Hypoxanthine Modified Polyethylene Glycol Diglycidyl Ether Gel for Ciprofloxacin Adsorption

A hypoxanthine modified polyethylene glycol diglycidyl ether gel was prepared by the ring opening polymerization of polyethylene glycol diglycidyl ether with hypoxanthine in a simple sol-gel method. The structure and composition were characterized by SEM, FT-IR, BET and XRD. The adsorption experiments of ciprofloxacin at different pH, temperature, contact time and initial concentration were studied. The results show that the gel is porous with the average pore size of 5.2 nm, the optimum adsorption pH is 5 and the saturated adsorption time is 240 minutes. The maximum equilibrium adsorption capacity of ciprofloxacin is 56.1 mg/g at 308 K according to the Langmuir model. The repeated adsorption experiments show that the gel could still adsorb 80% of the first adsorbed ciprofloxacin after 5 times of elution. These results indicate that the gel can be used as a practical adsorbent for ciprofloxacin in aqueous solution.

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Porous TiO2-Al2O3 Photocatalyst: The Effects of Calcination Time

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.496.165 ◽

2012 ◽

Vol 496 ◽

pp. 165-168 ◽

Cited By ~ 2

Author(s):

Wen Jie Zhang ◽

Hong Liang Xin

Keyword(s):

Composite Materials ◽

Average Pore Size ◽

Sol Gel ◽

Specific Area ◽

Maximum Activity ◽

Calcination Time ◽

Average Pore ◽

Porous Tio2 ◽

Al2o3 Composite ◽

Ft Ir

Porous TiO2-Al2O3 composite materials were prepared through sol-gel method after calcination at 500 oC for different time. FT-IR spectra of porous TiO2-Al2O3 composite materials revealed that the samples are composed of Al2O3 and TiO2. The sample calcinated for 2.5 h had the maximum specific area of 128.9 m2•g-1. High pore volume and average pore size were possessed by the samples calcinated for 1 h and 3 h. While being calcinated at 500 oC, photocatalytic activities of the materials increased at first and then dropped down with the increasing calcination time. The sample calcinated for 3 h showed the maximum activity of 35%.

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Silica Sol-Gel Supported Nickel Nano-Catalyst for Hydrogen Production Using Microreactors

MRS Proceedings ◽

10.1557/proc-0885-a10-09 ◽

2005 ◽

Vol 885 ◽

Author(s):

Krithi Shetty ◽

Shihuai Zhao ◽

Wei Cao ◽

Naidu V. Seetala ◽

Debasish Kuila

Keyword(s):

Steam Reforming ◽

Average Pore Size ◽

Sol Gel ◽

Supported Catalyst ◽

Silica Sol ◽

Average Pore ◽

Steam Reforming Of Methanol ◽

Nano Catalyst ◽

Before And After ◽

Reforming Reactions

ABSTRACTThe goal of this research is to investigate the activities of a non-noble nano-catalyst (Ni/SiO2) using Si-microreactors for steam reforming of methanol to produce hydrogen for fuel cells. The supported catalyst was synthesized by sol-gel method using Ni (II) salts and Si(C2H5O)4 as starting materials. EDX results indicate that the actual loading of Ni (5-6%) is lower than the intended loading of 12 %. The specific surface area of the silica sol-gel encapsulated Ni nano-catalyst is 452 m2/g with an average pore size of ∼ 3 nm. Steam reforming reactions have been carried out in a microreactor with 50 µm channels in the temperature range of 180-240 °C and atmospheric pressure. Results show 53% conversion of methanol with a selectivity of 74 % to hydrogen at 5 l/min and 200 °C. The magnetic properties of the catalysts were performed using a Vibrating Sample Magnetometer (VSM) to study the activity of the catalysts before and after the steam reforming reactions. The VSM results indicate much higher activity in the microreactor compared to macro-reactor and Ni forms non-ferromagnetic species faster in the microreactor.

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Sol-Gel Derived Silica Layers for Low-k Dielectrics Applications

MRS Proceedings ◽

10.1557/proc-612-d5.26.1 ◽

2000 ◽

Vol 612 ◽

Cited By ~ 4

Author(s):

Sylvie Acosta ◽

André Ayral ◽

Christian Guizard ◽

Charles Lecornec ◽

Gérard Passemard ◽

...

