Glow Discharge Electrolysis Plasma Research Articles

Synthesis of styrene–acrylate emulsion by glow discharge electrolysis plasma and its application for the conservation of simulated disrupting murals in Dunhuang Mogao grottoes

AbstractIn this work, a styrene (ST)–acrylate emulsion was synthesized via glow discharge electrolysis (GDE) plasma technique. A possible forming mechanism was proposed. Moreover, the adhesion property of the emulsion was evaluated for the conservation of simulated disrupting murals. The results showed that under optimum conditions, the solid content, emulsion conversion, and gel rate are 29.0%, 85.6%, and 1.04%, respectively. The obtained ST–acrylate emulsion is spherical in shape, with a particle size of about 100 nm. The property of ST–acrylate emulsion prepared by GDE is superior to that of the commercial ST–acrylate emulsion for the conservation of simulated disrupting murals. Compared with other methods, GDE has the advantages of simple steps, controllable reaction, environmental friendliness, no chemical initiator, and no N2 atmosphere.

Cathode glow discharge electrolysis synthesis of flower-like β-Ni(OH)2 microsphere for high-performance supercapacitor

Nanoscale β-Ni(OH)2 is considered to be one of the most promising electrode material for supercapacitors because of its low cost, long cycle life and high theoretical capacitance. However, its preparation often involves either high temperatures or the use of complicated alkaline system, water-soluble precursors and surfactants, which greatly restrict its development. In this paper, a 3D flower-like β-Ni(OH)2 microsphere was successfully fabricated at 500 V discharge voltage in NaCl electrolyte solution with adding a certain amount of CH3COONa as stabilizer via cathode glow discharge electrolysis (CGDE) plasma, in which Pt needle and Ni foil were acted as cathode and anode, respectively. The results of FT-IR, XRD, Raman and XPS demonstrated that the hexagonal phase β-Ni(OH)2 with structural defects is produced during the CGDE process. Morphological analysis by SEM, TEM and AFM revealed that β-Ni(OH)2 exhibits a 3D flower-like microsphere with a diameter of about 1–3 μm, which is assembled by dozens of ∼3.0 nm thick nanosheets. The specific surface area and average pore-size of the flower-like β-Ni(OH)2 microspheres are 184.9 m2 g−1 and 17.8 nm, respectively. A possible formation mechanism is proposed on the basis of Ostwald ripening. β-Ni(OH)2 exhibits a high specific capacitance of 1818 F g−1 at 3 A g−1 and good capacity retention of 85 % after 1000 charge–discharge cycles at current density of 5 A g−1. 3D flower-like β-Ni(OH)2 microsphere can be used as a highly promising candidate for the supercapacitor electrodes.

Preparation of Mn3O4 microspheres via glow discharge electrolysis plasma as a high-capacitance supercapacitor electrode material

Manganic manganous oxide (Mn3O4) microspheres were prepared at 550 V discharge voltage in 2 g L−1 NaNO3 solution by one-step method via cathode glow discharge electrolysis (CGDE) plasma technique for high-capacitance supercapacitor electrode materials, in which Mn foil and Pt needle point were served as anode and cathode, respectively. The structure, phase composition and morphology of as-prepared products were characterized by FT-IR, XRD, XPS, SEM, TEM and BET analysis. A mechanism for the fabrication of Mn3O4 microspheres was proposed. The electrochemical behaviors of the Mn3O4 microspheres were examined in 1.0 mol L−1 Na2SO4 electrolyte. The results showed that Mn3O4 microspheres are composed of small nanospheres with sizes of about 20 nm and large nanospheres with sizes of about 177 nm. Specific surface area of microspheres is 48.03 m2 g−1. The Mn3O4 microsphere as an electrode has an outstanding specific capacitance of 360 F g−1 at 0.5 A g−1 and a superior cycling property of 83.6 % capacity retention after 1000 cycles at 1 A g−1, evidencing the potential as an electrode material for supercapacitor.

