Microwave Plasma Torch Generated in Argon for Small Berries Surface Treatment

Advances in using non-thermal plasmas for healthier crop production: toward pesticide and chemical fertilizer-free agriculture

MAIN CONCLUSION

There is an urgent need for sustainable agriculture. Non-thermal plasma seed treatment offers a promising alternative by enhancing germination, nutrient uptake, and disease resistance, and reducing reliance on pesticides and fertilizers. There is an urgent need to transform agricultural practices to meet the challenges of sustainable food production amidst global population growth and environmental degradation. Traditional crop production methods heavily rely on pesticides and synthetic fertilizers, which pose significant risks to human health, disrupt ecosystems, and contribute to environmental pollution. Moreover, these methods are increasingly unsustainable due to rising costs and diminishing effectiveness, evolving pest resistance, and climate change impacts. Recently, non-thermal plasma (NTP) technology has emerged as a promising alternative for seed treatment in agriculture. NTP uses low-temperature plasma to modify seed surfaces, enhancing germination, vigor, and overall plant growth. Studies have demonstrated that NTP treatment improves nutrient uptake, increases disease resistance, and reduces the reliance on chemical inputs (pesticides and fertilizers), thereby promoting pesticide and chemical fertilizer-free agriculture. This paper explores recent research advancements in NTP seed treatment and its potential applications in sustainable agriculture. By exploring the mechanisms underlying the NTP effects on seed physiology, the paper provides a comprehensive understanding of how this technology can contribute to sustainable crop production. Furthermore, the paper discusses the strengths, weaknesses, opportunities, and challenges associated with the potential large-scale use of low-temperature plasmas in agriculture, aiming to accelerate the adoption of NTP and its commercialization in the agro-food industries. Overall, the goal of this paper is to highlight the transformative potential of NTP seed treatment in achieving healthier crop production that is environmentally friendly, economically viable, and capable of meeting the food demands of a growing global population.

Non-Thermal Atmospheric Plasma for Microbial Decontamination and Removal of Hazardous Chemicals: An Overview in the Circular Economy Context with Data for Test Applications of Microwave Plasma Torch

The transformation of our linear “take-make-waste” system to a cyclic flow of materials and energy is a priority task for society, but the circular use of waste streams from one industry/sector as a material input for another must be completely safe. The need for new advanced technologies and methods ensuring both microbiological safety and the removal of potential chemical residues in used materials and products is urgent. Non-thermal atmospheric plasma (cold atmospheric plasma—CAP) has recently attracted great research interest as an alternative for operative solutions of problems related to safety and quality control. CAP is a powerful tool for the inactivation of different hazardous microorganisms and viruses, and the effective decontamination of surfaces and liquids has been demonstrated. Additionally, the plasma’s active components are strong oxidizers and their synergetic effect can lead to the degradation of toxic chemical compounds such as phenols and azo-dyes.

Characteristics of 2.45 GHz Surface-Wave-Sustained Argon Discharge for Bio-Medical Applications

Cold atmospheric plasma (CAP) applications in various fields, such as biology, medicine and agriculture, have significantly grown during recent years. Many new types of plasma sources operating at atmospheric pressure in open air were developed. In order to use such plasmas for the treatment of biological systems, plasma properties should fulfil strong requirements. One of the most important is the prevention from heating damage. That is why in many cases, the post-discharge region is used for treatment, but the short living particles in the active discharge zone and reactions with them are missed in that case. We use the active region of surface-wave-sustained argon plasma for biological systems treatment. The previous investigations showed good bactericidal, virucidal, seeds germination and decontamination effects at a short treatment time, but the discharge conditions for bio-medical applications need specific adjustment. A detailed theoretical and experimental investigation of the plasma characteristics and their possible optimization in order to meet the requirements for bio-medical applications are presented in this paper. The length of the plasma torch, the temperature at the treatment sample position and the microwave radiation there are estimated and optimized by the appropriate choice of discharge tube size, argon flow rate and microwave power.

The Combination of Simultaneous Plasma Treatment with Mg Nanoparticles Deposition Technique for Better Mung Bean Seeds Germination

A novel method based on the combination of simultaneous cold plasma treatment with Mg nanoparticles deposition, applied to Mung bean seeds by improving their quality, is presented. The SRIM simulation reveals that only the very top layer of the seeds surface can be altered by the plasma. The experimental analysis indicates surface composition changes with a polar groups formation. These groups initiate the shift of surface characteristics from hydrophobic to hydrophilic. The chemical bond analysis shows the formation of MgO and Mg(OH)2 compounds, which acts as a positive factor for seeds germination and growth. The germination experiments showed a 70% outcome with an average of 73.9 mm sprouts length after 30 min of plasma treatment compared to the initial seeds (40% outcome and 71.3 mm sprouts length).

