of testing the performance of lightweight structural concrete containing hemp shives as an aggregate. It has been analysed how the higher binder content and use of the Portland cement affect the thermal and microbiological properties of the lightweight concrete. The aggregates of the plant origin and cement are incompatible because the plant chemical compounds, dissolved in water or an alkaline environment, inhibit cement hydration. To avoid this, mineralisation of the aggregates of plant origin is necessary. The most often used binder in hemp concrete is hydrated lime, a mineraliser. An addition of hydrated lime and sodium trisilicate was used for hemp shiv mineralisation in the tested materials with a cement binder. Concrete containing hemp shiv and cement binder, of which volume share in the concrete was at most 15%, was prepared as a reference concrete. In the remaining three concretes, the total content of the binder in relation to hemp shiv (by mass) was increased 2.5 times. It was shown that lime-binder hemp concrete offers a promising antimicrobial strategy, as it can inhibit bacterial and fungal growth on their surface with superior efficacy. The best results were obtained for tested concretes with the cement–lime binder regarding compressive strength; the average compressive strength was 9.56 MPa.