scholarly journals Degradation of dye wastewater by persulfate activated with Fe3O4/graphene nanocomposite

2016 ◽  
Vol 6 (4) ◽  
pp. 553-561 ◽  
Author(s):  
Xiao-Bao Gong
Keyword(s):  
Organic Contaminants ◽  
Precipitation Method ◽  
Order Kinetic ◽  
Dye Wastewater ◽  
X Ray Diffraction ◽  
First Order ◽  
Order Kinetic Model ◽  
Infrared Spectrometer ◽  
Graphene Nanocomposite ◽  
Co Precipitation

In this study, Fe3O4/graphene nanocomposite was synthesized through a liquid-phase co-precipitation method and characterized using X-ray diffraction and Fourier transform infrared spectrometer. The synthetic Fe3O4/graphene was used as a heterogeneous catalyst to activate persulfate to efficiently degrade methylene blue (MB). The target pollutant MB can be degraded by sulfate radicals depending on several parameters including persulfate and Fe3O4/graphene concentrations, pH and reaction temperature. Within 120 min of reaction time, almost 100% of 0.05 mM MB was removed by 1.5 mM persulfate in the presence of 150 mg/L of Fe3O4/graphene at pH = 6.0 and 25 °C. The degradation of MB was found to follow the pseudo-first-order kinetic model. The Fe3O4/graphene has much better stability and reusability than free Fe3O4 suggested by reuse tests. The results demonstrate that Fe3O4/graphene activated persulfate is a promising technology for remediation of water pollution caused by organic contaminants.

Removal of hexavalent chromium from aqueous solution by calcined Zn/Al-LDHs

2016 ◽  
Vol 74 (1) ◽  
pp. 229-235 ◽  
Author(s):  
Hui-Duo Yang ◽  
Yun-Peng Zhao ◽  
Shi-Feng Li ◽  
Xing Fan ◽  
Xian-Yong Wei ◽  
...  
Keyword(s):  
Hexavalent Chromium ◽  
Precipitation Method ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
X Ray Diffraction ◽  
Effects Of Ph ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Co Precipitation ◽  
Double Hydroxides

In this study, Zn/Al-layered double hydroxides (Zn/Al-LDHs) were synthesized by a co-precipitation method and characterized with X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy. Then the hexavalent chromium Cr(VI) adsorption experiments on calcined Zn/Al-LDHs were carried out to analyze the effects of pH, temperature, adsorption time, initial Cr(VI) concentration and adsorbent dosage on the removal of Cr(VI) from aqueous solutions. The maximum adsorption capacity for Cr(VI) on calcined Zn/Al-LDHs under optimal conditions was found to be over 120 mg/g. The kinetic and isotherm of Cr(VI) adsorption on calcined Zn/Al-LDHs can be described with the pseudo-second-order kinetic model and Langmuir isotherm, respectively.

Fabrication and Photocatalytic Decolorization Performance of ZnO

2011 ◽  
Vol 396-398 ◽  
pp. 823-826
Author(s):  
Jie Cheng ◽  
Jian Zhang Li ◽  
Jun Bo Zhong ◽  
Wei Hu
Keyword(s):  
Methyl Orange ◽  
Kinetic Model ◽  
Uv Irradiation ◽  
Precipitation Method ◽  
Order Kinetic ◽  
First Order ◽  
Photocatalytic Decolorization ◽  
Langmuir Hinshelwood Mechanism ◽  
Order Kinetic Model ◽  
Pseudo First Order

Paralled flaw precipitation method has been employed to synthesize nanostructured ZnO. The prepared photocatalyst was characterized by BET, XRD. The paper reveals that Methyl Orange (MO) can be decolorized effectively in ZnO suspension system under UV irradiation. The optimal loading of photocatalyst in our experimental condition for the decolorization of MO is 1g/L. The present study, on the base of Langmuir-Hinshelwood mechanism, illustrates that the decolorization reaction is a pseudo first order kinetic model with the limiting rate constant of 8.48×10-2 mgL-1min-1 and equilibrium adsorption constant 0.335 L/mg, respectively.

