Improved performance of non-thermal plasma reactor during decomposition of trichloroethylene: Optimization of the reactor geometry and introduction of catalytic electrode

The decomposition of trichloroethylene ITCE) by non-thermal plasma was investigated in a dielectric barrier discharge (DBD) reactor with a copper rod inner electrode and compared with a plasma-catalytic reactor. The particularity of the plasma-catalytic reactor is the inner electrode made of sintered metal fibers (SMF) coated by transition metal oxides. In order to optimize the geometry of the plasma reactor, the efficiency of TCE removal was compared for different discharge gap lengths in the range of 1-5 mm. Shorter gap lengths (1-3 mm) appear to be more advantageous with respect to TCE conversion. In this case TCE conversion varies between 67% and 100% for input energy densities in the range of 80-480 J/l, while for the 5 turn discharge gap the conversion was lower (53-97%) for similar values of the input energy. As a result of TICE oxidation carbon monoxide and carbon dioxide were detected in the effluent gas. Their selectivity was rather low, in the range 14-24% for CO2 and 11-23% for CO, and was not influenced by the gap length. Several other chlorinated organic compounds were detected as reaction products. When using MnOx/SMF catalysts as the inner electrode of the DBD reactor, the TCE conversion was significantly enhanced, reaching similar to 95% at 150 J/l input energy. The selectivity to CO2 showed a major increase as compared to the case without catalysts, reaching 58% for input energies above 550 J/l. (C) 2007 Elsevier B.V. All rights reserved

Toluene oxidation in a plasma-catalytic system

Oxidative removal of toluene in a dielectric barrier discharge reactor combined with manganese catalysts downstream was investigated. Toluene input concentration was varied in the range of 415-2227 ppm. The discharge was operated in pulsed mode, with short pulses of 23-35 kV peak voltage. At 7 W average power, toluene conversion was 60%-70%, independent on the toluene input concentration and on the total gas flow rate in the range of 110-330 SCCM (SCCM denotes cubic centimeter per minute at STP). Toluene total oxidation was favored at high residence time of the gas in the discharge zone and low toluene concentration, when the main reaction product was CO2 with selectivities of 80%-85%. The addition of the catalysts led to a 15%-20% increase in toluene conversion with respect to the values obtained in the plasma, due to oxidation with ozone on the catalyst surface. (c) 2006 American Institute of Physics

Plasma-assisted catalysis for volatile organic compounds abatement

A dielectric barrier discharge (DBD) combined with Mn-based phosphate catalysts placed downstream of the plasma reactor was investigated experimentally for total oxidation of toluene in air. The discharge was initiated by high voltage pulses of 18 kV amplitude and 1213 ns rise time. The pulse frequency increased from 14 to 80 Hz, for applied voltages in the range 18-28 kV. Discharge currents up to 100 A and approximately 50 ns duration were obtained. No other hydrocarbons except toluene were detected in the effluent gas. The yield of carbon dioxide formed in the discharge was up to 24%. As catalysts, MnPO4, Mn-APO-5 and Mn-SAPO-11 were tested, for temperatures up to 400 degrees C. Under purely catalytic conditions, the best behavior for toluene total oxidation was found for Mn-SAPO-11, with a CO2 yield up to 33%, at 400 degrees C. The combined application of plasma and catalysis showed a remarkable synergetic effect, even at low temperature, up to 100 degrees C, where the catalysts alone are not active. In this range, the CO2 yield increased up to 41%, for the Mn-SAPO catalyst. At 400 degrees C the highest CO2 yield was obtained for MnPO4, reaching 68%. The synergetic effect observed for the plasma-catalyst combination is attributed to ozone radicals formed in the discharge, which decompose on the catalyst surface, greatly contributing to toluene total oxidation. (c) 2005 Elsevier B.V. All rights reserved

Immunology of solid tumors beyond tumor-infiltrating lymphocytes: The role of tertiary lymphoid structures

Immune cells and other constituents of the immune system make up an important part of the tumor microenvironment. Due to increased knowledge on the biology of the immune system in solid tumors and the successes with the treatment of patients with drugs that target its function, interest in immuno-oncology has increased enormously since the first successful trials. The first part of this chapter gives an overview of our current understanding of the role of the immune system in solid tumors, with a focus on the role of tumor-infiltrating lymphocytes (TILs) and their organization in structures called tertiary lymphoid structures (TLS). The increased interest in immuno-oncology has also triggered the search for predictive and prognostic biomarkers. One of the best characterized tissue-based biomarkers of the immune response in solid tumor is the presence of TILs. The second part of the chapter, which focuses on breast cancer, describes currently available data on TILs as a prognostic biomarker, challenges on the assessment of TILs, and TLS and the efforts of the International Immuno-Oncology Biomarker Working Group on standardization of its assessment.SCOPUS: ch.binfo:eu-repo/semantics/publishe