scholarly journals Adsorption of anionic dye onto magnetic Fe3O4/CeO2 nanocomposite: Equilibrium, kinetics, and thermodynamics

2019 ◽  
Vol 37 (3-4) ◽  
pp. 185-204 ◽  
Author(s):  
Shaomin Gao ◽  
Wenwen Zhang ◽  
Zhaohui An ◽  
Shulin Kong ◽  
Donghui Chen
Keyword(s):  
Electron Microscopy ◽  
Energy Dispersive Spectrometer ◽  
Precipitation Method ◽  
Maximum Adsorption Capacity ◽  
Adsorption Model ◽  
X Ray Diffraction ◽  
Anionic Dye ◽  
Transmission Electron ◽  
Initial Ph ◽  
Pseudo Second Order

In this study, a magnetically separable Fe3O4/CeO2 (Fe/Ce) nanocomposite is synthesized by sol-precipitation method and characterized by field-emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, energy dispersive spectrometer , vibrating sample magnetometer, atomic absorption spectrometer, and zeta potential measurements. The Fe/Ce is used as sorbent to adsorb anionic dye of Acid Black 210 (AB210) from aqueous solutions, and the maximum adsorption capacity is about 90.50 mg/g, which is six times higher than that of the commercial CeO2. Dependence of absorption performance on essential factors, such as initial dye concentration, temperature and initial pH, are experimentally examined. The result shows that the adsorption kinetic of Fe/Ce follows pseudo-second-order model and the adsorption isotherm is well described by the Langmuir adsorption model. Furthermore, the thermodynamic analysis indicates that the adsorption of Fe/Ce for AB210 is spontaneous and endothermic.

scholarly journals A Facilely Synthesized Tourmaline-Biochar Composite For Enhanced Removal of Cr (VI) From Aqueous Solution

2021 ◽  
Author(s):  
Qi Lu ◽  
Siyi Huang ◽  
Xiaorui Ma
Keyword(s):  
Aqueous Solution ◽  
Pyrolysis Temperature ◽  
Adsorption Property ◽  
Energy Dispersive Spectrometer ◽  
Maximum Adsorption Capacity ◽  
X Ray Diffraction ◽  
Adsorption Mechanisms ◽  
Monolayer Adsorption ◽  
Initial Ph ◽  
Pseudo Second Order

Abstract A tourmaline-biochar composite (TMBC) was facilely synthesized to effectively remove Cr (Ⅵ) from aqueous solution. The effects of different ratio (TM: BC) and pyrolysis temperature on TMBC adsorption performance were compared for optimal condition of TMBC preparation. The TMBC samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) and scanning electron microscope-energy dispersive spectrometer (SEM-EDS). The kinetics and thermodynamics were analyzed to investigate the sorption mechanism for removal of Cr (VI). The results showed that the proper pyrolysis temperature was 650℃, and the ratio of TM and BC was 1:3. SEM results showed that there are many pores in the biochar structure, which is helpful for tourmaline dispersion. The adsorption kinetics was fitted well by the pseudo-second-order model, indicating the sorption is related to chemical absorption. Freundlich adsorption isotherms suggested monolayer adsorption between Cr (Ⅵ) and TMBC, and the maximum adsorption capacity of TMBC for Cr (Ⅵ) was 53.10 mg/g at initial pH 4.0, which is more than twice higher than pristine TM (17.85 mg/g). Such adsorption mechanisms included water automatically polarized, ion exchange and electrode adsorption, among which the automatic polarization of water caused by tourmaline was the unique adsorption property of TMBC. So TMBC composite can be used as an economic adsorbent in the remediation of heavy metal pollution in water.

scholarly journals Preparation of ureido-functionalized PVA/silica mesoporous fibre membranes via electrospinning for adsorption of Pb2+ and Cu2+ in wastewater

2017 ◽  
Vol 76 (9) ◽  
pp. 2526-2534 ◽  
Author(s):  
Meimei Zhou ◽  
Weizhen Tang ◽  
Pingping Luo ◽  
Jiqiang Lyu ◽  
Aixia Chen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Adsorption Capacity ◽  
Freundlich Isotherm ◽  
Isotherm Model ◽  
Maximum Adsorption Capacity ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Langmuir Isotherm Model ◽  
Pseudo Second Order ◽  
Adsorption Desorption

