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کاربرد نوع شرط:
- جایگاه : پژوهشی
- مجله: Iranian Journal of Chemistry and Chemical Engineering
- نوع مقاله: Journal Article
- کلمات کلیدی: optimization,Adsorption,biomass,Pb(II),Henna leaves
- چکیده:
- چکیده انگلیسی: In the present study, the removal of lead (II) ions from aqueous solutions was investigated by powdered Henna. Henna is a herbal material that can dramatically adsorb metal ions. Adsorption experiments were carried out in a batch system at room temperature. Then, the equilibrium concentration of each sample was analyzed by atomic adsorption device. The effects of various parameters such as time, initial concentration, adsorbent amount, and pH were investigated. pH, initial concentration, and adsorbent amount showed sharp effects on the adsorption rate. The effect of time on the process was not considerable, as well. The optimum operating conditions were found at pH of 4.78, time of 49.47 min, lead (II) initial concentration of 93.5 mg/L, and adsorbent amount of 1 g led to 97.8% removal of lead (II). Furthermore, Langmuir and Freundlich adsorption isotherms were investigated for the lead (II) adsorption process on Henna. The results showed that Langmuir's isotherm model is more suitable for this process (R2=0.947).
- انتشار مقاله: 17-05-1397
- نویسندگان: Reza Davarnejad,Amir Shoaie,Zahra Karimi Dastnayi,Mahboubeh Chehreh
- مشاهده
- جایگاه : پژوهشی
- مجله: Iranian Journal of Chemistry and Chemical Engineering
- نوع مقاله: Journal Article
- کلمات کلیدی: heavy metals,Adsorption,Chitosan,Wastewater,biomass
- چکیده:
- چکیده انگلیسی: In this research, the capabilities of Henna and Henna with chitosan microparticles adsorbents were studied in order to remove the ion Cd (II). Response Surface Method (RSM) and Central Composite Design (CCD) were used to minimize the number of experiments (21 runs) for Henna and (26 runs) for the Henna with chitosan microparticles. The parameters were pH (2-9), initial solution concentration [10-100 mg/L (ppm)], adsorbent dosage (0.1-1 g) and process time (20-150 min). It was concluded that Cd (II) removal increased from 13.78% to 70.06% with increasing the pH from 2 to 9 (maximum adsorption was at pH 9) for Henna and 82.81% to 97.60% for the Henna with chitosan microparticles. The Cd (II) removal was decreased from 78.73% to 40.44% for Henna and 96.47% to 90.37% for the Henna with chitosan microparticles with increasing the initial solution concentration (from 10 to 100 ppm). Furthermore, the Cd (II) removal was increased from 37.5% to 64.59% for Henna and from 86.74% to 97.76 % for the Henna with chitosan microparticles with the adsorbent dosage increment (from 0.1 to 1 g). The error for the optimum point between the statistical data and experimental ones were at 1.53% for Henna and at 1.61% for the Henna with chitosan microparticles. The Langmuir and Freundlich isotherm models were applied as the adsorption mechanism. Two correlations (with R2=0.9750 for Henna and R2=0.8538 for the Henna with chitosan microparticles) between the Langmuir model and experimental data were investigated although Freundlich model showed the better agreements between the theoretical data and experimental ones (R2=0.9949 for Henna and R2=0.9955 for the Henna with chitosan microparticles). It also showed that the Henna with chitosan microparticles is a fantastic adsorbent for Cd (II) removal.
- انتشار مقاله: 10-05-1396
- نویسندگان: Reza Davarnejad,Zahra Karimi Dastnayi
- مشاهده
- جایگاه : پژوهشی
- مجله: Iranian Journal of Chemistry and Chemical Engineering
- نوع مقاله: Journal Article
- کلمات کلیدی: optimization,Mass transfer,Diffusion,extraction,β-Carotene,Supercritical fluid
- چکیده:
- چکیده انگلیسی: In this study, the diffusivity and volumetric mass transfer coefficients for the extraction of β-carotene from crude palm oil using CO2 solvent in supercritical fluid were determined in the pressure range of 7.5-17.5 MPa and temperature range of 80-120 ºC. For this purpose, a statistical method was applied in order to minimize the number of experiments required. The volumetric mass transfer coefficient for the extraction of β-carotene was then correlated as a function of pressure, temperature and extraction time in order to study the effect of each of these variables on the coefficient. The experimental results showed that the maximum volumetric mass transfer coefficient was around 2.486 × 10-2 s-1 at pressure of 7.5 MPa, temperature of 100 ºC and extraction time of 1 hour. The minimum volumetric mass transfer coefficient was 0.046 × 10-2 s-1 at pressure of 17.5 MPa, temperature of 120 ºC and extraction time of 5 hours. The optimum volumetric mass transfer coefficient was statistically obtained around 6.700 × 10-3 s-1 at pressure of 17.7 MPa, temperature of 100.5 ºC and extraction time of 3.9 hours.
