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Xiuwen Cheng - One of the best experts on this subject based on the ideXlab platform.
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efficient removal of organic contaminant via activation of Potassium Persulfate by γ fe2o3 α mno2 nanocomposite
Separation and Purification Technology, 2019Co-Authors: Ruonan Guo, Lichao Nengzi, Xiuwen ChengAbstract:Abstract In this study, γ-Fe2O3/α-MnO2 nanocomposite, which possesses magnetism as well as excellent activation performance for Potassium Persulfate (PS) to degrade organic contaminants in water, was successfully fabricated through ultrasonic strategy. Noted, proportion between γ-Fe2O3 and α-MnO2 was optimized to achieve excellent magnetic and activation performance. Also, physicochemical properties of magnetic nanocomposite material (γ-Fe2O3/α-MnO2 1/7, FM1-7) are investigated by SEM, EDS, BET, XRD, TEM, XPS and vibrating sample magnetometer (VSM). Results show that γ-Fe2O3 nanoparticles is connected with α-MnO2 nanorods successfully, what’s more, FM1-7 nanocomposite crystal structure is intact and its crystallinity is excellent. Besides, in γ-Fe2O3/α-MnO2/PS reaction system, about 92.79% of Rhodamine B could be removed within 30 min. The result proves that when the γ-Fe2O3 content is 12.5%, γ-Fe2O3/α-MnO2 nanocomposite exhibits superior activation performance. γ-Fe2O3/α-MnO2/PS reaction shows the most excellent degradation towards Rhodamine B when it is compared with another reaction systems. Most importantly, in this study, the crucial role of γ-Fe2O3 and catalysis mechanism of γ-Fe2O3/α-MnO2 is also discussed in detail. In the Fenton-like system mediated by Fe(III) and Mn(IV), the redox reactions with the activation of PS happen on the surface of γ-Fe2O3/α-MnO2. Therefore, strong oxidizers of SRs (SO4 −), hydroxyl radicals ( OH) and even superoxide anion ( O2−) may be generated and participated in the degradation of Rhodamine B. What’s more, the result of repetitive experiment illustrates that magnetic FM1-7 sample possesses good recycle and reusability capacities. This study not only provides a feasible strategy to prepare catalyst which could be used to active PS, but also is expected to be applied to deal with many kinds of contaminants removal problem according to the practical requirement.
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construction of fe2o3 co3o4 exfoliated graphite composite and its high efficient treatment of landfill leachate by activation of Potassium Persulfate
Chemical Engineering Journal, 2019Co-Authors: Ruonan Guo, Qi Meng, Huixuan Zhang, Xinyi Zhang, Qingfeng Cheng, Xiuwen ChengAbstract:Abstract Landfill leachate, as one of high-ammonia nitrogen organic pollutants, has been characterized to be potentially dangerous on ground water and soil. However, traditional technologies cannot deal with these substances swiftly. Thus, in this study, exfoliated graphite (EG) immobilized ferric oxide and cobaltosic oxide species has been successfully constructed by a facile heating-precipitation strategy. Subsequently, physicochemical properties of Fe2O3/Co3O4/EG were investigated by scanning electron microscope, X-ray diffraction, N2 adsorption/desorption, X-ray photoelectron spectroscopy measurements. Results indicated that Fe2O3 and Co3O4 nano-particles were successfully deposited onto the surface and interstice of EG substrate. In addition, activation performance of Fe2O3/Co3O4/EG composite was evaluated by activating Potassium Persulfate (PS) to degrade the landfill leachate. In addition, effect of some critical operating parameters on the removal of landfill leachate was studied systematically. The experimental results showed that 90.6% of NH4+-N and 67.1% of COD in landfill leachate could be removed at the optimized conditions of pH 5, PS concentration 0.05 M and Fe2O3/Co3O4/EG dosage 0.1 g. Furthermore, Fe2O3/Co3O4/EG sample also displayed good recycle and reusable capacities. Besides these, high-efficient removal mechanism of Fe2O3/Co3O4/EG was proposed. This study provides a feasible strategy to prepare catalyst which could be potentially applied in refractory contaminants elimination.
Soorathep Kheawhom - One of the best experts on this subject based on the ideXlab platform.
