scholarly journals Degradation of Tetracycline by Birnessite under Microwave Irradiation

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Meng Liu ◽  
Guocheng Lv ◽  
Lefu Mei ◽  
Xiaoyu Wang ◽  
Xuebing Xing ◽  
...  

The efficiency and factors affecting tetracycline (TC) degradation by birnessite under microwave irradiation (MI) were investigated under different initial TC concentrations, solution pH, MI time, and MI power. The crystal structure, degradation efficiency, and reaction mechanism were investigated using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and ultraviolet-visible spectroscopy (UV-Vis). The results showed that birnessite was an excellent microwave catalyst. The maximum TC removal efficiency by birnessite was 99% under MI at 400 W for 30 min in strongly acidic media. Under MI, the surface activity of birnessite increased, resulting in the ability to accelerate TC removal in high temperature.

2020 ◽  
Vol 851 ◽  
pp. 9-15
Author(s):  
Ahmad Taufiq ◽  
M.Sofiyudin Nuroni ◽  
Nurul Hidayat ◽  
ST.Ulfawanti Intan Subadra ◽  
Sunaryono ◽  
...  

In this work, Fe3O4 nanoparticles (NPs) were synthesized using coprecipitation method and TiO2 NPs were synthesized using sonication method. Fe3O4/polyaniline and TiO2/polyaniline nanocomposites (NCs) were synthesized using polymerization methods. The samples were characterized by X-ray diffractometer, Fourier-transform infrared spectroscopy, and ultraviolet-visible spectroscopy. The results of X-ray diffraction data analysis presented that polyaniline decreased the crystallinity of Fe3O4 and TiO2 NPs. However, the crystal structure of Fe3O4 and TiO2 NPs did not change, which successively formed the cubic spinel and the tetragonal anatase phases. Furthermore, the functional groups of Ti-O-Ti and Fe-O were detected in the wavenumber ranges of 620-580 cm-1 and 410-520 cm-1, respectively. The presence of polyaniline was also detected by the emergence of a functional group of polyaniline which also showed that there was an interaction of Fe3O4 and TiO2 NPs with polyaniline. Meanwhile, the results of UV-Vis data analysis showed that the addition of polyaniline decreased the bandgap energy of Fe3O4 and TiO2 NPs significantly from 2.186 to 2.174 eV and from 3.374 to 3.320 eV, respectively.


Crystals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1144
Author(s):  
Konda Shireesha ◽  
Thida Rakesh Kumar ◽  
Tumarada Rajani ◽  
Chidurala Shilpa Chakra ◽  
Murikinati Mamatha Kumari ◽  
...  

This paper describes the synthesis and characterization of NiMgOH-rGO nanocomposites made using a chemical co-precipitation technique with various reducing agents (e.g., NaOH and NH4OH) and reduced graphene oxide at 0.5, 1, and 1.5 percent by weight. UV-visible spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, a particle size analyzer, and cyclic voltammetry were used to characterize the composite materials. The formation of the NiMgOH-rGO nanocomposite with crystallite sizes in the range of 10–40 nm was inferred by X-ray diffraction patterns of materials, which suggested interlayers of Ni(OH)2 and Mg(OH)2. The interactions between the molecules were detected using Fourier-transform infrared spectroscopy, while optical properties were studied using UV-visible spectroscopy. A uniform average particle size distribution in the range of 1–100 nm was confirmed by the particle size analyzer. Using cyclic voltammetry and galvanostatic charge/discharge measurements in a 6 M KOH solution, the electrochemical execution of NiMgOH-rGO nanocomposites was investigated. At a 1 A/g current density, the NiMgOH-rGO nanocomposites prepared with NH4OH as a reducing agent had a higher specific capacitance of 1977 F/g. The electrochemical studies confirmed that combining rGO with NiMgOH increased conductivity.


BioResources ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. 8631-8647
Author(s):  
Dongliang Zhao ◽  
Haibiao Yu ◽  
Xiuchun Bao ◽  
Jinwei Liu ◽  
Haoqiang Yuan ◽  
...  

Poplar and pine wood were extracted with water, 1% NaOH (wt%) solution, and benzene:ethanol solution (V1 : V2, 2 : 1) to investigate the governing factors and mechanism by which extractives affect wood structure and mechanical properties. The structure, pore distribution, crystal structure, and mechanical properties of samples were analyzed by Fourier transform infrared spectroscopy (FTIR), adsorption of N2 gas, X-ray diffraction (XRD), and mechanical testing, respectively. The results demonstrated that cellulose, hemicellulose, and lignin were degraded to some extent in the course of the dissolution of the extractives. This degradation had a great influence on the structure and quantity of pores. The extraction treatment did not change the crystallization type of the wood, but it increased the crystallinity of the wood, and the length and width of the crystallization area changed. In addition, the mechanical properties of wood were changed when the content of the extractives was reduced.


1999 ◽  
Vol 14 (2) ◽  
pp. 442-446 ◽  
Author(s):  
Yingchun Zhu ◽  
Tiao Liu ◽  
Chuanxian Ding

Four samples of TiO2 ultrafine particles (UFP) were obtained through different processes. The structure of TiO2 ultrafine particles and the factors influencing the structure were investigated with Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, and x-ray diffraction (XRD). Both Raman spectra and x-ray diffractograms show the similar regularity of the phase transformation among the four samples. The observed bimodal lineshape-structure in the Raman spectra is attributed to the intragrain and grain-boundary components of TiO2 UFP. The crystal structure of TiO2 UFP is found to be distorted by the surface structure such as OH and OCH2CH3 groups coordinated on the surface of TiO2 UFP.


