Plasma Treatment Technology Research Articles

Influence of the Plasma of Pd–Ce/Porous Biomass Carbons Catalysts on the Surface Texture with Enhance Catalytic Activity Toward CO Oxidation

The porous biomass carbons (PBCs) as catalyst supports were synthesized by simple hydrothermal and carbonization method, and the surface property of PBCs were designed by plasma treatment technology. The Pd and Ce loaded TPBCs (PBCs were treated with plasma) supports were evaluated for their catalytic activity in the CO oxidation reaction. The Pd–Ce/TPBCs-20 catalyst (Conditions: CO concentration: 1 vol%, Total flow rate: 50 mL min−1, Moisture: 4 vol%) exhibited the highest catalytic activity, and the complete conversion temperature (T100) was about 20 °C for CO catalytic oxidation. Moreover, the Pd–Ce/TPBCs-20 catalyst behaved an excellent stability with the CO conversion rate in the presence of moisture, remaining higher than 90% after 24 h on stream at 20 °C. Raman, XPS, H2-TPR and O2-TPD analysis revealed that the surface oxygen-containing functional groups and defect concentration will increase with increasing plasma treatment time, which could improved Pd and Ce diffusion and Pd–O–Ce bonding interactions, resulting in increased CO catalytic activity. In addition, chitosan as the raw material for the synthesis of PBCs support, is low-cost and easy to be obtained from nature. Therefore, the Pd–Ce/TPBCs catalysts have great potential for catalytic removal of CO in practical application.

Proteins and Amino Acids Treated with Atmospheric Plasma Show Significantly Increased Bioavailability in Humans.

Background:Muscle mass is an important determinant of metabolic health and physical function. It has previously been demonstrated that the postprandial rise in circulating essential amino acids acts as the main stimulus for muscle protein synthesis (MPS). The current study investigated the postprandial plasma essential amino acid (EAA) and branched-chain amino acid (BCAA) responses of (1) Hydrolyzed whey protein isolate (HWPI) compared to plasma treated non-hydrolyzed whey protein isolate (PT-NHWPI), (2) standard branch-chain amino acids (S-BCAA) compared to plasma treated branch-chained amino acids (PT-BCAA), (3) standard pea protein (S-PP), compared to plasma treated pea protein (PT-PP), and (4) HWPI compared to PT-PP.Methods:Ten subjects (24.6 ± 5.3 years; 178.8 ± 8.1 cm; 78.6 ± 10.1 kg) participated in a double-blind, randomized, crossover trial comparing four separate protein conditions (HWPI, PT-NHWPI, S-PP, PT-PP). A separate cohort of ten subjects (26.4 ± 7.4 years; 178.8 ± 5.9 cm; 85 ± 12.3 kg) participated in a double-blind randomized, crossover trial comparing two branch-chain amino acid conditions: S-BCAA and PT-BCAA. All conditions were administered following a 7-day washout. Plasma EAA and BCAA concentrations were assessed from blood donated by subjects at pre-consumption, 30-, 60-, 90-, 120-, and 180 minutes post-consumption.Results:Blood plasma levels of total EAA and BCAA concentration were significantly greater in all treated conditions at 30-, 60-, 90-, and 120 minutes post consumption (P < .05). There were no differences between PT-PP and HWPI.Discussion:All proteins significantly elevated EAAs, and BCAAs from basal levels. However, we conclude that the consumption of the treated proteins significantly raises blood levels of EAAs, and BCAAs to a greater extent across multiple dairy, vegan, and isolated BCAA conditions. Moreover, atmospheric plasma treatment of a vegan protein source makes its amino acid response similar to whey. Thus, protein supplementation with that has undergone Ingredient Optimized® atmospheric plasma treatment technology may be highly beneficial for improving the blood plasma amino acid response.

34.5: Four‐mask process Architecture using NH3 plasma treatment technology for Image Sticking Improvement in 32‐inch TV Product

A new method to improve the interface of A‐Si and SiNx in A‐Si TFT process, the influence of H content in PECVD system equipment and the A‐Si remain to image sticking are studied in the paper. The suitable NH3 plasma pretreatment power and time or A‐Si remain can decease the leakage current and to overcome the image sticking in four‐mask process

Electrocoagulation-floatation assisted pulsed power plasma technology for the complete mineralization of potentially toxic dyes and real textile wastewater