scholarly journals Degradation of rhodamine B with manganese dioxide nanorods

2018 ◽  
Vol 16 (5) ◽  
pp. 846-856 ◽  
Author(s):  
V. Sabna ◽  
Santosh G. Thampi ◽  
S. Chandrakaran
Keyword(s):  
Manganese Dioxide ◽  
Rhodamine B ◽  
Initial Period ◽  
Oxidative Degradation ◽  
Cost Effective ◽  
Precipitation Method ◽  
Order Kinetic ◽  
Initial Concentration ◽  
Order Kinetic Model ◽  
Co Precipitation

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.

scholarly journals Photocatalytic Degradation of a Basic Dye Using Zinc Oxide Nanocatalyst

2019 ◽  
Vol 81 ◽  
pp. 18-26 ◽  
Author(s):  
Maureen O. Chijioke-Okere ◽  
Nnaemeka John Okorocha ◽  
Basil N. Anukam ◽  
Emeka E. Oguzie
Keyword(s):  
Zinc Oxide ◽  
Malachite Green ◽  
Uv Light ◽  
Degradation Kinetics ◽  
Catalyst Loading ◽  
Order Kinetic ◽  
X Ray Diffraction ◽  
First Order ◽  
Malachite Green Dye ◽  
Order Kinetic Model

The potential of Calcinated and uncalcinated zinc oxide as effective Photocatatlyst for the degradation of malachite green dye, MG from aqueous medium using UV light has been identified. The photocatalysts were characterized using scanning electron microscope, SEM and x-ray diffraction, XRD. The SEM investigations of the calcinated ZnO revealed highly dispersed nanomaterials and the particles were of nanometer size in agreement with the XRD result. The uncalcinated zinc oxide, ZnO revealed some pronounced nanoparticles. The degradation of MG by the photocatalyst was found to be influenced by adsorbent loading and irradiating time. The optimum degradation was obtained at 0.5g catalyst loading of both calcinated and uncalcinated zinc oxide which is 98.48% and 96.31 % respectively at 150 minutes. The degradation kinetics conformed to the pseudo-first-order kinetic model. The present study showed that calcinated and uncalcinated zinc oxide ZnO can be effectively used as efficient photocatalyst for the degradation of Malachite green dyes from aqueous solutions and effluents.

scholarly journals Enhanced photocatalytic degradation of doxycycline using a magnetic polymer-ZnO composite

2018 ◽  
Vol 2017 (3) ◽  
pp. 791-801 ◽  
Author(s):  
Ali Mohammadi ◽  
Shabnam Pourmoslemi
Keyword(s):  
Aqueous Solution ◽  
Photocatalytic Degradation ◽  
Extraction Efficiency ◽  
Nano Particles ◽  
Order Kinetic ◽  
X Ray Diffraction ◽  
X Ray ◽  
First Order ◽  
Polymer Precipitation ◽  
Order Kinetic Model

Abstract A novel magnetic polymer-ZnO composite was prepared by incorporating Fe3O4 and ZnO nano-particles in the structure of an adsorbent polymer. Precipitation polymerization was used for synthesizing the adsorbent polymer and its efficiency for extracting doxycycline from aqueous solution was optimized according to several parameters including time, pH and amount of polymer. Results showed the highest extraction efficiency at neutral pH of the doxycycline solution in 20 min, and the capacity of the polymer was about 20 mg/g. The magnetic property of a material is important for fast and facile separation of composite particles after each use. Magnetic polymer-ZnO composite was synthesized by adding Fe3O4 and ZnO nano-particles to the polymerization mixture in order to take advantage of both sorption and photocatalytic degradation mechanisms. The obtained composite was characterized using X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy equipped with wavelength dispersive X-ray spectroscopy and used for enhanced photocatalytic degradation of doxycycline in aqueous solution. Results showed 76.5% degradation of doxycycline in 6 hours which was significantly higher than the degradation observed by an equivalent amount of ZnO nano-particles. Photocatalytic degradation of doxycycline fitted the pseudo first order kinetic model with a rate constant of 4 × 10−3 μg mL−1 min−1.

scholarly journals Optimal Synthesis and Mechanistic Performance of HCO-Doped-(Fe3O4)x Adsorbent for Sb(III)/Sb(V) Removal From Water