Fabrication of Fe3O4 nanoparticles by using cathode glow discharge electrolysis plasma and its electrochemical properties

In this work, Fe3O4 nanoparticles (NPs) were fabricated by one-step method using cathode glow discharge electrolysis (CGDE) plasma technique in 2.0 g L−1 Na2SO4 solution at 600, 650 and 700 V applied voltage, in which Pt needle point and scrap iron wire were served as cathode and anode, respectively. The fabricated products were characterized by FT-IR, XRD, SEM and TEM. A possible fabrication mechanism of Fe3O4 NPs under CGDE was proposed. In addition, electrochemical performance of Fe3O4 NPs as an electrode material for supercapacitors was investigated by cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy in 1 mol L−1 Na2SO3 electrolyte. The results showed that the particle sizes of the fabricated products are below 20 nm, Fe3O4 NPs as the electrode material have good reversibility which can reach 247 F g−1 specific capacitance at current density of 0.5 A g−1, and still keep 41.1% capacity retention after 5000 cycles. Fe3O4 NPs can be regarded as a promising and favorable candidate of electrode materials for supercapacitor. Compared with other methods, CGDE has the advantages of simple experimental equipment, no gas supply, mild reaction conditions and no secondary pollution. It is a green synthesis technique without adding alkali, surfactant and ferric salt containing both Fe2+ and Fe3+.

Addition of Hybrid Coupling Agent Based Natural Rubber‐Starch on Natural Rubber Composite

AbstractNatural rubber blended with biomass fibers as a filler is one of promising methods to produce high‐quality car tire that require good thermal resistance and low noise level caused by the frictional forces between the tire and road. Biomass fibers have suitable acoustic properties, good tensile strength, and also density regarding its chain molecule structure and porous structure. The major biomass byproduct from the palm oil industry in Indonesia is empty fruit bunches (EFBs). Because of the different polarity of natural rubber and EFBs, coupling agent has to be added for producing composite with good miscibility and desired mechanical properties. In this study the hybrid coupling agent based natural rubber‐starch prepared with glow discharge electrolysis plasma method is added to the natural rubber/EFBs fibers composite. The ratio of EFBs fibers to the composite is varied to 5, 10, and 15 phr, while the coupling agent is added at fixed 1 phr. Field emission scanning electron microscopy (SEM) and mechanical testing are used for the composite characterization. The mechanical tests showed that the addition of coupling agents provides greater tensile strength compared to composites without the addition of coupling agent. These results are supported by morphology analyses using SEM, showing the good interaction on the surface between the EFBs fibers and the natural rubber matrix with addition of the coupling agent.

Facile Synthesis of Fluorescence/Temperature Multisensitive Hybrid Hydrogels

Hybrid hydrogels based on poly(N-isopropylacrylamide) and poly(acrylamide) containing CdTe quantum dots with UV sensitive response and including NaYF4:Yb/Er nanoparticles have been prepared through glow discharge electrolysis plasma. The fluorescence characteristic and temperature sensitivity of the prepared hydrogels have been most extensively studied. In addition, scanning electron microscopy, X-ray diffraction, differential scanning calorimetry were determined to characterize the morphology, degree of crystallinity and the phase transformations of the hydrogels. The results suggested that the phase transition temperature of the hydrogels was 32.5°C and the hydrogels had good up-conversion and down-conversion fluorescence properties. Moreover, hybrid hydrogels had a reversible temperature response performance.

Synthesis of spindle-like CuO nanoparticles by using cathode glow discharge electrolysis plasma

Spindle-like CuO nanoparticles (NPs) were prepared in a single-step approach by using a cathode glow discharge electrolysis plasma (CGDEP) technique with 2.5 g L−1 NaNO3 as an electrolyte and 1.0 g L−1 cetyltrimethylammonium bromide (CTAB) as a stabilizer. When a sufficiently high voltage (>280 V) was applied, plasma was generated around the Pt needle point cathode. The copper foil anode was gradually consumed and black CuO NPs appeared. The active species formed during the CGDEP process were recorded on an optical fiber spectrometry. The structure and morphology of the CuO NPs were characterized by XRD and SEM. The results showed that spindle-like CuO NPs with the length of 250–350 nm were formed at 300 V discharge voltage.

