Optimization of ultrasonic-assisted copper ion removal from polluted water by a natural clinoptilolite nanostructure through a central composite design

Clay Minerals ◽  
2019 ◽  
Vol 54 (4) ◽  
pp. 339-347 ◽  
Author(s):  
Mohsen Sheydaei ◽  
Ali Balanejad Gasemsoltanlu ◽  
Asadollah Beiraghi

AbstractA natural clinoptilolite nanostructure (CNS) along with ultrasonic irradiation was used to remove Cu2+ ions from polluted water. In the first part of this work, natural clinoptilolite was converted to CNS by ball milling. The natural clinoptilolite and prepared CNS samples were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction, N2 adsorption/desorption and pH at the point of zero charge analyses. The SEM images showed the development of CNS from natural clinoptilolite by ball milling. The N2 adsorption/desorption and FTIR spectroscopy confirmed the greater specific surface area, pore volume and number of surface groups of the CNS compared to the natural clinoptilolite. In addition, the crystalline phase of the CNS was the same as the natural clinoptilolite. In the second part of this work, the ultrasonic-assisted sorption of Cu2+ ions from polluted water by CNS was investigated. These experiments were optimized with response surface methodology based on central composite designs. The effects of initial pH of solution, CNS dosage, sonication time and temperature on Cu2+ ion-removal efficiency were investigated. By using a CNS dosage of 500 mg L−1, an initial pH of 6, a sonication time of 12 min and a sonication temperature of 45°C as optimal conditions, 97% of Cu2+ ions were removed from contaminated water. The initial pH was the most effective variable. Ultrasonic-assisted sorption of Cu2+ was more effective than sorption alone, onto the CNS.

Clay Minerals ◽  
2009 ◽  
Vol 44 (3) ◽  
pp. 405-409 ◽  
Author(s):  
H. Faghihian ◽  
M. Pirouzi

AbstractAdsorption of cis-2-butene and trans-2-butene on clinoptilolite-rich tuff and ion-exchanged forms was investigated. Clinoptilolite samples were characterized by X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, chemical analysis and nitrogen adsorption techniques. Adsorption isotherms for cis and trans 2-butene on purified clinoptilolite (Cp) and modified forms (Na-Cp, K-Cp, Ca-Cp and Mg-Cp) were obtained at pressures up to 2.7 atm. and at 25ºC. The results show that natural clinoptilolite has a considerable potential for separation of the two hydrocarbons. Mg-Cp samples showed maximal uptake of both cis-2-butene and trans-2-butene.


2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Gregory P. Knowles ◽  
Alan L. Chaffee

Aminopropyl-functionalized hexagonal mesoporous silica (HMS) products, as are of interest for CO2capture applications, were separately prepared by mixing aminopropyltrimethoxysilane (APTS) and HMS in toluene via a conventional stirred reactor and via sonication assisted methods, to investigate the potential of sonication to facilitate the preparation of products with higher tether loadings and correspondingly higher CO2sorption capacities. Sonication was expected to improve both the dispersion of the substrate in the solvent and the diffusion of the silane throughout the mesoporous substrate. Structural properties of the products were determined by X-ray diffraction, N2adsorption/desorption (77 K), helium pycnometry, and elemental analysis, and CO2adsorption/desorption properties were determined via thermogravimetric and differential thermal analysis. The tether loadings of the sonication products (up to 1.8 tethers·nm−2) were found to increase with sonication time and in each case were greater than the corresponding product prepared by the conventional approach. It was also found that the concentration of the reagent mixture influenced the extent of functionalization, that the crude products cured effectively under N2flow as under vacuum, and that rinsing the crude products prior to curing was not essential. Sonication products with higher tether loadings were found to exhibit higher CO2sorption capacities as expected.


