Hierarchical MnO2 nanostructures: synthesis and their application in water treatment

Hierarchical MnO2 nanostructures were prepared through the reaction between KMnO4 and oleic acid at room temperature in the surfactant-free microemulsion system. The obtained samples were characterized by powder X-ray diffraction, N2 adsorption, scanning electron microscopy, and transmission electron microscopy. The results indicated that the flowerlike nanospheres were three-dimensional (3D) porous microstructures consisting of nanoplates. The surface area of the sample was 171.5 m2/g and the distribution of pore diameter lay within the range of 5–15 nm. The prepared hierarchically structured MnO2 showed excellent adsorption capacity and rapid adsorption rate for methylene blue ions in water. The maximum adsorption capacity of methylene blue was as high as 273.9 mg/g and 97.5% of the dye was removed within initial 5 min of contact time. Compared with other adsorbents, the synthesized hierarchical MnO2 nanostructures displayed a faster adsorption rate and higher adsorption capacity, which implied potential application for removing dye pollutants from waste water.

Download Full-text

Facile Preparation of Rod-like MnO Nanomixtures via Hydrothermal Approach and Highly Efficient Removal of Methylene Blue for Wastewater Treatment

Nanomaterials ◽

10.3390/nano9010010 ◽

2018 ◽

Vol 9 (1) ◽

pp. 10 ◽

Cited By ~ 37

Author(s):

Yuelong Xu ◽

Bin Ren ◽

Ran Wang ◽

Lihui Zhang ◽

Tifeng Jiao ◽

...

Keyword(s):

Electron Microscopy ◽

Methylene Blue ◽

Photoelectron Spectroscopy ◽

Degradation Mechanism ◽

Dye Adsorption ◽

Maximum Adsorption Capacity ◽

X Ray ◽

Transmission Electron ◽

Degradation Ratio ◽

Hydrothermal Approach

In the present study, nanoscale rod-shaped manganese oxide (MnO) mixtures were successfully prepared from graphitic carbon nitride (C3N4) and potassium permanganate (KMnO4) through a hydrothermal method. The as-prepared MnO nanomixtures exhibited high activity in the adsorption and degradation of methylene blue (MB). The as-synthesized products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), surface area analysis, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Furthermore, the effects of the dose of MnO nanomixtures, pH of the solution, initial concentration of MB, and the temperature of MB removal in dye adsorption and degradation experiments was investigated. The degradation mechanism of MB upon treatment with MnO nanomixtures and H2O2 was studied and discussed. The results showed that a maximum adsorption capacity of 154 mg g−1 was obtained for a 60 mg L−1 MB solution at pH 9.0 and 25 °C, and the highest MB degradation ratio reached 99.8% under the following optimum conditions: 50 mL of MB solution (20 mg L−1) at room temperature and pH ≈ 8.0 with 7 mg of C, N-doped MnO and 0.5 mL of H2O2.

Download Full-text

Study on Electrospun-Membrane-Based Filter to Rapidly Remove Reactive Yellow 2 from Wastewater

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.726-731.707 ◽

2013 ◽

Vol 726-731 ◽

pp. 707-711

Author(s):

Wen Peng Zhang ◽

Da Yong Wu ◽

Ya Kun Wang

Keyword(s):

Electron Microscopy ◽

Mesoporous Silica ◽

Adsorption Capacity ◽

Temperature Treatment ◽

High Temperature Treatment ◽

Isotherm Models ◽

Maximum Adsorption Capacity ◽

Electrospun Membrane ◽

Transmission Electron ◽

Prepared Material

Uniform highly ordered mesoporous silica nanofiber membrane was successfully prepared onto copper mesh via coaxial electrospinning combining with the solvent evaporation and extraction induced surfactant assembly process. After a high temperature treatment and amination, it was employed to remove reactive yellow 2 (RY2) in wastewater showing remarkable adsorption capacity. The maximum adsorption capacity can reach up to 371.7 mg/g. The structural properties of synthesized mesoporous silica were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Fourier transform infrared spectrum (FTIR). And the adsorption behavior of prepared material was analyzed through three kinds of isotherm models.

Download Full-text

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

Water Science & Technology ◽

10.2166/wst.2017.405 ◽

2017 ◽

Vol 76 (9) ◽

pp. 2526-2534 ◽

Cited By ~ 6

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.