In this study, experiments were conducted for the treatment of textile wastewater containing- a diazo dye i.e. Congo Red dye (CR) and a basic dye Methylene Blue (MB). Performances of Electrocoagulation-Flotation (EC-F) and Pulsed Power Plasma Treatment (PPT) technologies were evaluated individually and in combination. The effects of various parameters such as electrolysis time, electrical conductivity (EC, mS/cm), current density (mA/cm2) and initial concentrations of dye were experimentally optimized to get high removal efficiency. Using EC-F alone, the dye concentration was reduced from 50 mg/L to BDL (below detection level) and 50 mg/L to 3.1 mg/L for CR and MB dyes, respectively at a current density of 14.2 mA/cm2, electrical conductivity 8 mS/cm. To achieve this, an electrolysis time of 2 and 14 min were employed for CR and MB, respectively. To mitigate the problems of passivation of electrodes and sludge formation, EC-F was integrated with PPT treatment system. Also, the removal efficiencies of both the systems were evaluated by treating mixed dyes and real textile wastewater. It was found that by giving a partial treatment in EC-F followed by PPT was able to achieve 100% (TOC) degradation of MB with a total energy consumption of 50.55 kW h/kg dye removed and 39.3 kW h/kg dye for CR. The complete (100%) mineralization of the pollutant was achieved without any chemical addition and no waste (sludge) was produced at the end of novel hybrid treatment. The total treatment cost was reduced by 41.2% (86.04 kW h/kg dye to 50.55 kW h/kg dye) for MB and 30.7% (56.7 kW h/kg dye to 39.3 kW h/kg dye) for CR in hybrid system as compared to PPT treatment alone. Hybrid treatment was found to be an economical and a reliable technology for treating textile industry wastewater.

Effects on Surface and Physicochemical Properties of Dielectric Barrier Discharge Plasma-Treated Whey Protein Concentrate/Wheat Cross-Linked Starch Composite Film.

Dielectric barrier discharge (DBD) plasma is a new type of polymer surface modification technology. This study is mainly about the changes in film surface structure and physicochemical properties of whey protein concentrate (WPC)/wheat cross-linked starch (WCS) composite films after DBD plasma treatment with different plasma parameters. The results show that the proper plasma treatment parameters (400W to 60 s) can increase the surface roughness, tensile strength, barrier properties, and thermal stability of the edible film and decrease elongation at break and the water contact angle. X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and X-ray diffraction showed that DBD plasma treatment could increase the content of oxygen-containing groups on the WPC/WCS film surfaces instead of damaging the internal crystal structure. The results showed that use of proper DBD plasma treatment technology has a positive effect on the mechanical and barrier properties and thermal stability of WPC/WCS films. PRACTICAL APPLICATION: DBD plasma treatment can improve the mechanical, barrier, and thermal properties of WPC/WCS films without generating any pollution. The DBD plasma can be potentially applied in the enhancement of edible film properties. WPC/WCS films are more environmentally friendly than plastics and can be a replacement for traditional plastics.

Effect of Atmospheric Pressure Plasma Treatment on the Lap-Shear Strength of Adhesive-Bonded Sheet Molding Compound Joints

Atmospheric pressure plasma treatment (APPT) technology was used herein to treat sheet molding compound (SMC) substrates to increase the lap-shear strength of adhesive-bonded SMC joints. Further, the mechanisms behind the lap-shear strength improvements in APPT-treated adhesive-bonded SMC joints were explored. A maximum lap-shear strength about three times that of the as-received SMC joints was achieved when the APPT distance was set to 20 mm. The surface roughness, which exhibited little benefit to the lap-shear strength, was determined to not be the primary reason for the increase in lap-shear strength. Specifically, X-ray photoelectron spectra revealed that an increased amount of O-containing groups (i.e., C–O–H, C–O–C, H–O–C=O or R–O–C=O) following APPT contributed to the improved lap-shear strength. In addition, the surface free energy increased significantly after APPT, which improved the lap-shear strength of the adhesive-bonded SMC joints. Compared to the change of surface morphology, the changes in both the surface chemical property and surface free energy played larger roles in increasing the lap-shear strength of APPT-treated SMC joints.

