Liquid Phase Plasma Method Research Articles

Decomposition of the antibiotic sulfamethoxazole by the liquid-phase plasma process enhanced by peroxymonosulfate

In this study, sulfamethoxazole (SMZ) was successfully degraded using the liquid phase plasma (LPP) method, a new advanced oxidation process (AOPs). The effects of LPP process variables and side reactions on SMZ decomposition reactions were evaluated, and optimal LPP process conditions were determined based on these data. To increase the efficiency of the SMZ decomposition reaction, peroxymonosulfate (PMS) was added to the LPP reaction. The optimal addition amount was derived by tracking the change in the amount of oxidation radicals produced according to the addition of PMS. By analyzing the reaction intermediates generated in the SMZ decomposition reaction, the decomposition pathway of SMZ by the LPP method was proposed.

Evaluation of carbon black produced with hydrogen by the liquid phase plasma method as a conductive material for the anode of a supercapacitor

Carbon black is produced with H2 gas from a benzene solution using the liquid-phase precipitation (LPP) mathod. Subsequently, the carbon black is heat-treated and applied as a conductive material for a supercapacitor to evaluate its performance. Carbon black produced as primary particles by the LPP reaction aggregates and grows into a secondary structure, and then crystallizes through heat treatment to form multi-polygonal nanoshells. The electrical conductivity of carbon black increased by heat treatment, but when the temperature exceeded 1500 °C, the electrical conductivity rather decreased. Following heat treatment at 1500 °C, the electrode used as the conductive material exhibits the largest specific capacitance value and the smallest IR drop. As the carbon black produced via the LPP method exhibits better conductive properties than those of Super-P, the potential to use the present method as a new hydrogen production method is confirmed.

Acetaldehyde Adsorption Characteristics of Ag/ACF Composite Prepared by Liquid Phase Plasma Method.

Ag particles were precipitated on an activated carbon fiber (ACF) surface using a liquid phase plasma (LPP) method to prepare a Ag/ACF composite. The efficiency was examined by applying it as an adsorbent in the acetaldehyde adsorption experiment. Field-emission scanning electron microscopy and energy-dispersive X-ray spectrometry confirmed that Ag particles were distributed uniformly on an ACF surface. X-ray diffraction and X-ray photoelectron spectroscopy confirmed that metallic silver (Ag0) and silver oxide (Ag2O) precipitated simultaneously on the ACF surface. Although the precipitated Ag particles blocked the pores of the ACF, the specific surface area of the Ag/ACF composite material decreased, but the adsorption capacity of acetaldehyde was improved. The AA adsorption of ACF and Ag/ACF composites performed in this study was suitable for the Dose–Response model.

Assessing the photocatalytic activity of europium doped TiO2 using liquid phase plasma process on acetylsalicylic acid

In this study, europium (Eu) was precipitated in TiO2 powder using liquid phase plasma (LPP) process to prepare a photocatalyst with higher activity, even in the visible light range. Eu was uniformly deposited on the surface of TiO2 by the LPP method. It was observed that the amount of Eu precipitated on the TiO2 surface increased with increasing precursor concentration. XPS and EDS analysis showed that Eu was precipitated as europium oxide. The precipitation of Eu shifted the position of the Raman peak to a higher wavelength; with higher Eu content, the band gap energy decreased. Particularly, the photocatalytic efficiency of the Eu doped TiO2 photocatalyst (EDTP) in the visible light source was much higher than that of bare TiO2, and with higher Eu content, the photocatalytic activity was improved. Acetylsalicylic acid was attacked by HO∙ produced on the EDTP’s surface and assumed to be finally mineralized to H2O and CO2via two decomposition pathways, namely, decarboxylation and deacetylation.