2016 ◽  
Vol 839 ◽  
pp. 136-141
Author(s):  
Arrak Klinbumrung ◽  
Chalermchai Pilapong ◽  
Tawat Suriwong

Antimony sulfide (Sb2S3) nanostructure was synthesized using a 600 W microwave irradiation technique. The precursors including Sb(CH3CO2)3 and Na2S2O3.5H2O were dissolved into 50 mL ethylene glycol (EG) solution with containing 0 and 1 g of hydroxyethyl cellulose (HEC). Phase, morphology and optical properties of the as-synthesized products were determined by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible spectroscopy and photoluminescence (PL). Energy band gap of Sb2S3 nanostructure exhibits the value of 1.90 and 2.06 eV for synthesizing condition with and without HEC containing, respectively.


2013 ◽  
Vol 787 ◽  
pp. 205-207
Author(s):  
Hong Yan Zhou

A compound of (1E,2E)-1,2-di (-3-nitrobenzylidene) hydrazine was synthesized under microwave irradiation (500 w), giving high yields of products (93%). Its structure was determined IR, 1H NMR, MS, elemental analysis and X-ray diffraction. The crystal of the compound is Monoclinic, space group P2(1)/n with a = 6.9611(18), b = 7.823(2), c = 12.999(3) Å, α = 90, β = 105.215(4), γ = 90o, V= 683.1(3) Å3, Z=4, Dc=1.450g/cm3,μ=0.110 mm-1, F(000)=308, R=0.0401 and wR = 0.1131 for 1273 observed reflection with I>2σ (I). π-π stacking interactions contribute to the stability of the structure.


2012 ◽  
Vol 32 (2) ◽  
Author(s):  
Malgorzata M. Jaworska ◽  
Tomasz Kozlecki ◽  
Andrzej Gorak

Abstract Chitin is one of the most abundant biopolymers, but due to its high crystallinity, it is completely insoluble in most organic and inorganic solvents. Chitin is soluble only in solvents that can destroy intersheet and intrasheet H-bonds, and many of these solvents are toxic, corrosive, nondegradable, or mutagenic. Because of these drawbacks, there is a search for more environmentally friendly solvents for chitin. It has been shown that ionic liquids (ILs) can dissolve chitin at elevated temperatures (80°–110°C) or with application of microwave irradiation. The highest solubility of chitin in an IL was about 20% (1-ethyl-3-methylimidazolium acetate), whereas chitin was shown to be insoluble in 1-allyl-3-methylimidazolium chloride and 1-butyl-3-methylimidazolium formate. Dissolved chitin can be regenerated by mixing with water or methanol, where the polymer precipitates from the solution. X-ray diffraction patterns of native polymer and precipitates have been compared and only small changes in crystallinity have been observed. In addition, Fourier transform infrared spectra remained similar for both forms of chitin, native and regenerated. Presented data hold great promise for the improvement of the chemistry of chitin and open new routes for chemical and enzymatic modifications of this polymer.


2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Xuebing Xing ◽  
Jingwen Feng ◽  
Guocheng Lv ◽  
Kenan Song ◽  
Lefu Mei ◽  
...  

The efficiency of ciprofloxacin (CIP) adsorption on synthesized birnessite was systematically studied under varying physicochemical conditions, such as solution pH, contact time, initial CIP concentration, and different average oxidation states (AOS) of Mn in birnessite. X-ray diffraction (XRD), Fourier transform infrared (FTIR), and molecular simulations were employed to investigate the adsorption mechanism of CIP on birnessite. Experimental results showed that surface adsorption instead of cation exchange was responsible for the uptake of CIP on birnessite. The quantum mechanics simulation showed that the final energy of the interaction between CIP and birnessite was smaller under the condition when the AOS of Mn was lower, in comparison to the case when the AOS of Mn was high. The highest CIP adsorption occurred under a weak alkaline condition.


2020 ◽  
Vol 7 (2) ◽  
pp. 61-70
Author(s):  
Dmitry S. Tsvetkov ◽  
Maxim O. Mazurin

Crystal structure of mono-β-alaninium chloride has been studied by single crystal X-ray diffraction. The compound crystallizes in the orthorhombic system. The space group is Pbca, with the following lattice constants: a = 9.7414(5) Å, b = 7.4671(6) Å, c = 16.5288(11) Å, V = 1202.31(14) Å3, Z = 8. The asymmetric unit contains one β-alaninium cation (+NH3CH2CH2COOH) and one chloride anion. The structure was shown to consist of layers stacked along the c-axis and connected with each other by weak van der Waals forces. Each layer consists of two halves linked by hydrogen bonds between carbonyl and NH3+ groups and, also, between NH3+ groups and Cl- anions. Fourier transform infrared spectrum of β-alaninium chloride was recorded and analyzed. The spectroscopic results were found to support the conclusions of the structural study.


2006 ◽  
Vol 61 (11) ◽  
pp. 1421-1425 ◽  
Author(s):  
Maasoomeh Tabatabaee ◽  
Mitra Ghassemzadeh ◽  
Behnaz Zarabi ◽  
Bernhard Neumüllerc

Reaction of 4-amino-6-methyl-3-thio-3,4-dihydro-1,2,4-triazin-5(2H)-one (1) with 2-methoxybenzaldehyde, 4-methoxybenzaldehyde, 2-pyridinecarbaldehyde, and 2,4-dichlorobenzaldehyde under classical heating and microwave irradiation in a solventfree system led to the corresponding imines (Schiff bases) 2-5. All synthesized compounds have been characterized by IR and NMR spectroscopy, mass spectrometry and by X-ray diffraction studies.


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