scholarly journals Crown-Ether-Modified SBA-15 for the Adsorption of Cr(VI) and Zn(II) from Water

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5060
Author(s):  
Jong-Man Yoo ◽  
Sung Soo Park ◽  
Yong-Zhu Yan ◽  
Chang-Sik Ha

Recently, the release of some metal ions to the environment has been observed to cause serious damages to human health and the environment. Herein, a chromium(VI)- and zinc(II)-selective adsorbent (CB18crown6/SBA-15) was successfully fabricated through the covalent attachment of 4′-carboxybenzo-18-crown-6 (CB18crown6) as a ligand on mesoporous silica support (SBA-15). The CB18crown6/SBA-15 adsorbent was characterized by Fourier-transform infrared (FTIR) spectrometry, X-ray diffraction (XRD), N2 adsorption–desorption, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). To evaluate its ability to selectively capture Cr(VI) and Zn(II), adsorption experiments were conducted. The influences of pH, initial concentration of metal ions, and coexisting metal ions on the adsorption process were examined. The CB18crown6/SBA-15 selectively adsorbed Cr(VI) at pH 2 and Zn(II) at pH 5, respectively, from the mixed aqueous solutions of chromium, zinc, lithium, cadmium, cobalt, strontium, and cesium ions. The data for the adsorption of Cr(VI) onto the CB18crown6/SBA-15 were well explained by the Langmuir adsorption isotherm. In addition, the recycling and reuse of CB18crown6/SBA-15 was successfully achieved, and 71 and 76% reuse efficiency of Cr(VI) and Zn(II), respectively, was obtained after five cycles. This study suggests that the use of the CB18crown6/SBA-15 can be a feasible approach for the selective remediation of Cr(VI) and Zn(II) contamination.

2011 ◽  
Vol 236-238 ◽  
pp. 1873-1876 ◽  
Author(s):  
Jun Jie Tao ◽  
Yun Qiang Xu ◽  
Guo Wei Zhou ◽  
Cui Cui Wu ◽  
Hong Bin Song ◽  
...  

Ordered mesoporous SBA-15 was synthesized through hydrothermal process under acidic condition. The material was characterized by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), small-angle X-ray diffraction (SAXRD), and N2 adsorption-desorption. The results indicated that SBA-15 has 2-dimensional hexagonal p6mm mesoscopic structure and well-ordered parallel mesochannel. The as-obtained mesoporous silica was used for controlled release of water-insolube drug emodin. The loading capacity could achieve 6.64 mg/g, and the release profiles that studied in phosphate buffered saline (PBS, pH = 7.4) showed that released amount of emodin was 95.8 % after 48 h.


NANO ◽  
2013 ◽  
Vol 08 (05) ◽  
pp. 1350050
Author(s):  
MIN GUAN ◽  
HAI-PENG BI ◽  
ZUYUAN WANG ◽  
SHAOHUA BU ◽  
LING HUANG ◽  
...  

Mesoporous silicas SBA-15 are modified with β-Cyclodextrins (β-CD) by simple grafting method. β-CD functionalized SBA-15 was characterized by Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), nitrogen adsorption–desorption measurements, thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). Furthermore, the applicability of it is investigated through studying the adsorption properties of clenbuterol. It showed better adsorption capacities of clenbuterol than pure SBA-15. β-CD functionalized SBA-15 material has the potential applications in the treatment of clenbuterol contamination in food and environment science.


2021 ◽  
Vol 11 (1) ◽  
pp. xx-xx
Author(s):  
Nga Phan To ◽  
Lien Nguyen Hong ◽  
Tuyen Le Van ◽  
Nhan Phan Chi ◽  
Huyen Phan Thanh

Porous LaFeO3 were synthesised by nanocasting method using mesoporous silica (SBA-15) as a hard template and used as a visible-light-driven photocatalyst. The as-synthesised LaFeO3 photocatalyst were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray Diffraction (XRD), N2 adsorption-desorption, and Ultraviolet–Visible Diffuse Reflectance Spectroscopy (UV-vis DRS). The photo-Fenton catalytic activities of porous LaFeO3 were investigated for the degradation of oily-containing wastewater. The results showed that porous LaFeO3 had better photo-Fenton catalytic activity under visilbe light irradiation than pure LaFeO3. The remarkable improvement photo-Fenton catalytic activity of porous LaFeO3 material could be attributed to the synergistic effect of adsorption and visible light photo-Fenton processes thanks to its porous structure.


