Aluminium/iron mixed oxides obtained by co-precipitation method

In last years, various synthesis methods have been used for production of nanomaterials, composites/nanocomposites. For preparation of catalysts are used different methods such as hydrothermal, sol-gel and co-precipitation. Because Fe2O3 -Al2O3 mixed oxide system offer many advantages, its important to know if the combination of two transition metal oxides can affect their stoichiometry, surface, catalytic properties and textural structure. The aim of this study is represented by mixed of oxides who was obtained from the synthesis of aluminum nitrate and iron nitrate who was prepared by the co-precipitation method. Then, the characterization studies about the compounds obtained such as hematite, magnetite and the alumina were performed by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and UV-Vis spectrophotometry

Electrochemical oxygen uptake/release process over Ca-112 electrodes in aqueous solutions

This paper presents the electrochemical study of Y3+ substitution with Ca2+ ions on intake/release of oxygen. These studies were performed using alkaline solution (1 mol L-1 KOH) and also neutral solution (0.5 mol L-1 Na2SO4). All electrochemical behavior presented in this paper has been studied by cyclic voltammetry

Investigation of Cu2O as photocathode for P-type dye-sensitized solar cells

In p-type dye-sensitized solar cells (p-DSSCs), NiO is the most commonly used p-type semiconductor [1]. Considering the drawbacks of NiO, alternative p-type semiconductors with better optical transparency, lower VB edge position and higher hole mobility are desired for p-DSSCs [2]. The cuprous oxide (Cu2O) is a natively p-type semiconductor with a direct band gap of about 1.9–2.2 eV [3]. Non-toxic nature, the stability, natural abundance, low cost production, good electrical properties and a good absorption coefficient for visible light prompted to investigate the cuprous oxide as a material suitable for the realization of low cost and large scale p-DSSCs [4]. the nanoparticles have been intensively studied as photocathodes materials for DSSCs because of their larger specific surface areas to absorb more dye molecules. At the same time, the small-sized particles have shown that the inefficient ability to scatter the solar radiation which reduces the light-harvesting efficiency. Based on these premises, we propose to investigate the effect of micrometer-size structures on the photovoltaic performance of p-DSSCs based on cuprous oxide. In this work, 3D hierarchical structure built of the micrometer dendritic rods and the porous truncated octahedrons have been successfully synthesized via a facile one-step hydrothermal methods using copper (II) acetate and ethyl cellulose as reactants. The DSSC based on the porous structure exhibits approximately 15% increase in JSC and VOC than 3D hierarchical structure. XRD patterns of the Cu2O_1 and Cu2O_2 compound, obtained from hydrothermal method are shown in figure 1. All the diffraction peaks could be indexed as Cu2O (cuprite) with cubic structure (space group: Pn-3m; JCPDS Nr. 01-074-1230), only a small amount of CuO is detected as impurity in Cu2O_2 sample. The formation of CuO phase is determined by the time reaction which in the case of Cu2O_2 is still small to establish completely Cu+1 oxidation state

Mining activity: Environmental impact in the West area of Romania

Pollution is a major problem updated in every corner of the world. The sources of pollution are diverse, from the natural pollution to the anthropogenic pollution. Anthropogenic pollution has a significant impact. Industrial activity, with all its fields, represents one of the most important sources of anthropic pollution. Also, the mining activities can be a source of pollution worth considering. Even if the mining activity has been completed, the possibility of pollution exists. Mining activity is the major source of industrial waste. At present, the mining units can fall into three categories: active mining, where the activity continues; in conservation mining, where the closing and greening program has not yet been applied; closed mining, which are in the Closing and Greening Program. The most affected environmental factors can be the sources of water, soil, but also air

Electrochemical oxygen uptake/release process on Ca doped Y-114 electrodes in aqueous solutions

In present study, the electrochemical characterization of Y0.5Ca0.5BaCo4O7 compound in aqueous solution: alkaline (1 molL-1 KOH) and neutral (0.5 mol L-1 Na2SO4) was followed, correlated with the study of oxygen intake/release process. The use of neutral aqueous solutions is an element of originality in electrochemical studies performed on this family of layered cobalt perovskites. Electrochemical behavior has been studied by cyclic voltammetry and chronoelectrochemical methods: chronoamperometry and chronocoulometry

Influence of ceramic separator’s characteristics on microbial fuel cell performance

