scholarly journals Kinetic Studies on the Catalytic Degradation of Rhodamine B by Hydrogen Peroxide: Effect of Surfactant Coated and Non-Coated Iron (III) Oxide Nanoparticles

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2246
Author(s):  
Mohd Shaban Ansari ◽  
Kashif Raees ◽  
Moonis Ali Khan ◽  
M.Z.A. Rafiquee ◽  
Marta Otero

Iron (III) oxide (Fe3O4) and sodium dodecyl sulfate (SDS) coated iron (III) oxide (SDS@Fe3O4) nanoparticles (NPs) were synthesized by the co-precipitation method for application in the catalytic degradation of Rhodamine B (RB) dye. The synthesized NPs were characterized using X-ray diffractometer (XRD), vibrating sample magnetometer (VSM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Fourier transform infra-red (FT-IR) spectroscopy techniques and tested in the removal of RB. A kinetic study on RB degradation by hydrogen peroxide (H2O2) was carried out and the influence of Fe3O4 and SDS@Fe3O4 magnetic NPs on the degradation rate was assessed. The activity of magnetic NPs, viz. Fe3O4 and SDS@Fe3O4, in the degradation of RB was spectrophotometrically studied and found effective in the removal of RB dye from water. The rate of RB degradation was found linearly dependent upon H2O2 concentration and within 5.0 × 10−2 to 4.0 × 10−1 M H2O2, the observed pseudo-first-order kinetic rates (kobs, s−1) for the degradation of RB (10 mg L−1) at pH 3 and temperature 25 ± 2 °C were between 0.4 and 1.7 × 104 s−1, while in presence of 0.1% w/v Fe3O4 or SDS@Fe3O4 NPs, kobs were between 1.3 and 2.8 × 104 s−1 and between 2.6 and 4.8 × 104 s−1, respectively. Furthermore, in presence of Fe3O4 or SDS@Fe3O4, kobs increased with NPs dosage and showed a peaked pH behavior with a maximum at pH 3. The magnitude of thermodynamic parameters Ea and ΔH for RB degradation in presence of SDS@Fe3O4 were 15.63 kJ mol−1 and 13.01 kJ mol−1, respectively, lowest among the used catalysts, confirming its effectiveness during degradation. Furthermore, SDS in the presence of Fe3O4 NPs and H2O2 remarkably enhanced the rate of RB degradation.

2012 ◽  
Vol 178-181 ◽  
pp. 562-565
Author(s):  
Rui Cui Liu ◽  
Fu Yi Jiang ◽  
Zi Quan Liu

The experiment used iron chloride, iron dichloride and other agents as the main resources to prepare the nano Fe3O4 powder by co-precipitation method. Magnets were used to test the magnetism of the prepared nano Fe3O4 powder samples. And the photo-catalytic degradation of rhodamine B solution was used as the model reaction to test the photo-catalytic activity of the prepared nano Fe3O4 powder. The results showed that the prepared nano Fe3O4 powder samples had good magnetism but low photo-catalytic activity.


2013 ◽  
Vol 734-737 ◽  
pp. 2200-2203
Author(s):  
Guang Hua Wang ◽  
Kun Chen ◽  
Wen Bing Li ◽  
Dong Wan ◽  
Qin Hu ◽  
...  

Fe3O4 nanoparticles (Fe3O4 NPs) were successfully prepared via chemical co-precipitation method under the assistance of ultrasound irradiation and characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). a series of experiments were carried out to investigate the degradation of Rhodamine B(RhB) by the obtained heterogeneous Fe3O4 catalysts in the presence of H2O2. The effects of catalyst loading,initial pH, reaction temperature, oxidant concentration were discussed. The result indicated that the optimal conditions were Fe3O4 NPs dosage 0.7 g/L, initial pH=3.0, reaction temperature 60°C, oxidant concentration 20 mmol /L.


Author(s):  
Fengfeng Li ◽  
Mingxi Zhang ◽  
Jin Wang ◽  
Yongfeng Cai ◽  
Dushao Zhao ◽  
...  

Abstract In this work, we fabricate a highly efficient photocatalytic AgBr/Ag2CO3 heterojunction through the co-precipitation method. The obtained samples were characterized by means of X-ray diffraction, scanning electron microscopy, transmission electron microscopy, ultraviolet-visible diffuse reflectance spectra and X-ray photoelectron spectroscopy. The photocatalytic activities of obtained samples can be assessed by visible light (λ ≥ 400 nm) degradation of rhodamine B solution. X-ray diffraction revealed that the crystallinity of the AgBr/Ag2CO3heterojunction was significantly higher than pure AgBr and Ag2CO3. Moreover, the AgBr/ Ag2CO3 heterojunction prepared at pH = 6 has the best photocatalytic performance, it can raise the degradation degree of rhodamine B over 95% at 20 min. Finally, a possible photocatalytic mechanism is discussed.


