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کاربرد نوع شرط:
- جایگاه : پژوهشی
- مجله: Quarterly Journal of Applied Chemical Research
- نوع مقاله: Journal Article
- کلمات کلیدی: photocatalyst,Zinc oxide,Micro polyhedral,Nano plate,Triton X100
- چکیده:
- چکیده انگلیسی: In this work, growth and assembly of the micro polyhedral zinc oxide was performed using air
bubble assisted Triton X100, as a templating agent. In absence of air bubbling in the reaction
system the nano plate zinc oxide was synthesized. The prepared samples were characterized by Xray
diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and UV-Vis
spectrophotometer. The optical properties of the samples were evaluated by UV-Vis spectrum.
Photocatalytic application of the samples for simultaneous decolorization of methylene blue (MB)
and methyl orange (MO) dyes mixture in aqueous solution was examined. The Langmuir-
Hinshelwood model for decolorization kinetic data was investigated. The reusability of the samples
after five consecutive uses was examined. The photocatalytic results indicated that the micro
polyhedral zinc oxide is a promising candidate for simultaneous decolorization of the MO and MB
dyes (>90%).
- انتشار مقاله: 01-10-1397
- نویسندگان: Maryam Movahedi,Maryam Movahedi,Maryam Movahedi
- مشاهده
- جایگاه : پژوهشی
- مجله: Physical Chemistry Research
- نوع مقاله: Journal Article
- کلمات کلیدی: Adsorption,Magnetic nanocomposite,Congo red,ZnO,Polypyrrole
- چکیده:
- چکیده انگلیسی: In this work, magnetically separable ZnO-ZnFe2O4-PPy nanocomposite as an efficient adsorbent was synthesized by two steps. At first, zinc oxide (ZnO) and ZnFe2O4 nanoparticles were synthesized using simple and facile precipitation method. Then, ZnO-ZnFe2O4 mixed oxide was modified by polypyrrole (PPy). The adsorbent was characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), UV-Vis and scanning electron microscopy (SEM). The synthesized nanocomposite were used as adsorbent to remove Congo red dye from aqueous solution and were compared with pure ZnO and ZnO-PPy adsorbents. The ZnO-ZnFe2O4-PPy nanocomposite adsorbent showed a superior Congo red removal efficiency than ZnO and ZnO-PPy adsorbents. This efficiency is attributed to the charge of surface obtained in nanocomposite adsorbent. Furthermore, the adsorption kinetics of Congo red onto the nanocomposite followed by the pseudo-second-order kinetic model.
- انتشار مقاله: 20-09-1394
- نویسندگان: Asma Karamipour,Nahid Rasouli,Maryam Movahedi,Hossein Salavti
- مشاهده
- جایگاه : پژوهشی
- مجله: Iranian Journal of Chemistry and Chemical Engineering
- نوع مقاله: Journal Article
- کلمات کلیدی: photocatalyst,TiO2,ZnO,Phenol degradation,Dye modification
- چکیده:
- چکیده انگلیسی: ZnO and TiO2 nanoparticles wereimpregnated with merbromin dye and used as modified photocatalysts for degradation of phenol. Dye-modified ZnO and TiO2 showed significantly higher photocatalytic activity than neat ZnO and TiO2 under visible light illumination. Moreover, the prepared dye-modified ZnO showed superior photocatalytic efficiency in degradation of phenol compared to the dye-modified TiO2. In a period of 4 hours, dye-modified ZnO removed phenol almost completely while dye-modified TiO2 degraded it only to 47%. A cooperative working mechanism involving the possible photoactivation of both surface bound dye and semiconductor is proposed for the dye-modified systems. The suggested pathway is based on charge-transfer formalism. Furthermore, the study proposes some reasons for difference in reactivity of the dye-modified ZnO and TiO2 catalysts. Less aggregation of dye molecules on the surface of ZnO compared to TiO2 causes more prolonged lifetime of excited state of the dye on the surface of ZnO. Also, energy gap between the conduction band of semiconductor and LUMO level of merbromin in dye-modified ZnO is larger than dye-modified TiO2. Both above lead to more effective electron injection from the dye to ZnO which is hypothesized to be mainly responsible for the enhancement of the reaction rate of phenol degradation.
