scholarly journals Defluoridation of water by Ce-Ti hybrid oxide nanoparticles

2021 ◽  
Vol 947 (1) ◽  
pp. 012026
Author(s):  
Trung Dang-Bao ◽  
Hoa-Hung Lam ◽  
Thi-Hoai-Linh Dang

Abstract In the present work, Ce-Ti and Ce-Ti/Fe3O4 hybrid oxides were prepared by co-precipitation method and then characterized by X-ray diffraction (XRD), inductively coupled plasma atomic emission spectroscopy (ICP-AES) and scanning electron microscope (SEM) techniques. The nano-adsorbents were applied to remove fluoride (with the concentration range of 10–30 mg L−1) from aqueous solution, reaching the adsorption equilibrium within 30–60 minutes. Practically, the fluoride removal onto both nanomaterials was efficient at the neutral pH (pH 5–7) and obeyed the Langmuir adsorption isotherm with the maximum adsorption capacities of 22.78 mg g–1 (Ce-Ti) and 20.28 mg g–1 (Ce-Ti/Fe3O4) at room temperature.

2011 ◽  
Vol 284-286 ◽  
pp. 806-810
Author(s):  
Jun Wan ◽  
Jing Zhao ◽  
Ming Qiao Zhu ◽  
Huan Dai ◽  
Lei Wang

Au/Co3O4catalysts were prepared by a co-precipitation method and characterized by inductively coupled plasma-atomic emission spectrometry (ICP-AES), transmission electron microscope (TEM) and X-ray diffraction (XRD). The selective oxidation of cyclohexane to cyclohexanone and cyclohexanol was investigated over Au/Co3O4catalysts using molecular oxygen as oxidant. These catalysts showed higher activities as compared to the pure Co3O4under the same reaction conditions.


2011 ◽  
Vol 194-196 ◽  
pp. 878-881
Author(s):  
Hui Juan Ren ◽  
Zhen Feng Cui ◽  
De Hui Sun ◽  
Guang Yan Hong

The rare earth complex terbium (III)-pyromellitic acid (H4L)-1,10-phenanthroline (phen) nanorod was synthesized in the polyvinylpyrrolidone (PVP) matrix by a co-precipitation method. The chemical composition of the as-synthesized sample was speculated to be PVP/Tb4L3(phen)0.75∙7H2O by elemental analysis, inductively coupled plasma-atomic emission spectroscopy (ICP-AES), and Fourier transform infrared spectroscopy (FTIR). The transmission electron microscopy (TEM) result exhibited that the as-synthesized sample was nanorods with diameters of ca. 150 nm. The X-ray diffraction pattern (XRD) of the sample showed that it was a crystalline complex. The thermogravimetric curve (TGA) analysis exhibited that the sample is stable below 450 °C. UV–Vis diffuse reflectance spectra exhibited that there is a broad and strong absorption band in the range of 280-350 nm. The photoluminescence analyses (PLA) indicated that the as-synthesized sample emitted the characteristic green fluorescence of Tb (III) ions under ultraviolet light excitation.


2019 ◽  
Vol 20 (1) ◽  
pp. 175
Author(s):  
Zobair El Afia ◽  
Mohamed Youssef Messous ◽  
Mohamed Cherkaoui ◽  
Mounia Tahri

The synthesis of TiO2 co-doped by (Ce, Yb) rare earth couple has been realized. This couple of rare earth can convert a high-energy photon to two low energy photons to enhance the energy efficiency of silicon solar cells. The undoped, 2% Ce doped- and (2% Ce, 4% Yb) Codoped- Titanium oxide were prepared by the co-precipitation method. The Infrared spectroscopy FTIR-ATR analysis indicates a continuous visible absorption in the 750–400 cm–1 region, confirming the formation of a titanium-oxygen bond. The X-Ray Diffraction characterization showed the dominance of the rutile crystalline phase with the presence of anatase one and the calculated crystallite size is between 7 to 13 nm. The X-Ray Fluorescence confirms the insertion of the dopants while the Inductively Coupled Plasma Mass Spectrometry ICP-MS showed the ratio 2 between Ce and Yb concentration. The thermogravimetric analysis indicated that Ce/Yb doped titanium was thermally stable. The absorption in the UV-visible (200 and 1000 nm) has been improved proportionally with the dopants.


