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In the present study, to remove methylene blue (MB) from aqueous solution, some agricultural residues and cheap bioadsorbents such as sawdust of palm trees, eucalyptus, and sour lemon were used. To do this, significant parameters like contact time, temperature, pH, initial concentration, and adsorbent dosage were checked. The results affirmed that the best conditions for MB adsorption from aqueous solution were obtained such as the temperature of 25?°C, pH of 8, adsorbent dosage of 2g/L, contact time of 120?minutes, and dye concentration of 5?mg/l which under these conditions the adsorption efficiencies determined were 95.8, 93.4, and 92.8% using sawdust of palm tree, eucalyptus, and sour lemon, respectively. Also, the equilibrium behavior of adsorbents showed that the Freundlich model could better predict the adsorption behavior of the process due to having a larger correlation coefficient (R2). The maximum biosorption capacities by Langmuir isotherm model were also obtained 54, 53.5, and 52.4?mg/g for sawdust of palm trees, eucalyptus, and lemon, respectively, which were significant amounts. In addition, kinetic behavior of adsorption showed that pseudo-second-order model can describe the kinetics of the adsorption process better than the pseudo-first-order model. Moreover, kinetic, equilibrium, and thermodynamic behaviors of adsorption affirmed that the biosorption process was desirable, physisorption, spontaneous, and exothermic. 相似文献
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The complexation reactions between murexide and Co2+, Ni2+ and Cu2+ in C2H5OH-H2O mixtures have been investigated spectrophotometrically. The formation constants of the 1:1 complexes formed increase in the order Co2+ < Ni2+ < Cu2+ for all solvent mixtures studied, and log Kf is a linear function of the mole fraction of ethanol. The heat of complexation was determined calorimetrically for the nickel and copper complexes. The values of ΔH° and ΔS° are solvent-dependent, and all three complexes have negative ΔH° and positive ΔS° values. 相似文献
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Tayyebeh Madrakian Akram Esmaeili Azizeh Abdolmaleki 《Journal of Analytical Chemistry》2004,59(1):28-32
A new method for the rapid and sensitive determination of trace quantities of thiocyanate based on its Landolt effect on the bromate-hydrochloric acid reaction was developed. The induction period of the reaction is proportional to the SCN– concentration. The decolorization of methyl orange by the reaction products was used to monitor the reaction spectrophotometrically at 525 nm. We were able to determine thiocyanate in the range 2 × 10–7–4 × 10–5 M by this method. The relative standard deviation for 10 determinations of 1.5 × 10–6 M thiocyanate ion is 0.19% and the detection limit of the method was 7.00 × 10–8 M. The method was applied to the determination of thiocyanate in human blood serum and of saliva samples with satisfactory results. 相似文献
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This article aims to provide a survey of biological applications of Schiff base macrocycles and their metal complexes, with emphasis given to the synthesis of the compounds and to their uses as antibacterial and antifungal agents. The literature on the subject, published during the 2005–2019 period, is shortly reviewed. This is an informed report collecting information on the addressed topic in a concise systematic way, and can be expected to be useful as a fast literature catalogue for researchers working on this and related domains. 相似文献
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Elaheh Esmaeili Ali Morad Rashidi Yadollah Mortazavi Abbas Ali Khodadadi Mehdi Rashidzadeh 《天然气化学杂志》2013,(5):717-725
In the present study,CNFs,ZnO and Al2O3 were deposited on the SMFs panels to investigate the deactivation mechanism of Pd-based catalysts in selective acetylene hydrogenation reaction.The examined supports were characterized by SEM,NH3-TPD and N2adsorption-desorption isotherms to indicate their intrinsic characteristics.Furthermore,in order to understand the mechanism of deactivation,the resulted green oil was characterized using FTIR and SIM DIS.FTIR results confirmed the presence of more unsaturated constituents and then,more branched hydrocarbons formed upon the reaction over alumina-supported catalyst in comparison with the ones supported on CNFs and ZnO,which in turn,could block the pores mouths.Besides the limited hydrogen transfer,N2 adsorption-desorption isotherms results supported that the lowest pore diameters of Al2O3/SMFs close to the surface led to fast deactivation,compared with the other catalysts,especially at higher temperatures. 相似文献
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Elaheh Esmaeili Ali Morad Rashidi Yadollah Mortazavi Abbas Ali Khodadadi Mehdi Rashidzadeh 《Journal of Energy Chemistry》2013,22(5):717-725
In the present study, CNFs, ZnO and Al2O3 were deposited on the SMFs panels to investigate the deactivation mechanism of Pd-based catalysts in selective acetylene hydrogenation reaction. The examined supports were characterized by SEM, NH3-TPD and N2 adsorption-desorption isotherms to indicate their intrinsic characteristics. Furthermore, in order to understand the mechanism of deactivation, the resulted green oil was characterized using FTIR and SIM DIS. FTIR results confirmed the presence of more unsaturated constituents and then, more branched hydrocarbons formed upon the reaction over alumina-supported catalyst in comparison with the ones supported on CNFs and ZnO, which in turn, could block the pores mouths. Besides the limited hydrogen transfer, N2 adsorption-desorption isotherms results supported that the lowest pore diameters of Al2O3/SMFs close to the surface led to fast deactivation, compared with the other catalysts, especially at higher temperatures. 相似文献
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M. Sabooni M. Esmaeili H. Haratizadeh B. Monemar P. Paskov S. Kamiyama M. Iwaya H. Amano I. Akasaki 《Opto-Electronics Review》2007,15(3):163-167
We report results from optical spectroscopy such as photoluminescence (PL) and time resolved photo-luminescence (TRPL) techniques
from different well width MOCVD grown GaN/Al0.07Ga0.93N MQW samples. There is evidence of localization at low temperature in all samples. The decay time of all samples becomes
non-exponential when the detection energy is increased with respect to the peak of the emission. Localization of carriers
(excitons) is demonstrated by the “S-shape” dependences of the PL peak energies on the temperature. The time-resolved PL spectra
of the 3-nm well multi quantum wells reveal that the spectral peak position shifts toward lower energies as the decay time
increases and becomes red-shifted at longer decay times. There is a gradient in the PL decay time across the emission peak
profile, so that the PL process at low temperatures is a free electron-localized hole transition. 相似文献
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