2020 ◽  
Vol 3 (2) ◽  
pp. 12-23
Author(s):  
Asmaa Kamel Bahgaat ◽  
Helmy El-Sayed Hassan ◽  
Ahmed Abddel Aziz Melegy ◽  
Ahmed Mohamed Abd-El kareem ◽  
Manar Hassan Mohamed

Zeolite Na-Y was prepared from kaolin located in Wadi-Hagul, Suez, Egypt. The synthetic zeolite prepared by the hydrothermal reaction of kaolin was characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM) and cation exchange capacity (CEC). Cadmium ion removal was investigated using the synthetic solution of Cd2+ ions with different concentrations at room temperature (25 °C ± 0.2), initial pH of the solution and contact times. The optimum contact time for removal of Cd2+ ion was 10 min, with 0.1g of synthetic zeolite and pH 7.57. The experimental data were correlated using Langmuir, Freundlich and Harkins-Jura adsorption isotherms. The maximum adsorption capacity Qm obtained from the Langmuir isotherm was 14.006 mg/g for Cd2+ ion. Kinetic studies reveal that synthetic zeolite is more effective as adsorbent for removing cadmium ions


Clay Minerals ◽  
2020 ◽  
Vol 55 (2) ◽  
pp. 132-141
Author(s):  
Ali Boukhemkhem ◽  
Alejandro H. Pizarro ◽  
Carmen B. Molina

ABSTRACTIn this investigation, Maghnia (Ma) and Mostaganem (Ms) bentonite clays, mined from west Algeria, with no prior affinity for anionic dyes, were modified by simple ion exchange with aqueous Fe3+ solutions, followed by calcination at 500°C. The resulting materials, Fe-Ma and Fe-Ms, respectively, were employed as adsorbents for methyl orange. The starting materials and the two adsorbents were characterized by X-ray diffraction, N2 adsorption–desorption isotherms, Brunauer–Emmett–Teller specific surface area and X-ray fluorescence and by determining the point of zero charge. The effects of various variables, such as initial dye concentration, contact time, adsorbent dose, initial pH and adsorption temperature, were studied. The kinetics were well described by the pseudo-second-order model and the mechanism was determined from the intraparticle diffusion model, while corresponding isotherms fitted better to the Freundlich model. Thermodynamic parameters showed that the adsorption process was endothermic, spontaneous and physical in nature, accompanied by an increase of entropy.


2021 ◽  
Vol 11 (7) ◽  
Author(s):  
Sabarish Radoor ◽  
Jasila Karayil ◽  
Aswathy Jayakumar ◽  
Jyotishkumar Parameswaranpillai ◽  
Suchart Siengchin

AbstractIn the present work, we have developed a mesoporous silicalite-1 using CMC as a template for the removal of MB from aqueous solution. The synthesized silicalite-1 were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), Energy-dispersive X-ray spectroscopy (EDAX) and N2 adsorption–desorption isotherm (BET). XRD and FT-IR analysis confirmed the formation of crystallinity and development of MFI structure in the mesoporous silicalite-1. The adsorption of MB dye on mesoporous silicalite-1 was conducted by batch adsorption method. The effect of various parameters such as adsorbent dosage, initial dye concentration, contact time and temperature on the dye uptake ability of silicalite-1 was investigated. The operating parameters for the maximum adsorption are silicalite-1 dosage (0.1 wt%), contact time (240 min), initial dye concentration (10 ppm) and temperature (30 ℃). The MB dye removal onto mesoporous silicalite-1 followed pseudo-second-order kinetic and Freundlich isotherm. The silicalite-1 exhibits 86% removal efficiency even after six adsorption–desorption cycle. Therefore, the developed mesoporous silicalite-1 is an effective eco-friendly adsorbent for MB dye removal from aqueous environment.


Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1086
Author(s):  
Asma Abdulkareem ◽  
Anton Popelka ◽  
Patrik Sobolčiak ◽  
Aisha Tanvir ◽  
Mabrouk Ouederni ◽  
...  

This paper addresses the preparation and characterization of efficient adsorbents for tertiary treatment (oil content below 100 ppm) of oil/water emulsions. Powdered low-density polyethylene (LDPE) was modified by radio-frequency plasma discharge and then used as a medium for the treatment of emulsified diesel oil/water mixtures in the concentration range from 75 ppm to 200 ppm. Plasma treatment significantly increased the wettability of the LDPE powder, which resulted in enhanced sorption capability of the oil component from emulsions in comparison to untreated powder. Emulsions formed from distilled water and commercial diesel oil (DO) with concentrations below 200 ppm were used as a model of oily polluted water. The emulsions were prepared using ultrasonication without surfactant. The droplet size was directly proportional to sonication time and ranged from 135 nm to 185 nm. A sonication time of 20 min was found to be sufficient to prepare stable emulsions with an average droplet size of approximately 150 nm. The sorption tests were realized in a batch system. The effect of contact time and initial oil concentrations were studied under standard atmospheric conditions at a stirring speed of 340 rpm with an adsorbent particle size of 500 microns. The efficiency of the plasma-treated LDPE powder in oil removal was found to be dependent on the initial oil concentration. It decreased from 96.7% to 79.5% as the initial oil concentration increased from 75 ppm to 200 ppm. The amount of adsorbed oil increased with increasing contact time. The fastest adsorption was observed during the first 30 min of treatment. The adsorption kinetics for emulsified oils onto sorbent followed a pseudo-second-order kinetic model.


