scholarly journals Layered Rare-Earth Hydroxide Unilameller Nanosheets: Synthesis, Characterization, and Adsorption

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Solomon Omwoma ◽  
Adongo Stephen Odongo ◽  
Zablon Otieno ◽  
Silas Lagat ◽  
Joseph Owuor Lalah
Keyword(s):  
Rare Earth ◽  
High Efficiency ◽  
Colloidal Solution ◽  
Aqueous Media ◽  
Significant Loss ◽  
Adsorption Efficiency ◽  
Material Synthesis ◽  
Langmuir Adsorption ◽  
Sorbent Material ◽  
Adsorption Curve

Unilameller nanosheets with a lateral dimension of one nanometer have been isolated from a colloidal solution of europium-containing layered rare-earth hydroxide (LRH) material by the flocculation method. The nanosheets were achieved by changing pH of the colloidal solution from 6.7 to 11.5. The resultant flocculated nanosheets show high efficiency in sorption of fluoride anions from aqueous media (40 mmol/g), providing a potentially useful sorbent material for water purification technology. The sorbent material is demonstrated to be reusable for at least ten times without a significant loss of adsorption efficiency. And the results fit the Langmuir adsorption curve, indicating the chemisorption nature of the nanosheets. Most importantly, the isolated nanosheets are expected to widen the applicability and flexibility in material synthesis using two-dimensional nanomaterials.

scholarly journals Cellulose with bidentate chelating functionality: An adsorbent for metal ions from wastewater

BioResources ◽  
2019 ◽  
Vol 14 (3) ◽  
pp. 6247-6266
Author(s):  
Abdalhadi Deghles ◽  
Othman Hamed ◽  
Mai Azar ◽  
Bahia Abu Lail ◽  
Khalil Azzaoui ◽  
...  
Keyword(s):  
Metal Ions ◽  
High Efficiency ◽  
Adsorption Process ◽  
Sewage Sample ◽  
Cellulose Powder ◽  
Adsorption Efficiency ◽  
Adsorption Parameters ◽  
Langmuir Adsorption ◽  
Coordination Sites ◽  
Olive Industry

A cellulose derivative with multiple coordination sites for metals composed of cellulose powder and 1,2-pheneylnediamine was synthesized and evaluated as an adsorbent for metal ions from wastewater. The cellulose powder was generated from the solid waste of the olive industry. The adsorption efficiency of the cellulose amine polymer toward Fe(III) and Pb(II) was investigated as a function of adsorbent dose, temperature, pH, and time. The adsorption parameters that lead to excellent adsorption efficiency were determined. In addition, the polymer showed an excellent extraction efficiency toward approximately 20 metal ions present in a sewage sample. The cellulose amine derivative had several coordination sites that included amine, hydroxyl, and aromatic groups. The diversity and frequency of the coordination sites explained the high efficiency of the polymer for metal ions. The thermodynamic analysis results supported the spontaneous adsorption efficiency of the polymer at room temperature. The adsorption process fit well with the Langmuir adsorption isotherm model.

scholarly journals Fe3O4@SiO2-L-Cu(II): An efficient and easily recoverable catalyst for reducing/degrading environmental pollutants in aqueous medium

2021 ◽  
Author(s):  
Jaber Dadashi ◽  
Mohammad Khaleghian ◽  
Babak Mir Tamizdoust
Keyword(s):  
High Efficiency ◽  
Fourier Transforms ◽  
Organic Dyes ◽  
Aqueous Media ◽  
Environmental Pollutants ◽  
Catalytic Efficiency ◽  
Significant Loss ◽  
Homogeneous Catalyst ◽  
X Ray ◽  
Recoverable Catalyst

Abstract In the present study, a magnetically recoverable catalyst is synthesized through immobilizing copper (II) over the Fe3O4@SiO2 nanoparticles (NPs) surface [Fe3O4@SiO2-L-Cu (II)] (L = pyridine-4-carbaldehyde thiosemicarbazide). Accordingly, synthesized catalysts were determined and characterized by energy dispersive X-ray spectrometry (EDS), Fourier transforms infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), vibrating sample magnetometer (VSM), and thermogravimetric-differential thermal analysis (TG-DTA) procedures. Using [Fe3O4@SiO2-L-Cu (II)], 4-Nitrophenol (4-NP), Cr(VI), and organic dyes, e.g., Methylene blue (MB) and Congo Red (CR) were reduced in aqueous media. As shown by results of Catalytic performance investigations, [Fe3O4@SiO2-L-Cu (II)] performance was outstanding concerning reduction reactions in mild conditions. Remarkable attributes of this method are high efficiency, removal of a homogeneous catalyst, easy recovery from the reaction mix, and uncomplicated route. The amount of activity in this catalytic system was almost constant after several stages of recovery and reuse. The results show that the catalyst was efficient and easily recoverable in the successive run without a significant loss of catalytic efficiency.