Analysis of Oilfield Wastewater Treatment Effect Based on Low Temperature Plasma Treatment Process

In order to study the effect of different low temperature plasma treatment technology on the oil field's abolishment, the influence of low temperature plasma discharge frequency, scale inhibitor and the combined application of low temperature plasma and scale inhibitor on the quality of heavy oil wastewater and distilled water was analysed. When the discharge frequency of low temperature plasma was 900s-1, the decrease of oil content was 50.56%. The scale inhibitor also reduced the oil content of the heavy oil wastewater and the distilled water. However, the combined use of low temperature plasma and scale inhibitor would increase the content of oil and the content of metal ions in distilled water. The increase of oil content was 56%. The results showed that the low temperature plasma had obvious effect on reducing the oil content and SiO2 content in distilled water. Therefore, this study confirms the influence and mechanism of low-temperature plasma treatment on the quality of oil field wastewater.

10 A/567 V normally off p‐GaN gate HEMT with high‐threshold voltage and low‐gate leakage current

Normally off p-gallium nitride (GaN) gate high-electron-mobility transistors (HEMTs) on silicon substrate were fabricated with hydrogen plasma treatment technology, which features a high-resistivity cap layer (HRCL) at the access region. With hydrogen plasma treatment at the access region, the normally off operation was obtained with a threshold voltage of +2.5 V based on the linear extrapolation of the transfer curve. The fabricated HRCL-HEMT with a gate width of 49.7 mm exhibits a maximum drain current of 10 A at V GS = 8 V and a high off-state breakdown voltage of 567 V at V GS = 0 V with substrate grounded. Meanwhile, the HRCL-HEMT also shows low-gate leakage current of 1.3 × 10−7 and 3.3 × 10−10 A/mm at V GS = 8 V and = −30 V, respectively. The positive threshold voltage, high drain current, high-breakdown voltage and low-gate leakage show the potential of HRCL-HEMT for power switching applications.

Physical strength improvement of Eucalyptus alkaline hydrogen peroxide mechanical pulp by low-temperature plasma treatment

Low-temperature plasma treatment technology is an efficient and environmentally friendly surface treatment technology that has been extensively studied for the surface chemical modification to pulp fibers. In this study, Eucalyptus alkaline peroxide mechanical pulp (APMP) fibers were modified using a low-temperature plasma generator. The tensile index of the fibers after low-temperature plasma treatment under different conditions was measured and analyzed to evaluate the relationship between the plasma treatment conditions and the physical strength improvement of APMP. It was revealed that factors such as gas source (oxygen, argon, and nitrogen gases), discharge power, vacuum level, and modification time affected the physical strength properties of APMP. In addition, the change in carboxyl group content in the pulp fibers after low-temperature plasma treatment was measured using the Headspace Gas Chromatography (HS-GC) method. The carboxyl content in the fiber increased remarkedly after low-temperature plasma treatment, which was beneficial for improving the physical strength properties of paper made from the APMP.

Preparation of acylamino copper Phthalocyanine modified multiwalled carbon nanotubes thin films with oxygen plasma treatment

Hybrid thin films based on multi-walled carbon nanotubes (MWCNTs) and acylamino copper phthalocyanine (AM-CuPc) were prepared with oxygen plasma treatment technology. The effect of doping ratio on the photoelectric property of the films was investigated. The structure and morphology were characterized by Fourier transformed infrared spectrometer (FTIR) and field emission scanning electron microscopy (FESEM). The functional composites exhibited excellent dispersing property and the covalent bonds were formed between MWCNT and AM-CuPc. The UV–vis absorption spectra showed the absorbility was improved. In addition, the band gap was affected by the doping ratio and it was minimum of 1.63eV when the MWCNT-doping content was 40%. It will supply a new way to synthetize solar energy materials with different band gap.

Gasification of corn cob using non-thermal arc plasma

With high quality syngas consisting almost completely of H2 and CO, and solid carbon residues with high quality, the plasma treatment technology of biomass has been widely studied with the purpose of generating hydrogen. In this paper, the plasma gasification process of corn cob using non-thermal arc plasma was investigated after comparing various components of biomass, combining the physical truth of agricultural waste. The gas yield can reach 79.0% of the biomass feed without drying conditions at a discharge power of 25.2 W when using nitrogen as carrier gas with energy cost from the decomposition of corn cob is 5328 kJ/kgH2. Meanwhile, carbon conversion rate of 82.9%, CO selectivity of 39.9% and a ratio of H2/CO greater than 1.5 are obtained. It is found that different carrier gases have different impacts upon the reforming performance, and air is more beneficial for higher gas yield and CO selectivity. Besides, the presence of moisture is conducive to improve the gas yield, especially the production of hydrogen, carbon conversion rate and the molar ratio of H2/CO. Also, the varying tendencies of the gas products over the time at different experiment parameters are also discussed. Finally, the results of residual solid products were analyzed.