Keyword(s):

Average Pore Size ◽

Sol Gel ◽

Porous Silica ◽

Thin Layers ◽

Gaseous Ammonia ◽

Potential Candidate ◽

Average Pore ◽

Synthesis Strategy ◽

Silica Layers ◽

Highly Porous

AbstractPorous silica exhibits attractive dielectric properties, which make it a potential candidate for use as insulator into interconnect structures. A new way of preparation of highly porous silica layers by the sol-gel route was investigated and is presented. The synthesis strategy was based on the use of common and low toxicity reagents and on the development of a simple process without gaseous ammonia post-treatment or supercritical drying step. Defect free layers were deposited by spin coating on 200 mm silicon wafers and characterized. Thin layers with a total porosity larger than 70% and an average pore size of 5 nm were produced. The dielectric constant measured under nitrogen flow on these highly porous layers is equal to ∼ 2.5, which can be compared to the value calculated from the measured porosity, ∼ 1.9. This difference is explained by the presence of water adsorbed on the hydrophilic surface of the unmodified silica.

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Synthesis, Characterization and Optical Properties of PLA / P3HT Blends Thin Films

NeuroQuantology ◽

10.14704/nq.2021.19.5.nq21057 ◽

2021 ◽

Vol 19 (5) ◽

pp. 132-138

Author(s):

Maan Abd-Alameer Salih ◽

Q.S. Kareem ◽

Mohammed Hadi Shinen

Keyword(s):

Thin Films ◽

Optical Properties ◽

Spin Coating ◽

Ring Opening ◽

Energy Gap ◽

Ring Opening Polymerization ◽

X Ray Diffraction ◽

X Ray ◽

Conductivity Increase ◽

Ft Ir

In this exploration Poly lactic corrosive (PLA) was orchestrated the ring-opening polymerization Poly lactic corrosive (PLA) blended with poly(3-hexylthiophene) (P3HT) which prepared by solution. Blends thin films Synthesis by spin coating technique and using Tetrahydrofuran (THF) as solvent. PLA powder was 'characterized by' 'X-ray' 'diffraction', '(FT-IR)'. pure Optical properties (PLA), (PLA)/P3HT blends thin films with different percentage of P3HT (0, 1, 2, and 3) wt% were investigated using UV-VS spectroscopy The results showed that the absorption, absorption coefficient, extinction coefficient and conductivity increase with increasing the rate of deformation P3HT, The energy gap decreases with increasing deformation.

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Synthesis, characterization, and photocatalytic activity of silver and zinc co-doped TiO2 nanoparticle for photodegradation of methyl orange dye in aqueous solution

Canadian Journal of Chemistry ◽

10.1139/cjc-2018-0308 ◽

2019 ◽

Vol 97 (9) ◽

pp. 642-650 ◽

Cited By ~ 5

Author(s):

Gabriel O. Oladipo ◽

Akinola K. Akinlabi ◽

Samson O. Alayande ◽

Titus A.M. Msagati ◽

Hlengilizwe H. Nyoni ◽

...

Keyword(s):

