Determination of Volatile Fatty Acids from Raw Natural Rubber Drying Activity by Thermal Desorption-Gas Chromatography

Malodourous emission from raw natural rubber (NR) processing activities has become a public nuisance since residential and public development areas are gradually expanding near raw NR processing factories. The malodourous vapour mainly consists of volatile fatty acids (VFA) released from the breakdown of non-rubber constituents during drying stage of the raw rubber processing. An improved sampling methodology to characterise and monitor VFA from the drying stage was implemented. This study focused on the drying stage as the major source of malodour in the raw rubber processing. The thermal desorption-gas chromatography technique enabled direct sampling of air pollutants with minimal errors. It was found that acetic acid and propionic acids were present with highest concentrations. In general, concentrations of individual VFA varied throughout the drying stage. The raw NR processing factories were able to eliminate more than 71 % of total VFA using the relevant water scrubber treatment systems. The malodour characterization technique used in this study provides new technical information useful to develop more efficient malodour control systems for the raw NR processing industry.