A review of low-temperature plasma treatment of textile materials

In recent years, plasma treatment technology has attracted more attention in the textile industry, as it seems to be a promising economically and ecologically sound alternative to conventional wet-chemical processing techniques. Plasma surface treatment is a relatively simple process that is clean, solvent-free, time saving, and environmentally friendly. Moreover, plasma treatments offer the possibility to obtain typical textile finishes without changing the key textile properties. The efficiency of plasma treatment depends on several factors including the nature of the substrate and the treatment operating conditions. However, the application of plasma technology to different kinds of textile materials has not been fully exploited. This paper presents a review of the current literature on the surface modification of textiles by low-temperature plasma (LTP) technology. Its main objectives are to (i) investigate the influence of LTP treatment on the surface properties of natural and man made textile materials, (ii) outline the contribution of LTP treatment towards sustainable development, and (iii) examine the hurdles that LTP has to overcome in the textile industry.

Normally-off metamorphic AlInAs/AlInAs HEMTs on Si substrates grown by MOCVD**Project supported by the Young Scientists Fund of the National Natural Science Foundation, China (Grant No. 61401373), the Fundamental Research Funds for Central University, China (Grant No. XDJK2013B004 and 2362014XK13), and the Research Fund for the Doctoral Program of Southwest University, China (Grant No. SWU111030).

A combination of self-aligned fluoride-based plasma treatment and post-gate rapid thermal annealing was developed to fabricate a novel 120-nm T-shaped gate normally-off metamorphic Al0.49In0.51As/Ga0.47In0.53As HEMT device on a Si substrate grown by metal-organic chemical vapor deposition (MOCVD). A shift of the threshold voltage, from −0.42 V to 0.11 V was obtained and the shift can be effectively adjusted by the process parameter of CF4 plasma treatment. Furthermore, a side benefit of reducing the leakage current of the device up to two orders of magnitude was also observed. E-mode transistors with 120 nm gate length own fT up to 160 GHz and fmax of 140 GHz. These characteristics imply the potential of the fluoride-based plasma treatment technology for the fabrication of monolithic enhancement/depletion-mode mHEMTs, which also encourage the massive production with this low-cost technology.

Thermal plasma vitrification process as an effective technology for fly ash and chromium-rich sewage sludge utilization

The main goal of the vitrification process for environmental research is the destruction of hazardous waste. This study proposes the use of a thermal plasma treatment process to transform fly ash and chromium-rich sewage sludge into glassy products called vitrificates that can be stored on the land without harmful environmental effects. This is achieved by: (i) decreasing the temperature and energy used to adjust process cost minimization; and (ii) stabilization of vitrificates for different compositions of waste mixture. The chemical stabilization of final products was examined by heavy metals leachability tests. Hardness tests were done to verify the physical stabilization of vitrificates. The most stable vitrificates were obtained from a sample consisting of 90 wt% fly ash and 10 wt% chromium sludge. The thermal plasma treatment is an effective method which can be used to convert hazardous waste mixtures into less toxic or inert glassy products. The chemical composition of raw materials influenced the chemical and physical properties of the vitrificates and determined their internal structures. Mixtures of two different hazardous wastes reduces the process cost without negative environmental impact, which is an innovation in thermal plasma treatment technology. © 2013 Society of Chemical Industry

Preparation and surface modification of electrospun aligned poly(butylene carbonate) nanofibers

In this study, aligned poly(butylene carbonate) nanofibers were fabricated by electrospinning with a high-speed transfer roller as the receiving device. Cold plasma treatment technology was applied to improve its hydrophilicity and activity to expand its application in biological materials. The morphology of the fibers was investigated with scanning electron microscopy. X-ray diffraction was used to research the impact of the rotation speed on the crystallization and orientation degree of the crystals. The tensile properties of the materials were evaluated by a universal tester. The surface properties of the fibers pretreated by Helium (He) and those grafted with gelatin were evaluated with water contact angle measurement and X-ray photoelectron spectroscopy. The experimental results indicate that the order degree of fibers, crystallinity, and orientation of the crystalline region, including the mechanical properties, all increased correspondingly with the rotation speed. After plasma pretreatment, the hydrophilicity was improved significantly, and the grafting reaction was realized successfully. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Opinion on the use of plasma processes for treatment of foods*

The working group "Food technology and safety" of the DFG Senate Commission on Food Safety (SKLM) advises on new technologies concerning food processing. Treatment with plasma is a newly developed process, which is currently used only on a pilot scale in Europe. The novel plasma treatment technology is experimentally applied to consumer goods. There are also potential applications in the food sector, e.g. to inactivate microorganisms on food surfaces. There is still insufficient information on concomitant physical and chemical processes and changes induced in the food. On May 25th 2012, the SKLM issued a first statement on plasma treatment of foods in German. The English version was agreed on December 14th 2012.

