Increasing the·OH radical concentration synergistically with plasma electrolysis and ultrasound in aqueous DMSO solution

In recent years,significant increases in waste processing and material engineering have been seen by using advanced oxidation processes.The treatment results and energy yields of these processes are largely determined by the generation and retention of reactive oxygen species(ROS).However,increasing the amount of ROS remains a key challenge because of the unavailability of performance-and energy-efficient techniques.In this study,plasma electrolysis,ultrasound,and plasma electrolysis combined with ultrasound were used to treat dimethyl sulfoxide(DMSO)solutions,and the results showed that the two methods can synergistically convert filament discharge into spark discharge,and the conversion of the discharge mode can significantly increase the concentration of OH radicals and effectively improve the efficiency of DMSO degradation.We verified the rationality of the results by analyzing the mass transfer path of ROS based on the reaction coefficients and found that the OH radicals in aqueous solution were mainly derived from the decomposition of hydrogen peroxide.These findings indicated that the synergistic action of plasma electrolysis and ultrasound can enhance the production of chemically reactive species,and provide new insights and guiding principles for the future translation of this combined strategy into real-life applications.Our results demonstrated that the synergistic strategy of ultrasound and plasma electrolysis is feasible in the switching mode and increasing the ROS,and may open new routes for materials engineering and pollutant degradation.

On the Production of OH Radical through Plasma Electrolysis Mechanism for the Processing of Ammonia Waste Water

Plasma produced many active species such as OH radical and H radical. As well known, OH radical plays an important role in degrading complex pollutants. This study aims to measure the production of OH radicals and evaluate important parameters that have influent in degradation process of waste water contains ammonia in circulated system and analyze the level of energy consumptions are resulted by this research. The production of OH radical was detected by formation of hydrogen peroxide which was resulted by recombination reaction between OH radicals during plasma electrolysis process. From the measured concentration of hydrogen peroxide, obtained concentration of OH radical is 2,020 ppm. The depth of anode, applied voltage and ammonia initial concentration have affected ammonia degradation percentage and energy consumption level. The highest result for ammonia degradation percentage is 63.2% which gets from applied voltage 700 V, with depth of anode 1 cm, initial concentration of ammonia 100 ppm, and lowest energy consumption of 110 KJ/mmol.

Surface Microstructure and High Temperature Oxidation Resistance of Thermal Sprayed NiCoCrAlY Bond-Coat Modified by Cathode Plasma Electrolysis

The surface properties of the air-plasma sprayed bond-coat have been modified by cathode plasma electrolysis（CPE）. After modification, a re-melted layer without obvious pores and oxide stringers is formed,the gain size of re-melted layer is approximately 80–120 nm. It is shown, from cyclic oxidation at 1100℃,that a thin oxide scale mainly composed of α-Al;O;has been formed on the modified bond-coat and the oxidation resistance of the modified bond-coat has been significantly improved. Such beneficial result can be attributed to following effects: during CPE process, the plasma discharges with high temperature take place on the bond-coat surface. With plasma discharge treatment, the surface is melted and quickly re-solidified, the grain size decreases, and the pores and oxide stringers disappear. During cyclic oxidation, owing to the above modification of surface properties, the critical content of Al for selective oxidation is significantly decreased. Therefore, a continuous Al;O;scale is formed.

Poly (Acrylamide-co-Acrylic Acid) Hydrogel Induced by Glow-Discharge Electrolysis Plasma and Its Adsorption Properties for Cationic Dyes

In this paper, poly （acrylamide-co-acrylic acid） （P（AM-co-AA）） hydrogel was pre- pared in an aqueous solution by using glow-discharge electrolysis plasma （GDEP） induced copoly- merization of acrylamide （AM） and acrylic acid （AA）, in which N,N＇-methylenebisacrylamide （MBA） was used as a crosslinker. A mechanism for the synthesis of P（AM-co-AA） hydrogel was proposed. To optimize the synthesis condition, the following parameters were examined in detail： the discharge voltage, discharge time, the content of the crosslinker, and the mass ratio of AM to AA. The results showed that the optimum pH range for cationic dyes removal was found to be 5.0-10.0. The P（AM-co-AA） hydrogel exhibits a very high adsorption potential and the ex- perimental adsorption capacities for Crystal violet （CV） and Methylene blue （MB） were 2974.3 mg/g and 2303.6 mg/g, respectively. The adsorption process follows a pseudo-second-order kinetic model. In addition, the adsorption mechanism of P（AM-co-AA） hydrogel for cationic dyes was also discussed.