2016 ◽  
Vol 2016 ◽  
pp. 1-5 ◽  
Author(s):  
Jinghua Liu ◽  
Yinghua Niu ◽  
Xiong He ◽  
Jingyao Qi ◽  
Xin Li

TiO2-graphene (TiO2-RGO) nanocomposites were preparedviaa simple chemical method by using graphene oxide (GO) and TiO2nanoparticles as starting materials. The morphologies and structural properties of the as-prepared composites were characterized by X-ray diffraction, Raman spectroscopy, N2adsorption-desorption measurements, and transmission electron microscopy. TiO2-RGO nanocomposites exhibited great photocatalytic activity toward reduction of CO2into CH4(2.10 μmol g−1 h−1) and CH3OH (2.20 μmol g−1 h−1), which is attributed to the synergistic effect between TiO2and graphene.


2013 ◽  
Vol 742 ◽  
pp. 448-451
Author(s):  
Ming Feng Wang ◽  
Tou Gen Liao ◽  
Bao Kun Zhu ◽  
Yao Wang ◽  
Yan Qing Duan ◽  
...  

Mesoporous TiO2 with anatase crystalline structure (MTiO2) has been synthesized by using Lac Red as template. The synthesized mesoporous titania samples were characterized by a combination of various physicochemical techniques, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), N2 adsorption/desorption. It was found that without any external doping MTiO2 exhibited significant high adsorption abilities for adsorbing the gaseous acetaldehyde by the adsorption ratio of 39.15%.


2013 ◽  
Vol 341-342 ◽  
pp. 13-17
Author(s):  
Xiao Yun Zhang ◽  
Hong Yan Qin ◽  
Xiu Xin Zheng ◽  
Shi Hu Yu ◽  
Wei Wu

CO2solid adsorbent was prepared through impregnating acrylonitrile (AN) modified monoethanolamine (MEA) into structurally disordered mesoporous silica (M) pore channel. Its structure was characterized by X-ray diffraction characterization (XRD), N2adsorption-desorption tests (BET), Transmission electron microscopy (TEM) and Fourier transform infrared (FT-IR). The capacity of CO2adsorption and desorption were measured and evaluated by comparison with MEA-impregnated material. The results showed that the capacity of M-MN-50 reached up to 125.8 mg·g-1and could desorb completely at the temperature of 40 °C by vacuum with 2.6 KPa. The hybrid material exhibited satisfactory performance during 10 turnovers.


2021 ◽  
Vol 19 (4) ◽  
pp. 283-294
Author(s):  
Basma A.A. Balboul ◽  
A.K. Nohman ◽  
Randa F. Abd El-baki ◽  
Moutera S. Elshemery

Holmia supported γ-alumina nanocatalyst was prepared by impregnation of γ-alumina with aqueous solution of holmium acetate hydrate Ho(CH3COO)3.3.5 H2O. The physicochemical characteristics of the nanocatalyst calcined at 600°C were established by different techniques, using surface adsorption–desorption of N2 (SBET), thermogravimetric analysis (TGA), X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and UV–vis diffuse reflectance spectroscopy (DRS). The recorded optical reflectance of the sample showed that the new self-assembled nanocatalyst is excellent as host material for advanced optical applications. Moreover, the catalyst showed enhanced catalytic activity toward Isopropyl alcohol decomposition.


Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2617
Author(s):  
Inas A. Ahmed ◽  
Hala S. Hussein ◽  
Ahmed H. Ragab ◽  
Najla AlMasoud ◽  
Ayman A. Ghfar

In the present investigation, green nano-zerovalent copper (GnZVCu), activated carbon (AC), chitosan (CS) and alginate (ALG) nanocomposites were produced and used for the elimination of chromium (VI) from a polluted solution. The nanocomposites GnZVCu/AC-CS-alginate and AC-CS-alginate were prepared. Analysis and characterization were performed by the following techniques: X-ray diffraction, energy dispersive X-ray spectroscopy, scanning electron microscopy, transmission electron microscopy and Fourier transform infrared spectroscopy. The SEM analysis revealed that the nanocomposites are extremely mesoporous, which leads to the greatest adsorption of Cr+6 (i.e., 97.5% and 95%) for GnZVCu/AC-CS-alginate and AC-CS-alginate, respectively. The adsorption efficiency was enhanced by coupling GnZVCu with AC-CS-alginate with a contact time of 40 min. The maximum elimination of Cr+6 with the two nanocomposites was achieved at pH 2. The isotherm model, Freundlich adsorption isotherm and kinetics model and P.S.O.R kinetic models were discovered to be better suited to describe the exclusion of Cr+6 by the nanocomposites. The results suggested that the synthesized nanocomposites are promising for the segregation of Cr+6 from polluted solutions, specially the GnZVCu/AC-CS-alginate nanocomposite.


2020 ◽  
Vol 20 (3) ◽  
pp. 1670-1677 ◽  
Author(s):  
Tingshun Jiang ◽  
Guofang Gao ◽  
Cheng Yang ◽  
YuLin Mao ◽  
Minglan Fang ◽  
...  

A series of Ag-Co-MCM-41 with different metal loadings have been synthesized through the hydrothermal method. All the prepared catalysts were characterized by N2 adsorption–desorption, X-ray diffraction analysis, transmission electron microscopy. The results revealed that the structure of MCM-41 was well preserved and Ag and Co have been introduced successfully into the mesoporous channels of MCM-41. The liquid-phase catalytic oxidation of styrene on these catalysts was investigated using H2O2 as an oxidizing agent and acetone as a solvent in thermostatic water bath. The influence of metal loading, the catalyst dose, temperature, time and styrene/oxidant molar ratio on the conversion of styrene and yield and selectivity of benzaldehyde was investigated. Also, the reusability of the catalysts was evaluated.


Nanomaterials ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 586 ◽  
Author(s):  
Ayman H. Kamel ◽  
Amr A. Hassan ◽  
Abd El-Galil E. Amr ◽  
Hadeel H. El-Shalakany ◽  
Mohamed A. Al-Omar

In this research, CuFe2O4 nanoparticles were synthesized by co-precipitation methods and modified by coating with thiophene for removal of Hg(II) ions from aqueous solution. CuFe2O4 nanoparticles, with and without thiophene, were characterized by x-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), energy dispersive x-ray (EDX), high-resolution transmission electron microscopy (HRTEM) and Brunauer–Emmett–Teller (BET). Contact time, adsorbent dose, solution pH, adsorption kinetics, adsorption isotherm and recyclability were studied. The maximum adsorption capacity towards Hg2+ ions was 7.53 and 208.77 mg/g for CuFe2O4 and CuFe2O4@Polythiophene composite, respectively. Modification of CuFe2O4 nanoparticles with thiophene revealed an enhanced adsorption towards Hg2+ removal more than CuFe2O4 nanoparticles. The promising adsorption performance of Hg2+ ions by CuFe2O4@Polythiophene composite generates from soft acid–soft base strong interaction between sulfur group of thiophene and Hg(II) ions. Furthermore, CuFe2O4@Polythiophene composite has both high stability and reusability due to its removal efficiency, has no significant decrease after five adsorption–desorption cycles and can be easily removed from aqueous solution by external magnetic field after adsorption experiments took place. Therefore, CuFe2O4@Polythiophene composite is applicable for removal Hg(II) ions from aqueous solution and may be suitable for removal other heavy metals.


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