Download Full-text

Montmorillonite-anchored magnetite nanocomposite for recovery of ammonium from stormwater and its reuse in adsorption of Sc3+

Nanotechnology for Environmental Engineering ◽

10.1007/s41204-021-00151-y ◽

2021 ◽

Vol 6 (3) ◽

Author(s):

Jianzhi Song ◽

Varsha Srivastava ◽

Tomas Kohout ◽

Mika Sillanpää ◽

Tuomo Sainio

Keyword(s):

Electron Microscopy ◽

Adsorption Capacity ◽

Photoelectron Spectroscopy ◽

Selective Adsorption ◽

Maximum Adsorption Capacity ◽

Suitable Model ◽

Transmission Electron ◽

Adsorbent Surface ◽

Langmuir Isotherm Model ◽

Co Precipitation

AbstractThe treatment of stormwater to remove and recover nutrients has received increasing interest. The objective of this study was to develop a novel adsorbent that is easy to handle, has good adsorption capacity, and is economical to use. A novel nanocomposite of montmorillonite (MT)-anchored magnetite (Fe3O4) was synthesised by co-precipitation as an adsorbent for ammonium. The MT/Fe3O4 nanocomposite had pore sizes (3–13 nm) in the range of narrow mesopores. The dispersion of the anchored Fe3O4 was confirmed by transmission electron microscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy (XPS). The nanocomposite exhibited higher affinity towards ammonium than the original MT. The Langmuir isotherm model was found to be the most suitable model to explain the ammonium adsorption behaviour of the nanocomposite. The maximum adsorption capacity for ammonium was 10.48 mg/g. The adsorption mechanism was a combination of ion exchange and electrostatic interaction. In an authentic stormwater sample, the synthesised adsorbent removed 64.2% of ammonium and reduced the amount of heavy metal contaminants including Mn, Ni, Cu and Zn. Furthermore, the ammonium loading on MT/Fe3O4 during adsorption functionalised the adsorbent surface. Additionally, the spent nanocomposite showed potential for rare earth elements (REEs) adsorption as a secondary application, especially for the selective adsorption of Sc3+. The versatile application of montmorillonite-anchored magnetite nanocomposite makes it a promising adsorbent for water treatment. Graphic abstract

Download Full-text

Scanning and Transmission Microscopy of Nematocyst Batteries in Epitheliomuscular Cells of Hydra

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100066097 ◽

1971 ◽

Vol 29 ◽

pp. 410-411 ◽

Cited By ~ 1

Author(s):

Jane A. Westfall ◽

S. Yamataka ◽

Paul D. Enos

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Osmium Tetroxide ◽

External Surface ◽

Three Dimensional ◽

Surface Structures ◽

Transmission Microscopy ◽

Transmission Electron ◽

Freeze Dried ◽

Scanning Electron

Scanning electron microscopy (SEM) provides three dimensional details of external surface structures and supplements ultrastructural information provided by transmission electron microscopy (TEM). Animals composed of watery jellylike tissues such as hydras and other coelenterates have not been considered suitable for SEM studies because of the difficulty in preserving such organisms in a normal state. This study demonstrates 1) the successful use of SEM on such tissue, and 2) the unique arrangement of batteries of nematocysts within large epitheliomuscular cells on tentacles of Hydra littoralis.Whole specimens of Hydra were prepared for SEM (Figs. 1 and 2) by the fix, freeze-dry, coat technique of Small and Màrszalek. The specimens were fixed in osmium tetroxide and mercuric chloride, freeze-dried in vacuo on a prechilled 1 Kg brass block, and coated with gold-palladium. Tissues for TEM (Figs. 3 and 4) were fixed in glutaraldehyde followed by osmium tetroxide. Scanning micrographs were taken on a Cambridge Stereoscan Mark II A microscope at 10 KV and transmission micrographs were taken on an RCA EMU 3G microscope (Fig. 3) or on a Hitachi HU 11B microscope (Fig. 4).

Download Full-text

Simulation of three Dimensional Defect Images in Transmission Electron Microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100092311 ◽

1976 ◽

Vol 34 ◽

pp. 470-471

Author(s):

W. D. Cooper ◽

C. S. Hartley ◽

J. J. Hren

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Three Dimensional ◽

Crystalline Lattice ◽

Continuum Models ◽

Thin Foils ◽

Transmission Electron ◽

Microscope Images ◽

General Computer Program ◽

General Computer

Interpretation of electron microscope images of crystalline lattice defects can be greatly aided by computer simulation of theoretical contrast from continuum models of such defects in thin foils. Several computer programs exist at the present time, but none are sufficiently general to permit their use as an aid in the identification of the range of defect types encountered in electron microscopy. This paper presents progress in the development of a more general computer program for this purpose which eliminates a number of restrictions contained in other programs. In particular, the program permits a variety of foil geometries and defect types to be simulated.The conventional approximation of non-interacting columns is employed for evaluation of the two-beam dynamical scattering equations by a piecewise solution of the Howie-Whelan equations.

Download Full-text

Efficient Adsorption of Methylene Blue by Porous Biochar Derived from Soybean Dreg Using a One-Pot Synthesis Method

Molecules ◽

10.3390/molecules26030661 ◽

2021 ◽

Vol 26 (3) ◽

pp. 661

Author(s):

Zhiwei Ying ◽

Xinwei Chen ◽

He Li ◽

Xinqi Liu ◽

Chi Zhang ◽

...