Degradation of Anionic Dye Eosin by Glow Discharge Electrolysis Plasma

This paper describes a novel method for the degradation of eosin by using glow discharge electrolysis （GDE）. The effects of various parameters on the removal efficiency were studied. It was found that the eosin degradation could be raised considerably by increasing the applied voltage and the initial concentration, or by decreasing pH of the aqueous solution. Fe^2＋ ion had an evident accelerating effect on the eosin degradation. The degradation process of eosin obeyed a pseudo-first-order reaction. The relationship between the degradation rate constant k and the reaction temperature T could be expressed by Arrhenius equation with which the apparent activation energy Ea of 14.110 kJ· mol^-1 and the pre-exponential factor k0 of 2.065× 10^-1 min^-1 were obtained, too. The determination of hydroxyl radical was carried out by using N, N-dimethyl -p-nitrosoaniline （RNO） as a scavenger. The results showed that the hydroxyl radical plays an important role in the degradation process.

Novel interface engineering of LDH-based materials on Mg alloy for efficient photocatalytic systems considering the geometrical linearity of condensed phosphates

This study presents a facile and rapid method for synthesizing novel Layered Double Hydroxide(LDH)nanoflakes,exploring their application as a photocatalyst,and investigating the influence of condensed phosphates'geometric linearity on their photocatalytic properties.Herein,the Mg O film,obtained by plasma electrolysis of AZ31 Mg alloys,was modified by growing an LDH film,which was further functionalized using cyclic sodium hexametaphosphate(CP)and linear sodium tripolyphosphate(LP).CP acted as an enhancer for flake spacing within the LDH structure,while LP changed flake dispersion and orientation.Consequently,CP@LDH demonstrated exceptional efficiency in heterogeneous photocatalysis,effectively degrading organic dyes like Methylene blue(MB),Congo red(CR),and Methyl orange(MO).The unique cyclic structure of CP likely enhances surface reactions and improves the catalyst's interaction with dye molecules.Furthermore,the condensed phosphate structure contributes to a higher surface area and reactivity in CP@LDH,leading to its superior photocatalytic performance compared to LP@LDH.Specifically,LP@LDH demonstrated notable degradation efficiencies of 93.02%,92.89%,and 88.81%for MB,MO,and CR respectively,over a 40 min duration.The highest degradation efficiencies were observed in the case of the CP@LDH sample,reporting 99.99%for MB,98.88%for CR,and 99.70%for MO.This underscores the potential of CP@LDH as a highly effective photocatalyst for organic dye degradation,offering promising prospects for environmental remediation and water detoxification applications.

Innovative approach to boosting the chemical stability of AZ31 magnesium alloy using polymer-modified hybrid metal oxides

Meeting the demands of complex and advanced applications requires the development of high-performance hybrid materials with unique properties.However,the integration of polymeric frameworks with MgO/WO_(3) composite layers faces challenges due to the lack of understanding of the formation mechanism and the challenge of determining the impact of self-assembled architecture on anticorrosive properties.In this study,we aimed to enhance the corrosion resistance of the MgO layer produced by plasma electrolysis(PE)of AZ31 Mg alloy by incorporating WO_(3) with partially phosphorated poly(vinyl alcohol)(PPVA).Two types of porous MgO layers were produced using the PE process with an alkaline-phosphate electrolyte,one with and one without WO_(3) nanoparticles,which were subsequently immersed in an aqueous solution of PPVA.Incorporating PPVA into the WO_(3)-MgO layer resulted in hybrids being deposited in a fragmented manner,creating a“laminar reef-like structure”that sealed most of the structural defects in the layer.The PPVA-sealed WO_(3)-based coating exhibited superior corrosion resistance compared to the other samples.Computational analyses were employed to explore the mechanism underlying the formation of PPVA/WO_(3) hybrids on the MgO layer.These findings suggest that PPVA-WO_(3)-MgO hybrid coatings can potentially improve corrosion resistance in various fields.

