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Non thermal plasma (NTP) reactors packed with non-catalytic or catalytic packing material have been widely used for the abatement of volatile organic compounds such as toluene, benzene, etc. Packed bed reactors are single stage reactors where the packing material is placed directly in the plasma discharge region. The presence of packing material can alter the physical (such as discharge characteristics, power consumption, etc.) and chemical characteristics (oxidation and destruction pathway, formation of by-products, etc.) of the reactor. Thus, packed bed reactors can overcome the disadvantages of NTP reactors for abatement of volatile organic compounds (VOCs) such as lower energy efficiency and formation of unwanted toxic by-products. This paper aims at reviewing the effect of different packing materials on the abatement of different aliphatic, aromatic and chlorinated volatile organic compounds. [ABSTRACT FROM AUTHOR]

Energy consumption is an important concern for the removal of volatile organic compounds (VOCs) from waste air with non-thermal plasma (NTP). Although the combination of NTP with heterogeneous catalysis has shown to reduce the formation of unwanted by-products and improve the energy efficiency of the process, further optimization of these hybrid systems is still necessary to evolve to a competitive air purification technology. A newly developed innovative technique, i.e., the cyclic operation of VOC adsorption and NTP-assisted regeneration has attracted growing interest of researchers due to the optimized energy consumption and cost-effectiveness. This paper reviews this new technique for the abatement of VOCs as well as for regeneration of adsorbents. In the first part, a comparison of the energy consumption between sequential and continuous treatment is given. Next, studies dealing with adsorption followed by NTP oxidation are reviewed. Particular attention is paid to the adsorption mechanisms and the regeneration of catalysts with in-plasma and post-plasma processes. Finally, the influence of critical process parameters on the adsorption and regeneration steps is summarized. [ABSTRACT FROM AUTHOR]

Abstract: In the present study, non-thermal plasma treatments using three different gases (air, nitrogen and argon) were used to activate the cotton surface for subsequent poly(N-isopropylacrylamide)/chitosan microgel (PN/CS) incorporation. The different surface modifications obtained on cotton and their effect on the microgel incorporation were investigated using X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). It was found that PN/CS microgel particles with a diameter of 180nm were tightly adhered to the cotton fabric surface. Nitrogen and argon plasma treated cotton presented better results in terms of microgel incorporation. The concept presented could lead to the development of a novel material with the highly attractive feature of responsiveness to the environmental stimuli. [Copyright &y& Elsevier]

To remove the toxic formaldehyde efficiently, a non-thermal plasma (NTP) system incorporated with MnO x –Fe 2 O 3 catalyst has been developed herein. A response surface methodology (RSM) was utilized to explore the effects of a variety of experimental parameters (gas flow rate, molar ratio of Fe/Mn, and discharge power) on formaldehyde degradation systematically. The results demonstrated that the discharge power has the greatest impact on the formaldehyde degradation process, while the molar ratio of Fe/Mn has the least influence. Moreover, the amount of adsorbed oxygen species, reducibility, and average specific surface area of the tested catalyst are estimated as the dominant factors influencing the catalytic performance. Importantly, the optimal formaldehyde removal efficiency (95.01%) and CO 2 selectivity (86.20%) were acquired at 5 W discharge power, 0.5 L min−1 gas flow rate, and 0.71 Fe/Mn molar ratio. This study can thus provide an efficient strategy for formaldehyde removal. [Display omitted] • Efficient oxidation of formaldehyde to CO 2 in the post-plasma-MnO x –Fe 2 O 3 system. • Modeling and optimization of formaldehyde removal process in the PPC system. • Discharge power is the most significant factor affecting the HCHO degradation. • Optimum formaldehyde removal (95.01%) and CO 2 selectivity (86.20%) were obtained. • Active oxygen specie is beneficial factor for formaldehyde oxidation. [ABSTRACT FROM AUTHOR]

The abatement of toluene was studied in a sequential adsorption-plasma catalysis (APC) process. Within this process, Hopcalite was used as bifunctional material: as adsorbent (storage stage) and as catalyst via the oxidation of adsorbed toluene (discharge stage). It was observed that the desorption and oxidation activity of the adsorbed toluene was significantly affected the process variables. In addition, the adsorption time influenced the CO2 selectivity and CO2 yield by changing the interaction between the catalyst and the plasma generated species. At least four APC sequences were performed for each examined condition suggesting that Hopcalite is very stable under plasma exposure during all the sequences. Consequently, these results could contribute to advance the plasma–catalyst system with an optimal VOC oxidation efficiency. The catalytic activity, amount of toluene adsorbed, amount of toluene desorbed and product formation have been quantified by FT-IR. Moreover, the catalyst was characterized by XRD, H2-TPR, N2 adsorption–desorption analysis and XPS. Hopcalite shows a good CO2 selectivity and CO2 yield when the APC process is performed with an adsorption time of 20 min and a plasma treatment with a discharge power of 46 W which leads to a low energy cost of 11.6 kWh·m−3 and energy yields of toluene and CO2 of 0.18 (±0.01) g·kWh−1 and 0.48 (±0.06) g·kWh−1 respectively. [ABSTRACT FROM AUTHOR]

In this work, cyclopropylamine (CPA) monomer was plasma-polymerized on poly (ε-caprolactone) nanofiber meshes using various deposition durations to obtain amine-rich surfaces in an effort to improve the cellular response of the meshes. Scanning electron microscopy and X-ray photoelectron spectroscopy (XPS) were used to investigate the surface morphology and surface chemical composition of the PCL samples, respectively. The measured coating thickness was found to linearly increase with deposition duration at a deposition rate of 0.465 nm/s. XPS analysis revealed that plasma exposure time had a considerable effect on the surface N/C and O/C ratio as well as on amino grafting efficiency and amino selectivity. In addition, cell studies showed that cell adhesion and proliferation significantly improved for all coated samples. [ABSTRACT FROM AUTHOR]

