This work studies the hydrothermal synthesis of zeolitic materials from three types of industrial waste (granite cutting sludge; slate cutting sludge and aggregate washing sludge), which are regarded as low-cost materials. The synthesis was carried out through acid pretreatment with aqua regia to minimize iron content, followed by alkaline melting at 600°C followed by a hydrothermal crystallization stage at 180°C for 12 h. Characterization of the three synthesized zeolite materials by X-ray fluorescence, X-ray diffraction, Fourier-transform infrared spectroscopy and scanning electron microscopy with energy-dispersive X-ray spectroscopy confirmed that the methodology used induced the formation of LOS (Losod) zeolite (Na12Al12Si12O48·xH2O) as the predominant phase in all products, regardless of the waste used as the raw material. The end-products have a significant amorphous fraction (33–43 wt.%) and a zeolitic crystalline fraction (51–66 wt.%) and are enriched in Na and Al, and they have Si/Al and Na/Al ratios ranging from 1.27 to 1.39 and from 0.58 to 1.05, respectively, characteristic of low-silica zeolites. The synthetic zeolites showed reduced CO2 adsorption capacities at room temperature (0.50–0.55 mmol g–1) compared to commercial zeolites such as 13X (3.45 mmol g–1).

The accurate identification of clay minerals and associated phases remains challenging, particularly in fine-grained samples with complex assemblages. To assist in their identification, this study introduces MinMatch, a database and automated search program containing over 500 oxide compositions of clay minerals and their associated phases from soils, sediments and rocks. The program compares normalized oxide data with reference entries and ranks potential matches using Pearson correlation coefficients, supported by SiO2:Al2O3 ratios and additional statistical and graphical parameters. Its performance is demonstrated using mineral oxide datasets from well-characterized samples of the 12th Reynolds Cup competition, derived from coarse- and fine-grained separates analysed using energy-dispersive X-ray spectroscopy combined with scanning and transmission electron microscopy. The results show that MinMatch consistently ranks compositionally equivalent minerals among the top matches and successfully discriminates between closely related varieties. The approach provides a rapid, quantitative and reproducible tool for clay mineral studies, complementing X-ray diffraction and other analytical methods.

The reduction of volatile organic compounds (VOCs), especially the oxidation of highly toxic and chemically resistant toluene, remains a challenge in environmental catalysis. In this research, a porous TiO2/SiO2 support was initially fabricated through titanium pillaring of montmorillonite and then calcined and acid-leached as an efficient platform for Pt nanoparticle immobilization to yield Pt–TiO2/SiO2. The experimental data showed that the catalyst loaded with 0.37 wt.% Pt (0.37Pt–TiO2/SiO2) exhibits superior toluene oxidation performance, reaching a T90 of 190°C. Moreover, the catalyst exhibited remarkable water resistance, maintaining high efficiency even in the presence of 10% water vapour and outstanding long-term stability, with no substantial deactivation after 48 h of continuous operation. The performance improvement is explained by the high dispersion of Pt nanoparticles on the support and the metal–support interaction between Pt and TiO2, characterized by electron transfer from TiO2 to Pt. This interaction facilitates the adsorption and activation of reactant molecules. In situ diffuse reflectance Fourier-transform infrared spectroscopy explained the catalytic mechanism: toluene is sequentially transformed into benzyl alcohol, benzaldehyde and benzoate intermediates, which are subsequently converted to maleic anhydride by opening the ring and eventually mineralized into CO2 and H2O. This work developed a high-performance, durable catalyst using cost-effective and abundant natural minerals, offering promising prospects for practical abatement of industrial VOCs.

Oil-based drilling fluids (OBDFs) are widely used in high-temperature ultra-deep wells, high-inclination wells, horizontal wells and various complex wellbores due to their excellent lubricity, high temperature stability, salt tolerance and contamination resistance. However, the intrusion of drill cuttings during drilling destabilizes water-in-oil (W/O) emulsion drilling fluids. Therefore, bentonite – a common component of drill cuttings – was selected to study the factors influencing its dispersion stability in W/O emulsions. The macroscopic stability of the system was evaluated via static observation, and the dispersion state was characterized using optical microscopy. Additionally, the viscosity, the contact angle of bentonite after adsorption of various surfactants, the interfacial tension and the charge of the bentonite particles were measured. The results indicate that various surfactants affect dispersion stability through distinct mechanisms. The system stabilized by a non-ionic surfactant exhibited low interfacial tension and the greatest stability. Furthermore, dispersion stability increased with surfactant concentration. Finally, binary surfactant systems were formulated with Span80. Calcium stearate demonstrated a significant synergistic effect with Span80, improving the stability of the bentonite dispersed in the emulsion, with an optimal ratio of 1:1. The mechanism of the stable dispersion of bentonite in oil was analysed, providing theoretical guidance for improving the stability of W/O emulsion drilling fluids during drilling operations.