Photo-reduction of Chromium from water by TiO2 nanoparticles

MRS Advances ◽  
2018 ◽  
Vol 3 (42-43) ◽  
pp. 2667-2674 ◽  
Author(s):  
M. Ali Ahmed ◽  
A. Taj Elsir ◽  
F. Mohammed ◽  
H. A. Elbushra ◽  
S. Tawer ◽  
...  

AbstractThis work aims to develop simple and cost-effective methods in reduction of Cr(VI) from water to less toxic and easy separated Cr(III) using Titanium dioxide (TiO2).TiO2 nanoparticles are prepared by a sol-gel method using titanium tetra-chloride and characterized using X-Ray Diffraction (XRD), Scanning electron microscope (SEM), Energy dispersive X-ray Fluorescence spectrometer (EDX) and UV-visible spectroscopy. XRD shows Anatase structure of TiO2 after annealing at 600°C for four hours. The particles size is estimated to be 70 nm using SEM.UV-Visible spectroscopy indicated that TiO2 nanoparticles played important role in decreasing the concentration of Cr (VI) in water samples for different pH range of 1 to 4. The decrease in Cr(VI) concentration after the treatment is ascribed to the reduction caused by the photocatalyst effect that resulted from the presence of TiO2 nanoparticle in water samples under direct exposure to direct sunlight.

2014 ◽  
Vol 496-500 ◽  
pp. 362-365 ◽  
Author(s):  
Qing Xiang Lin ◽  
Feng Miao ◽  
Yi Huang

CuAlO2microcrystallites were synthesized by Sol-gel method at 1200°C with Cu (CH3COO)2·H2O, Al (NO3)3·9H2O and ethylene glycol as raw materials. The phase composition,morphology,and optical properties of CuAlO2microcrystallites were chatacterized by X-ray diffraction, Scanning electron microscope,Photoluminescence and UV-visible spectroscopy respectively. The results of XRD show that CuAlO2with delafossite crystal structure is obtained. The defect emission were observed through PL spectrum test. It can be concluded that Cu-vacancy may be the possible reason of the observed activated p-type conductivity of CuAlO2. Can be found three characterized peak (λ1=290nm, λ2=410nm, λ3=430 nm) on the spectra.


2006 ◽  
Vol 514-516 ◽  
pp. 1155-1160 ◽  
Author(s):  
Talaat Moussa Hammad

Sol gel indium tin oxide thin films (In: Sn = 90:10) were prepared by the sol-gel dipcoating process on silicon buffer substrate. The precursor solution was prepared by mixing SnCl2.2H2O and InCl3 dissolved in ethanol and acetic acid. The crystalline structure and grain orientation of ITO films were determined by X-ray diffraction. The surface morphology of the films was characterized by scanning electron microscope (SEM). Optical transmission and reflectance spectra of the films were analyzed by using a UV-visible spectrophotometer. The transport properties of majority charge carriers for these films were studied by Hall measurement. ITO thin film with electrical resistivity of 7.6 ×10-3 3.cm, Hall mobility of approximately 2 cm2(Vs)-1 and free carrier concentration of approximately 4.2 ×1020 cm-3 are obtained for films 100 nm thick films. The I-V curve measurement showed typical I-V characteristic behavior of sol gel ITO thin films.


Author(s):  
B. Anandh ◽  
A. Muthuvel ◽  
M. Emayavaramban

The present investigation demonstrates the formation of silver nanoparticles by the reduction of the aqueous silver metal ions during exposure to the Lagenaria siceraria leaf extract. The synthesized AgNPs have characterized by UV-visible spectroscopy, X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) techniques. AgNPs formation has screened by UV-visible spectroscopy through colour conversion due to surface plasma resonance band at 427 nm. X-ray diffraction (XRD) confirmed that the resulting AgNPs are highly crystalline and the structure is face centered cubic (fcc). FT-IR spectrum indicates the presence of different functional groups present in the biomolecules capping the nanoparticles. Further, inhibitory activity of AgNPs and leaf extract were tested against human pathogens like gram-pastive (Staphylococcus aureus, Bacillus subtilis), gram-negative (Escherichia coli and Pseudomonas aeruginosa). The results indicated that the AgNPs showed moderate inhibitory actions against human pathogens than Lagenaria siceraria leaf extract, demonstrating its antimicrobial value against pathogenic diseases