Facile synthesis of poly N-isopropylacrylamide/acrylamide-quantum dots hybrid hydrogels and their fluorescence temperature sensitive behaviors

ABSTRACTPoly (N-isopropylacrylamide) (PNIPAM) is an intelligent hydrogel which exhibits volume transition in response to temperature change. This work reports the PNIPAM/AM-QDs hybrid hydrogels, in which N-isopropylacrylamide, acrylamide as monomers and CdTe/CdS quantum dots (QDs) as filler, are prepared by glow discharge electrolysis plasma (GDEP). The hydrogels are investigated by transmission electron microscopy (TEM), X-ray diffraction (XRD), FTIR spectra, differential scanning calorimetry (DSC) and PL spectra, as well as the swelling rate, temperature sensitivity and fluorescence reversibility. The results show that the PNIPAM hydrogels and QDs are cross-linked by coordination bond, and the QDs are well dispersed and combined firmly in the networks of the hydrogels. The phase transition temperature of PNIPAM/AM-QDs hybrid hydrogels is 32.5°C. The fluorescence intensity of hydrogels is 1490 a.u. and 20 a.u. at 20 and 40°C, respectively. Furthermore, the luminescence intensity of hydrogels is almost not weakened after five heating-cooling cycles, which should be used as a temperature-controlled light switch.

Chitosan/attapulgite/poly(acrylic acid) hydrogel prepared by glow-discharge electrolysis plasma as a reusable adsorbent for selective removal of Pb2+ ions

A chitosan/attapulgite/poly(acrylic acid) (CS/ATP/PAA) hydrogel was prepared by glow-discharge electrolysis plasma (GDEP) technique, in which N,N'-methylene-bis-acrylamide was acted as a crossing-linker, and then it was used as an adsorbent for the removal of Pb2+ ions from aqueous solutions. A possible polymerization mechanism is proposed. The structure, morphology and adsorption mechanism of CS/ATP/PAA hydrogel were characterized by FTIR, XRD, SEM and XPS techniques. The influences of pH, contact time and initial concentration on the Pb2+ adsorption were systematically examined. The selective adsorption of CS/ATP/PAA hydrogel for Pb2+ ions with the coexistence of Cd2+, Co2+ and Ni2+ ions was investigated, as well. In addition, regeneration of hydrogel was also discussed in detail. The results indicated that the optimal adsorption pH was 4.8, and the time of adsorption equilibrium was 60 min. The adsorption behaviors fitted well to the pseudo-second-order kinetic model and Langmuir isotherm. The maximum adsorption capacity of CS/ATP/PAA hydrogel for Pb2+ ions based on Langmuir isotherm was 531.9 mg g–1. The CS/ATP/PAA adsorbent exhibited promising selectivity for Pb2+ ions with the coexistence of Cd2+, Co2+ and Ni2+ ions, and excellent reusability using EDTA-4Na solution as desorption solution. The adsorption process of Pb2+ ions on CS/ATP/PAA hydrogel was presented by the coordination between N or O atoms and Pb2+ ion, and the ion-exchange between Na+ and Pb2+ ions.

Electrolyte Effect to Copolymer Grafting of Starch onto Natural Rubber Using Glow Discharge Electrolysis Plasma (GDEP) Method

Natural rubber has an important role in many applications such as tyre products due to excellent elasticity and high friction causing wear on the tire and leading to energy dissipation in the form of heat and noise. Although reinforcing both inorganic and organic fillers can be a solution, it generally needs expensive coupling agent. Finding an excellent coupling agent by considering to environmentally friendly materials and economic aspect, is an interesting study. This study reported modification of natural rubber through copolymer grafting of starch onto natural rubber latex using Glow Discharge Electrolysis Plasma (GDEP) with varying of electrolyte. The experimental indicated that the electrolytes generally give significant effect to percent yield of the hybrid natural rubber-starch product. The highest percent yield is obtained from adding KCl. Addition of the divalent salts such as MgCl2and CaCl2disturbs the process due to reaction the salts with stabilizing system in natural rubber latex. Addition of NaOH is able to enhance the reaction performance with considering the radical elements recombination. The starch part as polar part and the natural rubber as non polar part building up the hybrid natural rubber-starch products, correlate with hydrophilicity and degradation of the both parts. This study results in the lowest contact angle of 54.80, the highest percent yield of 8.6 %,, and the highest starch content in the product of 1.6%.