Abstract Ureido-functionalized mesoporous polyvinyl alcohol/silica composite nanofibre membranes were prepared by electrospinning technology and their application for removal of Pb2+ and Cu2+ from wastewater was discussed. The characteristics of the membranes were investigated by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and N2 adsorption-desorption analysis. Results show that the membranes have long fibrous shapes and worm-like mesoporous micromorphologies. Fourier transform infrared spectroscopy confirmed the membranes were successfully functionalized with ureido groups. Pb2+ and Cu2+ adsorption behavior on the membranes followed a pseudo-second-order nonlinear kinetic model with approximately 30 minutes to equilibrium. Pb2+ adsorption was modelled using a Langmuir isotherm model with maximum adsorption capacity of 26.96 mg g−1. However, Cu2+ adsorption was well described by a Freundlich isotherm model with poor adsorption potential due to the tendency to form chelating complexes with several ureido groups. Notably, the membranes were easily regenerated through acid treatment, and maintained adsorption capacity of 91.87% after five regeneration cycles, showing potential for applications in controlling heavy metals-related pollution and metals reuse.

scholarly journals Enhanced Photocatalytic Activity of Cu2O Cabbage/RGO Nanocomposites under Visible Light Irradiation

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1712
Author(s):  
Appusamy Muthukrishnaraj ◽  
Salma Ahmed Al-Zahrani ◽  
Ahmed Al Otaibi ◽  
Semmedu Selvaraj Kalaivani ◽  
Ayyar Manikandan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thermo Gravimetric Analysis ◽  
Visible Region ◽  
Catalytic Performance ◽  
Precipitation Method ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dye Pollutants ◽  
Transmission Electron

Towards the utilization of Cu2O nanomaterial for the degradation of industrial dye pollutants such as methylene blue and methyl orange, the graphene-incorporated Cu2O nanocomposites (GCC) were developed via a precipitation method. Using Hummers method, the grapheme oxide (GO) was initially synthesized. The varying weight percentages (1–4 wt %) of GO was incorporated along with the precipitation of Cu2O catalyst. Various characterization techniques such as Fourier-transform infra-red (FT-IR), X-ray diffraction (XRD), UV–visible diffused reflectance (UV-DRS), Raman spectroscopy, thermo gravimetric analysis (TGA), energy-dispersive X-ray analysis (EDX), and electro chemical impedance (EIS) were followed for characterization. The cabbage-like morphology of the developed Cu2O and its composites were ascertained from field-emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HR-TEM). In addition, the growth mechanism was also proposed. The results infer that 2 wt % GO-incorporated Cu2O composites shows the highest value of degradation efficiency (97.9% and 96.1%) for MB and MO at 160 and 220 min, respectively. Further, its catalytic performance over visible region (red shift) was also enhanced to an appreciable extent, when compared with that of other samples.

scholarly journals Magnetic PbFe12O19-TiO2 nanocomposites and their photocatalytic performance in the removal of toxic pollutants

2018 ◽  
Vol 41 (3-4) ◽  
pp. 53-62 ◽  
Author(s):  
Behnaz Lahijani ◽  
Kambiz Hedayati ◽  
Mojtaba Goodarzi
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Performance ◽  
Sol Gel ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Gel Method ◽  
Sol Gel Method ◽  
Photocatalytic Effect ◽  
Transmission Electron ◽  
Ultraviolet Light Irradiation

Abstract In this work, the PbFe12O19 nanoparticles were prepared by the simple and optimized precipitation method with different organic surfactants and capping agents. In the next step, the TiO2 nanoparticles were synthesized using the sol-gel method. At the final step, the PbFe12O19-TiO2 nanocomposites were prepared via the sol-gel method. The effect of the precipitating agent on the morphology and particle size of the products was investigated. The prepared products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Fourier transform infrared spectroscopy. The results obtained by the vibrating sample magnetometer show the magnetic properties of the ferrite nanostructures. The photocatalytic effect of the PbFe12O19-TiO2 nanocomposite on the elimination of the azo dyes (acid black, acid violet and acid blue) under ultraviolet light irradiation was evaluated. The results indicate that the prepared nanocomposites have acceptable magnetic and photocatalytic performance.

scholarly journals Synthesis of Co3O4 Nano Aggregates by Co-precipitation Method and its Catalytic and Fuel Additive Applications

2019 ◽  
Vol 17 (1) ◽  
pp. 865-873 ◽  
Author(s):  
Muhammad Ramzan Saeed Ashraf Janjua
Keyword(s):  
Electron Microscopy ◽  
Precipitation Method ◽  
Fuel Additive ◽  
X Ray Diffraction ◽  
Efficient Catalyst ◽  
Calcination Process ◽  
Electron Microscopies ◽  
Transmission Electron ◽  
Co Precipitation ◽  
Individual Particles

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.

