توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱MERCURY ADSORPTION ON A CARBON SORBENT DERIVED FROM WALNUT SHELL
نویسنده(ها): ، ،
اطلاعات انتشار: دوازدهمین کنگره ملی مهندسی شیمی ایران، سال
تعداد صفحات: ۱۰
A carbonaceous sorbent derived from an Iranian walnut shell (WS) were prepared by chemical activation method using ZnCl2 as an activating reagent. WS may be used in water treatment to remove mercury (Hg++) from water. The adsorption of mercury ion (Hg++) were performed from aqueous solutions at 302 K. Adsorption studies of Hg (II) were carried out by varying several conditions such as: treatment time, metal ion concentration, adsorbent amount, pH and solution temperature. It was also determined that Hg (II) adsorption follows both Langmuir and Freundlich isotherms. It was shown that Hg (II) uptake decreases with increasing pH of the solution. The monolayer sorption capacity was obtained as 151.5 mg\g.<\div>

۲Extraction and determination of Cu (II) in wastewaters by new combinational solid\Liquid microextraction technique; Functionalized MWCNTs in hollow fiber and flame atomic absorption spectroscopy
نویسنده(ها): ، ، ،
اطلاعات انتشار: سومین کنفرانس نانوساختارها، سال
تعداد صفحات: ۵
This paper discusses new application in hollow fiber based solid\liquid phase microextraction technique for determination of Cu(II) by atomic absorption spectrometry.The application of LPME to determination of pollutants in several matrices resulted in high enrichment factors of analytes in low concentration as well as selectivity because of the discriminatory nature of the hollow fiber preventing extraction of large molecules and \ or suspended matter. This technique was used of two–phase system in which the donor aqueous phase containing copper (II) ion and phase receptor including functionalized carbon nanotubes and octanol into a polypropylene hollow fiber segment. The influences of the experimental parameters including pH of the solutions, amounts of MWNTs, and sample volume etc. on the enrichment factor of analyte ions were investigated. Under the optimized extraction conditions, the method showed good linearity, low limits of detection and very excellent enrichment factor (EF=404 for HF–MWCNTs–NaClO , EF= 446 for HF–MWCNTs–HNO3<\div>

۳Application of almond green hull for the removal of cobalt ion from aqueous solution
اطلاعات انتشار: اولین کنفرانس بین المللی تصفیه فاضلاب و بازیافت آب، فناوری ها و یافته های نو، سال
تعداد صفحات: ۶
The presence of heavy metals in the environment is of important concern due to their toxicity and health effects on human and other living creatures. Cobalt is one of the usual toxic heavy metal present in the waste water of nuclear power plants and many other industries. The standard level of cobalt in drinking water is 2 µgL–1 but values up to 107 µgL–1 have been also reported. Many different adsorbents have been used for the removal of cobalt. In the present investigation, almond green hull, an agriculture solid waste, was used for the adsorption of Co(II) from aqueous solutions. The efficiency of this adsorbent was studied using batch adsorption technique under different experimental conditions such as adsorbent dose, initial metal–ion concentration, contact time, adsorbent particle size, and chemical treatment. Optimum dose of adsorbent for maximum metal–ion adsorption were 0.25 g for 51.5 mgL–1 and 0.4 g for 110 mgL–1 concentrated solutions, respectively. Also, the adsorption of Co(II) on almond green hull followed pseudo second–order kinetics. Adsorption isotherms were expressed by Langmuir and Freundlich adsorption models. The Langmuir adsorption model fits the experimental data reasonably well compared to the Freundlich model. Maximum adsorption capacity of this new sorbent was found to be 45.5 mgg–1. The present study revealed that such a low cost material may be used as an efficient adsorbent for the removal of cobalt from wastewater streams.<\div>

۴Effect of copper slag on mechanical properties of self–compacting concrete
نویسنده(ها): ، ،
اطلاعات انتشار: نهمین کنگره بین المللی مهندسی عمران، سال
تعداد صفحات: ۸
The building industry is turning increasingly to the use of self–compacting concrete (SCC) in order to improve many aspects of building construction as SCC offers several advantages in technical, economical and environmental terms. Fresh SCC flows into place and around obstruction under its own weight to fill the formwork completely and self–compact without any segregation and blocking. Copper slag is a by–product obtained during the matte smelting and refining of copper. Current options of management of this slag are recycling, recovering of metal, production of value added products and disposal in slag dumps or stockpiles. This paper presents the result of a study undertaken to investigate the feasibility of using copper slag as a fine aggregate in self–compacting concrete. The results indicate that 30% of copper slag can be successfully used as sand replacement to obtain SCC with comparable strength characteristics<\div>

۵Influence of SiO2 in TiO2 matrix on tribological properties of TiO2
نویسنده(ها): ، ،
اطلاعات انتشار: هفتمین کنگره ملی مهندسی شیمی، سال
تعداد صفحات: ۸
TiO2 thin film was grown on a glass substrate by sol–gel process followed by high temperature treatment at 500◦C. TiO2 films demonstrated a very good wear resistance, endurance life and enhancing tribological characteristics. Energy Dispersive X–ray Spectroscopy (EDS) was used to indicate elements that contain in the film. EDS result showed that besides Ti, O and Si elements there is a small amount of Ca, Na, Mg elements diffused from the glass substrate. X–ray Diffraction (XRD) analysis indicated that TiO2 films contain only anatase phase. The morphologies of the original and worn surfaces of the samples were analyzed by means of Scanning Tunneling Microscope (STM) and Scanning Electron Microscopy (SEM). The tribological properties of TiO2 thin film sliding against the AISI–52100 steel pin were evaluated with a pin on disk system. The results indicate that TiO2 films are superior in reducing friction and resisting wear compared with that of glass substrate. SEM observation of worn surfaces indicates that the glass wear is characteristic of brittle fracture and severe abrasion. The superior friction reduction and wear resistance of multilayer TiO2 films are attributed to slight plastic deformation as well as good adhesion of the film to the substrate.<\div>

