Comparison of physical technologies for biomass control in biofilters treating gaseous toluene

This paper presents the synthesis and evaluation of a carbon molecular sieve membrane (CMSM) grown inside a MEMS-fabricated μ-preconcentrator for sampling highly volatile organic compounds. An array of µ-pillars measuring 100 µm in diameter and 250 µm in height were fabricated inside a microfluidic channel to increase the attaching surface for the CMSM. The surface area of the CMSM was measured as high as 899 m2/g. A GC peak amplification factor >2 × 104 was demonstrated with gaseous ethyl acetate. Up to 1.4 L of gaseous ethanol at the 100 ppb level could be concentrated without exceeding the capacity of this microchip device. Sharp desorption chromatographic peaks (<3.5 s) were obtained while using this device directly as a GC injector. Less volatile compounds such as gaseous toluene, m-xylene, and mesitylene appeared to be adsorbed strongly on CMSM, showing a memory effect. Sampling parameters such as sample volatilities, sampling capacities, and compound residual issues were empirically determined and discussed.

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Oxidation of Aqueous Toluene by Gas-Phase Pulsed Corona Discharge in Air-Water Mixtures Followed by Photocatalytic Exhaust Air Cleaning

Catalysts ◽

10.3390/catal11050549 ◽

2021 ◽

Vol 11 (5) ◽

pp. 549

Author(s):

Maarja Kask ◽

Marina Krichevskaya ◽

Sergei Preis ◽

Juri Bolobajev

Keyword(s):

Corona Discharge ◽

Gas Phase ◽

Contact Time ◽

Closed Loop ◽

Simultaneous Treatment ◽

Pulsed Corona Discharge ◽

Air Cleaning ◽

Pulsed Corona ◽

Volatile Organic ◽

Gaseous Toluene

The treatment of wastewaters containing hazardous volatile organic compounds (VOCs) requires the simultaneous treatment of both water and air. Refractory toluene, extensively studied for its removal, provides a basis for the comparison of its abatement methods. The oxidation of aqueous toluene by gas-phase pulsed corona discharge (PCD) in combination with the subsequent photocatalytic treatment of exhaust air was studied. The PCD treatment showed unequalled energy efficiencies in aqueous and gaseous toluene oxidation, reaching, respectively, up to 10.5 and 29.6 g·kW−1·h−1. The PCD exhaust air contained toluene residues and ozone in concentrations not exceeding 0.1 and 0.6 mg·L−1, respectively. As a result of the subsequent photocatalytic treatment, both airborne residues were eliminated within a contact time with TiO2 as short as 12 s. The results contribute to the possible application of the studied approach in closed-loop energy-saving ventilation systems.

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Efficient solar-light conversion for optimizing the catalytic ozonation of gaseous toluene with PdO -LaFeO3

Applied Catalysis B Environmental ◽

10.1016/j.apcatb.2021.120004 ◽

2021 ◽

Vol 288 ◽

pp. 120004

Author(s):

Junxian Gao ◽

Lingling Tang ◽

Zhizhang Shen ◽

Yuming Dong ◽

Zhenyu Wang ◽

...

Keyword(s):

Catalytic Ozonation ◽

Solar Light ◽

Gaseous Toluene

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Silica Monolith for the Removal of Pollutants from Gas and Aqueous Phases

Molecules ◽

10.3390/molecules26051316 ◽

2021 ◽

Vol 26 (5) ◽

pp. 1316

Author(s):

Vanessa Miglio ◽

Chiara Zaccone ◽

Chiara Vittoni ◽

Ilaria Braschi ◽

Enrico Buscaroli ◽

...

Keyword(s):

Rhodamine B ◽

Water Solution ◽

Synthesis Method ◽

Textural Properties ◽

Adsorption Properties ◽

Water Soluble ◽

Silica Monoliths ◽

Physico Chemical ◽

Gaseous Toluene ◽

Mcm 41

This study focused on the application of mesoporous silica monoliths for the removal of organic pollutants. The physico-chemical textural and surface properties of the monoliths were investigated. The homogeneity of the textural properties along the entire length of the monoliths was assessed, as well as the reproducibility of the synthesis method. The adsorption properties of the monoliths for gaseous toluene, as a model of Volatile Organic Compounds (VOCs), were evaluated and compared to those of a reference meso-structured silica powder (MCM-41) of commercial origin. Silica monoliths adsorbed comparable amounts of toluene with respect to MCM-41, with better performances at low pressure. Finally, considering their potential application in water phase, the adsorption properties of monoliths toward Rhodamine B, selected as a model molecule of water soluble pollutants, were studied together with their stability in water. After 24 h of contact, the silica monoliths were able to adsorb up to the 70% of 1.5 × 10−2 mM Rhodamine B in water solution.

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