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Synthesis and radiation grafting modification of hydroxyl controlled AM/HEMA polymer microspheres
摘要： The, smooth-faced, highly cross-linked, hydroxyl controlled, micrometer-sized polymer micro-spheres of acrylamide (AM) and 2-hydroxyethyl methacrylate (HEMA) were prepared by reverse suspension polymerization. The polymerization parameters showed considerable influence on the morphologies and dispersion of the polymer particles, such as the stirring rate, polymerization temperature, monomer loading, initiator concentration, and crosslinking agent concentration, which makes it flexible to control the hydroxyl number of AM/HEMA microspheres by controlling polymerization conditions. Subsequently, the polymer particles was radiated with 60Co c-rays(dose rate: 4.0 kGy/h) in pure oxygen environment for 24 h, as a result, free radicals are generated on the surface of the polymer microspheres. Afterward, AM was allowed to be graft-polymerized on microspheres AM/HEMA in the manner of “grafting onto,” resulting in the grafted microspheres PAM–AM/HEMA. This work provides optimized parameters to fabricate micron-sized AM/HEMA microspheres, and further expands the functionalization of AM/HEMA microspheres and its application fields.
关键词： polymer microspheres,graft-modification,hydroxyl controlled,Synthesis
更新于2025-09-23 15:19:57
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Shaping Metallic Nanolattices: Design by Microcontact Printing from Wrinkled Stamps
摘要： A method for the fabrication of well-defined metallic nanostructures is presented here in a simple and straightforward fashion. As an alternative to lithographic techniques, this routine employs microcontact printing utilizing wrinkled stamps, which are prepared from polydimethylsiloxane (PDMS), and includes the formation of hydrophobic stripe patterns on a substrate via the transfer of oligomeric PDMS. Subsequent backfilling of the interspaces between these stripes with a hydroxyl-functional poly(2-vinyl pyridine) then provides the basic pattern for the deposition of citrate-stabilized gold nanoparticles promoted by electrostatic interaction. The resulting metallic nanostripes can be further customized by peeling off particles in a second microcontact printing step, which employs poly(ethylene imine) surface-decorated wrinkled stamps, to form nanolattices. Due to the independent adjustability of the period dimensions of the wrinkled stamps and stamp orientation with respect to the substrate, particle arrays on the (sub)micro-scale with various kinds of geometries are accessible in a straightforward fashion. This work provides an alternative, cost-effective, and scalable surface-patterning technique to fabricate nanolattice structures applicable to multiple types of functional nanoparticles. Being a top-down method, this process could be readily implemented into, e.g., the fabrication of optical and sensing devices on a large scale.
关键词： metallic nanolattices,oligomeric polydimethylsiloxane,microcontact printing,hydroxyl-functional poly(2-vinyl pyridine),gold,wrinkled stamps,nanoparticle assembly,polydimethylsiloxane wrinkles
更新于2025-09-23 15:19:57
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Degradation of carbamazepine by vacuum-UV oxidation process: Kinetics modeling and energy efficiency
摘要： Vaccum-ultraviolet (VUV) is effective for elimination of organic contaminants in aqueous environment and degradation of carbamazepine (CBZ) by VUV irradiation was systematically investigated in this study. A dynamic kinetic model was developed to simulate the destruction of CBZ that is mainly initiated by hydroxyl radicals (HO?). The second-order rate constant of the reaction between CBZ and HO? was determined to be 1.4×109 M-1 s-1. Effect of initial CBZ concentration, VUV irradiation intensity and natural organic matter (NOM) were further investigated in several batch experiments. The predicted CBZ removal rates increased with the increasing VUV intensity, while decreased with the increasing initial CBZ and NOM concentrations. Based on the electrical energy per order (EE/O) calculation, the optimal VUV intensity was determined to be 7.5×10-8 Einstein s-1. Meanwhile, several intermediates/products were identified and their time-dependent evolution profiles were determined, and finally a plausible degradation pathway of CBZ was proposed. Ecotoxicity assessment indicated that the potential toxicity of CBZ and its oxidation products should be paid more attention in the VUV process.
关键词： Kinetic model,Degradation pathway,Energy efficiency,Hydroxyl radical
更新于2025-09-19 17:15:36
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ZnO-Bi2O3/graphitic carbon nitride photocatalytic system with H2O2-assisted enhanced degradation of Indigo carmine under visible light
摘要： Indigo carmine in aqueous solution was effectively degraded using ZnO-Bi2O3/Graphitic Carbon Nitride heterojunction structure by visible light/H2O2 system. The mechanism of photocatalytic degradation of Indigo carmine shows the responsible species for the degradation of Indigo carmine in the ZnO-Bi2O3-xC3N4/H2O2/visible light system (x = 0, 1, 2, and 3) is the hydroxyl radicals which were generated from the reaction of e? and h? with H2O2. Under optimal conditions, ZnO-Bi2O3-2C3N4/H2O2/Vis system degraded more than 93% of Indigo carmine in 180 min. Besides, the kinetic of the photocatalytic process was detailed. These results demonstrate that the ZnO-Bi2O3-2C3N4/H2O2/visible light system may become a promising approach to achieve efficient environmental remediation as an environmentally friendly oxidant.
