Solution Plasma Process Research Articles

Solution Plasma Process and Bioactivity Against Yeast and Bacteria for Selenium Nanoparticle Synthesis in an Ethanol–Water Mixture

Solution Plasma Process and Bioactivity Against Yeast and Bacteria for Selenium Nanoparticle Synthesis in an Ethanol–Water Mixture

Evaluation of the oxidative degradation of aromatic dyes by synthesized nano ferrate(VI) as a simple and effective treatment method

In this study, ferrate nanoparticles are prepared by solution plasma process and are employed for degradation of different dyes including Bromothymol blue, Cresol Red, Methylene blue, Methyl orange, Methyl Red, Methyl violet and Blue 203. TEM image indicates that particle size of synthesized nano-ferrate is lower than 50 nm. The effects of nanoparticle dosage, pH and temperature on dye degradation are examined. The degradation efficiency indicates that ferrate is capable for oxidation of dyes with high efficiency in very low reaction time. Moreover, removal efficiency of dyes increases more than 96 % by enhancing ferrate dosage especially with multiple addition of ferrate in very low dosage. The optimum temperature for oxidation is 25° and effective pH range is 6–8. The reaction kinetic of dye oxidation with ferrate is second order reaction and the calculated overall reaction rate constants indicate higher values for methyl orange and blue 203. The oxidation efficiency indicates no considerable variation in the presence of anions SO42−, Cl−, and HCO3− and monovalent cations K+ and Na+, while divalent and trivalent cations (Mg2+, Ca2+, Cu2+ and Fe3+) and humic acid inhibit dyes oxidation. In addition, real water systems including tap and river water without pH control are applied and the results show that removal efficiencies for most of dyes change very low. Mineralization efficiency of dyes measured by total organic carbon are about 50 % indicates that dyes are not degraded to CO2 completely. In addition, liquid chromatography equipped with mass spectrometry analysis after oxidation proves the TOC removal data.

Highly stable gold nanoparticles in an aqueous solution without any stabilizer prepared by a solution plasma process evaluated through capillary zone electrophoresis.

Gold nanoparticles (AuNP) were prepared by a solution plasma process in the presence of H2O2, and they were dispersed in an aqueous solution without any stabilizer generally used. The dispersion stability of the AuNP in an aqueous solution was evaluated by capillary zone electrophoresis (CZE). An anionic broad peak was detected with the AuNP by CZE based on its wide variations in size and net charge. The broad peak also suggests that the AuNP were well dispersed in an aqueous solution. The dispersion stability of AuNP was evaluated from the viewpoints of long-term dispersion, salt concentration, and organic co-solvent. The anionic broad peak attributed to the dispersed AuNP was successfully detected for at least 55weeks from the preparation with less shot signals of the aggregates. The AuNP was also well dispersed in aqueous NaCl solutions with its concentrations up to 30mmol L-1, as well as with ethanol co-solvent up to 40%(v/v). The AuNP prepared by the solution plasma process was proved to be highly stable in an aqueous solution.

Solution plasma synthesis of bacterial cellulose acetate derived from nata de coco waste incorporated with polyether block amide

Cellulose acetate (CA), one of the most important cellulose derivatives, is used in various applications especially in membranes, films, fibers, filters, and polymers. Because of the tough and flexible character and resistance to acids of CA, bacterial cellulose acetate (BCA) has been used as reinforcement for high performance separator purposes. In this study, BCA was synthesized through the heterogeneous acetylation in acetic solution with H2SO4 as catalyst by solution plasma process (SPP) of bacterial cellulose (BC) extracted form nata de coco waste. The SPP was considered as mild, simple, and fast method for many kinds of synthesis. The solution plasma time was studied to obtain considerably high DS values (in this work, DS = 1.95). The high DS values are an important feature when considering an environmental factor, good liquid transport and excellent absorption. Furthermore, the BCA incorporated with poly ether block amide by electrospinning method is successfully fabricated as nanofibrous membranes. The proposed PEBAX/BCA nanofibrous membranes display superior sufficient porosity (74.7%), exceptional liquid electrolyte uptake (364.6%), sufficient thermal dimensional stability at 150 °C, great electrochemical stability (discharge capacity at 0.2C = 102.14 mAh g−1), and high ionic conductivity (9.12 × 10−3 S/cm). Furthermore, the PEBAX/BCA nanofibrous membranes can be used as high-performance separators enhancing its safety for Li-ion battery applications.