Plasma-Based Biofunctionalization of Vascular Implants

Polymeric and metallic materials are used extensively in permanently implanted cardiovascular devices and devices that make temporary but often prolonged contact with body fluids and tissues. Foreign body responses are typically triggered by host interactions at the implant surface, making surface modifications to increase biointegration desirable. Plasma-based treatments are extensively used to modify diverse substrates; modulating surface chemistry, wettability and surface roughness, as well as facilitating covalent biomolecule binding. Each aspect impacts on facets of vascular compatibility including endothelialization and blood contact. These modifications can be readily applied to polymers such as Dacron and expanded polytetrafluoroethylene, which are widely used in bypass grafting and the metallic substrates of stents, valves and pacemaker components. Plasma modification of metals is more challenging given the need for coating deposition in addition to surface activation, adding the necessity for robust interface adhesion. This review examines the evolving plasma treatment technology facilitating the biofunctionalization of polymeric and metallic implantable cardiovascular materials.

Densification of spin-on-glass (SOG) film by RF plasma treatment

We propose a spin-on glass (SOG) film densification technique based on the plasma-treatment technology. We demonstrated the densification of the SOG film at the temperature of lower than 53 degree C without compulsory cooling. We investigate the plasma-densification condition and found that the optimum RF power needed to densify the SOG film. This technique is applicable for production processes in wide range of electronic devices.

Fabrication and characterization of spray dried Al 2O 3–ZrO 2–Y 2O 3 powders treated by calcining and plasma

In this paper, the Al 2O 3-20 wt.%ZrO 2 (8 wt.%Y 2O 3) feedstocks were fabricated and treated by spray drying, calcination, and plasma treatment technology. The morphology of feedstocks was characterized by scanning electron microscope (SEM). The phase structure and grain size were analyzed by X-Ray diffraction (XRD). The flowability and density were measured by Hall Flowmeter and density instrument, respectively. The sphericity and flowability of feedstocks treated by plasma flame increased greatly compared with that of the feedstocks without plasma treatment, and the particle surfaces were very smooth. The optimum flowability was obtained when the critical plasma spray parameter (CPSP) was 363. The compactness also increased greatly with the increment of CPSP, and the maximum value of compactness was got with CPSP of 325. Calcination can make the grain grow and plasma treatment can lead to the decrement of grain size. The phase structure of Al 2O 3 did not change, which was α-Al 2O 3 in the composites. The phase structure of ZrO 2 (8 wt.%Y 2O 3) changed from t-phase to c-phase which was affected greatly by plasma treatment.

Surface properties of AlxGa1‐xN/GaN heterostructures treated by fluorine plasma: an XPS study

AbstractThe variations in surface potential and the Schottky barrier height ΦB in fluorine‐plasma‐treated AlxGa1‐xN/GaN heterotructures are systematically studied by x‐ray photoelectron spectroscopy (XPS), giving insights into the mechanisms underlying the strong threshold voltage shift in AlxGa1‐xN/GaN HEMTs by the F plasma treatment technology. It is found that the treatment resulted in a fluorinated surface containing masses of AlF3, with the surface potential of Al0.25Ga0.75N/GaN heterostructure increased by ∼0.38 eV during the first 60 seconds of the treatment. Annealing at 400 °C in N2 ambient for 10 minutes does not affect the surface potential, but results in quick reduction of AlF3, consistent with the relative poor thermal stability of AlF3 reported in literature. ΦB between Ni and F‐plasma‐treated Al0.25Ga0.75N surface was extrapolated from the shift in Ga 2p3/2 core‐level and exhibits a small increase of 0.20 eV. The enhanced ΦB is much smaller than the positive shift in Vth observed from HEMTs fabricated with the same treatment conditions, suggesting that the primary factor responsible for the conversion from depletion‐mode to enhancement‐mode AlxGa1‐xN/GaN by F plasma treatment is not the surface modifications, but rather the negative fixed charges carried by F ions in AlxGa1‐xN/GaN heterostructures. (© 2011 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)