The Types of Plasma Reactors in Wastewater Treatment

Water pollution is a serious problem in the development of society of China. The plasma technology is one of the advanced oxidation technologies which is an efficient method in wastewater treatment. In this paper the degradation mechanism of organic pollutants in water by plasma is suggested, which is the main chemical reactions and physical effects, the different types of discharge and the corresponding reactors have been mentioned, including pulsed discharge plasma reactor, gliding arc discharge reactor and contact glow discharge electrolysis plasma reactor, especially the reactions in dielectric barrier discharge plasma. The plasma combined with another oxidation reaction processes also are reviewed, including catalyst, Ultraviolet radiation and Fenton reaction combined with plasma reactor.

Glow discharge electrolysis plasma initiated synthesis of upconversion luminescent and temperature sensitive multifunctional hydrogel

ABSTRACTIn the present work, a novel multifunctional hydrogel that simultaneously possesses strong upconversion luminescence (UL) and temperature responsibility was fabricated based on the crosslinking of hemicellulose and ricinoleic acid capped NaYF4:Yb/Er in the presence of Poly (N-isopropylacrylamide) (PNIPAM) and polyacrylamide (PAAm) aqueous solution by using glow discharge electrolysis plasma (GDEP) initiated technique. Its structure and properties were characterized by wide angle X-ray diffraction, FT-IR spectra, scanning electron microscopy, transmission electron microscope and fluorescence spectra. The obtained hydrogel exhibited reversibly temperature-dependent UL and highly enhanced sensibility. The luminescence intensity and transmittance of hydrogel showed a sharp decrease in the range of 32–35°C. Furthermore, the luminescence intensity of hydrogel was almost not weakened after five heating-cooling cycles, which may allow their use in remote control thermosensitive switch.

키토산 기반 미세다공성 고분자의 Pd2+에 대한 선택적 흡착성 및 재사용성

A green and simple glow-discharge electrolysis plasma (GDEP) technique was used to synthesize the chitosan/attapulgite/poly(acrylic acid-co-2-acrylamido-2-methyl-1-propanesulfonic acid) (CS/ATP/P(AA-co-AMPS)) microporous polymer. The results showed that the optimum pH for the adsorption of PbSUP2+/SUP, CdSUP2+/SUP, CoSUP2+/SUP, and CuSUP2+/SUP is 4.8, and time of adsorption equilibrium is 60 min. Adsorption kinetics fits well to the pseudo-second-order model. The maximum adsorption capacities for PbSUP2+/SUP, CdSUP2+/SUP, CuSUP2+/SUP and CoSUP2+/SUP are 500.0, 301.7, 180.0 and 151.7 mg gSUP-1/SUP, respectively. The microporous polymer has higher adsorption selectivity toward PbSUP2+/SUP with the coexistence of CdSUP2+/SUP, CoSUP2+/SUP, and CuSUP2+/SUP. The CS/ATP/P(AAco-AMPS) possesses promising regeneration and reusability using 2.0 g L–1 ethylenediamine tetraacetic acid tetrasodium salt (EDTA-4Na) solution as eluent. CS/ATP/P(AA-co-AMPS) can be used as a very promising absorbent for the separation purification and selective recovery of PbSUP2+/SUP in aqueous solution containing CdSUP2+/SUP, CoSUP2+/SUP, and CuSUP2+/SUP ions.

Reusability and selective adsorption of Pb2+ on chitosan/P(2-acrylamido-2-methyl-1-propanesulfonic acid-co-acrylic acid) hydrogel

