Structure investigation of nano-FeO(OH) modified clinoptilolite tuff for antimony removal

Biomimetic sol-gel synthesis was used to prepare new FeO(OH) zeolite (clinoptilolite tuff) adsorbent effective for antimony removal. The product was compared with other on the market accessible natural or commercial adsorption materials like granulated ferric hydroxide GEH, powder of zero valent iron (ZVI)- nanofer and the new synthesized oxi(hydr)oxide FeO(OH) and characterized by XRD, XPS, Raman, FT IR, TG, DTA, DTG, TEM and SEM techniques. Based upon the SEM analysis, the oxidized nanofer sample revealed the existence of hematite and goethite and morphology of FeO(OH) dopant confirmed the presence of ferrihydrite, in less extent also magnetite and hematite. Recorded exothermic maxima on DTA curves for powdered FeO(OH) zeolite at 460 °C and for pure component FeO(OH) at 560 °C indicated an 100 °C shifted exothermic effect, which characterized strong chemical interaction of FeO(OH) with zeolite structure. Based upon the XPS analyses, also the difference between Fe species in the raw and FeO(OH) doped zeolite was found in increasing Si/Al ratio, however only at the surface below app. 5 nm, measured as 3.94 for raw and 5.38 for sample treated with alkalic solution. The plotting of adsorption isotherms in the system studied clearly showed the increasing uptake capacity of the adsorbents towards antimony with the increased S(BET) data (GEH ˃FeO(OH)˃FeO(OH) zeolite˃nanofer)

Usuwanie metanu z powietrza wentylacyjnego kopalń na monolitycznych katalizatorach palladowych w instalacji wielkolaboratoryjnej

The catalytic process of methane removal from mine ventilation air was simulated using a prototype large laboratory installation. Methane was oxidized over a bed of 4 metal monolithic catalysts containing 5 g Pd in 1 dm3 catalyst, at various methane concentrations and air flow rates. With 0.75-0.92% methane concentration in the air, at air flow rates of 25 m3/h and 30 m3/h, catalytic oxidation yielded methane removal exceeding 91% at temperatures of the gas entering the catalyst of 343 degrees of Celsius to 356 degrees of Celsius. In the process studied, the monolithic catalysts manufactured at Wrocław University of Technology showed a higher activity as compared with commercial catalysts of the same volume and Pd content.W prototypowej instalacji wielkolaboratoryjnej przeprowadzono symulacje procesu katalitycznego usuwania metanu z powietrza wentylacyjnego kopalń. Metan utleniano na złożu 4 katalizatorów na metalicznym nośniku monolitycznym o zawartości 5 g palladu w 1 dm3 katalizatora przy różnych stężeniach metanu i natężeniach przepływu powietrza. Przy stężeniach metanu 0,75-0,92% i natężeniach przepływu powietrza 25 m3/h i 30 m3/h uzyskano ponad 91% przereagowania metanu przy temperaturach gazów wprowadzanych na katalizator w zakresie od 343 stopni Celsjusza do 356 stopni Celsjusza. W przeprowadzonych badaniach katalizatory monolityczne wykonane na Politechnice Wrocławskiej wykazywały wyższą aktywność od katalizatorów komercyjnych o tej samej objętości i zawartości palladu

Pd/DNA as Highly Active and Recyclable Catalyst of Suzuki–Miyaura Coupling

Pd/DNA catalysts were prepared in a mixed H2O/EtOH solvent using palladium precursors, Pd(OAc)2 and PdCl2, in different dosages and salmon fish sperm DNA. As prepared, the Pd/DNA contained Pd(II) and Pd(0) nanoparticles of various sizes and morphologies, depending on the preparation method. Pd/DNA efficiently catalyzed the Suzuki⁻Miyaura cross-coupling of various aryl bromides with phenylboronic acids. The catalyst was recovered by simple phase separation and then reused in seven consecutive cycles with a high activity