2018 ◽  
Vol 16 (5) ◽  
pp. 846-856 ◽  
Author(s):  
V. Sabna ◽  
Santosh G. Thampi ◽  
S. Chandrakaran

Abstract This is an investigation on oxidative degradation of rhodamine B (RhB) by manganese dioxide (MnO2) nanorods synthesized by redox co-precipitation method. Field emission scanning electron microscopy of MnO2 nanorods at an electron voltage of 10 kV revealed a rod-like morphology for the synthesized nanoparticles. Fourier transform infrared spectra exhibited characteristic peaks of MnO2. Surface area of MnO2 nanorods was 277 m2/g. Effect of various parameters like initial concentration and pH of RhB solution, time of contact between MnO2 nanorods and RhB, dosage of MnO2, and stirring speed on decolouration of RhB was evaluated in batch experiments. Rapid decolouration in the initial period of the reaction was observed due to the adsorption of RhB molecules onto the surface of MnO2 nanorods followed by oxidative degradation. Percentage decolouration decreased with increase in initial concentration and increased with increase in dosage, speed of stirring the mixture and with increase in pH up to pH 7. Near complete decolouration was achieved at a dose of 0.5 g/L of MnO2 nanorods from 20 mg/L RhB solution within 3 min. Observations fitted best to the pseudo second order kinetic model. This study could pave the way for development of cost-effective, nontoxic nanostructures for treatment of wastewaters containing RhB.


Author(s):  
Jiangpo Zhang ◽  
Qi Xia ◽  
Xiaofeng Hong ◽  
Jianjun Chen ◽  
Daijun Liu

Abstract In the present study, different ratios of layered double hydroxides (LDHs) were synthesized via co-precipitation method. The synthesized LDHs were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), nitrogen adsorption-desorption analysis, point of zero charges (pHpzc), scanning electron microscopy (SEM) and Transmission Electron Microscopy (TEM). Phosphate adsorption performances were estimated by batch adsorption experiments; desorption hysteresis and adsorption mechanism were also investigated. The XRD, SEM and TEM results confirmed the multilayer structure of the synthesized LDHs. The pseudo-second-order kinetic model and the Freundlich model describe the adsorption behavior of LDHs best. The maximum adsorption capacity is 185.86 mg-KH2PO4/g for Mg2Al-NO3 LDH. When the dosage of LDHs was greater than 2 g/L, the phosphorus content in the solution decreased from 30 mg-P/L to 0.077 mg-P/L after adsorption by Mg2Al-NO3 LDH. All the results reveal that Mg2Al-NO3 LDH is a potential adsorbent for removing phosphate from aqueous solution.


Author(s):  
Ghazanfar Abbas ◽  
Rizwan Raza ◽  
Muhammad Ashraf Chaudhry ◽  
Bin Zhu

The entire world’s challenge is to find out the renewable energy sources due to rapid depletion of fossil fuels because of their high consumption. Solid Oxide Fuel Cells (SOFCs) are believed to be the best alternative source which converts chemical energy into electricity without combustion. Nanostructured study is required to develop highly ionic conductive electrolyte for SOFCs. In this work, the calcium doped ceria (Ce0.8Ca0.2O1.9) coated with 20% molar ratio of two alkali carbonates (CDC-M: MCO3, where M = Na and K) electrolyte was prepared by co-precipitation method in this study. Ni based electrode was used to fabricate the cell by dry pressing technique. The crystal structure and surface morphology was characterized by X-Ray Diffractometer (XRD), Scanning Electron Microscopy (SEM) and High Resolution Transmission Electron Microscopy (HRTEM). The particle size was calculated in the range of 10–20nm by Scherrer’s formula and compared with SEM and TEM results. The ionic conductivity was measured by using AC Electrochemical Impedance Spectroscopy (EIS) method. The activation energy was also evaluated. The performance of the cell was measured 0.567W/cm2 at temperature 550°C with hydrogen as a fuel.


2015 ◽  
Vol 11 (9) ◽  
pp. 3950-3958 ◽  
Author(s):  
Chandrakant Vedu Nandre ◽  
C.P. Sawant

In the present study photocatalytic degradation of hazardous water soluble alizarin red dye by using Fe-Co nanoparticles  has been investigated. Fe-Co nanoparticles was synthesized by chemical co-precipitation method and characterized by TEM, SEM, EDAX and XRD. The photocatalytic degradation have been studied with the help of variety of parameters such as catalytic dose, dye concentration, pH, contact time and most important chemical oxygen demand. It was observed that The photocatalytic degradation of alizarin red dye by using Fe-Co nanoparticles was an effective ,economic, ecofriendly and faster mode of removing dye from an aqueous solution. The optimum condition for the degradation of the dye was 50 mg/L,pH 8.0, catalyst dose 60 mg/L and contact time 60 minutes. The kinetic studies also have been studied.