Composition and Microstructure of a Natural Nano-Structure Mineral: Six-Ring Rock

2011 ◽  
Vol 295-297 ◽  
pp. 869-872
Author(s):  
Qing Shan Li ◽  
Xin Wang ◽  
Jun Liu ◽  
Guang Zhong Xing
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Energy Dispersive Spectrometer ◽  
The Body ◽  
X Ray Diffraction ◽  
Nano Structure ◽  
X Ray ◽  
Transmission Electron ◽  
Nano Size ◽  
Scanning Electron

Six-ring Rock is widely used as containers of water and additives to produce health care products. In this paper, the composition and microstructure of Six-ring Rock have been investigated by using scanning electron microscopy, energy dispersive spectrometer, transmission electron microscopy, x-ray diffraction and other technologies. Results show that Six-ring Rock is composed of CaMg(CO3)2, SiO2 and KAlSi3O8. Fe atoms exist in CaMg(CO3)2 by replacing Mg atoms. Six-ring Rock shows nano-size lamellar and acerose microstructures on the surface, and nano-size monocrystals in the body. Six-ring Rock is a natural nano structure mineral.

Synthesis and Photocatalytic Activity of Visible-Light Responsive BiOBr/GO Composites

2017 ◽  
Vol 751 ◽  
pp. 807-812
Author(s):  
Tuangphorn Prasitthikun ◽  
X. Wu ◽  
Tsugio Sato ◽  
Charusporn Mongkolkachit ◽  
Pornapa Sujaridworakun
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Visible Light ◽  
High Efficiency ◽  
Precipitation Method ◽  
Mixed Solution ◽  
Diffuse Reflection Spectroscopy ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Photocatalytic Activities

High efficiency BiOBr/GO composites photocatalyst were successfully synthesized via a facile precipitation method. The precursors were prepared by dissolving Bi (NO3)3.5H2O and KBr in glycerol and distilled water, respectively. Various amounts (0.1-2 wt%) of graphene oxide were added into the mixed solution precursors, and stirred at room temperature to get precipitated powder without further heat treatment. The obtained products were characterized for phase, morphology, optical properties and surface area by X-ray diffraction (XRD), transmission electron microscopy (TEM), filed-emission scanning electron microscopy (FE-SEM), UV-Vis diffuse reflection spectroscopy (DRS) and Brunauer–Emmett–Teller (BET), respectively. The morphology and structure of as-synthesized samples were composed of numerous fine plates of BiOBr dispersed on the GO sheets. The photocatalytic activities of BiOBr/GO composites were evaluated by rhodamine B degradation under visible light irradiation. As the results, the significant increase in photodegradation of BiOBr/GO composite comparing with pure BiOBr was observed. Among all samples, the composite with 1 wt% of graphene oxide showed the highest photocatalytic performance.

Adsorptive removal of PPCPs by biomorphic HAP templated from cotton

2016 ◽  
Vol 74 (1) ◽  
pp. 276-286 ◽  
Author(s):  
Bin Huang ◽  
Dan Xiong ◽  
Tingting Zhao ◽  
Huan He ◽  
Xuejun Pan
Keyword(s):  
Adsorption Mechanism ◽  
Adsorption Process ◽  
Freundlich Isotherm ◽  
Kinetic Studies ◽  
Precipitation Method ◽  
Adsorptive Removal ◽  
Transmission Electron ◽  
Initial Ph ◽  
Pseudo Second Order ◽  
Co Precipitation

Biomorphic nano-hydroxyapatite (HAP) was fabricated by a co-precipitation method using cotton as bio-templates and employed in adsorptive removal of ofloxacin (OFL) and triclosan (TCS) that are two representative pharmaceuticals and personal care products (PPCPs). The surface area and porosity, crystal phase, functional group, morphology and micro-structure of the synthesized HAP were characterized by Brunauer–Emmett–Teller isotherm, X-ray powder diffraction, Fourier transform infrared spectroscopy, scanning electron macroscopic and transmission electron microscopy. The effects of initial pH, ionic strength, initial concentration, contact time and temperature on the removal of PPCPs were studied in a batch experiment. The adsorption of OFL and TCS was rapid and almost accomplished within 50 min. Kinetic studies indicated that the adsorption process of OFL and TCS followed the pseudo-first-order and pseudo-second-order models, respectively. The Freundlich isotherm described the OFL adsorption process well but the adsorption of TCS fitted the Langmuir isotherm better. Thermodynamics and isotherm parameters suggested that both OFL and TCS adsorption were feasible and spontaneous. Hydrogen bond and Lewis acid–base reaction may be the dominating adsorption mechanism of OFL and TCS, respectively. Compared to other adsorbents, biomorphic HAP is environmentally friendly and has the advantages of high adsorption capacity, exhibiting potential application for PPCPs removal.