Strategies for Microbial Decontamination of Fresh Blueberries and Derived Products

Increasing consumption of blueberries is associated with appreciation of their organoleptic properties together with their multiple health benefits. The increasing number of outbreaks caused by pathogenic microorganisms associated with their consumption in the fresh state and the rapid spoilage of this product which is mainly caused by moulds, has led to the development and evaluation of alternatives that help mitigate this problem. This article presents different strategies ranging from chemical, physical and biological technologies to combined methods applied for microbial decontamination of fresh blueberries and derived products. Sanitizers such as peracetic acid (PAA), ozone (O3), and electrolyzed water (EOW), and physical technologies such as pulsed light (PL) and cold plasma (CP) are potential alternatives to the use of traditional chlorine. Likewise, high hydrostatic pressure (HHP) or pulsed electrical fields (PEF) successfully achieve microbial reductions in derivative products. A combination of methods at moderate intensities or levels is a promising strategy to increase microbial decontamination with a minimal impact on product quality.

Impact of Microwave Plasma Torch on the Yeast Candida glabrata

Recently, various cold plasma sources have been tested for their bactericidal and fungicidal effects with respect to their application in medicine and agriculture. The purpose of this work is to study the effects of a 2.45 GHz microwave generated plasma torch on a model yeast example Candida glabrata. The microwave plasma was generated by a surfatron resonator, and pure argon at a constant flow rate of 5 Slm was used as a working gas. Thanks to a high number of active particles generated in low-temperature plasma, this type of plasma has become highly popular, especially thanks to its bactericidal effects. However, its antimycotic effects and mechanisms of fungal inactivation are still not fully understood. Therefore, this study focuses on the antifungal effects of the microwave discharge on Candida glabrata. The main focus is on the measurement and evaluation of changes in inactivation effects caused by varying initial concentration of Candida glabrata cells, applied microwave power and exposure time. The discharge was applied on freshly inoculated colonies of Candida glabrata spread on the agar plates and its inhibitory effects were observed in the form of inhibition zones formed after the subsequent cultivation.

Numerical 3D Modeling: Microwave Plasma Torch at Intermediate Pressure

This study represents a self-consistent three-dimensional (3D) fluid plasma model coupled with Maxwell equations at an intermediate pressure between 1000 and 5000 Pa. The model was established using the finite element method to analyze the effects of time–space characteristics, which is the variation of plasma parameters with time and the 3D spatial distribution of plasma parameters in the plasma torch at various times. The numerical modeling was demonstrated in three different stages, where the growth of electron density is associated with time. From the distribution characteristics of molecular ions, it can be concluded that they are distributed mainly at the port of the quartz tube of the torch, which is larger than the center of the tube. The density ratio of molecular ion to electron is decreased because of the reduction of pressure and distance, which has been calculated from the port to the center of the quartz tube. The analysis of microwave plasma parameters indicated that intermediate pressure is useful for modeling and plasma source designing, especially for carbon dioxide conversion.

Atmospheric Pressure Microwave Plasma Jet for Organic Thin Film Deposition

In this work, the potential of a microwave (MW)-induced atmospheric pressure plasma jet (APPJ) in film deposition of styrene and methyl methacrylate (MMA) precursors is investigated. Plasma properties during the deposition and resultant coating characteristics are studied. Optical emission spectroscopy (OES) results indicate a higher degree of monomer dissociation in the APPJ with increasing power and a carrier gas flow rate of up to 250 standard cubic centimeters per minute (sccm). Computational fluid dynamic (CFD) simulations demonstrate non-uniform monomer distribution near the substrate and the dependency of the deposition area on the monomer-containing gas flow rate. A non-homogeneous surface morphology and topography of the deposited coatings is also observed using atomic force microscopy (AFM) and SEM. Coating chemical analysis and wettability are studied by XPS and water contact angle (WCA), respectively. A lower monomer flow rate was found to result in a higher C–O/C–C ratio and a higher wettability of the deposited coatings.

Safety Control of Whole Berries by Cold Atmospheric Pressure Plasma Processing: A Review

HIGHLIGHTS

CAPP technology has high application potential for decontamination of berries. Impacts of CAPP in aspects of food safety and security still need to be addressed. Optimized treatment parameters need to be investigated for each berry type.