2011 ◽  
Vol 239-242 ◽  
pp. 2488-2491
Author(s):  
Hui Juan Ren ◽  
De Hui Sun ◽  
Zhen Feng Cui ◽  
Guang Yan Hong

The europium(III)-benzoic acid(HL)-1,10-phenanthroline(phen) complex was synthesized in the ethanol-H2O system by a precipitation method. The morphology of the minicrystal complex with diameters of ca. 1.0 µm is characterized by scanning electron microscopy (SEM). Elemental analysis and inductively coupled plasma-atomic emission spectroscopy (ICP-AES) are used to determine the chemical composition of the complex. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction analysis (XRD) are used to examine the structure of the complex. The results show that the complex is a new kind of crystalline complex and the composition of the complex is speculated to be EuL3(phen). The thermogravimetric curve (TGA) analysis indicates that the complex is stable below 232 °C in air. The photoluminescence analyses (PLA) exhibit that the complex emits the characteristic red fluorescence of Eu (III) ions at 613nm under ultraviolet light excitation.


2011 ◽  
Vol 121-126 ◽  
pp. 1500-1503
Author(s):  
Hui Juan Ren ◽  
Hua Yang ◽  
De Hui Sun ◽  
Zhen Feng Cui ◽  
Guang Yan Hong

Rare earth europium (Eu(III))-pyromellitic acid (H4L)-1,10-phenanthroline (phen) ternary luminescent complex has been synthesized in polyvinylpyrrolidone (PVP) matrix by precipitation method. The chemical constitution of the complex has been demonstrated as PVP/EuL4/3L(phen)•2H2O by a combination of elemental analysis, inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and Fourier-transform infrared spectroscopy (FT-IR). X-ray diffraction analysis (XRD) has shown that the complex is a new kind of crystal whose structure is totally different from two ligands. The morphology of the complex has been investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results have shown that the complex has a rodlike crystal structure and the diameter of the rod is about 400 nm. Thermogravimetric analysis (TG) has indicated that the luminescent complex is thermally stable below 300 °C. Photoluminescence spectra (PL) have revealed that the complex can emit Eu3+ characteristic red fluorescence under ultraviolet excitation.


2017 ◽  
Vol 68 (1) ◽  
pp. 168-171 ◽  
Author(s):  
Letitia Doina Duceac ◽  
Cristina Elena Dobre ◽  
Ioana Pavaleanu ◽  
Gabriela Calin ◽  
Simona Nichitus ◽  
...  

Preventing diseases is deemed to be the major goal of our century especially when an excessive fluoride in drinking water can cause dental fluorosis, bone stiffness, rheumatism and skeletal fluorosis. Fluoride uptake from groundwater implies a worldwide multidisciplinary effort in order to develop renewable, cheap, human friendly materials. Among other materials, hydrotalcites could be good candidates for an efficient fluoride removal from water due to their adsorption, anion exchange and reconstruction properties. These nanostructured materials were synthesized using co-precipitation method in controlled conditions. Presence of anions in the interlayer structure and morphological aspects were performed by FTIR and SEM techniques. Thermal treatment of hydrotalcites showed good adsorption capacities for water defluoridation mostly due to their tendency to restore the original structure.


2006 ◽  
Vol 118 ◽  
pp. 639-644
Author(s):  
Hye Sung Kim ◽  
Su Chak Ryu

Hydroxyapatite (Ca10(PO4)6(OH)2, HAp) powders is synthesized using the mixed powders of CaCO3 refined from oyster shells and phosphoric acid (H3PO4-98%, Daejung) as starting materials. The characteristic evaluation and chemical analysis of the synthesized powders is performed by X-ray diffraction (XRD), Fourier-transformed infra-red spectroscopy (FT-IR), and inductively-coupled plasma atomic emission spectroscopy (ICPAES). XRD analysis of synthetic powder by heat treatment at 1300°C for 2hrs shows only HAp peaks corresponding to stoichiometric HAp. It is confirmed by ICP-AES test that impurities such as Zn, In, Ti, Ba, Cd, Pb, and Mn, is not detected at all, but small amounts of Ti and Be is observed (0.099ppm Ti and 0.002ppm Ba). Variation of bone density is measured by giving medication of HAp powder with drinking water into human body continuously for three month. After the medication, the bone density is higher than the medication before. This means that HAp powder made from this process can be used as improver of bone density.


Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 250 ◽  
Author(s):  
Francesco Baldassarre ◽  
Angela Altomare ◽  
Nicola Corriero ◽  
Ernesto Mesto ◽  
Maria Lacalamita ◽  
...  

Europium-doped hydroxyapatite Ca10(PO4)6(OH)2 (3% mol) powders were synthesized by an optimized chemical precipitation method at 25 °C, followed by drying at 120 °C and calcination at 450 °C and 900 °C. The obtained nanosized crystallite samples were investigated by means of a combination of inductively coupled plasma (ICP) spectroscopy, powder X-ray diffraction (PXRD), Fourier Transform Infrared (FTIR), Raman and photoluminescence (PL) spectroscopies. The Rietveld refinement in the hexagonal P63/m space group showed europium ordered at the Ca2 site at high temperature (900 °C), and at the Ca1 site for lower temperatures (120 °C and 450 °C). FTIR and Raman spectra showed slight band shifts and minor modifications of the (PO4) bands with increasing annealing temperature. PL spectra and decay curves revealed significant luminescence emission for the phase obtained at 900 °C and highlighted the migration of Eu from the Ca1 to Ca2 site as a result of increasing calcinating temperature.


2013 ◽  
Vol 777 ◽  
pp. 15-18 ◽  
Author(s):  
Jiu Xu Liu ◽  
Feng Wang ◽  
Jian Xing Shen ◽  
Qi Hui Lai ◽  
Ying Gai

nanohydroxyapatite (nanoHA) powders were prepared by liquid phase precipitation method, using diammonium hydrogen phosphate and calcium nitrate tetrahydrate as raw materials. It was studied that the prepared nanoHA powders not sintered and sintered at 800°C to adsorption of Cu2+ and Pb2+ in aqueous solutions, respectively. The structure and size of nanoHA powders was investigated by X-ray diffraction (XRD) and the concentrations of Cu2+and Pb2+ in aqueous solutions were tested by inductively coupled plasma emission spectrometer. The results revealed that the nanoHA powders have obvious absorption function for Cu2+ and Pb2+ in aqueous solutions. In addition, the absorption ratio was affected by the size of nanoHA.


2018 ◽  
Vol 32 (10) ◽  
pp. 1850119
Author(s):  
Chunrui Liu ◽  
Li Dai ◽  
Luping Wang ◽  
Yu Shao ◽  
Zhehua Yan ◽  
...  

Zr:Yb:Tm:LiNbO3 crystals with various [Li]/[Nb] ratios (0.946, 1.05, 1.20 and 1.38) were grown by the Czochralski technique. Distribution coefficients of Zr[Formula: see text], Yb[Formula: see text] and Tm[Formula: see text] ions were analyzed by the inductively coupled plasma-atomic emission spectrometer (ICP-AES). The influence of [Li]/[Nb] ratio on the composition and defect structure of Zr:Yb:Tm:LiNbO3 crystals was investigated by X-ray diffraction and IR transmission spectrum. The results show that as the [Li]/[Nb] ratio increases in the melt, the distribution coefficients of Yb[Formula: see text] and Tm[Formula: see text] ions both increase while that of Zr[Formula: see text] ion deceases. When the [Li]/[Nb] ratio increases to 1.20 in the melt, Zr:Yb:Tm:LiNbO3 crystal is nearly stoichiometric. In addition, when the [Li]/[Nb] ratio reaches up to 1.38, Nb[Formula: see text] are completely replaced and Li[Formula: see text] starts to impel the Zr[Formula: see text], Yb[Formula: see text] and Tm[Formula: see text] into the normal Li sites.


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