Humic substances reduce the oxygen mass transfer in the air–water interface. Issue 6 (2nd April 2020)

• Record Type: Journal Article
• Authors: de Souza Lopes Silva, Pedro; Mateus, Marcos Vinícius; Ferreira, Deusmaque Carneiro; da Luz, Mário Sérgio; Araújo Naves, Emiliane Andrade; Martins, Mário Machado; Goulart, Luiz Ricardo; Cunha, Luís Carlos Scalon; de Souza Inácio Gonçalves, Julio Cesar
• Is Part Of: AIChE journal. Volume 66:Issue 6(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-04-02
• Subjects: gas–water interface -- grid‐stirred tank -- humic substances -- oxygen mass transfer -- reaeration; Chemical engineering -- Periodicals; Génie chimique -- Périodiques; 660.28
• DOI: 10.1002/aic.16971
• Languages: English
• ISSNs: 0001-1541

Abstract

Abstract: The aim of this study was to investigate the influence of humic substances (HS) on volumetric oxygen‐transfer coefficient ( K L a ) under different turbulence intensities at the air–water interface. The experiments were carried out in an oscillating grid tank which provided three levels of turbulence intensities (Reynolds numbers of 5, 116, 10, 316, and 15, 433). For each turbulence level, 15 different HS concentrations were tested and the K L a was estimated. The results showed that, regardless of the turbulence level in the tank, HS reduces K L a . The maximum reduction was 17%. The barrier effect, produced by the occupation of HS molecules at the interface, was the main phenomenon responsible for the reduction in the oxygen transfer. A relationship between the oxygen transfer velocity and turbulent kinetic energy showed that in the presence of HS, the air–water interface behaves like an immobile surface, reducing the oxygen diffusion and surface renewal.