Keyword(s):

Electron Microscopy ◽

Methylene Blue ◽

Photoelectron Spectroscopy ◽

Synthesis Method ◽

Urban Pollution ◽

Maximum Adsorption Capacity ◽

One Pot ◽

Average Pore ◽

X Ray ◽

Isotherm Equation

Soybean dreg is a by-product of soybean products production, with a large consumption in China. Low utilization value leads to random discarding, which is one of the important sources of urban pollution. In this work, porous biochar was synthesized using a one-pot method and potassium bicarbonate (KHCO3) with low-cost soybean dreg (SD) powder as the carbon precursor to investigating the adsorption of methylene blue (MB). The prepared samples were characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM), elemental analyzer (EA), Brunauer-Emmett-Teller (BET), X-ray diffractometer (XRD), Raman spectroscopy (Raman), Fourier transform infrared spectrometer (FTIR), and X-ray photoelectron spectroscopy (XPS). The obtained SDB-K-3 showed a high specific surface area of 1620 m2 g−1, a large pore volume of 0.7509 cm3 g−1, and an average pore diameter of 1.859 nm. The results indicated that the maximum adsorption capacity of SDB-K-3 to MB could reach 1273.51 mg g−1 at 318 K. The kinetic data were most consistent with the pseudo-second-order model and the adsorption behavior was more suitable for the Langmuir isotherm equation. This study demonstrated that the porous biochar adsorbent can be prepared from soybean dreg by high value utilization, and it could hold significant potential for dye wastewater treatment in the future.

Download Full-text

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

Polymers ◽

10.3390/polym13111712 ◽

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.

Download Full-text

Radiation Induced Formation of Acrylated Palm Oil (APO) Nanoparticles Using Cetyltrimethylammonium Bromide Microemulsion System

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.364.278 ◽

2011 ◽

Vol 364 ◽

pp. 278-282

Author(s):

Rida Tajau ◽

Dahlan Khairul Mohd. Zaman ◽

Mohd Hilmi Mahmood ◽

Wan Md Zin Wan Yunus ◽

Hashim Kamaruddin

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Palm Oil ◽

Chemical Structure ◽

Cetyltrimethylammonium Bromide ◽

Control Process ◽

Microemulsion System ◽

Transmission Electron ◽

Radiation Induced ◽

The Fourier Transform

In this study, we report the preparation of Acrylated Palm Oil (APO) nanoparticles using aqueous Cetyltrimethylammonium bromide (CTAB) microemulsion system. This microemulsion system which contains the dispersed APO nanodroplets was subjected to the gamma irradiation to induce the formation of the crosslinked APO nanoparticles. The dynamic light scattering (DLS), the Fourier Transform Infrared (FTIR) spectrocospy and the Transmission Electron Microscopy (TEM) were used to characterize the size and the chemical structure of the nanoparticle. Sized of the APO nanoor microparticle can be varied depended on the volumes of the modified palm oil and the irradiation doses. Their size is in the range of 73 to 100 nanometer (nm) after irradiation using gamma irradiator. This radiation-induced method provides a free initiator induced and easy to control process as compared to the classical or chemical initiator process.

Download Full-text

Ouricuri (Syagrus coronata) fiber: a novel biosorbent to remove methylene blue from aqueous solutions

Water Science & Technology ◽

10.2166/wst.2016.495 ◽

2016 ◽

Vol 75 (1) ◽

pp. 106-114 ◽

Cited By ~ 19

Author(s):

Lucas Meili ◽

Társila Santos da Silva ◽

Daniely Carlos Henrique ◽

João Inácio Soletti ◽

Sandra Helena Vieira de Carvalho ◽

...

Keyword(s):

Methylene Blue ◽

Experimental Design ◽

Aqueous Solutions ◽

Adsorption Capacity ◽

Adsorption Process ◽

Fiber Diameter ◽

Aqueous Media ◽

Process Efficiency ◽

Maximum Adsorption Capacity ◽

Equilibrium Studies

In this work, the potential of ouricuri (Syagrus coronata) fiber as a novel biosorbent to remove methylene blue (MB) from aqueous solutions was investigated. The fiber was prepared and characterized according to the fundamental features for adsorption. A 23 experimental design was used to evaluate the effects of adsorbent dosage (M), fiber diameter (D) and agitation (A) on the adsorption capacity. In the more adequate conditions, kinetic and equilibrium studies were performed. The experimental design results showed that M = 10 g L−1), D = 0.595 mm and A = 200 rpm were the more adequate conditions for MB adsorption. Based on the kinetic study, it was found that the adsorption process was fast, being the equilibrium was attained at about 5 min, with 90% of color removal. The isotherm was properly represented by the Sips model, and the maximum adsorption capacity was 31.7 mg g−1. In brief, it was demonstrated that ouricuri fiber is an alternative biosorbent to remove MB from aqueous media, taking into account the process efficiency and economic viewpoint.

Download Full-text