Reusability and selective adsorption toward Pb2+ with the coexistence of Cd2+, Co2+, Cu2+ and Ni2+ ions on chitosan/P(2-acrylamido-2-methyl-1-propanesulfonic acid-co-acrylic acid) [CS/P(AMPS-co-AA)] hydrogel, a multi-functionalized adsorbent containing –NH2, –OH, –COOH and –SO3H groups was studied. The CS/P(AMPS-co-AA) was prepared in aqueous solution by a simple one-step procedure using glow discharge electrolysis plasma technique. The reusability of adsorbent in HNO3, EDTA-2Na and EDTA-4Na was investigated in detail. The competitive adsorption of the metal ions at the initial stage was compared between their equal mass concentration and equal molar concentration. In addition, the adsorption mechanism of the adsorbent for adsorption of Pb2+ was also analyzed by XPS. The results showed that the optimum pH of adsorption was 4.8, and time of adsorption equilibrium was about 180 min. Adsorption kinetics fitted well in the pseudo second-order model. The equilibrium adsorption capacities of Pb2+, Cd2+, Co2+, Cu2+, and Ni2+ at pH 4.8 were obtained as 673.3, 358.3, 176.7, 235.0 and 171.7 mg g−1, in their given order. The adsorbent displayed an excellent reusability using 0.015 mol L−1 EDTA-4Na solution as the eluent, and the desorption ratio could not correctly reflect the true characteristics of adsorption/desorption process. Moreover, the adsorbent showed good adsorption selectivity for Pb2+. The molar adsorption capacity at the initial stage with equal molar concentration was more reliable than the mass adsorption capacity during the study of selective adsorption. According to the XPS results, the adsorption of Pb2+ ions by the CS/P(AMPS-co-AA) absorbent could be attributed to the coordination between N atom and Pb2+ and ion-exchange between Na+ and Pb2+.

Synthesis and characterization of poly(N-isopropylacrylamide)/graphene oxide nanocomposite hydrogels by using glow discharge electrolysis plasma

ABSTRACTA novel poly(N-isopropylacrylamide) (PNIPAM)-based hydrogel with incorporation of graphene oxide (GO) was successfully prepared by glow discharge electrolysis plasma (GDEP). The structure and morphology of the PNIPAM/GO nanocomposite hydrogels were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM), as well as by determination of swelling, mechanical property, phase transformation behaviors, and photo-thermal conversion performance. The results revealed that the phase transition temperatures of all the nanocomposite hydrogels were approximately 33°C and the hydrogel (PG-2), under discharge voltage 600 V, had faster change of swelling ratios for distilled water, more sensitive to pH, and better photo-thermal property than other nanocomposite hydrogels. In addition, shrinkage of the network hydrogels and enhancement of the compressive strength and Young’s modulus took place at higher discharge voltage. This work provided a new pathway for preparation of PNIPAM/GO nanocomposite hydrogels, with environmental friendliness and excellent photo-thermal property, which may allow their use in the intelligence remote controlled area.

Selective adsorption and reusability behavior for Pb2+ and Cd2+ on chitosan/poly(ethylene glycol)/poly(acrylic acid) adsorbent prepared by glow-discharge electrolysis plasma

Using Pearson’s hard and soft acids and bases (HSAB) principle as the design guideline, a novel chitosan/poly(ethylene glycol)/poly(acrylic acid) (CS/PEG/PAA) hydrogel adsorbent containing hard Lewis base adsorption site (i.e., amino group, hydroxyl group, ether linkage, carboxylate ions) was prepared by glow-discharge electrolysis plasma (GDEP) technique and then applied for the selective adsorption of Pb2+. A copolymerization mechanism initiated by GDEP was proposed. The structure, thermal stability, and morphology of CS/PEG/PAA adsorbent were characterized by FT-IR, thermogravimetry/differential thermogravimetry (TG/DTG), and SEM. The effects of the solution pH and contact time on the single-component adsorption were examined by batch experiments. Competitive adsorptions of Pb2+ and Cd2+ were carried out under equal mass concentration and equal molar concentration. In addition, regeneration and reusability of adsorbent were also investigated in detail. The results showed that the maximum adsorption capacities for Pb2+ and Cd2+ are 431.7 and 265.0 mg g−1, respectively. The kinetic behaviors of the adsorption and the fourth desorption for single component and the competitive adsorption for Pb2+ follow the pseudo-second-order model with pH = 4.8. The CS/PEG/PAA adsorbent has good adsorption selectivity for Pb2+ with the coexistence of Cd2+. The adsorbent displays excellent regeneration and reusability in the EDTA-4Na solution.

A simple method for the production of hydrogels based on hemicellulose in aqueous solution

A simple method of bamboo hemicellulose-based hydrogel with multiple responses properties was proposed employing glow discharge electrolysis plasma (GDEP). The network of hydrogels was characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The mechanical properties, swelling, and stimuli responses were also investigated. The results showed that swelling ratio of hydrogel under 570 V and 90 s was 903.6 g/g. Too long discharge time or high discharge voltage indicated high compression stress and modulus. The hydrogels exhibited excellent sensitivity to pH and salts, which indicated their widely application such as adsorption, separation, and drug release systems.