This study aimed at evaluating the influence of clay properties on the performance of microbial fuel cell made using ceramic separators. Performance of two clayware microbial fuel cells (CMFCs) made from red soil (CMFC-1) typically rich in aluminum and silica and black soil (CMFC-2) with calcium, iron and magnesium predominant was evaluated. These MFCs were operated under batch mode using synthetic wastewater. Maximum sustainable volumetric power density of 1.49 W m-3 and 1.12 W m-3 was generated in CMFC-1 and CMFC-2, respectively. During polarization, the maximum power densities normalized to anode surface area of 51.65 mW m-2 and 31.20 mW m-2 were obtained for CMFC-1 and CMFC-2, respectively. Exchange current densities at cathodes of CMFC-1 and CMFC-2 are 3.38 and 2.05 times more than that of respective anodes, clearly indicating that the cathodes supported much faster reaction than the anode. Results of laboratory analysis support the presence of more number of exchangeable cations in red soil, representing higher proton exchange capacity of CMFC-1 than CMFC-2. Higher power generation was observed for CMFC-1 with separator made of red soil. Hence, separators made of red soil were more suitable for fabrication of MFC to generate higher power

Influence of ceramic separator’s characteristics on microbial fuel cell performance

<p class="PaperAbstract">This study aimed at evaluating the influence of clay properties on the performance of microbial fuel cell made using ceramic separators. Performance of two clayware microbial fuel cells (CMFCs) made from red soil (CMFC-1) typically rich in aluminum and silica and black soil <br /> (CMFC-2) with calcium, iron and magnesium predominant was evaluated. These MFCs were operated under batch mode using synthetic wastewater. Maximum sustainable volumetric power density of 1.49 W m^-3 and 1.12 W m^-3 was generated in CMFC-1 and CMFC-2, respectively. During polarization, the maximum power densities normalized to anode surface area of 51.65 mW m^-2 and 31.20 mW m^-2 were obtained for CMFC-1 and CMFC-2, respectively. Exchange current densities at cathodes of CMFC-1 and CMFC-2 are 3.38 and 2.05 times more than that of respective anodes, clearly indicating that the cathodes supported much faster reaction than the anode. Results of laboratory analysis support the presence of more number of exchangeable cations in red soil, representing higher proton exchange capacity of CMFC-1 than CMFC-2. Higher power generation was observed for CMFC-1 with separator made of red soil. Hence, separators made of red soil were more suitable for fabrication of MFC to generate higher power.</p

2-[1-(4-Bromophenyl)-3-hydroxy-3-(4-methoxyphenyl)propyl]cyclohexanol

In the title compound, C22H27BrO3, the cyclohexane ring adopts a chair conformation. The dihedral angle between the benzene rings is 41.9 (4)degrees. In the crystal, molecules are linked by O-H center dot center dot center dot O and C-H center dot center dot center dot O hydrogen bonds, forming a three-dimensional network. In addition, pi-pi stacking interactions [centroid-centroid distance = 3.953 (6) angstrom] between the benzene rings of the methoxybenzene groups occur

Evaluation of Performance of Functionalized Amberlite XAD7 with Dibenzo-18-Crown Ether-6 for Palladium Recovery

Due to the increased demand for palladium, as well due to its reduced availability in nature, its recovery from diluted waste solutions becomes a necessity, and perhaps an emergency. As a result of economic and technological development, new materials with improved adsorbent properties that are more efficient for metallic ions’ recovery were synthesized and introduced to market. The goal of this study was to obtain a new adsorbent material by functionalizing through impregnation a commercial polymeric support that was both inexpensive and environmentally friendly (Amberlite XAD7) with crown ether (di-benzo-18-crown-6—DB18C6). Crown ethers are known for their ability to form complexes within metallic ions, by including them inside of the ring, regardless of its atomic size. Adsorbent material was prepared by impregnation using the solvent-impregnated resin method (SIR). To highlight the presence of crown ether on the resin surface, a new synthesized material was characterized by scanning electron microscopy (SEM), elemental analysis X-ray energy dispersive spectroscopy (EDX) and Fourier transform infrared spectroscopy (FT-IR). The specific surface of the adsorbent material was also determined by the Brunauer–Emmett–Teller (BET) method. Adsorbent performances of the prepared material were highlighted by kinetic, thermodynamic and equilibrium studies and a possible mechanism was also proposed. The influence of specific parameters for the adsorption process (contact time, temperature, Pd(II) initial concentration) on the maximum adsorption capacity was pursued