Assessment of photocatalytic performance of Fe/N-TiO2 photocatalysts prepared by liquid phase plasma process

Abstract To improve the photocatalytic performance of TiO2 photocatalysts, a new method, liquid phase plasma (LPP) method, was used to introduce nitrogen and iron oxide. Interstitial or substitutional nitrogen and Fe3+ iron nanoparticles were impregnated on the surface of TiO2 by LPP reaction without additional chemical reduction agent and the amount of iron of modified TiO2 photocatalysts was affected by the amount of initial precursor. The adsorption edge of modified TiO2 photocatalysts was shifted to the visible region in proportion to the amount of nitrogen and iron oxide, and the band gap energy was decreased, and the photocatalytic activity was confirmed by PL and EPR analysis. The photocatalytic activities of modified TiO2 photocatalysts were measured under UV and blue LED lamps and compared with pure TiO2 powder (P-25). The modified TiO2 exhibited better photocatalytic degradation performance than pure TiO2 under blue LED light conditions, but exhibited low degradation activity under UV LED light conditions. Through GC–MS analysis, it was found that the methylene blue was finally decomposed into an inorganic substance through intermediates such as benzene sulfonic acid and phenol by OH radicals. From these results, we found that the modified TiO2 photocatalysts can be easily prepared using the LPP method and can be used in the visible region.

Preparation of silicon oxide–carbon composite from benzene and trimethoxyphenylsilane by a liquid phase plasma method for supercapacitor applications

Silicon oxide–carbon composites (SiOCCs) were deposited directly in a reactant aqueous solution using a liquid-phase plasma (LPP) method and applied as a supercapacitor electrode. The SiOCCs formed rapidly at the initial stages of the LPP reaction by the carbonization of benzene and TMPS, but the production of SiOCC decreased over the reaction time. The SiOCCs formed cluster chains by agglomeration, which were composed mostly of carbon with oxygen and silicon distributed uniformly. A higher TMPS content in the reactant solution resulted in the inclusion of more silicon and oxygen in SiOCCs. Most of the Si components synthesized by the LPP reaction form SiO2 bonds and some have carbon-bonded chemical structures. The SiOCCs particles were agglomerated in amorphous form with a size of approximately 10 to 40 nm and the d-spacing appeared to contain SiO2 particles of approximately 0.31 nm. As the content of silicon oxide in SiOCCs is increased, the specific surface area increased and the specific capacitance increased. In addition, the pseudocapacitance characteristics showed the lowest resistance. On the other hand, a higher silicon oxide content in SiOCCs resulted in higher capacitance loss due to volume expansion of silicon dioxide in the charge-discharge process.

Fabrication of Gd-La codoped TiO2 composite via a liquid phase plasma method and its application as visible-light photocatalysts

TiO2 was doped simultaneously with Gd and La using a liquid phase plasma (LPP) reaction to produce a photocatalyst with excellent photoactivity in the visible light region. Gadolinium chloride hexahydrate and lanthanum chloride heptahydrate precursors were used to dope the TiO2 powder with polycrystalline Gd2O3 and La2O3 particles. The doping of TiO2 with rare earth elements using LPP reaction decreased the band gap; the band gap of Gd-La codoped TiO2 photocatalysts (GLTP) was the lowest. The photodegradation efficiency of the TiO2 photocatalysts doped with either Gd or La was superior that of bare TiO2 but the photodegradation efficiency of GLTP was highest in both ultraviolet and visible light sources. Acetaminophen (Acetyl-para-aminophen, APAP) was ultimately decomposed to CO2 and H2O via intermediates, such as p-nitrophenol, hydroquinone and hydroxylhydroquinone, by hydroxyl radicals (HO) formed on the surface of GLTP.

Facile Synthesis and Characterization of Zinc Oxide Nanoparticle on Activated Carbon Using Liquid Phase Plasma Method.

Zinc oxide/activated carbon nanocomposites were synthesized by impregnating zinc oxide nanoparticles onto activated carbon powder using liquid phase plasma (LPP) method. Zinc oxide nanoparticles on the surface of activated carbon were fabricated rapidly by the LPP method due to reducing the zinc ion in aqueous solution. The obtained zinc oxide/activated carbon nanocomposites were characterized by XPS, HRTEM, and EDS. The amount of zinc oxide nanoparticles impregnated increased with increasing initial precursor concentration. Approximately 150~300 nm sized spherical shaped nanoparticles were uniformly dispersed on the surface of activated carbon powder.