Methyl Orange ◽

Pore Size ◽

Average Pore Size ◽

Sol Gel ◽

Average Crystallite Size ◽

Rutile Phase ◽

Absorption Bands ◽

Average Pore ◽

Methyl Orange Dye ◽

Co Doped

In this study, TiO2 nanocrystals, 1 mol% Ag-doped TiO2, and 1 mol% Ag and 0.6 mol% Zn co-doped TiO2 powders were synthesized by the sol–gel route. Their photocatalytic activities on methyl orange dye under visible irradiation were investigated. The powders were characterized by X-ray diffraction (XRD), UV–visible spectroscopy (UV–vis), Brunauer–Emmett–Teller (BET), and Fourier transform infrared spectroscopy (FTIR). The XRD results revealed the presence of a rutile phase with an average crystallite size of 9 and 11 nm. The UV–vis spectra showed a red-shift towards a longer wavelength with the corresponding decrease in band gap from 2.9 to 2.5 eV. The BET surface areas of the nanoparticles ranged from 4.7 to 11.8 m2 g−1 with an average pore size between 18.9 and 56.6 nm. The Ag-doped TiO2 has the largest surface area of 11.8 m2 g−1, whereas the Ag–Zn co-doped TiO2 was found to have the highest pore size and volume. The absorption bands at 750–500 cm−1 were attributed to the –O–Ti–O– bond in the TiO2 lattice. The photocatalytic efficiency was highest at an optimum pH of 4.1 for Ag–Zn co-doped TiO2. The results confirmed that Ag-doped and Ag–Zn co-doped TiO2 were more effective than pure TiO2. The kinetic data were fitted into a pseudo first-order equation using a Langmuir–Hinshelwood kinetic model.

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Fabrication and Characterization of Strontium-Substituted Hydroxyapatite-CaO-CaCO3 Nanofibers with a Mesoporous Structure as Drug Delivery Carriers

Pharmaceutics ◽

10.3390/pharmaceutics10040179 ◽

2018 ◽

Vol 10 (4) ◽

pp. 179 ◽

Cited By ~ 10

Author(s):

Shiao-Wen Tsai ◽

Wen-Xin Yu ◽

Pai-An Hwang ◽

Sheng-Siang Huang ◽

Hsiu-Mei Lin ◽

...

Keyword(s):

Drug Carrier ◽

Drug Loading ◽

Average Pore Size ◽

Sol Gel ◽

Mesoporous Structure ◽

Drug Carriers ◽

Burst Release ◽

Doping Amount ◽

Sem Images ◽

Average Pore

Hydroxyapatite (HAp) is the main inorganic component and an essential part of hard bone and teeth. Due to its excellent biocompatibility, bioactivity, and osteoconductivity, synthetic HAp has been widely used as a bone substitute, cell carrier, and therapeutic gene or drug carrier. Recently, numerous studies have demonstrated that strontium-substituted hydroxyapatite (SrHAp) not only enhances osteogenesis but also inhibits adipogenesis in mesenchymal stem cells. Mesoporous SrHAp has been successfully synthesized via a traditional template-based process and has been found to possess better drug loading and release efficiencies than SrHAp. In this study, strontium-substituted hydroxyapatite-CaO-CaCO3 nanofibers with a mesoporous structure (mSrHANFs) were fabricated using a sol–gel method followed by electrospinning. X-ray diffraction analysis revealed that the contents of CaO and CaCO3 in the mSrHANFs decreased as the doping amount of Sr increased. Scanning electron microscopy (SEM) images showed that the average diameter of the mSrHANFs was approximately 200~300 nm. The N2 adsorption–desorption isotherms demonstrated that the mSrHANFs possessed a mesoporous structure and that the average pore size was approximately 20~25 nm. Moreover, the mSrHANFs had excellent drug- loading efficiency and could retard the burst release of tetracycline (TC) to maintain antibacterial activity for over 3 weeks. Hence, mSrHANFs have the potential to be used as drug carriers in bone tissue engineering.

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Synthesis and characterization of poly(1-methyltrimethylene carbonate) (PMTMC) by mean ring-opening polymerization

Revista Bases de la Ciencia. e-ISSN 2588-0764 ◽

10.33936/rev_bas_de_la_ciencia.v5i3.1863 ◽

2020 ◽

Vol 5 (3) ◽

pp. 21

Author(s):

Jesús Miguel Contreras Ramírez ◽

Meribary Monsalve

Keyword(s):