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enhanced cycling performance of rechargeable zinc air flow batteries using Potassium Persulfate as electrolyte additive
International Journal of Molecular Sciences, 2020Co-Authors: Ramin Khezri, Soraya Hosseini, Abhishek Lahiri, Shiva Rezaei Motlagh, Mai Thanh Nguyen, Tetsu Yonezawa, Soorathep KheawhomAbstract:Zinc-air batteries (ZABs) offer high specific energy and low-cost production. However, rechargeable ZABs suffer from a limited cycle life. This paper reports that Potassium Persulfate (KPS) additive in an alkaline electrolyte can effectively enhance the performance and electrochemical characteristics of rechargeable zinc-air flow batteries (ZAFBs). Introducing redox additives into electrolytes is an effective approach to promote battery performance. With the addition of 450 ppm KPS, remarkable improvement in anodic currents corresponding to zinc (Zn) dissolution and limited passivation of the Zn surface is observed, thus indicating its strong effect on the redox reaction of Zn. Besides, the addition of 450 ppm KPS reduces the corrosion rate of Zn, enhances surface reactions and decreases the solution resistance. However, excess KPS (900 and 1350 ppm) has a negative effect on rechargeable ZAFBs, which leads to a shorter cycle life and poor cyclability. The rechargeable ZAFB, using 450 ppm KPS, exhibits a highly stable charge/discharge voltage for 800 cycles. Overall, KPS demonstrates great promise for the enhancement of the charge/discharge performance of rechargeable ZABs.
Wenyen Chiu - One of the best experts on this subject based on the ideXlab platform.
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graft polymerization of vinyl acetate onto granular starch comparison on the Potassium Persulfate and ceric ammonium nitrate initiated system
Journal of Applied Polymer Science, 2006Co-Authors: Sunmou Lai, Trongming Don, Y H Liu, Wenyen ChiuAbstract:This work was undertaken to discuss in depth the vital differences in the morphological development during synthesis, and properties of starch-g-poly-(vinyl acetate) copolymers using two different initiators, Potassium Persulfate (KPS) and ceric ammonium nitrate (CAN). KPS-initiated system gave relatively low values of grafting ratio and grafting efficiency, indicating a great tendency for the formation of poly(vinyl acetate) homopolymer (PVAc). Yet, higher values were seen for the CAN-initiated system. Transmission electron microscope observations indicated a relatively broad distribution of latex particles for the KPS-initiated system. The surface potential of latex particles was about −3.5 mV, which turned out to be insufficient to maintain stability of latex particles. On the other hand, a uniform particle size distribution was found for the CAN-initiated system, as the surface potential of latex particles was 21.5 mV. Moreover, radicals on starch molecules were generated directly through a redox reaction with positively charged ceric ion. The hydrophobic PVAc chains were thus grafted on starch, resulting in an amphiphilic graft copolymer, which provides a sufficient stabilization degree as a role of surfactant to render a relatively uniform distribution of latex particles. The synthesized starch-g-poly(vinyl acetate) copolymers were further converted to starch-g-poly(vinyl alcohol) through saponification, which were subjected to evaluations regarding the biodegradation and cell culture capability. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3017–3027, 2006
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free radical degradation of chitosan with Potassium Persulfate
Polymer Degradation and Stability, 2002Co-Authors: Shihchang Hsu, Trongming Don, Wenyen ChiuAbstract:A thermal dissociation initiator, Potassium Persulfate (KPS), is added to the chitosan solution at 70 � C; immediately, the solution viscosity and the molecular weight of chitosan decrease in a very short time. Size exclusion chromatography, nuclear magnetic resonance and electron spin resonance were used to study the degradation mechanism. A free radical degradation mechanism of chitosan by KPS is then proposed. When KPS is thermally dissociated into anionic radicals, they are attracted to the cationic amino group in the chitosan ring. Subsequently, the anionic radical attacks the C-4 carbon and transfers the radical to the C-4 carbon by subtracting the hydrogen from it. The presence of free radical at C-4 carbon eventually results in the breakage of the glycosidic C– O–C bond in the chitosan main chain. According to this mechanism, the concentrations of KPS, total free radicals and the degraded chitosan chain at different degradation times are all calculated by solving the rate equations. Finally, the calculated average molecular weights of the degraded chitosan chains at different reaction times agree with the experimental values. # 2001 Elsevier Science Ltd. All rights reserved.