Facile precipitation of tin oxide nanoparticles on graphene sheet by liquid phase plasma method for enhanced electrochemical properties

A high-performance lithium ion battery (LIB) electrode was prepared by precipitating tin oxide nanoparticles on graphene powder by the liquid phase plasma (LPP) method. The particles generated by the LPP reaction are spherical SnO2 nanoparticles with a size of 5-10 nm, as confirmed by a variety of analytical devices. The quantity of SnO2 nanoparticles partially aggregated on the graphene sheet surface increases as the initial concentration of the tin precursor increases. The SnO2/graphene nanocomposites (SGNC) electrodes prepared by the LPP method demonstrated improved cycling stability and reversible lithium storage capacity as compared to the bare graphene electrode. The precipitated tin oxide improves the lithium storage capacity, but excess tin oxide nanoparticles rather reduced the cycling stability.

Facile synthesis of iron-ruthenium bimetallic oxide nanoparticles on carbon nanotube composites by liquid phase plasma method for supercapacitor

Iron-ruthenium bimetallic oxide nanoparticles were precipitated on carbon nanotubes by liquid-phase plasma method. We also evaluated the physicochemical and electrochemical properties of prepared composite for supercapacitor electrode. Polycrystalline about 10 to 25 nm-sized bimetallic nanoparticles were evenly precipitated on the carbon nanotube (CNT) and consisted of Fe3+ and Ru4+. Bimetallic oxide nanoparticles’ composition depended on the ratio of the metal precursor concentration and standard reduction potential. The C-V area and specific capacitance of iron-ruthenium oxide nanoparticle/carbon nanotube (IRCNT) composite electrodes was higher than that of untreated CNT electrode, and increased with increasing ruthenium content. The cycling stability of IRCNT composite electrode was higher than untreated CNT electrode, especially iron element was more stable.

Tin Oxide/Carbon Nanocomposites as the Electrode Material for Supercapacitors Using a Liquid Phase Plasma Method.

Tin oxide/carbon nanocomposite (TOCNC) was synthesized using a liquid phase plasma method, to be used as the electrode of supercapacitor. Spherical tin oxide amorphous nanoparticles with the size of 5 nm were dispersed uniformly on activated carbon powder (ACP) surface. The quantity of tin oxide nanoparticle precipitate increased with increasing LPP duration and the specific capacitance of TOCNC increased with increasing LPP duration. The TOCNC prepared through the LPP process showed smaller resistances and larger initial resistance slopes than bare ACP and this effect was intensified by increasing the LPP process duration.

Impregnation of Cobalt on Graphene Sheet Using Liquid Phase Plasma Method for Lithium-Ion Batteries Application

Impregnation of Cobalt on Graphene Sheet Using Liquid Phase Plasma Method for Lithium-Ion Batteries Application

Characterization of Bimetallic Fe-Ru Oxide Nanoparticles Prepared by Liquid-Phase Plasma Method.

The bimetallic Fe-Ru oxide nanoparticles were synthesized in the liquid-phase plasma (LPP) method which employed iron chloride and ruthenium chloride as precursors. The active species (OH·, Hα, Hβ, and OI) and the iron and ruthenium ions were observed in the plasma field created by the LPP process. The spherical-shaped bimetallic Fe-Ru oxide nanoparticles were synthesized by the LPP reaction, and the size of the particles was growing along with the progression of the LPP reaction. The synthesized bimetallic Fe-Ru oxide nanoparticles were comprised of Fe2O3, Fe3O4, RuO, and RuO2. Ruthenium had a higher reduction potential than iron and resulted in higher ruthenium composition in the synthesized bimetallic nanoparticles. The control of the molar ratio of the precursors in the reactant solution was found to be employed as a means to control the composition of the elements in bimetallic nanoparticles.

Synthesis of cobalt oxide-manganese oxide on activated carbon electrodes for electrochemical capacitor application using a liquid phase plasma method

An Electrochemical capacitor electrode material was prepared by precipitating cobalt-manganese oxide nanoparticles on the surface of activated carbon powder (ACP) using a liquid phase plasma method. Polycrystalline spherical 100–170 nm-sized metal oxide nanoparticles were precipitated onto the ACP surface with a high degree of uniformity. The initial concentration of precursor influenced the composition of the precipitated nanoparticles. The nanoparticles were bimetallic oxide nanoparticles composed mainly of Co2+ and Mn3+. Increases in the amount of metal oxide nanoparticles precipitated on ACP, were accompanied by reduced specific surface area, average pore size, and total pore volume, as well as by increased specific capacitance. The metal oxide nanoparticles improved the cyclic stability of the electrochemical capacitor and reduced equivalent series resistance.