Ring Opening ◽

Molar Mass ◽

Thermal Polymerization ◽

Ring Opening Polymerization ◽

Active Species ◽

Size Exclusion ◽

Polymerization Process ◽

Molar Ratio ◽

Molecular Characteristics ◽

Ft Ir

In this work, the activity of samarium (III) acetate (Sm(OAc)3) was evaluated as a possible initiator in the ring opening polymerization (ROP) of 1-methyltrimethylene carbonate (MTMC). The effects of temperature (Tr) and monomer-initiator molar ratio (M/I) on the molecular characteristics (conversion, dispersity, and molar mass) of the polymers obtained were analyzed. The reaction temperature was varied between 90 and 160 °C and the molar ratio M/I between 200 and 1000. The molar mass of the products was obtained by size exclusion chromatography (SEC), while its structure was analyzed using FT-IR and 1H-NMR spectroscopy. Thermal polymerization experiments (in the absence of an initiator) were performed in order to evaluate the effectiveness of the initiator. The comparison between the thermal polymerization of MTMC and its polymerization in the presence of Sm(OAc)3, suggests that acetate has very low catalytic activity as the initiator of the ROP of PMTMC. The molar masses of the polymers obtained ranged between 6000 and 10000 Dalton, and the monomer to polymer conversions varied between 9 and 30 %. SEC chromatograms showed monomodal and symmetric curves, suggesting that only one type of active species participates in the polymerization process. Based on the structural analysis, a polymerization mechanism was proposed in which the water possibly acts as the only active species that initiates the reaction. Palabra clave: Samarium (III) acetate, ring-opening polymerization, 1-methyltrimethylenecarbonate, poly(1-methyltrimethylenecarbonate). Abstract En este trabajo se evaluó la actividad del acetato de samario (III) (Sm(OAc)3) como posible iniciador en la polimerización de apertura de anillo (PAA) del carbonato de 1-metiltrimetileno (MTMC). Se analizaron los efectos de la temperatura (Tr) y relación molar monómero-iniciador (M/I) sobre las características moleculares (conversión, dispersidad y masa molar) de los polímeros obtenidos. La temperatura de reacción se varió entre 90 y 160 °C y la relación molar M/I entre 200 y 1000. La masa molar de los productos se obtuvo mediante cromatografía de exclusión por tamaño, mientras que su estructura fue analizada mediante espectroscopia FT-IR y 1H-RMN. Además, se realizaron algunos experimentos de polimerización térmica (en ausencia de iniciador) que sirvieron de referencia para evaluar la efectividad del iniciador. La comparación de los resultados obtenidos en la polimerización térmica y en presencia del Sm(OAc)3 indicó que este último presenta muy poca actividad catalítica como iniciador de la PAA de PMTMC. Las masas molares de los polímeros obtenidos oscilaron entre 6000 y 10000 Dalton, mientras que las conversiones de monómero a polímero variaron entre 9 y 30%. Los cromatogramas SEC mostraron curvas mono-modales y simétricas, indicando que en el proceso de polimerización participa un solo tipo de especie activa. En base al análisis estructural, mediante técnicas espectroscópicas, se propuso un mecanismo de reacción para la polimerización en la que el agua posiblemente actúa como la única especie activa iniciadora de la reacción. Keywords: Acetato de samario (III), polimerización por apertura de anillo, 1-metiltrimetilencarbonato, poli(1-metiltrimetilencarbonato).

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Tailored Crosslinking Process and Protective Efficiency of Epoxy Coatings Containing Glycidyl-POSS

Polymers ◽

10.3390/polym12030591 ◽

2020 ◽

Vol 12 (3) ◽

pp. 591 ◽

Cited By ~ 1

Author(s):

Mirjana Rodošek ◽

Mohor Mihelčič ◽

Marija Čolović ◽

Ervin Šest ◽

Matic Šobak ◽

...

Keyword(s):