Synthesis, characterization and adsorption of cationic dyes by CS/P(AMPS-co-AM) hydrogel initiated by glow-discharge-electrolysis plasma

In this work, a novel chitosan/P(2-acrylamido-2-methyl-1-propanesulfonic acid-co-acrylic amide) (CS/P(AMPS-co-AM)) hydrogel was successfully prepared by a simple one-step method using glow-discharge-electrolysis plasma (GDEP) initiated copolymerization, in which N,N′-methylenebisacrylamide was used as a cross-linking agent. A copolymerization mechanism of AMPS and AM onto CS initiated by GDEP was proposed. The structure, thermal stability and morphology of CS/P(AMPS-co-AM) hydrogel were characterized by Fourier transform infrared (FTIR), X-ray diffraction (XRD), TG/DTG, and scanning electron microscope (SEM). This hydrogel was employed as an absorbent for the removal of methylene blue (MB) and malachite green (MG) from aqueous solutions. The effects of pH, contact time and equilibrium concentration on the dye adsorption were investigated batchwise. FTIR and XRD indicated that AM and AMPS were grafted onto the CS backbone successfully, forming copolymer. TG/DTG suggested that grafted AMPS and AM onto CS could change the thermal stability of the CS. SEM showed a unique three-dimensional porous structure for the CS/P(AMPS-co-AM) hydrogel. The optimum pH for the removal of cationic dyes was 5.8, and time of adsorption equilibrium was achieved in 90 min. The CS/P(AMPS-co-AM) hydrogel exhibited a very high adsorption potential, and its adsorption capacities calculated based on the Langmuir isotherm for MB and MG were 1,538.5 and 917.4 mg g−1, respectively. The dye adsorption data fitted well to the pseudo-second-order model and Langmuir model at 25 °C with pH 5.8.

Synthesis, characterization, and property testing of PGS/P(AMPS-co-AM) superabsorbent hydrogel initiated by glow-discharge electrolysis plasma

A palygorskite/poly(2-acrylamido-2-methyl-1-propanesulfonic acid-co-acrylamide) (PGS/P(AMPS-co-AM)) superabsorbent hydrogel was prepared in aqueous solution using glow-discharge electrolysis plasma (GDEP) as an initiator and N,N′-methylene-bis-acrylamide as a cross-linker. A possible copolymerization mechanism initiated by GDEP was proposed. The structure, thermal stability, and morphology of PGS/P(AMPS-co-AM) were characterized by FT-IR, XRD, TG-DTG, and SEM. The swelling kinetics, pH-reversibility, and influence of various pH and salt solutions on the swelling were investigated. Adsorption kinetics and adsorption mechanism of hydrogel for dyes were studied in detail. The results indicated that the equilibrium swelling of hydrogel is 652.6 g g−1 in distilled water. The swelling of the hydrogel in salt solutions from highest to lowest is Na+ > Mg2+ > Fe3+. The hydrogel has pH-reversibility responsive to the pH and salts solutions. The adsorption process of dyes follows the pseudo-second-order kinetic model with multi-step diffusion process. In addition, PGS/P(AMPS-co-AM) hydrogel can be regenerated and reused.

Glow discharge electrolysis plasma initiated preparation of temperature/pH dual sensitivity reed hemicellulose-based hydrogels

The temperature/pH dual sensitivity reed hemicellulose-based hydrogels have been prepared through glow discharge electrolysis plasma (GDEP). The effect of different discharge voltages on the temperature and pH response performance of reed hemicellulose-based hydrogels was inspected, and the formation mechanism, deswelling behaviors of reed hemicellulose-based hydrogels were also discussed. At the same time, infrared spectroscopy (FT-IR), scanning differential thermal analysis (DSC) and scanning electron microscope (SEM) were adopted to characterize the structure, phase transformation behaviors and microstructure of hydrogels. It turned out to be that all reed hemicellulose-based hydrogels had a double sensitivity to temperature and pH, and their phase transition temperatures were all approximately 33°C, as well as the deswelling dynamics met the first model. In addition, the hydrogel (TPRH-3), under discharge voltage 600V, was more sensitive to temperature and pH and had higher deswelling ratio.