۶Comparison of the Photocatalytic activity of TiO2 with the TiO2:SiO2 thin film
نویسنده(ها): ، ،
اطلاعات انتشار: هفتمین کنگره ملی مهندسی شیمی، سال
تعداد صفحات: ۸
Nanocrystalline films of TiO2 and TiO2:SiO2 with high photocatalytic activity was prepared on glass substrate via the sol–gel method. The films were subjected to high temperature treatment at 500˚C for growing TiO2 crystals. Energy Dispersive X–ray Spectroscopy (EDS) was used to indicate the elements in the films. The EDS result showed that besides Ti, O and Si elements, there were small amounts of Ca, Na and Mg presented in the film that were diffused from the glass substrate. X–ray diffraction (XRD) analysis indicated that TiO2:SiO2 films contain only anatase phase. Scanning electron microscopy (SEM) was used to study the films surface morphology. The TiO2:SiO2 films that were contacted with methyl orange (MO) in the aqueous solution (10 mg.L–1) and irradiated with UV showed a high photocatalytic activity. UV spectrophotometry technique was used to monitor the degradation of methyl orange (MO) by the reduction of main absorbance peak at 464 nm. The results showed that complete degradation was achieved after 1.5 hr.<\div>

۷Performance of Adsorption Equations on IAS Theory for the Prediction of Adsorption Equilibrium of CH4\C2H6 and CH4\CO2 on Activated Carbons
نویسنده(ها): ، ، ،
اطلاعات انتشار: پانزدهمین کنگره ملی مهندسی شیمی ایران، سال
تعداد صفحات: ۴
In the present study, the adsorption equilibrium of pure methane, ethane and CO2 gases as well as their binary mixtures was studied on activated carbon prepared from macadamia nutshell (AC–MNS). The ideal adsorbed solution theory (IAST) using Langmuir (Langmuir–IAST), Sips (Sips–IAST), Toth (Toth–IAST), and Unilan (Unilan–IAST) equations along with the fast ideal adsorbed solution theory (Fast–IAST) were used to predict the binary adsorption equilibriums. Also, by investigating three adsorption cases with different degree of heterogeneity, the effect of system heterogeneity on the prediction of binary mixture adsorption in terms of model accuracy and computation time was studied. Results suggest that although the Langmuir–IAST and Fast–IAST models have attractive high speed of calculation, they do not have sufficient accuracy in predicting the experimental results. Moreover, the Sips–IAST greatly increases the computation time especially at high system heterogeneity. From the results, the Toth–IAST and Unilan–IAST models with the acceptable accuracy and computation time are proposed as powerful models for predicting adsorption equilibrium of binary mixtures.<\div>

۸Photocatalytic Decolorization of methyl orange dye using Iron oxide–doped Titanium oxide nano–photocatalysts
نویسنده(ها): ، ،
اطلاعات انتشار: پنجمین همایش ملی مهندسی فرآیند، پالایش و پتروشیمی، سال
تعداد صفحات: ۸
TiO2\Fe3O4 and TiO2\Fe2O3 nanocomposites with various ratios were synthesized by an ultrasonic–assisted deposition–precipitation method and their UV–light decolorization of methyl orange (MO) dye was investigated. The effect of Fe3O4\TiO2 and Fe2O3–TiO2 nanocomposites ratio on the photocatalytic activity and magnetic property of the nanocomposites was studied by comparing their decolorization curves and magnetism in the presence of magnet, respectively. The results revealed that the decolorization efficiency of 1 wt% Fe3O4\TiO2 nanocomposite reached about 40% within 60 min UV irradiation at room temperature. However, this sample showed the least magnetism. Also, the ability of synthesized nanocomposites in holding the adsorbed methyl orange dye on their surface and the effect of pH were investigated<\div>

۹THE KEY ROLE OF ACTIVATION PROCESS IN ETHANOL ELECTROOXIDATION BY PALLADIUM NANOPARTICLES
نویسنده(ها): ، ، ،
اطلاعات انتشار: سومین کنفرانس بین المللی نفت، گاز و پتروشیمی، سال
تعداد صفحات: ۱۰
A Keggin type polyoxometalate (POM), phosphomolybdic acid (PMo12), has been employed to encapsulated and stabilisepseudo–spherical Pd nanoparticles (PdNPs) via a green synthesis procedure. The resulting nanohybrid phosphomolybdic acid–stabilised PdNPs (PdNPs@PMo12) werecharacterised by transmission electron microscopy (TEM), high–angle annular dark field–scanningtransmission electron microscopy (HAADF–STEM), Energy–dispersive X–ray spectroscopy (EDS),Fourier transform infrared spectroscopy (FTIR) and powder X–ray diffraction (XRD). The PdNPs@PMo12 were used as an electrocatalyst for ethanol oxidation in alkaline media and the best electrocatalytic activity was assessed by applying an activation process. The electrochemical data (chronoamperometry, cyclic voltammetery and linear sweep voltammetry) allow us to attribute thesuperior performance of the nanohybrid to the generation of Pd–OHads sites at the surface of the PdNPs@PMo12, being reinforced by the formation of new molybdenum species on the surface of the electrocatalyst<\div>
نمایش نتایج ۱ تا ۹ از میان ۹ نتیجه