2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Denise S. Cordeiro ◽  
Fernando L. Cassio ◽  
Larissa Ciccotti ◽  
Thiago L. R. Hewer ◽  
Paola Corio ◽  
...  

AbstractPraseodymium doped TiO2 nanoparticles were successfully prepared by the sol–gel method and characterized by X-ray powder diffraction, N2 adsorption–desorption isotherm, and UV–vis spectroscopy. The effects of the dopant on the crystallite size, specific surface area, average pore diameter, pore volume, and bandgap energy were investigated. The photocatalytic activity of the catalysts was evaluated by bisphenol A degradation and mineralization, which is a representative endocrine disruptor. Furthermore, under visible light irradiation the Pr-modified TiO2 photocatalysts exhibited higher photocatalytic efficiency than unmodified TiO2. When praseodymium was loaded (1.0–5.0%) onto the surface of TiO2, the rates of degradation and mineralization were increased 3–5 times.


2020 ◽  
Vol 13 (1) ◽  
pp. 126
Author(s):  
Guozhen Zhang ◽  
Xingxing Huang ◽  
Jinye Ma ◽  
Fuping Wu ◽  
Tianhong Zhou

Electrochemical oxidation technology is an effective technique to treat high-concentration wastewater, which can directly oxidize refractory pollutants into simple inorganic compounds such as H2O and CO2. In this work, two-dimensionally stable anodes, Ti/RuO2-IrO2-SnO2, have been developed in order to degrade organic pollutants from pharmaceutical wastewater. Characterization by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) showed that the oxide coating was successfully fabricated on the Ti plate surface. Electrocatalytic oxidation conditions of high concentration pharmaceutical wastewater was discussed and optimized, and the best results showed that the COD removal rate was 95.92% with the energy consumption was 58.09 kW·h/kgCOD under the electrode distance of 3 cm, current density of 8 mA/cm2, initial pH of 2, and air flow of 18 L/min.


Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1519
Author(s):  
Jong Gyeong Kim ◽  
Sunghoon Han ◽  
Chanho Pak

The price and scarcity of platinum has driven up the demand for non-precious metal catalysts such as Fe-N-C. In this study, the effects of phosphoric acid (PA) activation and phosphorus doping were investigated using Fe-N-C catalysts prepared using SBA-15 as a sacrificial template. The physical and structural changes caused by the addition of PA were analyzed by nitrogen adsorption/desorption and X-ray diffraction. Analysis of the electronic states of Fe, N, and P were conducted by X-ray photoelectron spectroscopy. The amount and size of micropores varied depending on the PA content, with changes in pore structure observed using 0.066 g of PA. The electronic states of Fe and N did not change significantly after treatment with PA, and P was mainly found in states bonded to oxygen or carbon. When 0.135 g of PA was introduced per 1 g of silica, a catalytic activity which was increased slightly by 10 mV at −3 mA/cm2 was observed. A change in Fe-N-C stability was also observed through the introduction of PA.


Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 529
Author(s):  
Hongjuan Zheng ◽  
Kongjun Zhu ◽  
Ayumu Onda ◽  
Kazumichi Yanagisawa

Eu(OH)3 with various shape-controlled morphologies and size, such as plate, rod, tube, prism and nanoparticles was successfully synthesized through simple hydrothermal reactions. The products were characterized by XRD (X-Ray Powder Diffraction), FE-SEM (Field Emission- Scanning Electron Microscopy) and TG (Thermogravimetry). The influence of the initial pH value of the starting solution and reaction temperature on the crystalline phase and morphology of the hydrothermal products was investigated. A possible formation process to control morphologies and size of europium products by changing the hydrothermal temperature and initial pH value of the starting solution was proposed.


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