关键词： Indigo carmine,Hydroxyl radicals,Mineralization,Photocatalyst,Degradation
更新于2025-09-19 17:15:36
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Microwave discharge electrodeless mercury lamp (Hg-MDEL): an energetic, mechanistic and kinetic approach to the degradation of Prozac?
摘要： A photochemical reactor composed of an Hg-MDEL was applied in photodegradation studies of fluoxetine (Prozac?). The reactor exhibited to be an efficient hydroxyl radical generation system, since constant of formation of OH? formation is optimized through the adjustment of this parameter. An increase in the initial hydroxycoumarin (4HC) and 7-hydroxycoumarin (7HC) solutions resulted in the kinetics constant value, the mean kinetic constant was k = 10.64 ± 1.25 min -1 and R 2 = 0.943 ± 0.131. The Prozac? photodegradation studies showed that the application of the pseudo-first-order applied for degradation of Prozac?, the study of variation of the microwave power allowed a concentration of Prozac from 33 to 134 μmol L-1 resulted in a 21% decrease in the kinetic significant increase in the rate of degradation of the Prozac?, indicating that the hydroxyl radical the OH? quantification studies conducted with coumarin (COU), 4- kOH = 3.14 ± 0.18 min-1. When the Hg-MDEL reactor was 100% for its highest concentration (134 μmol L-1) at the time of 0.75 min. As for the solution of Prozac? 101 μmol L-1, the energy consumption was 6 kWh g-1, achieving a removal of 99%. formation of hydroxyl radicals, a high degradation rate of organic compounds (Prozac?, COU influence exerted by the transformation products. In general, the total removal of Prozac? was kinetics should be limited to the time of up to 0.50 min for the respective system, due to the Finally, the photochemical system presented in this work demonstrates a high efficiency in the and 7HC) and low energy consumption.
关键词： hydroxyl radical,direct photolysis,fluoxetine,pharmaceuticals,and kinetics,degradation mechanism
更新于2025-09-19 17:15:36
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Photocatalytic degradation of acetaminophen over Ag, Au and Pt loaded TiO2 using solar light
摘要： The sustainability and feasibility of using solar irradiation instead of UV light in photocatalysis is a promising approach for water remediation. In this study, photocatalytic degradation (PCD) of a widely used analgesic and antipyretic drug, acetaminophen (AP), with noble metal loaded TiO2 photocatalysts (Ag/TiO2, Au/TiO2 and Pt/TiO2) was investigated in aqueous suspension using solar light. The deposition of noble metals (Ag, Au and Pt) onto the TiO2 surface enhanced the PCD of AP under different operating conditions including pH, surfactants and drug excipients. However, lower degradation rate constants of AP were obtained under simulated and direct solar light as compared to UV light. The degradation mechanism of AP under UV as well as simulated solar light was found to follow similar, though not identical, reaction pathways leading to hydroxylated intermediates (e.g. 4-acetamidoresorcinol (4-AR), 4-acetamidocatechol (4-AC) and hydroquinone (HQ)) through competitive routes. The PCD of AP followed a pseudo first order kinetics according to Langmiur-Hinshelwood model. Noble metal (Ag, Au and Pt) loaded TiO2 photocatalysts can be used effectively to degrade AP in water under both solar and UV light.
关键词： Solar light,Hydroxyl radical,Noble metal,Acetaminophen,TiO2
更新于2025-09-19 17:15:36
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Hydroiodic Acid Additive Enhanced the Performance and Stability of PbS-QDs Solar Cells via Suppressing Hydroxyl Ligand
摘要： The recent emerging progress of quantum dot ink (QD?ink) has overcome the complexity of multiple?step colloidal QD (CQD) film preparation and pronouncedly promoted the device performance. However, the detrimental hydroxyl (OH) ligands induced from synthesis procedure have not been completely removed. Here, a halide ligand additive strategy was devised to optimize QD?ink process. It simultaneously reduced sub?bandgap states and converted them into iodide?passivated surface, which increase carrier mobility of the QDs films and achieve thicker absorber with improved performances. The corresponding power conversion efficiency of this optimized device reached 10.78%. (The control device was 9.56%.) Therefore, this stratege can support as a candidate strategy to solve the QD original limitation caused by hydroxyl ligands, which is also compatible with other CQD?based optoelectronic devices.
