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Increasing mass transfer of volatile organic compounds in air scrubbers: a fundamental study for different gas–liquid systems

Bruneel, Joren, Walgraeve, Christophe, Dumortier, Stefanie, Stockman, Jonas, Demeyer, Peter, Van Langenhove, Herman
Journal of chemical technology and biotechnology 2018 v.93 no.5 pp. 1468-1476
additives, air, aldehydes, cyclodextrins, hydrophobicity, industrial wastes, integrated pest management, liquids, mass transfer, models, oils, partition coefficients, scrubbers, silicone, solvents, sulfides, volatile organic compounds
BACKGROUND: Air scrubbers are commonly used as treatment techniques for industrial waste gases containing volatile organic compounds (VOCs). Mass transfer of hydrophobic compounds to liquid can be increased using water soluble additives in the scrubbing liquid or applying water‐miscible or immiscible solvents. The design of air scrubbers requires reliable partition data, which are limited in the literature. This manuscript provides partitioning data of new scrubber liquids and subsequent research will link the partitioning data with mass transfer characteristics in a pilot‐scale scrubber. RESULTS: The DynAb method was applied for the first time to a broad set of gas–liquid systems to study the partitioning behaviour of volatile organic sulphides and aldehydes. Cyclodextrins (CD) were chosen as water soluble additives. Silicone oil (SO) and isopropylmyristate (IPM) were used as water immiscible solvents, whereas dipropylene glycol methyl ether was applied as a water‐miscible solvent. The inclusion of VOCs into the CD structure is very compound specific. Binding constants were calculated to quantify the CD‐VOC affinity and the partitioning behaviour of the VOCs with oils and solvents was quantified. The air‐to‐water partition coefficient of hexanal could be reduced more than 50 times with a concentration of 72 g L‐¹ α‐CD. IPM (100% v/v) could reduce the air‐to‐IPM partitioning coefficient by a factor of 120 for dimethyl disulphide. CONCLUSION: The determined partition coefficients can be used for suitability evaluation for the design and modelling of air treatment systems. A broad range of evaluated gas–liquid systems provides quantitative knowledge about VOC behaviour. © 2017 Society of Chemical Industry