Enhanced Removal of Hydrophobic Short-Chain n-Alkanes from Gas Streams in Biotrickling Filters in Presence of Surfactant

Emissions of n-alkanes are facing increasingly stringent management challenges. Biotrickling filtration in the presence of surfactants is a competitive alternative for the enhanced removal of n-alkanes. Herein, sodium dodecyl benzene sulfonate (SDBS) was added into the liquid phase feeding a biotrickling filter (BTF) to enhance the removal of various short-chain n-alkanes from n-hexane (C6) to methane (C1). The removal performance of C6- C1 and microbial response mechanisms were explored. The results showed that the removal efficiency (RE) of n-alkanes decreased from 77 +/- 1.3 to 35 +/- 5.6% as the carbon chain number of nalkanes decreased from C6 to C1, under the conditions of an nalkane inlet load of 58 +/- 3.0 g/m3middoth and EBCT of 30 s. The removal performance of n-alkanes was enhanced significantly by the introduction of 15 mg/L SDBS, as the RE of C6 reached 99 +/- 0.7% and the RE of C1 reached 74 +/- 3.3%. The strengthening mechanisms were that the apparent Henry's law coefficient of n-alkanes decreased by 11 +/- 1.4-30 +/- 0.3%, and the cell surface hydrophobicity of microorganisms improved from 71 +/- 5.6 to 87 +/- 4.0% with the existence of SDBS. Moreover, the presence of SDBS promoted the succession and activity of the microbial community. The activities of alkane hydroxylase and alcohol dehydrogenase were 5.8 and 5.9 times higher than those without SDBS, and the concentration of the cytochrome P450 gene was improved 2.2 times. Therefore, the addition of SDBS is an effective strategy that makes BTF suitable for the removal of various nalkanes from waste gas streams.

Automated summary

This study investigated the removal performance of n-alkanes and microbial response mechanisms in a biotrickling filter (BTF) in the presence of surfactant. The results showed that the addition of sodium dodecyl benzene sulfonate (SDBS) significantly enhanced the removal efficiency of n-alkanes and promoted the activity and succession of the microbial community.