NANOSIZED Co-OXIDE SYSTEM AS EFFICIENT HETEROGENEOUS CATALYST FOR LOW-TEMPERATURE COMPLETE OXIDATION OF FORMALDEHYDE IN AQUEOUS SOLUTIONS

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NANOCOMPOSITE OXIDE SYSTEMS FOR OXIDATION OF CO AND VOLATILE ORGANIC COMPOUNDS IN GASEOUS PHASE

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NANOSIZED CO-OXIDE SYSTEM AS EFFICIENT HETEROGENEOUS CATALYST FOR LOW-TEMPERATURE COMPLETE OXIDATION OF FORMALDEHYDE IN AQUEOUS SOLUTIONS

Formaldehyde is considered a carcinogen compound because causes DNA damage, mutations in microorganisms and mammalian cells. Therefore, treatment of effluents containing HCHO prior disposal into waterways is an important target from the environmental point of view. In the present study liquid-phase catalytic oxidation of 50 mg dm-3 HCHO with NaOCl at mild conditions was studied using nanosized Co-oxide system as catalyst. CoOx was synthesized by non-conventional ultrasound assisted precipitation-oxidation method with reverse order of precipitation. The synthesis’ conditions favour the formation of catalytic systems with desired structure, morphology and surface properties typical of environmental catalysts. The catalyst was characterized by XRD, FT-IR spectroscopy, thermal and chemical analyses. The catalytic activity of CoOx was evaluated through both the rate constant (k, min-1) and the overall degree of HCHO conversion (, %). The effect of main operational parameters influencing HCHO degradation efficiency such as catalyst loading, temperature, and oxidant concentration was investigated. The method of the planned experiment has been applied for determination of the optimal technological parameters of the process. Results obtained show that the optimal conditions for achieving complete conversion of HCHO are temperature 30oC, catalyst loading 1.5 g dm-3, and NaOCl concentration 15 ml dm-3

Long-term Population Survey of the Eastern Imperial Eagle in the Thracian Eco-region (Bulgaria and Turkey)

The Thrace geographical region comprises territories of three states and covers an area of about 70,000 km2. At the end of the 19th century, the Eastern Imperial Eagle (Aquila heliaca) was widespread throughout the region, occupying a variety of habitats. The mid-20th century marked the beginning of its dramatic decline, and in the latter half of the century the birds breeding in Northern Thrace amounted to 15-20 pairs, Eastern Thrace harbored scattered pairs along the lower reaches of the Maritsa River, while in Western Thrace the population was estimated at 6-10 pairs only. Since 2000, the systematic conservation activities implemented by Bulgarian NGO’s have improved the status of the Imperial Eagle in Bulgaria (Northern Trace). At the same time, in Western Thrace (the Greek part), only one pair was confirmed by the Dadia Reserve. Since 2008, intensive field research in European Turkey identified an abundant and stable population of the species. In Bulgaria, 44 different breeding territories were established, while in European Turkey the number of identified breeding territories was 48. Most of the pairs were distributed in the European Green Belt area, along the former Iron Curtain, were human access had been strictly limited, thus preserving extremely rich biodiversity. Based on a long-term population survey of these species in Bulgaria and European Turkey, we estimated this sub-population of the species at about 80–90 breeding pairs. Breeding of several pairs in Greece, in the Greece-Turkey border area, along the Evros River, is also possible

Metamagnetism and Magnetocaloric Effect of LiPr(PO3)(4) Crystal

We have studied the magnetic and magnetocaloric behaviors of a single crystal of LiPr(PO3)(4) through DC magnetization (M) and heat-capacity (C-p) measurements. The analysis of M data indicates an establishment of magnetic order at low temperatures that results in the departure of magnetic-susceptibility behavior from the Curie-Weiss law. Under the application of high magnetic fields, the antiferromagnetic ground state is unstable, leading to a first-order metamagnetic transition to a ferromagnetic phase. Because the critical field of this transition increases with increasing temperature above the Neel temperature, it is thought to be related to the spin-flop process, spin populations on multiplets, and jj-coupling. In particular, after the transition, the maximum magnetic-entropy change (Delta S-max) increases according to a power law y proportional to H-n, with n = 1.54. Under an applied field H = 50 kOe, the |Delta S-max| value at 2 K is about 9.8 J/kg K. Using thermodynamic relations and C-p(T, H) data, the largest adiabatic-temperature change of LiPr(PO3)(4) calculated at 2 K is about 2.8 K for the field of H = 20 kOe, which is attainable using a permanent magnet

Investigating the magnetic and magnetocaloric behaviors of LiSm(PO3)4

We report a detailed study on the magnetic behaviors and magnetocaloric (MC) effect of a single crystal of lithium samarium tetraphosphate, LiSm(PO3)4. The analyses of temperature-dependent magnetization data have revealed magnetic ordering established with decreasing temperature below Tp, where Tp is the minimum of a dM/dT vs. T curve and varies as a linear function of the applied field H. The Curie temperature has been extrapolated from Tp(H) data, as H → 0, to be about 0.51 K. The establishment of magnetic-ordering causes a substantial change in the heat capacity Cp. Above Tp, the crystal exhibits paramagnetic behavior. Using the Curie-Weiss (CW) law and Arrott plots, we have found the crystal to have a CW temperature θCW ≈ −36 K, and short-range magnetic order associated with a coexistence of antiferromagnetic and ferromagnetic interactions ascribed to the couplings of magnetic dipoles and octupoles at the Γ7 and Γ8 states. An assessment of the MC effect has shown increases in value of the absolute magnetic-entropy change (|ΔSm|) and adiabatic-temperature change (ΔTad) when lowering the temperature to 2 K, and increasing the magnetic-field H magnitude. Around 2 K, the maximum value of |ΔSm| is about 3.6 J kg−1 K−1 for the field H = 50 kOe, and ΔTad is about 5.8 K for H = 20 kOe, with the relative cooling power (RCP) of ∼82.5 J kg−1. In spite of a low MC effect in comparison to Li(Gd,Tb,Ho)(PO3)4, the absence of magnetic hysteresis reflects that LiSm(PO3)4 is also a candidate for low-temperature MC applications below 25 K