Ring Opening ◽

Protective Coatings ◽

Diglycidyl Ether ◽

Scanning Calorimetry ◽

Protective Efficiency ◽

Crosslinking Process ◽

Operational Temperature ◽

Epoxy Ring Opening ◽

Ft Ir ◽

Oligomeric Silsesquioxane

Versatile product protective coatings that deliver faster drying times and shorter minimum overcoat intervals that enable curing at faster line speeds and though lower energy consumption are often desired by coating manufacturers. Product protective coatings, based on silsesquioxane-modified diglycidyl ether of bisphenol-A (DGEBA) epoxy resin, are prepared through a glycidyl ring-opening polymerization using dicyandiamide (DICY) as a curing agent. As silsesquioxane modifier serves the octaglycidyl-polyhedral oligomeric silsesquioxane (GlyPOSS). To decrease the operational temperature of the curing processes, three different accelerators for crosslinking are tested, i.e., N,N-benzyl dimethylamine, 2-methylimidazole, and commercial Curezol 2MZ-A. Differential scanning calorimetry, temperature-dependent FT-IR spectroscopy, and rheology allow differentiation among accelerators’ effectiveness according to their structure. The former only contributed to epoxy ring-opening, while the latter two, besides participate in crosslinking. The surface roughness of the protective coatings on aluminum alloy substrate decreases when the accelerators are applied. The scanning electron microscopy (SEM) confirms that coatings with accelerators are more homogeneous. The protective efficiency is tested with a potentiodynamic polarization technique in 0.5 M NaCl electrolyte. All coatings containing GlyPOSS, either without or with accelerators, reveal superior protective efficiency compared to neat DGEBA/DICY coating.

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Preparation and Structural Analysis of Magnesium Oxide Aerogels

MRS Advances ◽

10.1557/adv.2017.362 ◽

2017 ◽

Vol 2 (57) ◽

pp. 3505-3510

Author(s):

Jiankai Zhang ◽

Xiaohong Chen ◽

Ran Liu ◽

Huaihe Song ◽

Zhihong Li

Keyword(s):

Specific Surface ◽

Surface Area ◽

Magnesium Oxide ◽

Specific Surface Area ◽

Average Pore Size ◽

Sol Gel ◽

Average Pore ◽

X Ray ◽

Water As Solvent ◽

Saxs Analysis

ABSTRACTMagnesium oxide aerogels were made by sol-gel process using magnesium methoxide as precursor, methanol and deionized water as solvent with ethanol supercritical fluid drying. The influences of the different factors on the gel time and the specific surface area of magnesium oxide aerogels were studied, and the structure and morphology were characterized by Scanning Electron Microscopy (SEM), Transmission Electron Microscope (TEM) and X-ray diffraction (XRD), and the Small Angle X-ray Scatter (SAXS) was utilized to determine the fractural structure of the magnesium oxide aerogels. The results show that MgO aerogels belong to the typical mesoporous materials with rich network and highly developed pore structure, and the specific surface area is 904.9 m2/g, the apparent density is 0.055 g/cm3, the average pore size is 19.6 nm. The results of SAXS analysis show that the fractal dimension of the MgO aerogels is 2.32 in high q area which proves the existence of rough surface and pore fractal structure.

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Synthesis of miktoarm star-shaped and inverse star-block copolymers by a combination of ring-opening polymerization and click chemistry

e-Polymers ◽

10.1515/epoly-2018-0180 ◽

2018 ◽

Vol 18 (6) ◽

pp. 559-568 ◽

Cited By ~ 3

Author(s):

Xiaoqi Yan ◽

Jianbo Li ◽

Tianbin Ren

Keyword(s):

Block Copolymer ◽

Ring Opening ◽

Click Reaction ◽

Ring Opening Polymerization ◽

Structure And Properties ◽

Star Block Copolymer ◽

Ft Ir ◽

Miktoarm Star ◽

Star Block Copolymers ◽

Ft Ir Spectroscopy

AbstractBased on the combination of the “arm-first” and “core-first” strategies, the miktoarm star-shaped copolymer PLLA2PCL2 and the inverse star-block copolymer (PCL-b-PLLA)2-core-(PCL-b-PLLA)2 were designed and synthesized by the combination of ring-opening polymerization (ROP) and a click reaction. The miktoarm star-shaped copolymer PLLA2PCL2 was synthesized by a click reaction of an azido macroinitiator PLLA2(N3)2 and HC≡C-PCL. The inverse star-block copolymer (PCL-b-PLLA)2-core-(PCL-b-PLLA)2 was synthesized by a click reaction of an azido macroinitiator (PCL-b-PLLA)2(N3)2 and HC≡C-PCL-b-PLLA. The structures of these star polymers were confirmed by nuclear magnetic resonance (NMR), Fourier-transform infrared (FT-IR) spectroscopy and gel permeation chromatograph (GPC). The inverse star-block copolymer could be used to study the potential relationship between polymer structure and properties, which has a unique structure and good crystallization properties.

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