The impact of combination of solution plasma processing and pulsed electric field on the viability of probiotic bacteria, microbial growth, and structure of yoghurt drink

In this study, the properties of the milk treated with combination of solution plasma (SP) processing and pulsed electric field (PEF) for different periods (5 and 10 min) was investigated. The microbiological, physicochemical, and sensory properties of the probiotic yoghurt drink (Ayran) produced from these milks were determined during storage. PEF was performed at voltage 3500 V, repetition 17,000 Hz, and pulse width 2.58 μs on the raw milk. Lactobacillus acidophilus and Bifidobacterium animalis subsp. lactis probiotic cultures were used in production with conventional yoghurt bacteria Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus. In addition to the probiotic viability, texture and sensory quality in terms of consumer preference were investigated. It was determined that the viscosity and dry matter values of the solution plasma-treated samples were lower compared to the samples produced by heat treatment, and these values decreased further with the increase in plasma application time. It was also found that the maximum increase in L* and b* values of all samples during storage was in the samples treated with plasma for 10 min. The viability of the probiotic bacteria in probiotic Ayran samples were determined to be within the therapeutic level (>6.27 log10 cfu ml−1) with higher scores for sensorial qualifications. Practical applications Consumers’ expectations of more nutritious and microbiologically safe food have enabled the development of new processing technologies. Probiotic fermented milk products are products that provide health benefits in the prevention of gastrointestinal diseases, regulation of metabolism, and stimulation of the immune system. The processing of these dairy products with non-thermal technologies provides advantages in preserving their functional properties.

Novel green synthesis of graphene oxide-manganese dioxide using solution plasma process for energy storage

Graphene oxide-manganese dioxide (GO-MnO2) forms an interesting family of nanocomposites that have been widely studied and applied to many electrochemical applications, including supercapacitors. However, a number of reported preparation methods still suffer several disadvantages, including complex preparation, long synthesis time, and detrimental effects on the environment as a result of excessive use of chemicals. In contrast, solution plasma process (SPP) offers a simple method that can be used to synthesize nanomaterials with minimal use of chemical reagents and short preparation time under ambient processing conditions. This work demonstrated that SPP-based preparation of the GO-MnO2 composite can be achieved. Moreover, the SPP regime was found to enable interaction between the Mn ions and the exfoliated GO sheets, with the capability of upscaling the preparation. The highest specific capacitance of the GO-MnO2 composite was obtained when only 10 min of SPP discharge time was used, resulting in the specific capacitance of 218 F g−1 at a scan rate of 5 mV s−1 in 1 M Na2SO4 aqueous electrolyte solution. This method provides a facile in situ approach to deposit MnO2 onto the GO sheets and could offer a promising, green alternative strategy to prepare similar electrode materials for other applications.

Effect of pH value and the distance between the electrodes on physicochemical properties of chitosan under SPP treatment

Solution plasma process (SPP) was employed to degrade chitosan. The effects of the initial pH value and the distance between the electrodes on the steady shear flow behavior, structural characterization, molecular conformation, and antioxidant activity of chitosan were investigated. The results revealed that a lower initial pH value and a narrower distance between the electrodes were beneficial to the decrease in viscosity and increase in shear-thinning capacity. Structural characterization of the chitosan by FT-IR and 1H NMR showed that chemical structure of chitosan was not destroyed at different process parameters. The results of XRD, HPSEC-MALLS, SEM, and AFM indicated that SPP degradation clearly decreased the crystallinity, molecular weight, molecular size, and molecular aggregation of chitosan. At initial pH values of 2.8 and 5.8, the molecular weight was 27.16 and 44.25 kDa, at the distance between the electrodes of 4 and 8 mm, it was 35.88 and 66.17 kDa, respectively. The results of DPPH and hydroxyl radical scavenging assays demonstrated that a lower initial pH value and a narrower distance between the electrodes enhanced the antioxidant activity.