- انتشار مقاله: 27-10-1391
- نویسندگان: Simin Janitabar Darzi,Maryam Movahedi
- مشاهده
- جایگاه : پژوهشی
- مجله: Chemical Methodologies
- نوع مقاله: Journal Article
- کلمات کلیدی: Adsorption,Congo red,kinetic adsorption,Magnetic adsorbent
- چکیده:
- چکیده انگلیسی: In the present research, a series of magnetic chitosan based composites with the general formula of NixMn1−xFe2O4/CS were synthesized from spinel-type transition metal ferrites [NixMn1−xFe2O4 (where x= 0, 0.2, 0.5 and 1.0)] and chitosan (CS) as a polymer. The structure and composition of the synthesized samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). The adsorption activity of the synthesized magnetic chitosan based composites was evaluated for the removal of Congo red (CR) dye from aqueous solution. Furthermore, the influence of the Mn content on adsorption capacity of the synthesized magnetic chitosan based composites were studied. The results of adsorption kinetic of CR dye using spinel-type transition metals NixMn1−xFe2O4 and NixMn1−xFe2O4/CS followed pseudo- second order model. The results indicated that 74% of CR dye solution were removed via adsorption using Ni0.5Mn0.5Fe2O4/CS after 180 min. The adsorption performance show that the chitosan based composites can be more efficient than spinel-type transition metals for removal of CR dye. Moreover, the magnetic chitosan based composites can be quickly separated from the aqueous solution by an external magnet after adsorption process.
- انتشار مقاله: 14-04-1396
- نویسندگان: Nahid Rasouli,Hossein Salavati,Maryam Movahedi,Ali Rezaei
- مشاهده
- جایگاه : پژوهشی
- مجله: Asian Journal of Green Chemistry
- نوع مقاله: Journal Article
- کلمات کلیدی: Layered double hydroxide,Magnetic separation,Adsorption kinetics,Anionic diazo dye
- چکیده:
- چکیده انگلیسی: A novel magnetic layered double hydroxide known as Zn0.5Cu0.5 Fe2O4@SiO2@Ni−Cr layered double hydroxide was synthesized with Zn0.5 Cu0.5Fe2O4, SiO2 and Ni−CrLDH by using coprecipitation method. In order to compare the adsorption efficiency, the Ni−CrLDH sample also was synthesized. The synthesized samples were characterized by X−ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). The adsorption of Congo red (CR) by magnetic layered double hydroxide depended upon the contact time, initial dye concentration and pH. The adsorption of the Congo red (CR) reached equilibrium at 180 min and followed the pseudo−second−order kinetic equation. The adsorption capacity of the magnetic layered double hydroxide changed significantly between pH 4−10 and the maximum dye removal were 88% for CR. Moreover, the magnetic layered double hydroxide can be quickly separated from the aqueous solution by an external magnet before and after adsorption process. This indicated that the Zn0.5Cu0.5Fe2O4@SiO2@Ni−CrLDH composite was an effective adsorbent for CR dye removal with quick separation. The adsorption performance of the synthesized Zn0.5 Cu0.5Fe2O4, SiO2 and Ni−CrLDH and comparing with Ni−CrLDH show that the Zn0.5Cu0.5Fe2O4@SiO2@Ni−CrLDH can be more efficient than Ni−CrLDH for removal of CR dye.
- انتشار مقاله: 11-05-1396
- نویسندگان: Fatemeh Arab,Nahid Rasouli,Maryam Movahedi
- مشاهده
- جایگاه : پژوهشی
- مجله: Advanced Journal of Chemistry-Section A
- نوع مقاله: Journal Article
- کلمات کلیدی: Adsorption,Composite,Layered double hydroxide,Dye removal
- چکیده:
- چکیده انگلیسی: In this work, the MgZnAl-LDH/Zeolite Y and (MgZnAl-LDH+MgFe2O4)@SiO2 composites based on layered double hydroxide (LDH) were synthesized and characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and energy-dispersive X-ray spectroscopy (EDX) analysis. The efficiency of the samples was assessed for simultaneous removal of cationic and anionic dyes from the solution. In this work, methylene blue and methyl orange as cationic and anionic dyes were used. The performance of prepared composites was also compared with their components. The results demonstrated that the Zeolite Y sample could only remove the methylene blue dye from the solution. The MgFe2O4 sample is not able to remove any of the anionic and cationic dyes. The simultaneous removal of the methylene blue and methyl orange dyes is observed by the MgZnAl-LDH sample. The MgZnAl-LDH/Zeolite Y and (MgZnAl-LDH+MgFe2O4)@SiO2 composites revealed similar performance to the MgZnAl-LDH. Moreover, the MgZnAl-LDH@SiO2 composite showed lower efficiency compared with that of the MgZnAl-LDH. In addition, different kinetic models including, the pseudo-first-order, pseudo-second-order, and particle diffusion models were examined for the simultaneous removal of dyes. The kinetic data revealed the adsorption process could be well fitted by the pseudo-second-order kinetic model. The methylene blue dye removal by (MgZnAl-LDH+MgFe2O4)@SiO2 sample occurred by the adsorption on the surface and intra-particle diffusion.
- انتشار مقاله: 24-07-1399
- نویسندگان: Fatemeh Tavoosi,Maryam Movahedi,Nahid Rasouli
- مشاهده