scholarly journals Study of the adsorption and photocatalytic properties of copper oxide with different morphologies in removal of Cr(III) ion from aqueous media

2019 ◽  
Vol 80 (5) ◽  
pp. 827-835
Author(s):  
Jamileh Kondabey ◽  
Mohammad Hossein Ghorbani ◽  
Hossien Aghaie ◽  
Reza Fazaeli
Keyword(s):  
Removal Efficiency ◽  
Contact Time ◽  
Industrial Wastewater ◽  
Photocatalytic Oxidation ◽  
High Efficiency ◽  
Aqueous Media ◽  
Adsorption Efficiency ◽  
Adsorbent Dosage ◽  
Toxic Pollutant ◽  
Photocatalytic Processes

Abstract Chromium Cr(III) is considered as a toxic pollutant in industrial wastewater. Photocatalytic processes can be used as an efficient method for the treatment of heavy metal wastewaters. This study was conducted to synthesize copper (II) oxide (CuO) with dendrite, leaf and feather morphologies. Synthesized CuO with dendrite and leaf morphologies were characterized by XRD, SEM, and BET/BJH and CuO with feather morphology by XRD, SEM, BET/BJH, FTIR, TEM and DRS techniques. Parameters such as morphology CuO, the contact time (h), and adsorbent dosage (g) in adsorption of Cr(III) and morphology CuO, pH and initial concentration of Cr(III) in the photocatalytic oxidation were investigated. The results demonstrate that CuO feather at 24 h contact time with 0.1 g adsorbent with an adsorption efficiency of 57.24% has the highest efficiency compared to CuO of dendrite and leaf. Oxidation results demonstrate that CuO feather at 2 h with 0.1 g adsorbent dosage and pH = 7 had 89.14% removal efficiency. Also, oxidation results demonstrate that CuO feather at 2 h with 0.1 g adsorbent dosage and pH = 8 had 99.99% removal efficiency, which indicates the high efficiency of the feather.

scholarly journals Adsorption of Rare Earth Elements from Aqueous Solutions Using Geopolymers

Proceedings ◽  
2018 ◽  
Vol 2 (10) ◽  
pp. 567 ◽  
Author(s):  
Željka Fiket ◽  
Ana Galović ◽  
Gordana Medunić ◽  
Martina Furdek Turk ◽  
Maja Ivanić ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Aqueous Solutions ◽  
High Efficiency ◽  
Low Cost ◽  
Coal Ash ◽  
Industrial Sector ◽  
Efficient Removal ◽  
Model Solutions ◽  
Technology Applications

Rare earth elements, i.e., lanthanides, are important components of many recently developed technology applications. However, their increasing use in the industrial sector, medicine, and agriculture over the last few decades has provided them with the title of “new pollutants”. Different methods are now applied for the removal of various pollutants from wastewaters, whereby the emphasis is placed on adsorption due to its simplicity, high efficiency, and low cost. In the present study, geopolymers prepared from coal ash were examined regarding their capacity for the adsorption of lanthanides from model solutions. The obtained results indicate the efficient removal of lanthanides by prepared geopolymers, depicting them as effective adsorbents for this group of elements.

Adsorption of the harmful hormone ethinyl estradiol inside hydrophobic cavities of CTA+ intercalated montmorillonite

2016 ◽  
Vol 74 (3) ◽  
pp. 663-671 ◽  
Author(s):  
A. E. Burgos ◽  
Tatiana A. Ribeiro-Santos ◽  
Rochel M. Lago
Keyword(s):  
Cetyltrimethylammonium Bromide ◽  
High Efficiency ◽  
Interlayer Space ◽  
Ethinyl Estradiol ◽  
Significant Loss ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hydrophobic Cavity ◽  
Adsorption Capacities ◽  
Derivative Thermogravimetry