Solution Plasma Processing as an Environmentally Friendly Method for Low-Molecular Chitosan Production

Solution Plasma Processing as an Environmentally Friendly Method for Low-Molecular Chitosan Production

Synthesis of Cu<sub>2</sub>O-decorated WO<sub>3</sub> by Solution Plasma Process

Synthesis of Cu<sub>2</sub>O-decorated WO<sub>3</sub> by Solution Plasma Process

Au nanoparticle-decorated TiO2 hollow fibers with enhanced visible-light photocatalytic activity toward dye degradation.

TiO2 hollow fibers (THF) were prepared by a template method using kapok as a biotemplate and subsequently decorated by plasmonic Au nanoparticles using a solution plasma process. The THF exhibited an anatase phase and a hollow structure with a mesoporous wall. Au nanoparticles with a diameter of about 5–10 nm were uniformly distributed on the THF surface. Au nanoparticles-decorated TiO2 hollow fibers (Au/THF) have enhanced photocatalytic activity toward methylene blue degradation under visible light-emitting diode (Vis-LED) as compared to pristine THF and P25. This could be attributed to combined effects including effective light-harvesting by a hollow structure, large surface area due to a mesoporous wall of THF, and visible-light absorption and efficient charge separation induced by Au nanoparticles. The Au/THF also showed good recyclability and separation ability.

Morphology control of ZnO nanostructures using Zn and W electrodes in solution plasma process

The morphology of ZnO nanostructures was controlled by the type of electrodes used, without chemical additives in the solution plasma process. Nanorod and nanosheet-type ZnO were synthesized using Zn and W electrodes, respectively. In the solution plasma process, the ZnO nanostructure can be fabricated because of the unique reaction between ions and radicals at the plasma/liquid interface. During this reaction, ions generated from the metal electrode influence the morphology of ZnO by adsorption on the (001) facet. Zn(OH)42− ions promoted crystal growth in the [001] direction, resulting in a rod structure. In contrast, the sheet structure was formed owing to the inhibition of growth in the [001] direction by WO42− ions.

Solution plasma process for synthesizing polydiacetylene materials: Toward industrial utilization of colorimetric sensors

A new route for synthesizing polydiacetylene (PDA) is introduced. Plasma is generated in a liquid matrix through a pair of electrodes, producing the excited atomic or molecular species, radicals, and UV radiation. The products of solution plasma process (SPP) act as initiators to induce polymerization of diacetylene monomers. Our results demonstrate that irreversible thermochromic PDA and reversible thermochromic PDA/Zn2+/ZnO nanocomposite can be effectively synthesized. The addition of ethanol significantly increases the polymerization rate. These PDA materials can be fabricated into paper-based colorimetric sensors for detecting volatile organic solvents, acids, bases, and surfactants. This synthetic pathway could be applied for industrial-scale applications.

Structure and properties of nanocarbons-encapsulated WC synthesized by solution plasma process in palm oils

