Fuelling phytoremediation: gasoline degradation by green wall systems-a case study

Abstract

The capacity for indoor plants including green wall systems to remove specific volatile organic compounds (VOCs) is well documented in the literature; however under realistic settings, indoor occupants are exposed to a complex mixture of harmful compounds sourced from various emission sources. Gasoline vapour is one of the key sources of these emissions, with several studies demonstrating that indoor occupants in areas surrounding gasoline stations or with residentially attached garages are exposed to far higher concentrations of harmful VOCs. Here we assess the potential of a commercial small passive green wall system, commercially named the 'LivePicture Go' from Ambius P/L, Australia, to drawdown VOCs that comprise gasoline vapour, including total VOC (TVOC) removal and specific removal of individual speciated VOCs over time. An 8-h TVOC removal efficiency of 42.45% was achieved, along with the complete removal of eicosane, 1,2,3-trimethyl-benzene, and hexadecane. Further, the green wall also effectively reduced concentrations of a range of harmful benzene derivatives and other VOCs. These results demonstrate the potential of botanical systems to simultaneously remove a wide variety of VOCs, although future research is needed to improve upon and ensure efficiency of these systems over time and within practical applications.

Keywords: Gasoline vapour; Green wall; Indoor air quality; Phytoremediation; VOCs.

Fig. 1

Experimental small-scale green wall biofilters (n = 9) maintained within a climate-controlled research glasshouse

Fig. 2

Experimental set-up for GC-MS speciation, including planted biofilter, heat bath for gasoline vapour generation and an SPME fibre for pVOC absorption

Fig. 3

Relative TVOC drawdown for each treatment over 8 h. Error bands represent the SEM

Fig. 4

Speciated pVOCs identified in GC-MS analysis of each treatment. Grey boxes depict VOC functional groups. Each tile represents a timepoint, with its colour depicting the mean peak height (log scale), which is indicative of the remaining quantity of each VOC (for interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article)