ROLE OF SAWDUST IN THE REMOVAL OF IRON FROM AQUEOUS SOLUTION

Sawdust, inexpensive material has been utilized as an absorbent for the removal of iron from aqueous solution for their safe disposal. The adsorption experiments of untreated sawdust (SD)and treated sawdust (SDC) have been carried out at room temperature using the batch test. The Langmuir and Freundlich isotherms were used to observe sorption phenomena of sawdust in the removal of iron. The results indicate that the sawdust was capable in removing iron in aqueous solution. The results have shown that the Langmuir isotherm was found well fitted into the experimental data as compared to the Freundlich isotherm. It was found that, chemisorptions and physisorption were the prime mechanism for the process of adsorption to occur between the sawdust and iron. The results also proved that the acid sulphuric treated sawdust is much better than that of untreated sawdust as an adsorbent for iron

On Physical Vapor Deposition of Organic Semiconductor CuPc Thin Films in High Gravity

Thin organic films of p-type semiconductor copper phthalocyanine (CuPc, C32H16N8Cu) deposited by vacuum evaporation on glass substrates at different gravity conditions, from 50 g to –50 g (g – denotes the terrestrial gravity acceleration) in a centrifugal machine, were investigated. Thickness distribution of the film deposited was determined by measurement of absorbance using a scanning light beam probe. An anisotropic distribution of the film was observed in the direction of source and substrate rotation. The anisotropy is associated with centrifugal motion of the source-substrate system. In a direction perpendicular to the rotation, the deposition distribution was isotropic and obeyed, in principle, the theoretical approach which requires a maximum deposition in the centre of the sample. The experimentally observed influence of the acceleration on the deposition rate of the CuPc films on the substrate was simulated

EFFECT OF DIMETHYLFORMAMIDE ON THE GELS STRUCTURE OF SiO2 -gels MATERIALS FROM TMOS AND TEOS

The effect of dimethylformamide (DMF) on the gelation processes of tetramethoxysilane (TMOS) and tetraethoxysilane (TEOS) were investigated by Polarization Microscope. The hydrolysis and polycondensation reactions are carried out at 50°C, with ammonium fluoride catalysts. The sol-gel was investigated on the SiO2-gels formed using CP MAS29Si NMR spectroscopy, BET and XRD. The results have shown that the hydrolysis rate are as a function of the quantity DMF; the highest concentration of DMF produces the fastest gelation time[3, 4]. Both products showed the same textural properties. N adsorption-desorption isotherms have indicated that at higher quantity DMF an ncrease in particle sizes and greater increase in the mean pore size. Micrographs have shown hat sols are made of primary particles of about 10-20 Å in diameter. These primary structural units organize to form the secondary particles with diameter about 40-70 Å at the agglomeration solid

ELECTROCHEMICAL PERFORMANCES AND CORROSION INHIBITION OF AA6061 IN TROPICAL SEAWATER

The corrosion performances of AA6061 aluminum alloy in tropical seawater was investigated using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and their morphology was characterized by the scanning electron microscopy (SEM). The results showed that the presence of sodium benzoate as an inhibitor significantly decrease the corrosion current densities (i corr ), corrosion rates and double layer capacitance (C dl ), whilst increasing the polarization resistance (R p ). The scanning electron microscopy (SEM) images indicated that the mechanism of charge transfer and the formation of thin film have been taken place on the specimens

ELECTROCHEMICAL PERFORMANCES AND CORROSION INHIBITION OF AA6061 IN TROPICAL SEAWATER

The corrosion performances of AA6061 aluminum alloy in tropical seawater was investigated using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and their morphology was characterized by the scanning electron microscopy (SEM). The results showed that the presence of sodium benzoate as an inhibitor significantly decrease the corrosion current densities (i corr ), corrosion rates and double layer capacitance (C dl ), whilst increasing the polarization resistance (R p ). The scanning electron microscopy (SEM) images indicated that the mechanism of charge transfer and the formation of thin film have been taken place on the specimens

EXAFS studies of rare-earth metaphosphate glasses

An extended x-ray-absorption fine structure (EXAFS) study has been carried out on a range of rare-earth metaphosphate R(PO3)(3) glasses of growing interest in optical communications and laser technologies. Phosphate glasses modified using the rare-earth oxides Pr6O11, Nd2O3, Eu2O3, Gd2O3, Tb2O3, and Ho2O3, have been investigated using their respective rare-earth L(III) absorption edges. The data provide information on the local environment of the rare-earth ion within the phosphate glass matrix constructed from linked PO4 tetrahedra. The rare-earth ions occupy sites with an average coordination number in the range, 6 less than or equal to N less than or equal to 8, the surrounding atoms being oxygen. The first shell interatomic distance over the range of rare-earth ions establishes the rare-earth contraction of ionic radii with increasing atomic number in a series of glasses. There is also evidence for a rare-earth-phosphorus correlation between 2.7 and 3.6 Angstrom: and a further rare-earth-oxygen correlation at approximately 4 Angstrom. The EXAFS spectrum shows no evidence for R-R correlations within the short-range order, a result especially pertinent to the optical and magnetic properties of the glasses. The fractal dimensionality 4C(11)/B of these glasses, obtained from the elastic stiffnesses determined from ultrasonic wave velocities, ranges between 2.3 and 2.8, indicating that their connectivity tends towards having a three-dimensional character

Natural honey as corrosion resistant for Aluminium Alloy

The corrosion behaviour of AA6061 aluminium alloy in tropical seawater was investigated using weight loss measurement and electrochemical polarization technique. The electrochemical measurements showed that the presence of natural honey as corrosion resistant significantly decrease the corrosion current densities (icorr) and corrosion rates. It was observed that the inhibition efficiencies increased with the increasing concentrations of the resistant. Potentiodyanamic curves suggested that natural honey suppressed both cathodic and anodic processes. A good fit to Langmuir adsorption isotherm was obtained between the degree of surface coverage and the concentration of natural honey. It can be concluded that natural honey is an excellent corrosion resistant for aluminium alloy immersed in tropical seawater

Study on the use of ocean wave as renewable energy

The increase in oil prices, the depletion of coal resources and the possible threat to the environment due to effluents from fossil fuels has prompted the technological developments in the utilization of renewable sources of energy such as ocean wave, etc. The ocean is the world’s largest collector and storage medium for solar energy. At the same time, it produces various forms of energy while interacting with the atmosphere. Wave energy is an indirect and condensed form of solar energy. Wave gathers their energy from the wind. Wave gather, store and transmit this energy thousands of kilometers with little loss. As long as sun shines, wave energy will never be depleted. Indirect use of thermo-fluid engineering knowledge is applied to convert wave energy as useful energy. The wave energy conversion activities should be preceded by the estimation of wave power potential which needs the collection of wave data all along the coastline of the countries. Assessing the performance of a Wave Energy Converter (WEC) that is, predicting the effective amount of energy converted from the incident wave field over certain period of time in nominal operation conditions necessarily requires a precise knowledge of the local wave climate. The main wave characteristics are commonly given in terms wave height, period, direction of propagation and power. The power in wave can be expressed by the formula P = 0.55 H2s T, kW per meter of crest length, where Hs, is the significant wave height in meter and T, is wave energy period in seconds. This paper aims to describe the importance of data, data collection methods, important parameters to estimate the potential wave energy, available wave energy conversion methods, economic and environmental impacts. Power and energy efficiency relationships are discussed