2020 ◽  
Author(s):  
Renjian Deng ◽  
Jun Zhang ◽  
Xiaoliang Hu ◽  
Chuanqu Zhu ◽  
Fubing Xie ◽  
...  
Keyword(s):  
Surface Area ◽  
Precipitation Method ◽  
Hydroxyl Groups ◽  
Complexation Reaction ◽  
Order Kinetic ◽  
Ionic Charge ◽  
Adsorption Performance ◽  
Potential Applications ◽  
Order Kinetic Model ◽  
Co Precipitation

Concern over potential antimony mediated toxicity from mining and smelting activities has instigated novel concepts toward removing aqueous antimony ions. The iron based adsorbent Fe3O4/HCO was found to be efficient for treating antimony-containing wastewater However, ineffective methodology for preparation limited its effective adsorption capacity and thus wider application. In this study, a new type of HCO-doped-(Fe3O4)x adsorbent was prepared by co-precipitation method for doping Fe3O4 into HCO sludge (HCO), thereby improving adsorption performance for Sb(III) and Sb(V) ions, with the maximum adsorbing capacity being 44.46 mg/g and 47.91 mg/g, respectively. According to the results of BET, SEM-EDS, XRD and XPS, it were confirmed that the FeOOH and X≡Fe-OH were formed during the preparation process, bring about the increased the surface area, thus resulting in further increase of surface area, hydroxyl groups and the net negative ionic charge. Moreover, the adsorption kinetics followed the pseudo-second-order kinetic model which indicated that adsorption process of Sb(III)/Sb(V) by HCO-doped-(Fe3O4)x adsorbent was controlled by chemical reaction. The main adsorption mechanism is that antimony ion and amorphous iron oxide X≡Fe-OH undergo coordination exchange reaction and complexation reaction with CeO2 or Ce2O3. Furthermore, HCO-doped-(Fe3O4)x could adapt to wide pH and had stable adsorption ability after regeneration. The good adsorption performance of HCO-doped-(Fe3O4)x makes it a potential applications of adsorbent for removal of antimony.

scholarly journals Enhanced Performance of Chitosan via a Novel Quaternary Magnetic Nanocomposite Chitosan/Grafted Halloysitenanotubes@ZngFe3O4 for Uptake of Cr (III), Fe (III), and Mn (II) from Wastewater

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2714
Author(s):  
Mahmoud F. Mubarak ◽  
Ahmed H. Ragab ◽  
Rasha Hosny ◽  
Inas A. Ahmed ◽  
Hanan A. Ahmed ◽  
...  
Keyword(s):  
Metal Ions ◽  
High Efficiency ◽  
Precipitation Method ◽  
High Electron ◽  
Order Kinetic ◽  
Equilibrium System ◽  
Adsorption Removal ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Co Precipitation

A novel chitosan/grafted halloysitenanotubes@Zngmagnetite quaternary nanocomposite (Ch/g-HNTs@ZngM) was fabricated using the chemical co-precipitation method to remove the ions of Cr (III), Fe (III), and Mn (II) from wastewater. The characteristics of the synthesized Ch/g-HNTs@ZngM quaternary nanocomposite were investigated using FTIR, SEM, XRD, GPC, TGA, TEM, and surface zeta potential. The characterization analysis proved that the mentioned nanocomposite structure contains multiple functional groups with variable efficiencies. Additionally, they proved the existence of magnetic iron in the nanocomposite internal structure with the clarity of presentation of gaps and holes of high electron density on its surface. The results showed that the pH and time to reach an equilibrium system for all the studied metal ions were obtained at 9.0 and 60 min, respectively. The synthesized Ch/g-HNTs@ZngM nanocomposite exhibited maximum adsorption removal of 95.2%, 99.06%, and 87.1% for Cr (III), Fe (III), and Mn (II) ions, respectively. The pseudo-second-order kinetic model and, for isotherm, the Langmuir model were best fitted with the experimental data. The thermodynamic parameters indicated the exothermic and spontaneous nature of the adsorption reaction as proven by the ΔH° and ΔG° values. Additionally, chemical adsorption by the coordination bond is supposed as the main mechanism of adsorption of the mentioned metal ions on the nanocomposite. Finally, Ch/g-HNTs@ZngM displays prospected advantages, such as a low-expense adsorbent, high efficiency and availability, and an eco-friendly source, that will reduce the environmental load via an environmentally friendly method.