Kaolin in the net-like horizon of laterite in Hubei, south China

Clay Minerals ◽  
2009 ◽  
Vol 44 (1) ◽  
pp. 51-66 ◽  
Author(s):  
Hanlie Hong ◽  
Zhaohui Li ◽  
Muzhuang Yang ◽  
Ping Xiao ◽  
Huijuan Xue
Keyword(s):  
Electron Microscopy ◽  
South China ◽  
Energy Dispersive Spectrometer ◽  
Clay Mineralogy ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Chemical Index ◽  
Mineral Components ◽  
Chemical Index Of Alteration ◽  
Matrix Components

AbstractThe clay mineralogy and chemical composition of the white veins, red matrix and both Fe- and Mn-bearing nodules occurring in a laterite profile in Hubei, south China were investigated using X-ray diffraction, scanning electron microscopy equipped with an energy-dispersive spectrometer, and high-resolution transmission electron microscopy. The results show that the mineral components of the red matrix are mainly quartz, kaolinite, halloysite, goethite and minor illite, whereas the white net-like veins contain mostly quartz, kaolinite, halloysite, and illite. In the net-like horizon, the chemical index of alteration (CIA, the ratio of Al2O3/(Al2O3+CaO+K2O+Na2O)) and the TiO2/Al2O3 ratio are 89.8% and 0.021 for the white vein and 90.7% and 0.025 for the red matrix, respectively. Both white-vein and red-matrix components have similar TiO2/Al2O3 ratios, and are similar to the ratio 0.027 of the unaltered bedrock. The similarity in TiO2/Al2O3 values indicates that all three portions of the laterite soil share the same origin. Also, although the white-vein and red-matrix components differ in Fe2O3 abundance, the similar CIA values do imply similar degrees of alteration. The Fe-bearing and Mn-bearing nodules were produced by the local accumulation of Fe2O3 and MnO, respectively. Halloysite in the weathering profile occurs in two different morphologies, tubular and platy crystals. Tubular halloysite occurs both in the red matrix and the Fe-bearing nodule whereas platy halloysite occurs only in the white vein and Mn-bearing nodule assemblages. Crystallization of small tubular halloysite from Si and Al concretions in the red matrix is observed, indicating that the morphology of these crystals in the weathering environment is mainly controlled by Fe3+ cations, whereas platy halloysite may be derived from the hydration of kaolinite.

scholarly journals Nanoparticle Beads of Chitosan-Ethylene Glycol Diglycidyl Ether/Fe for the Removal of Aldrin

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
G. García Rosales ◽  
P. Ávila-Pérez ◽  
J.O. Reza-García ◽  
A. Cabral-Prieto ◽  
E.O. Pérez-Gómez
Keyword(s):  
Electron Microscopy ◽  
Aqueous Solutions ◽  
Iron Nanoparticles ◽  
Sorption Process ◽  
Diglycidyl Ether ◽  
Maximum Adsorption Capacity ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Chitosan Beads ◽  
Transmission Electron

This article reports on the preparation of iron nanoparticles (FeNPs) supported in chitosan beads (Chi-EDGE-Fe) for removing aldrin from aqueous solutions. The FeNPs and Chi-EDGE-Fe beads were characterized by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR), and the Mössbauer spectroscopy (MS) techniques. TEM, XRD, and MS showed that the FeNPs had core-shell structures consisting of a core of either Fe0 or Fe2B and a shell of magnetite. Furthermore, SEM images showed that Chi-EDGE-Fe beads were spherical with irregular surfaces and certain degrees of roughness and porosity, whilst the sorbent mean pore size was 204 nm, and the occluded iron nanoparticles in the chitosan material had diameters of 70 nm and formed agglomerates. The sorbent beads consisted of carbon, oxygen, chlorine, aluminum, silicon, and iron according to the SEM-EDS analysis. Functional groups such as O-H, C-H, -CH2, N-H, C-O, C-OH, and Fe-OH were detected in the FTIR spectra. In addition, a characteristic band appeared at about 1700 cm−1 after the sorption process involving aldrin. MS also showed that the iron nanoparticles in the beads probably oxidized into NPs of α-Fe2O3 as a result of the supporting process. The isotherm of the aldrin removal followed the Langmuir–Freundlich model and presented a maximum adsorption capacity of 74.84 mg/g, demonstrating that chitosan-Fe beads are promising sorbents for the removal of toxic pollutants in aqueous solutions.

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