Preparation and Characterization of Low Molecular Weight Heparin by Liquid Phase Plasma Method.

An liquid phase plasma process system was applied to the production of low molecular weight heparin. The molecular weight of produed heparin decreased with increasing liquid phase plasma treatment time. The abscission of the chemical bonds between the constituents of heparin by liquid phase plasma reaction did not alter the characteristics of heparin. Formation of any by-products due to side reaction was not observed. It is suggested that heparin was depolymerized by active oxygen radicals produced during the liquid phase plasma reaction.

Effect of the surfactant on size of nickel nanoparticles generated by liquid-phase plasma method

The effect of anionic and cationic surfactants on the generation of nickel nanoparticles in a liquid-phase plasma was investigated. The size and morphology of nanoparticles generated under different conditions were observed. When no surfactant was added, more and larger particles were generated under a longer plasma treatment time and a higher electrical conductivity of the solution. When an anionic surfactant SDS was added, spherical nickel nanoparticles with various sizes were generated, with no clear evidence for the effect of SDS observed. When a cationic surfactant CTAB was added, very small nanoparticles (≤ 10 nm) could be obtained with a short reaction time. When the reaction time was too long (≥ 60 minutes), larger polygonal or wisker-shaped particles were generated.

Preparation and Characterization of Cobalt/Graphene Composites Using Liquid Phase Plasma System.

Liquid phase plasma (LPP) method was applied, for the first time, to the impregnation of cabalt nanoparticles onto graphene. Nanoparticles were dispersed uniformly on the surface of the two-dimensional graphene sheet. The electron miocroscopy observation showed approximately 2-7 nm sized spherical nanoparticles deposited on the surface of graphene sheets. The XPS and EDX analyses revealed that both metal Co and CoO were present in the Co/graphene composites synthesized by the LPP method.

Synthesis of manganese oxide/activated carbon composites for supercapacitor application using a liquid phase plasma reduction system

Manganese oxide/carbon composite electrode was synthesized using liquid-phase plasma method, to be applied to supercapacitor. Spherical manganese oxide nanoparticles smaller than 10 nm were dispersed uniformly on the surface of YP-50F. The increase in the amount of manganese oxide precipitated on YP-50F resulted in improved specific capacitance, charge–discharge rate, and Warburg impedance but specific surface area and total pore volume were decreased.

Synthesis of tin and tin oxide nanoparticles using liquid phase plasma in an aqueous solution

Liquid phase plasma method was applied to the synthesis of Sn nanoparticles. Tin chloride was used as the tin precursor. Dendrite-shaped particles were formed at the initial stage of the reaction, while spherical nanoparticles were generated at longer discharge time. When the discharge time was too long (longer than 50min in this study), anisotropic SnO2 nanoparticles were produced. With increasing dosage of Cetyltrimethylammonium bromide, used as the surfactant, the Sn particle size decreased, while the degree of dispersion of the particles increased. Higher electrical conductivity of the reactant solution resulted in the production of larger Sn nanoparticles. The solution pH decreased with increasing plasma discharge time until 50min, after which pH slightly increased, co-occurring with the formation of SnO2 nanoparticles.

Preparation and Characterization of Copper Nanoparticles via the Liquid Phase Plasma Method

Polycrystalline copper nanoparticles were synthesized from copper chloride dihydrate solution using the liquid phase plasma reduction method. A bipolar pulsed power supply with tungsten electrodes was used to generate discharge in the aqueous solutions. While large size of dendrite-shaped copper nanoparticles were mostly observed in the initial stage and particle size decreased with discharge time. The particles were dispersed with less and less small particles by the addition of CTAB and anisotropic shapes nanoparticles were mostly observed at long time plasma-treated with high concentration of surfactant. Many spots could be seen in the selected area diffraction pattern (SADP) for polycrystalline particles. Keywords: Bipolar pulsed discharge, copper, liquid phase plasma, nanoparticle, surfactant.