- انتشار مقاله: 31-02-1392
- نویسندگان: Reza Davarnejad,Norazlila Mohammad Niza,Shahrzad Arpanahzadeh,Melika Zakeri
- مشاهده
- جایگاه : پژوهشی
- مجله: Iranian (Iranica) Journal of Energy & Environment
- نوع مقاله: Journal Article
- کلمات کلیدی:
- چکیده:
- چکیده انگلیسی:
- انتشار مقاله: 11-10-1348
- نویسندگان: Reza Davarnejad,Mostafa Moraveji
- مشاهده
- جایگاه : پژوهشی
- مجله: International Journal of Engineering, Transactions A: Basics
- نوع مقاله: Journal Article
- کلمات کلیدی: Response surface methodology,Activated Sludge,COD removal,Pharmaceutical wastewater,Photo Electro-Fenton
- چکیده:
- چکیده انگلیسی: In this study, Chemical Oxygen Demand (COD) from a pharmaceutical wastewater (PhW) was reduced by several techniques such as electro-Fenton (EF), photo electro-Fenton (PEF) and activated sludge (AS) processes and the obtained data were compared with each other. The effects of several parameters such as pH, current density, H2O2/Fe2+ molar ratio, volume ratio of H2O2/PhW, reaction time and UVA light were studied on the COD reduction through the EF and PEF processes. The Box-Behnken Design (BBD) under Response Surface Methodology (RSM) was applied to design and then optimize these processes. The optimal conditions for 87% of COD removal through the EF process were at pH of 3.27, current density of 57 mA/cm2, H2O2/Fe2+ molar ratio of 3.5, volume ratio of H2O2/PhW of 1.34 ml/l and reaction time of 56.32 min while the optimal conditions for 91.6% of COD removal through PEF process were at pH of 3.5, current density of 57.5 mA/cm2, H2O2/Fe2+ molar ratio of 3.81, volume ratio of H2O2/PhW of 1.5 ml/l, reaction time of 10.12 min and 6 W UVA light while 77.70% of COD removal was obtained by the AS process with residence time of 1020 min. According to the kinetic study, the second order reaction (with high R2 data) could properly model the EF and PEF processes.
- انتشار مقاله: 25-01-1398
- نویسندگان: Rezvan Behfar,Reza Davarnejad,Rouhollah Heydari
- مشاهده
- جایگاه : پژوهشی
- مجله: International Journal of Engineering, Transactions A: Basics
- نوع مقاله: Journal Article
- کلمات کلیدی: Simulation,Nanofluid,heat transfer,Circular tub
- چکیده:
- چکیده انگلیسی: The CFD simulation of heat transfer characteristics of a nanofluid ina circular tube under convective heat transferwas considered using the fluentsoftware (version 6.3.26) in the laminar flow. Al2O3nano- particles in water with concentrations of 0.5, 1.0, 1.5, 2 and 2.5% were studied in the simulation. All thermo-physical properties of nanofluids were temperature independent. It was concluded that heat transfer coefficient increased with the Peclet number. Furthermore, it increased by increasing the concentration of nano-particles in nanofluid. The simulated data were in good agreement with the literature (with the discrepancy of less than 10%).
- انتشار مقاله: 11-10-1348
- نویسندگان: Melica Zakeri,Sara Barati,Reza Davarnejad
- مشاهده
- جایگاه : پژوهشی
- مجله: International Journal of Engineering, Transactions A: Basics
- نوع مقاله: Journal Article
- کلمات کلیدی: TiO2,CFD,Nanofluid,Convective heat transfer coefficient,Single phase
- چکیده:
- چکیده انگلیسی: This paper reports a numerical study on the force convection heat transfer and flow characteristics of a nanofluid containing water and Tio2 with various volume fractions (0.002
- انتشار مقاله: 11-10-1348
- نویسندگان: Reza Mohammadi Ardehali,Reza Davarnejad
- مشاهده
- جایگاه : پژوهشی
- مجله: Advances in Environmental Technology
- نوع مقاله: Journal Article
- کلمات کلیدی: Solid-State method,Ball mill,Methanol,Green catalyst,environmental-friendly
- چکیده:
- چکیده انگلیسی: In this research study, methanol synthesis catalysts were manufactured with various mole ratios of metal carbonates (zinc, copper and aluminum carbonate) and ammonium hydrogen carbonate via a green solid-state method that employed a ball mill apparatus. Some parameters for the catalyst preparation, such as Al mole percent, Cu/Zn mole ratio, rotations milling speeds and aging time, were optimized to obtain the maximum catalyst activity. The prepared catalysts were compared with the best quality industrial catalyst under the same temperature and pressure condition in a titanium tabular fixed bed reactor. This novel method has many advantages in comparison to the conventional method. The main advantage of the solid-state method is that the methanol synthesis catalyst can be produced without using solvent. Furthermore, this new method reduces operating costs due to the elimination of the filtration and washing steps. Methanol synthesis catalytic activity was maximized at an optimized mole ratio of Cu/Zn of 1.9234 and an Al mole percent of 8 at the maximum grinding speed (450 rpm) during an aging time of 30 min, which showed higher activity (240 gCH3OH/kg cat.h) in comparison with an industrial catalyst sample (218 gCH3OH/kg cat.h). The production of a green catalyst, which requires less water and results in higher catalyst activity, can be widely used for methanol synthesis catalytic applications.
- انتشار مقاله: 07-12-1395
- نویسندگان: Neda Mirhosseini,Mohammad Reza Mirani,Reza Davarnejad,Marzie Hamidzade,Abbas Taeb
- مشاهده