Palm oil is produced in the ASEAN region. The overhang of stocks, propellant fouling in the production process and used oils existed there. It is a crucial issue to make efficient use of such palm oils. Solution plasma process (SPP) is one step non-thermal plasma in the liquid phase. Our laboratory has already synthesized the nanocarbons materials, graphene, hetero-graphene from organic molecules by SP. Organic ones engineer these material sources. When the functionalized nanocarbon can be synthesized from natural products and their dust, the functionalized carbon materials are supplied by the green process and low price. We had already synthesized nanocarbons by SP from the palm oils. The nanocarbons were covered enhanced electrical conductivity of nanocarbons, which is referred to the nanocarbons-encapsulated WC (tungsten carbides). In this study, we aimed to evaluate the structure and the properties of nanocarbons-encapsulated WC to provide the nanocarbons-encapsulated. The solution plasma was generated by the bipolar pulsed power supply through two tungsten electrodes using 2 μs pulse widths and frequencies (100, 150, and 180 kHz) for 30 min. We found that the observed plasma types depended on the discharge conditions. Conversion percentage of the oil to WC-encapsulated nanocarbon (% yield) was increased with frequency. The obtained X-ray diffraction patterns are showed the crystalline structure. The morphology of nanocarbon capsules WC are spherical shapes and less than 10 nm size. The electrochemical properties indicate that the ORR activity in an acidic medium under saturated O2 significantly disappears in the case of the nanocarbon-encapsulated WC synthesised in the high frequency (180 kHz). The synthesized nanocarbons-encapsulated WC might be applied in data storage and energy applications.

High electrical conductivity and oxidation reduction reaction activity of tungsten carbide/carbon nanocomposite synthesized from palm oil by solution plasma process

In this study, the enhancement of electrical conductivity and Oxidation Reduction Reaction (ORR) activity of tungsten carbide/carbon (WC/C) nanocomposite was successfully synthesized from palm oil by solution plasma process (SPP). For the synthesis, plasma fields with different frequency were applied the bipolar pulsed power supply connected with two tungsten electrodes. The properties of the synthesized WC/C nanocomposite were varied by using a different frequency. The electrical conductivity increased with the frequencies. The highest electrical conductivity was 4.27×10−2 S cm−1, which is higher than that of Ketjen Black (7.37 × 10−3 S cm−1). The WC/C nanocomposites were observed the surface area 160 m2 g−1, pore volume 0.53 cm3 g−1, average pore diameter 16.29 nm, basal plane crystallite size 18.0 nm, and the average compound granule diameter less than 100 nm. The cyclic voltammetry measurement was showed that the ORR activity of WC/C nanocomposites were obtained the good performance in alkaline solution for fuel cell application.

Characteristics of polyaniline nanoparticles prepared by electrochemical solution plasma process for flexible devices

This paper systematically investigates the characteristics of polyaniline (PANI) nanoparticles (NPs) synthesized by an electrochemical solution plasma process (SPP) method in terms of various case studies such as gas flow rates, synthesis times, and post-heating temperatures. The FE-SEM and XRD results show that PANI NPs have spherical particles with a nanoscale and crystalline phases of PANI NPs show amorphous nature with the (020) and (200) crystallographic planes. In FT-IR and XPS spectra, several peaks are observed in PANI NPs powders, which are related to carbon-containing groups and nitrogen-containing groups due to PANI polymer units.

Production of Oligoalginate via Solution Plasma Process and Its Capability of Biological Growth Enhancement.

The objective of the study was to depolymerize alginate into short-length oligoalginates, adopting the simple solution plasma process (SPP) technique, for successful use in free radical scavenging and growth promotion in cell culture and agricultural practices. Alginate at various concentrations was depolymerized to oligoalginates using SPP by discharging for various times. The depolymerization into oligoalginates was proved by DNS, TLC, FT-IR, and HPAEC analyses and caused decrease in viscosity. Oligoalginates derived from 0.5% alginate (100mg∙mL-1) showed the highest antioxidant activities in vitro. The oligoalginates enhanced growth of the human embryonic kidney (HEK293) cells to significant levels in a concentration-dependent manner without any extent of toxicity. The oligoalginates also promoted growth of lettuce. Thus, SPP is a powerful technique to break down alginate into oligoalginates that can be utilized as a free radical scavenger and as a growth promoter of animal cells and agricultural plants.

Insight on Solution Plasma in Aqueous Solution and Their Application in Modification of Chitin and Chitosan.