Ramin Khezri - One of the best experts on this subject based on the ideXlab platform.
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enhanced cycling performance of rechargeable zinc air flow batteries using Potassium Persulfate as electrolyte additive
International Journal of Molecular Sciences, 2020Co-Authors: Ramin Khezri, Soraya Hosseini, Abhishek Lahiri, Shiva Rezaei Motlagh, Mai Thanh Nguyen, Tetsu Yonezawa, Soorathep KheawhomAbstract:Zinc-air batteries (ZABs) offer high specific energy and low-cost production. However, rechargeable ZABs suffer from a limited cycle life. This paper reports that Potassium Persulfate (KPS) additive in an alkaline electrolyte can effectively enhance the performance and electrochemical characteristics of rechargeable zinc-air flow batteries (ZAFBs). Introducing redox additives into electrolytes is an effective approach to promote battery performance. With the addition of 450 ppm KPS, remarkable improvement in anodic currents corresponding to zinc (Zn) dissolution and limited passivation of the Zn surface is observed, thus indicating its strong effect on the redox reaction of Zn. Besides, the addition of 450 ppm KPS reduces the corrosion rate of Zn, enhances surface reactions and decreases the solution resistance. However, excess KPS (900 and 1350 ppm) has a negative effect on rechargeable ZAFBs, which leads to a shorter cycle life and poor cyclability. The rechargeable ZAFB, using 450 ppm KPS, exhibits a highly stable charge/discharge voltage for 800 cycles. Overall, KPS demonstrates great promise for the enhancement of the charge/discharge performance of rechargeable ZABs.
Masayoshi Okubo - One of the best experts on this subject based on the ideXlab platform.
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hollow particles are produced by the burying of sulfate end groups inside particles prepared by emulsion polymerization of styrene with Potassium Persulfate as initiator in the absence presence of a nonionic emulsifier
Polymer Chemistry, 2017Co-Authors: Chujuan Huang, Masayoshi Okubo, Hiroshi Kobayashi, Mineho MoritakaAbstract:We prepared submicrometer-sized polystyrene (PS) particles by emulsion polymerization with/without polyoxyethylene nonylphenyl ether nonionic emulsifier (Emulgen 911), and examined how water absorption was affected by polymer end-groups derived from hydrophilic (ionic) or hydrophobic (nonionic) initiator and/or incorporated nonionic emulsifier when they were inside these particles. PS particles having sulfate end-groups, which were prepared using a Potassium Persulfate initiator with/without Emulgen 911, absorbed a certain amount of water inside them, whereas those having isobutyronitrile end-groups derived from 2,2′-azobis(isobutyronitrile) initiator did not. Absorption of water inside the particles caused by the incorporated Emulgen 911 alone was minimal in the absence of the sulfate end-groups. Considering that sulfate end-groups existing at the particle surface do not contribute to water absorption into the particles, these results indicate that sulfate end-groups did not only exist at the surface of the PS particles but were also buried inside the PS particles during the emulsion polymerization. This offers a clear explanation of a longtime enigma in (emulsifier-free) emulsion polymerization. Both the ionic end-groups buried in the particles and the nonionic emulsifier incorporated inside cooperate to absorb water, thus resulting in the formation of hollow PS particles.
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the acceleration of decomposition of Potassium Persulfate in the presence of sodium dodecyl sulfate and polymer particles as a model of emulsion polymerization system
Colloid and Polymer Science, 1991Co-Authors: Masayoshi Okubo, M Fujimura, T MoriAbstract:The decomposition rates of Potassium Persulfate (KPS) in aqueous solutions containing sodium dodecyl sulfate (SDS) in the presence of polystyrene or poly(methyl methacrylate) particles as models of emulsion polymerization systems were measured by isotachophoresis. “Free” SDS molecules dispersed in the monomolecular state had an ability to accelerate the KPS decomposition, but SDS molecules adsorbed onto the polymer particles did not accelerate it.