关键词： Surface passivation,Quantum dots ink,Hydroxyl ligand,HI additive,Solar cells
更新于2025-09-19 17:13:59
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Simultaneous measurement of CO and OH in flames using a single broadband, femtosecond laser pulse
摘要： In this short communication, we report simultaneous measurement of CO and OH in flames using a single femtosecond (fs)-duration laser source. Two-photon excitation of CO A 1 (cid:2) ←← X 1 ?+ (3,0), (4,0) and (5,0) bands and single-photon excitation of OH A 2 ?+ ← X 2 (cid:2) (1,0) band are achieved simultaneously using one fs-duration laser pulse near 283 nm. Subsequently, crosstalk-free, laser-induced fluorescence (LIF) emissions are detected from the v’ = 3, 4 and 5 upper vibrational levels of CO in the 200–230 nm region, and (1,1) and (0,0) bands of OH near the 310-nm region. A detailed spectroscopic investigation of CO in a gas cell is followed by simultaneous detection of CO and OH in C 2 H 4 /air flames. The measured CO and OH profiles as a function of flame equivalence ratio agree well with equilibrium calculations. The present study extends the applicability of broadband fs-LIF imaging of OH in flames, and reveal an alternate method to obtain heat release rate in turbulent flames via simultaneous OH and CO measurements.
关键词： Femtosecond diagnostics,Carbon monoxide,Laser-induced fluorescence,Hydroxyl radical
更新于2025-09-19 17:13:59
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Prickly pear fruit extract as photosensitizer for dye-sensitized solar cell
摘要： In this study, we have explored prickly pear fruit extract as a photosensitizer in dye-sensitized solar cells (DSSC). The photosensitizer was isolated from prickly pear fruits by extraction method using ethanol as solvent. Structural, morphological and optical properties of prickly pear extract characterized by XRD, SEM, UV-VIS-DRS, FTIR spectra, respectively. UV-VIS absorption and FTIR spectra of prickly pear fruit extract confirm the presence of betacyanin and hydroxyl groups anchoring onto the TiO2 surface. The absorption maxima at 534 nm in the visible region is prominent. The presence of betacyanin in the extract is indicative that the dye will be useful as a sensitizer in DSSC. Reflectance edge of TiO2 is red-shifted upon the adsorption of natural dye. The XPS analysis showed the charge state of hydroxyl (O-H) groups that are attached with the natural dye adsorbed onto the surface of TiO2. The fabricated DSSC had a conversion efficiency (?) of 0.56 % with highest fill factor (FF) of 85.0%, open-circuit voltage (Voc) of 0.56 V and short circuit-current density (Jsc) with 1.17 mA/cm2. The value obtained for the fill factor is promising to further explore the prickly pear extract for applicability in DSSC by improving the efficiency.
关键词： Dye-sensitized solar cells,Hydroxyl groups,Prickly pear fruit extract,Photosensitizer,TiO2,Fill factor,Betacyanin,Conversion efficiency
更新于2025-09-19 17:13:59
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Oral mucosal irritation potential of antimicrobial chemotherapy involving hydrogen peroxide photolysis with high-power laser irradiation for the treatment of periodontitis
摘要： In the present study, we assessed the oral mucosal irritation potential of antimicrobial chemotherapy involving hydrogen peroxide (H2O2) photolysis with a 405-nm laser device at an output power of ≥100 mW in hamsters. Twenty-four cheek pouches from 12 male Syrian hamsters received 7-min treatment with pure water (PW), 3% H2O2, laser irradiation of PW at 100 mW, laser irradiation of 3% H2O2 at 100 mW, laser irradiation of PW at 200 mW, or laser irradiation of 3% H2O2 at 200 mW (n = 4 each). The diameter of the irradiation area was set at 3 mm; accordingly, the calculated irradiances (optical power densities) of the 100- and 200-mW laser lights were approximately 1400 and 2800 mW/cm2, respectively. In addition, 12 cheek pouches from six animals received laser irradiation of 3% H2O2 at 100 mW for 1, 3, or 5 min (n = 4 each). Each treatment was repeated three times at 1-h intervals. Macroscopic and histological changes were evaluated 24 h after the last treatment. In addition, in vitro bactericidal activity of the treatment against periodontal pathogens was evaluated. We found that 405-nm laser irradiation of 3% H2O2 caused moderate to severe oral mucosal irritation when performed at powers of 100 and 200 mW for ≥3 min, while the same treatment performed at 100 mW for 1 min resulted in mild irritation. Moreover, 1-min H2O2 photolysis at 100 mW caused a >4-log decrease in viable bacterial counts. These findings suggest that 1-min H2O2 photolysis, which can effectively kill periodontal pathogens, may be acceptable when a 405-nm laser device is used at 100 mW. However, use of the laser at a lower power would be preferable for the prevention of unnecessary oral mucosal irritation.
关键词： hydroxyl radicals,photolysis,periodontitis,oral mucosal irritation,laser irradiation,antimicrobial chemotherapy,hydrogen peroxide
更新于2025-09-16 10:30:52