Włodzimierz Mozgawa

Ettringite (Ca₆[Al(OH)₆]₂(SO₄)₃⋅26H₂O) is an important hydration product involved in the immobilization of oxyanion contaminants in cementitious systems; however, the structural effects of arsenate(V) and chromate(VI) incorporation remain poorly understood. This study investigates the influence of both oxyanions on the formation and structure of ettringite-based materials using X-ray diffraction (XRD) with Rietveld refinement and Fourier-transform infrared spectroscopy (FT-IR). Ettringite remained the dominant crystalline phase in all samples, with no detectable secondary crystalline compounds. Chromate incorporation caused only minor changes in lattice parameters, whereas arsenate addition resulted in a decrease in unit cell volume, mainly due to contraction along the c axis. FT-IR analysis confirmed preservation of the ettringite framework and revealed local structural modifications, particularly for arsenate-bearing samples. The results indicate that the presence of both oxyanions is associated with structural changes in ettringite-bearing materials, with arsenate causing a stronger structural response within the investigated compositional range.

This study investigates the adsorption of paracetamol from aqueous solutions using natural clinoptilolite and its modified forms. The raw zeolite (p-CLI) was converted into its protonic (H-CLI) and organo-modified (o-CLI) counterparts through ammonium exchange and calcination, and treatment with hexadecyltrimethylammonium bromide (HDTMA-Br), respectively. The materials were characterized by XRD, FT-IR, and SEM analyses. XRD confirmed that the clinoptilolite crystalline framework was preserved after both modifications, while FT-IR and SEM revealed partial removal of exchangeable cations in H-CLI and the formation of an HDTMA-derived organic layer on the external surface of o-CLI. Adsorption experiments were carried out under batch conditions at initial paracetamol concentrations of 0.5–10 mg/L, and equilibrium paracetamol concentrations were determined using differential pulse voltammetry (DPV). The raw clinoptilolite exhibited negligible adsorption capacity (<0.10 mg/g) due to its hydrophilic surface and microporous framework, which limit interaction with neutral organic molecules. Conversion to the protonic form slightly enhanced the adsorption performance (~0.15 mg/g), while HDTMA modification resulted in a modest additional increase (~0.25 mg/g), attributed to the formation of hydrophobic and organophilic surface sites. Overall, the results indicate that surface functionalization can improve the affinity of clinoptilolite toward weakly polar pharmaceuticals; however, the adsorption capacities remain limited. The novelty of this work lies in combining voltametric quantification with a direct comparison of proton-exchanged and surfactant-modified clinoptilolite to elucidate how specific structural and surface changes influence paracetamol uptake.

In the presented work, titanosilicate with the MWW structure (Ti-MWW) was hydrothermally synthesized using boron and titanium precursors, with piperidine as a structure-directing agent. The resulting layered zeolite precursor, with a Si/Ti molar ratio of 50, was treated in an HNO₃ solution to remove extraframework Ti and B species. The acid-modified zeolite was functionalized with transition metal cations (Cu²⁺, Fe²⁺, Mn²⁺) and trinuclear oligocations (Fe(3) and Mn(3)). The application of this catalytic system is supported by the presence of titanium in the catalytic support structure—similar to a commercial system, V₂O₅–TiO₂. The obtained samples were characterized with respect to their structure (P-XRD, DRIFT), textural parameters (low-temperature N₂ sorption), surface acidity (NH₃-TPD), transition metal content (ICP-OES) and form (UV–vis DRS) as well as catalyst’s reducibility (H₂-TPR). Ti-MWW zeolite samples modified with transition metals were evaluated as catalysts for the selective catalytic reduction of NO with ammonia (NH₃-SCR). The effective temperature range for the NO conversion varied depending on the type of active phase used to functionalize the porous support. The catalytic performance was influenced by transition metal content, its form, and accessibility for reactants as well as interactions between the active phase and titanium-containing support. Among the catalysts tested, the copper-modified Ti-MWW zeolite showed the most promising results, maintaining 90% NO conversion rates across a relatively broad temperature range from 200 to 325 °C. This catalyst meets the requirements of modern NH₃-SCR installations, which aim to operate in the low-temperature region, below 250 °C.

Analyzing the effect of anions on the structure of geopolymers is crucial because anions can significantly influence the material’s chemical stability, mechanical properties, and long-term durability. Understanding these effects helps optimize geopolymer compositions for various applications, such as construction materials and waste encapsulation. This research report describes the effects of nitrate, sulfate, and phosphate anions on alkali-activated blast furnace slag’s structural integrity and properties. Advanced techniques like XRD, FT-IR, Raman spectroscopy, and XPS have been employed to analyze structural modifications caused by anions, providing insights into their interactions and effects. These anions generally decrease compressive strength by disrupting geopolymerization and altering microstructure. For example, sulfate ions lead to the formation of ettringite, while phosphate ions bind calcium into separate phases. We can also observe microstructural changes, such as increased porosity with phosphate, which significantly reduces strength. Nitrate’s effect is less detrimental but still influences the overall structural dynamics.

Carbon fiber reinforced polymer composites are a dynamically developing group of lightweight composites for applications in the automotive, wind energy, aerospace, and sports sectors. Interfacial connection is the weakest place in these materials. In this study, an attempt was made to improve adhesion between carbon fiber and epoxy resin. For this purpose, nanoparticles of graphene oxide were added to a polymer matrix. The results of the three-point bend test showed that the strength of samples with added graphene oxide increased. Improvement of adhesion between components, reduction of the pull-out effect and change in the method of crack propagation were observed. An attempt was made to explain this effect using spectroscopic methods, both IR and Raman. On the basis of the obtained results, chemical bonds between the individual components of the composites were identified.

Zeolite Y is one of the earliest known and most widely used synthetic zeolites. Many experimental investigations verify the valuable ion exchange capability of this zeolite. In this study, we assessed the effects of ion exchange on its vibrational spectra. We applied classical lattice dynamics methods for IR and Raman intensity calculations. Computed spectra of optimized zeolite Y structures with different cations were compared with experimental data. The spectra obtained in this study are in agreement with previous experimental and computational studies on zeolites from the faujasite group.

Boroaluminosilicate geopolymers were used for the immobilization of heavy metals. Then, their mechanical properties, phase composition, structure, and microstructure were investigated. The addition of borax and boric acid did not induce the formation of any crystalline phases. Boron was incorporated into the geopolymeric network and caused the formation of N–B–A–S–H (hydrated sodium boroaluminosilicate) gel. In the range of a B/Al molar ratio of 0.015–0.075, the compressive strength slightly increased (from 16.1 to 18.7 MPa), while at a ratio of 0.150, the compressive strength decreased (to 12 MPa). Heavy metals (lead and nickel) were added as nitrate salts. The loss of the strength of the geopolymers induced by heavy metals was limited by the presence of boron. However, it caused an increase in heavy metal leaching. Despite this, heavy metals were almost entirely immobilized (with immobilization rates of >99.8% in the case of lead and >99.99% in the case of nickel). The lower immobilization rate of lead was due to the formation of macroscopic crystalline inclusions of PbO·xH₂O, which was vulnerable to leaching.