Abstract: This paper reviews recent achievements and the current status of non-thermal plasma (NTP) technology for the abatement of volatile organic compounds (VOCs). Many reactor configurations have been developed to generate a NTP at atmospheric pressure. Therefore in this review article, the principles of generating NTPs are outlined. Further on, this paper is divided in two equally important parts: plasma-alone and plasma–catalytic systems. Combination of NTP with heterogeneous catalysis has attracted increased attention in order to overcome the weaknesses of plasma-alone systems. An overview is given of the present understanding of the mechanisms involved in plasma–catalytic processes. In both parts (plasma-alone systems and plasma–catalysis), literature on the abatement of VOCs is reviewed in close detail. Special attention is given to the influence of critical process parameters on the removal process. [Copyright &y& Elsevier]

Biocompatible BPA-PPD polyimide is widely used in the packaging of implantable devices. Plasma activation can improve its interaction with the surrounding tissue upon implantation. The influence of He, air, N 2 and Ar plasma activation on polyimide's surface hydrophilicity, roughness, topography, composition and cell-surface interaction was evaluated, along with the influence of hydrophobic recovery on such properties. All plasma activations increased the surface hydrophilicity but neither the roughness nor topography changed. The increase was attributed to the incorporated O- and N-functionalities. 24 h after the activations the surface hydrophilicity decreased while maintaining the functionalities, due to the functionalities' reorientation/migration towards the bulk of polyimide. Air and N 2 activations improved the cell-surface interactions with fibroblasts. These were equally influenced by the surface hydrophilicity and the surface functionalities availability. The hydrophobic recovery lowered the initial cell adhesion but not the cell proliferation, as the hydrophobic recovery was progressively reversed in the culture media. Image 1 • Air and N 2 plasma activations can improve polyimide's cell-surface interactions. • Moderate hydrophilicity and surface functionalities drove cell-surface interactions. • The hydrophobic recovery effect on the cell-surface interactions was reversed. [ABSTRACT FROM AUTHOR]

• Plasma polymerised cyclopropylamine coatings, rich in NH 2 groups, are deposited. • Water immersion causes dissolution or delamination of the plasma coatings. • After immersion, the coatings partly maintain their chemical functionalities. • The coatings are biocompatible regardless of their aqueous stability. Amino-rich thin coatings, known to show superior cell adhesion, proliferation and viability, are prepared in this study by means of plasma polymerisation. The Yasuda parameter (W/FM) is used as a scaling factor for the deposition of cyclopropylamine based plasma polymer films (CPA-PPFs) making use of a dielectric barrier discharge (DBD) operated at sub-atmospheric pressure. In this paper, the experimental research is focussed on the stability of the CPA-PPFs in water, a property of PPFs which is often overlooked in literature. More specifically, after their plasma-assisted fabrication, the polymerised samples are immersed in water for 24 h after which the coatings are chemically evaluated using Fourier transform infrared (FTIR) and X-ray photoelectron (XPS) spectroscopy. The obtained results reveal that for all W/FM values under study water immersion results in a significant loss in C N/C N groups and a shift of primary to secondary/tertiary amines combined with the incorporation of oxygen at the surface as amides and alcohols/ethers. Moreover, FTIR, XPS chemical depth profiling (by means of C 60 sputtering) and scanning electron microscopy (SEM) results also reveal that at W/FM values ≤ 288 MJ/kg, the PPFs are gradually dissolving during water immersion, while at W/FM values > 288 MJ/kg, the PPFs are delaminating from the substrate due to their high crosslinking degree. Nevertheless, cell-coating interaction studies reveal no signs of cytotoxicity 1 day after cell seeding and show that the thin coatings remaining on the substrate still strongly increase the adhesion of fibroblasts. In the near future, efforts will be undertaken to avoid the delamination from the substrate of the PPFs prepared at high W/FM values. [ABSTRACT FROM AUTHOR]

• Efficiency towards TCE abatement: Cu-Mn oxide (PPC) > Cu-Mn oxide (Catalysis) > NTP. • Impact of the catalyst synthesis route (Redox versus Co-precipitation) in PPC. • NTP assisted Cu-Mn oxide prepared by Redox route shows the highest CO 2 yield. The removal of dilute trichloroethylene (TCE) in moist air by post-plasma catalysis (PPC) using Cu-Mn mixed oxides heated at 150 °C was investigated. Cu-Mn mixed oxides were prepared by redox- and co-precipitation method. In comparison to the catalytic oxidation and non-thermal plasma (NTP) process, PPC was found to be the best process to convert TCE into CO 2 , in particular when Cu-Mn oxide was synthetized by redox precipitation method. The highest TCE conversion efficiency of more than 80% was obtained at the energy density of 60 J.L−1 using the catalyst prepared by redox-precipitation process in PPC configuration. The performance of Cu-Mn oxide prepared by redox-precipitation method did not show increase in TCE conversion with energy density which is attributed to the changes on the catalyst surface (such as reduction in S BET , chlorine poisoning and Mn enrichment). Although, Cu-Mn oxide prepared by co-precipitation method showed a lower TCE conversion, it exhibited a better stability in the PPC process for TCE abatement. [ABSTRACT FROM AUTHOR]