Sustainability and environmental concerns have persuaded researchers to explore renewable materials, such as nature-derived polysaccharides, and add value by changing chemical structures with the aim to possess specific properties, like biological properties. Meanwhile, finding methods and strategies that can lower hazardous chemicals, simplify production steps, reduce time consumption, and acquire high-purified products is an important task that requires attention. To break through these issues, electrical discharging in aqueous solutions at atmospheric pressure and room temperature, referred to as the “solution plasma process”, has been introduced as a novel process for modification of nature-derived polysaccharides like chitin and chitosan. This review reveals insight into the electrical discharge in aqueous solutions and scientific progress on their application in a modification of chitin and chitosan, including degradation and deacetylation. The influencing parameters in the plasma process are intensively explained in order to provide a guideline for the modification of not only chitin and chitosan but also other nature-derived polysaccharides, aiming to address economic aspects and environmental concerns.

Plasma-Assisted Synthesis of Multicomponent Nanoparticles Containing Carbon, Tungsten Carbide and Silver as Multifunctional Filler for Polylactic Acid Composite Films.

Multicomponent nanoparticles containing carbon, tungsten carbide and silver (carbon-WC-Ag nanoparticles) were simply synthesized via in-liquid electrical discharge plasma, the so-called solution plasma process, by using tungsten electrodes immersed in palm oil containing droplets of AgNO3 solution as carbon and silver precursors, respectively. The atomic ratio of carbon:W:Ag in carbon-WC-Ag nanoparticles was 20:1:3. FE-SEM images revealed that the synthesized carbon-WC-Ag nanoparticles with particle sizes in the range of 20–400 nm had a spherical shape with a bumpy surface. TEM images of carbon-WC-Ag nanoparticles showed that tungsten carbide nanoparticles (WCNPs) and silver nanoparticles (AgNPs) with average particle sizes of 3.46 nm and 72.74 nm, respectively, were dispersed in amorphous carbon. The carbon-WC-Ag nanoparticles were used as multifunctional fillers for the preparation of polylactic acid (PLA) composite films, i.e., PLA/carbon-WC-Ag, by solution casting. Interestingly, the coexistence of WCNPs and AgNPs in carbon-WC-Ag nanoparticles provided a benefit for the co-nucleation ability of WCNPs and AgNPs, resulting in enhanced crystallization of PLA, as evidenced by the reduction in the cold crystallization temperature of PLA. At the low content of 1.23 wt% carbon-WC-Ag nanoparticles, the Young’s modulus and tensile strength of PLA/carbon-WC-Ag composite films were increased to 25.12% and 46.08%, respectively. Moreover, the PLA/carbon-WC-Ag composite films possessed antibacterial activities.

Solution Plasma-Synthesized Black TiO2 Nanoparticles for Solar–Thermal Water Evaporation

Black TiO2 nanoparticles (b-TiO2) with superior solar–thermal water evaporation performance are prepared using a one-step solution plasma process (SPP) in ambient conditions. It is found that radic...

Deposition of carbon–tungsten carbide on coir pulp to improve its compatibility with polylactic acid

To increase hydrophobicity of surfaces of coir pulp, carbon–tungsten carbide (WC) was synthesized and simultaneously deposited on coir pulp by applying in-liquid electrical discharge plasma, so-called solution plasma process (SPP). As a result, water contact angle of carbon-WC deposited coir pulp was 123.4°, whereas that of coir pulp was 82.8°. The carbon-WC deposited coir pulp was then used as a filler in polylactic acid (PLA) to attain composite films of PLA/carbon-WC deposited coir pulp. The deposition of carbon-WC on coir pulp not only increased hydrophobicity of coir pulp but also improved compatibility between the filler and PLA. Even at the low filler content of 0.75 wt%, tensile strength and Young’s modulus of composite films of PLA/carbon-WC deposited coir pulp increased up to 45.73% and 22.79%, respectively compared with those of neat PLA film. Furthermore, the presence of carbon-WC deposited coir pulp in the PLA composite films could enhance the formation of crystalline structure of PLA. Accordingly, SPP is an interesting tool for surface modification of coir pulp in order to achieve surface-functionalized coir pulp for using as a filler in green composites.