2019 ◽  
Vol 17 (1) ◽  
pp. 865-873 ◽  
Author(s):  
Muhammad Ramzan Saeed Ashraf Janjua

AbstractThe nano aggregates of cobalt oxide (Co3O4) are synthesized successfully by adopting simple a co precipitation approach. The product obtained was further subjected to the calcination process that not only changed it morphology but also reduces the size of individual particles of aggregates. The prepared nano aggregates are subjected to different characterization techniques such as electron microscopies (scanning electron microscopy and transmission electron microscopy) and X-ray diffraction and results obtained by these instruments are analyzed by different software. The characterization results show that, although the arrangement of particles is compact, several intrinsic spaces and small holes/ pores can also be seen in any aggregate of the product. The as synthesized product is further tested for catalytic properties in thermal decomposition of ammonium perchlorate and proved to be an efficient catalyst.


2020 ◽  
Vol 81 (5) ◽  
pp. 1080-1089
Author(s):  
Huan-Yan Xu ◽  
Dan Lu ◽  
Qu Tan ◽  
Xiu-Lan He ◽  
Shu-Yan Qi

Abstract Bismuth oxyhalides (BiOXs, X = Cl, Br and I) are emerging photocatalytic materials with unique layered structure, flexible band structure and superior photocatalytic activity. The purpose of this study was to develop a facile alcoholysis route to prepare BiOClxI1−x nanosheet solid solutions at room temperature. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), UV-vis diffuse reflectance spectroscopy (UV-vis DRS), photoluminescence emission spectroscopy (PL) and Brunauer–Emmett–Teller (BET) surface area analyzer were used to characterize the as-prepared photocatalysts. These results revealed that two-dimension BiOClxI1−x nanosheet solid solutions could be obtained with high percentage of {001} crystal facets exposed. Moreover, the formation of solid solution could regularly change the optical absorption thresholds and band gaps of BiOClxI1−x photocatalysts. The photocatalytic experiments indicated that BiOCl0.75I0.25 exhibited the highest photocatalytic performance for the degradation of Rhodamine B (RhB) under simulated sunlight irradiation and the photocatalytic process followed a pseudo-first-order kinetic equation. A possible mechanism of RhB photodegradation over BiOClxI1−x solid solutions was proposed based on the structural properties of BiOClxI1−x solid solutions and RhB photosensitization.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Sasikala Sundar ◽  
V. Ganesh

Abstract Magnetic nanoparticles of iron oxide (γ-Fe2O3) have been prepared using bio-assisted method and their application in the field of biosensors is demonstrated. Particularly in this work, different nanostructures of γ-Fe2O3 namely nanospheres (NS), nanograsses (NG) and nanowires (NW) are prepared using a bio-surfactant namely Furostanol Saponin (FS) present in Fenugreek seeds extract through co-precipitation method by following “green” route. Three distinct morphologies of iron oxide nanostructures possessing the same crystal structure, magnetic properties, and varied size distribution are prepared and characterized. The resultant materials are analyzed using field emission scanning electron microscopy, transmission electron microscopy, powder X-ray diffraction, X-ray photoelectron spectroscopy, vibrating sample magnetometer and Fourier transform infrared spectroscopy. Moreover, the effect of reaction time and concentration of FS on the resultant morphologies of γ-Fe2O3 nanostructures are systematically investigated. Among different shapes, NWs and NSs of γ-Fe2O3 are found to exhibit better sensing behaviour for both the individual and simultaneous electrochemical detection of most popular biomarkers namely dopamine (DA) and uric acid (UA). Electrochemical studies reveal that γ-Fe2O3 NWs showed better sensing characteristics than γ-Fe2O3 NSs and NGs in terms of distinguishable voltammetric signals for DA and UA with enhanced oxidation current values. Differential pulse voltammetric studies exhibit linear dependence on DA and UA concentrations in the range of 0.15–75 µM and 5 μM – 0.15 mM respectively. The detection limit values for DA and UA are determined to be 150 nM and 5 µM. In addition γ-Fe2O3 NWs modified electrode showed higher sensitivity, reduced overpotential along with good selectivity towards the determination of DA and UA even in the presence of other common interferents. Thus the proposed biosensor electrode is very easy to fabricate, eco-friendly, cheaper and possesses higher surface area suggesting the unique structural patterns of γ-Fe2O3 nanostructures to be a promising candidate for electrochemical bio-sensing and biomedical applications.


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