Studying adsorption of methylene blue onto chitosan – mangetite composite

2021 ◽  
Vol 11 (1) ◽  
pp. 60-66
Author(s):  
Quy Bui Minh ◽  
Oanh Do Thi ◽  
Vinh Nguyen Dinh ◽  
Linh Nguyen Thi Ngoc ◽  
Hoa Nguyen Thi Hong ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Diffraction Method ◽  
Precipitation Method ◽  
Isotherm Models ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Co Precipitation ◽  
Microscopy Techniques

The chitosan/mangetite composite in the mass ratio chitosan:mangetite of 9:1 (CM91) was synthesised by co-precipitation method. The characteristics of the chitosan/mangetite composite was estimated by X-ray diffraction method (XRD) and scanning electron microscopy techniques (SEM). The methylene blue adsorption ability onto CM91 composite was well at value pH 9, equilibrium contact time of 20 minutes. The experimental adsorption data fitted into pseudo–Langmuir adsorption isotherm models. The adsorption followed pseudo-second order kinetic model very well. The maximum adsorption capacity of that composite which caculated by Langmuir equation was 94,18 mg/g.

Magnetic and dielectric properties of BiFeO3 nanoparticles

2015 ◽  
Vol 7 (2) ◽  
pp. 1393-1403
Author(s):  
Dr R.P VIJAYALAKSHMI ◽  
N. Manjula ◽  
S. Ramu ◽  
Amaranatha Reddy
Keyword(s):  
Diffuse Reflectance Spectrum ◽  
Precipitation Method ◽  
Secondary Phases ◽  
X Ray Diffraction ◽  
Bifeo3 Nanoparticles ◽  
Transmission Electron ◽  
Multiferroic Bifeo3 ◽  
Pure Phase ◽  
Simple Chemical ◽  
Co Precipitation

Single crystalline nano-sized multiferroic BiFeO3 (BFO) powders were synthesized through simple chemical co-precipitation method using polyethylene glycol (PEG) as capping agent. We obtained pure phase BiFeO3 powder by controlling pHand calcination temperature. From X-ray diffraction studies the nanoparticles were unambiguously identified to have a rhombohedrally distorted perovskite structure belonging to the space group of R3c. No secondary phases were detected. It indicates single phase structure. EDX spectra indicated the appearance of three elements Bi, Fe, O in 1:1:3. From the UV-Vis diffuse reflectance spectrum, the absorption cut-off wavelength of the BFO sample is around 558nm corresponding to the energy band gap of 2.2 eV. The size (60-70 nm) and morphology of the nanoparticles have been analyzed using transmission electron microscopy (TEM).   Linear M−H behaviour and slight hysteresis at lower magnetic field is observed for BiFeO3 nanoparticles from Vibrating sample magnetometer studies. It indicates weak ferromagnetic behaviour at room temperature. From dielectric studies, the conductivity value is calculated from the relation s = L/RbA Sm-1 and it is around 7.2 x 10-9 S/m.

scholarly journals Photoluminescent Properties of Hydroxyapatite and Hydroxyapatite/Multi-Walled Carbon Nanotube Composites

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 832
Author(s):  
Edna X. Figueroa-Rosales ◽  
Javier Martínez-Juárez ◽  
Esmeralda García-Díaz ◽  
Daniel Hernández-Cruz ◽  
Sergio A. Sabinas-Hernández ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Hexagonal Phase ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Multi Walled Carbon Nanotube ◽  
Nanotube Composites ◽  
Carbon Nanotube Composites ◽  
Co Precipitation ◽  
Functionalized Mwcnts

Hydroxyapatite (HAp) and hydroxyapatite/multi-walled carbon nanotube (MWCNT) composites were obtained by the co-precipitation method, followed by ultrasound-assisted and microwave radiation and thermal treatment at 250 °C. X-ray diffraction (XRD) confirmed the presence of a hexagonal phase in all the samples, while Fourier-transform infrared (FTIR) spectroscopy elucidated the interaction between HAp and MWCNTs. The photoluminescent technique revealed that HAp and the composite with non-functionalized MWCNTs present a blue luminescence, while the composite with functionalized MWCNTs, under UV-vis radiation shows an intense white emission. These findings allowed presentation of a proposal for the use of HAp and HAp with functionalized MWCNTs as potential materials for optoelectronic and medical applications.

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