2018 ◽  
Vol 64 (4) ◽  
pp. 381
Author(s):  
Muhammad Tufiq Jamil ◽  
Javed Ahmad ◽  
Syed Hamad Bukhari ◽  
Murtaza Saleem

Rare earth nano sized pollycrystalline orthoferrites and orthocromites ReT mO3 (Re = La, Nd, Gd, Dy, Y and T m = Fe, Cr) have been synthesized by sol-gel auto combustion citrate method. The samples have been characterized by means of X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), and UV-visible spectroscopy. The samples are single phase as confirmed by XRD analysis and correspond to the orthorhombic crystal symmetry with space group pbnm. Debye Scherer formula and Williamson Hall analysis have been used to calculate the average grain size which is consistent with that of determined from SEM analysis and varied between 25-75 nm. The elemental compositions of all samples have been checked by EDX analysis. Different crystallographic parameters are calculated with strong structural correlation among Re and Tm sites. The optical energy band gap has been calculated by using Tauc relation estimated to be in the range of 1.77 - 1.87 eV and 2.77 - 3.14 eV, for ReFeO3 and ReCrO3, respectively.


2014 ◽  
Vol 896 ◽  
pp. 541-544
Author(s):  
Is Fatimah ◽  
N. Nunani Yuyun

ZnO-SiO2/Laponite was prepared by sol-gel preparation procedure consit of SiO2 pillarization to laponite followed by ZnO dispersion by using zinc acetate as precursor. The obtained material was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), diffuse reflectance UV-Visible (DRUV-Vis) and N2 adsorption-desorption analysis. The photocatalytic performance of the amterial in methylene blue decolorization was also investigated. Compared with ZnO-SiO2 nanoparticles, it is concluded that ZnO-SiO2/Laponite possess higher photocatalytic activity which obey Temkin isotherm model.


2021 ◽  
Author(s):  
Ahmed ZITI ◽  
Bouchaib HARTITI ◽  
Amine BELAFHAILI ◽  
Hicham LABRIM ◽  
Salah FADILI ◽  
...  

Abstract Quaternary semiconductor Cu2NiSnS4 thin film was made by the sol-gel method associated to dip-coating technique on ordinary glass substrates. In this paper, we have studied the impact of dip-coating cycle at different cycles: 4, 5 and 6 on the structural, compositional, morphological, optical and electrical characteristics. CNTS thin films have been analyzed by various characterization techniques including: X-ray diffractometer (XRD), Raman measurements, scanning electron microscope (SEM), energy dispersive X-ray spectroscope (EDS), UV-visible spectroscopy and four-point probe method. XRD spectra demonstrated the formation of cubic Cu2NiSnS4 with privileged orientation at (111) plane. Crystallite size of cubic CNTS thin films increase with from 6.30 to 9.52 with dip-coating cycle augmented. Raman scattering confirmed the existence of CNTS thin films by Raman vibrational mode positioned at 332 cm− 1. EDS investigations showed near-stoichiometry of CNTS sample deposited at 5 cycles. Scanning electron microscope showed uniform surface morphologies without any crack. UV-visible spectroscopy indicated that the optical absorption values are larger than 104 cm− 1, Estimated band gap energy of CNTS absorber layers decrease from 1.64 to 1.5 eV with dip-coating cycle increased. The electrical conductivity of CNTS thin films increase from 0.19 to 4.16 (Ω cm)-1. These characteristics are suitable for solar cells applications.