Plasma electrolytic liquefaction of cellulosic biomass

In this paper, the rapid liquefaction of a corncob was achieved by plasma electrolysis, providing a new method for cellulosic biomass liquefaction. The liquefaction rate of the corncob was 95% after 5 min with polyethylene glycol and glycerol as the liquefying agent. The experiments not only showed that H~+ ions catalyzed the liquefaction of the corncob, but also that using accelerated H~+ ions, which were accelerated by an electric field, could effectively improve the liquefaction efficiency. There was an obvious discharge phenomenon, in which the generated radicals efficiently heated the solution and liquefied the biomass, in the process of plasma electrolytic liquefaction. Finally, the optimum parameters of the corncob liquefaction were obtained by experimentation, and the liquefaction products were analyzed.

Synthesis of Poly (Butyl Methacrylate/Butyl Acrylate) Highly Absorptive Resin Using Glow Discharge Electrolysis

A highly absorptive resin poly （butyl methacrylate （BMA）-co-butyl acrylate （BA）） was prepared by emulsion polymerization, which was initiated by glow discharge electrolysis plasma （GDEP）. The effects of discharge voltage, discharge time, monomer ratio and the amounts of cross- linking agent were examined and discussed in detaiI. The chemical structure of the obtained resin was characterized by means of attenuated total reflectance Fourier transform infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy. The optimal conditions were ob- tained as： discharge voltage was 600 V, discharge time was 8 min, the ratios of BMA：BA being 2：1 for chloroform and 3：1 for xylene, with 2% N, N＇-methylenebis. Under optimal conditions, the oil absorbency was 70 g/g for chloroform and 46 g/g for xylene. Moreover, the absorptive dynamical behavior of the resulting resin was also investigated.

Power-to-chemicals:sustainable liquefaction of food waste with plasma-electrolysis

The increasing amount of food waste from various industrial,agricultural,and household sources is an environmental burden if managed inappropriately.Numerous waste management approaches have been developed for the disposal of food waste,but still suffer from either high cost,production of toxic by-products,or secondary environmental pollutions.Herein,we report a new and sustainable plasma electrolysis biorefinery route for the rapid and efficient liquefaction of food waste.During the plasma electrolysis process,only the solvent is added to liquefy the waste,and anions in the waste can contribute to catalyzing the biowaste conversion.While liquefying the waste,the highly reactive species produced in the plasma electrolysis process can efficiently reduce the content of O,N,and Cl in the liquefied products and oxidize most of the metals into solid residues.Especially,the removal rate of Na and K elements was greater than 81%,which is significantly higher than using the traditional oil bath liquefaction,resulting in a relatively high-quality biocrude oil with a high heating value of 25.86 MJ·kg^(-1).Overall,this proposed strategy may provide a new sustainable and eco-friendly avenue for the power-to-chemicals valorization of food waste under benign conditions.

Anode Plasma Electrolytic Saturation of Titanium Alloys with Nitrogen and Oxygen

In this work, we investigated the features of the anode plasma electrolytic saturation of titanium alloys with nitrogen and oxygen. In this case, the titanium samples may be heated to 1050 ℃ using aqueous solutions of ammonium chloride as working electrolyte. The weight of titanium samples is found to change due to their oxidation and anode dissolution. An X-ray diffractometer, a scanning electron microscope,nuclear proton backscattering and an optical microscope were used to characterize the phase and elemental composition of the modified layer. The electrolyte composition（10 wt% ammonium chloride, 5wt% ammonia） and processing mode（850 ℃, 5 min） of commercially pure titanium（CP-Ti） allowing to obtain the hardened surface layer up to 0.1 mm with microhardness of 220 HV were proposed. Surface roughness Ra of samples after their nitriding for 5 min at 800 ℃ decreases from 1.67 to 0.082 μm. The anode plasma electrolytic nitriding could decrease friction coefficient and increase wear resistance of the CP-Ti. It is found that the anodic nitriding of low alloy titanium alloys reduces their corrosion rate in an aqueous solution of sulphuric（4.5%） and salt（0.2%） acids by 2 orders of magnitude. Results of cyclic testing show that anodic nitriding of commercial titanium leads to a decrease in corrosion rate by 8 times in solution of hydrochloric acid（6%） with addition of protein and vitamin.