Hydrophobic cavities produced by cetyltrimethylammonium cation (CTA+) exchanged and trapped in the interlayer space of montmorillonite were used to remove the harmful hormone contaminant ethinyl estradiol (EE2) from water. X-ray diffraction, thermogravimetry/derivative thermogravimetry, elemental analysis (carbon, hydrogen, nitrogen), Fourier transform infrared, scanning electron microscopy/energy dispersive spectroscopy, Brunauer–Emmett–Teller and contact angle analyses showed that the intercalation of 9, 16 and 34 wt% CTA+ in the montmorillonite resulted in the d001 expansion from 1.37 to 1.58, 2.09 and 2.18 nm, respectively. EE2 adsorption experiments showed that the original clay montmorillonite does not remove EE2 from water whereas the intercalated composites showed high efficiency with adsorption capacities of 4.3, 8.8 and 7.3 mg g−1 for M9CTA+, M16CTA+ and M34CTA+, respectively. Moreover, experiments with montmorillonite simply impregnated with cetyltrimethylammonium bromide showed that the intercalation of CTA+ to form the hydrophobic cavity is very important for the adsorption properties. Simple solvent extraction can be used to remove the adsorbed EE2 without significant loss of CTA+, which allows the recovery and reuse of the adsorbent for at least five times.

scholarly journals Bis-NHC–Ag/Pd(OAc)2 Catalytic System Catalyzed Transfer Hydrogenation Reaction

Catalysts ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 8
Author(s):  
Hui-Ju Chen ◽  
Chien-Cheng Chiu ◽  
Tsui Wang ◽  
Dong-Sheng Lee ◽  
Ta-Jung Lu
Keyword(s):  
Functional Groups ◽  
Catalytic System ◽  
High Efficiency ◽  
Aqueous Media ◽  
Hydrogenation Reaction ◽  
Transfer Hydrogenation ◽  
Terminal Alkynes ◽  
Wide Range ◽  
Transfer Hydrogenation Reaction

The bis-NHC–Ag/Pd(OAc)2 catalytic system (NHC = N-heterocyclic carbene), a combination of bis-NHC–Ag complex and Pd(OAc)2, was found to be a smart catalyst in the Pd-catalyzed transfer hydrogenation of various functionalized arenes and internal/terminal alkynes. The catalytic system demonstrated high efficiency for the reduction of a wide range of various functional groups such as carbonyls, alkynes, olefins, and nitro groups in good to excellent yields and high chemoselectivity for the reduction of functional groups. In addition, the protocol was successfully exploited to stereoselectivity for the transformation of alkynes to alkenes in aqueous media under air. This methodology successfully provided an alternative useful protocol for reducing various functional groups and a simple operational protocol for transfer hydrogenation.

scholarly journals Recent Design Optimization Methods for Energy-Efficient Electric Motors and Derived Requirements for a New Improved Method—Part 1

Proceedings ◽  
2018 ◽  
Vol 2 (22) ◽  
pp. 1400
Author(s):  
Johannes Schmelcher ◽  
Max Kleine Büning ◽  
Kai Kreisköther ◽  
Dieter Gerling ◽  
Achim Kampker
Keyword(s):  
Rare Earth ◽  
Design Optimization ◽  
Energy Efficient ◽  
Degrees Of Freedom ◽  
High Efficiency ◽  
Optimization Problems ◽  
Computing Time ◽  
Optimization Methods ◽  
Electric Motors ◽  
Electric Cars

Energy-efficient electric motors are gathering an increased attention since they are used in electric cars or to reduce operational costs, for instance. Due to their high efficiency, permanent-magnet synchronous motors are used progressively more. However, the need to use rare-earth magnets for such high-efficiency motors is problematic not only in regard to the cost but also in socio-political and environmental aspects. Therefore, an increasing effort has to be put in finding the best design possible. The goals to achieve are, among others, to reduce the amount of rare-earth magnet material but also to increase the efficiency. In the first part of this multipart paper, characteristics of optimization problems in engineering and general methods to solve them are presented. In part two, different approaches to the design optimization problem of electric motors are highlighted. The last part will evaluate the different categories of optimization methods with respect to the criteria: degrees of freedom, computing time and the required user experience. As will be seen, there is a conflict of objectives regarding the criteria mentioned above. Requirements, which a new optimization method has to fulfil in order to solve the conflict of objectives will be presented in this last paper.

Sign in / Sign up

Export Citation Format

Share Document