2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Thilagavathi Thirugnanam

Fibers irregular and seed-like microcrystalline ZnO were synthesized by using a cost-effective and low temperature aqueous sol-gel method. Various polymers, namely, polyethylene glycol 6000 (PEG 6000) and polyvinyl pyrrolidone (PVP), were used as structure directing agents. The samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The X-ray diffraction pattern revealed the formation of phase-pure ZnO micropowders. It is observed that the polymers play an important role in modifying the surface morphology and the size of the crystallites. A compact granular morphology is observed for the ZnO samples without polymer. The samples exhibit microparticles of size 100 nm for PVP and for PEG-mediated growth, whereas microporous corrugated morphology is observed for added PEG-mediated micropowder. FTIR study is used to confirm the structural modifications occurring in the polymers.


Crystals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 424 ◽  
Author(s):  
Jia-Le Li ◽  
Wei-Dong Li ◽  
Zi-Wei He ◽  
Shuai-Shuai Han ◽  
Shui-Sheng Chen

A new compound, namely, [Zn(L)2]n (1) was obtained by the reaction of 2-methyl-4-(4H-1,2,4-triazol-4-yl) benzoic acid (HL) with ZnSO4·7H2O, and the compound was characterized by single-crystal X-ray diffraction, infrared spectroscopy, elemental analysis, powder X-ray diffraction (PXRD), and thermogravimetric analysis. The linear HL ligands were deprotonated to be L− anions and act as two-connectors to link Zn2+ to form a two-dimensional (2D) lay structure with (4, 4) topology. The large vacancy of 2D framework allows another layer structure to interpenetrate, resulting in the formation of 2D + 2D → 2D parallel interpenetration in 1. The weak interactions, such as hydrogen bonding and π–π stacking interactions, connect the adjacent 2D layers into a three-dimensional (3D) coordination polymer. The solid-state UV-visible spectroscopy and luminescent property have also been studied.


2018 ◽  
Vol 32 (19) ◽  
pp. 1840044
Author(s):  
Aditya Dalal ◽  
Animesh Mandal ◽  
Shubhada Adhi ◽  
Kiran Adhi

Aluminum (0.5 at.%)-doped ZnO (AZO) thin films were deposited by pulsed laser deposition technique (PLD) in oxygen ambient of 10[Formula: see text] Torr. The deposited thin films were characterized by x-ray diffraction (XRD), photoluminescence (PL), Raman spectroscopy and uv–visible spectroscopy (UV–vis). Next, graphene oxide (GO) was synthesized by Hummers method and was characterized by XRD, UV–vis spectroscopy, Raman spectroscopy and transmission electron microscopy (TEM). Thereafter, GO solution was drop-casted on AZO thin films. These films were then characterized by Raman Spectroscopy, UV–vis spectroscopy and PL. Attempt is being made to comprehend the modifications in properties brought about by integration.


Minerals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1042
Author(s):  
Nikita V. Chukanov ◽  
Anatoly N. Sapozhnikov ◽  
Roman Yu. Shendrik ◽  
Marina F. Vigasina ◽  
Ralf Steudel

Five samples of differently colored sodalite-group minerals from gem lazurite deposits were studied by means of electron microprobe and wet chemical analyses, infrared, Raman, electron spin resonance (ESR) and UV-Visible spectroscopy, and X-ray diffraction. Various extra-framework components (SO42−, S2− and Cl− anions, S3•−, S2•− and SO3•− radical anions, H2O, CO2, COS, cis- as well as trans- or gauche-S4 neutral molecules have been identified. It is shown that S3•− and S4 are the main blue and purple chromophores, respectively, whereas the S2•− yellow chromophore and SO3•− blue chromophore play a subordinate role. X-ray diffraction patterns of all samples of sodalite-group minerals from lazurite deposits studied in this work contain superstructure reflections which indicate different kinds of incommensurate modulation of the structures.


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