Achieving efficient biodegradation of hydrophobic toluene via the enhancement of β-cyclodextrin and atomization

Industrial production processes produce large amounts of toluene, endangering human health and air quality. The hydrophobicity of toluene limits the removal performance in biotrickling filters (BTFs). To improve the removal efficiency of toluene in BTFs, β-cyclodextrin (β-CD) coupled with atomization was employed in this study. The results showed that β-CD and atomization significantly enhanced the biodegradation of toluene and the maximum elimination capacity reached 90.9 g/(m3·h). At the optimized conditions that β-CD additional of 12.5 g/L and an atomizer with power of 19.8 W, the removal efficiency of toluene was up to 92.6 % (inlet concentration, 0.7 g/m3), which was 17 % higher than that of the control. The use of β-CD combined with atomization increased the extracellular protein and polysaccharide contents. The biofilm surface hydrophobicity of the experimental group reached 79 % which was 1.34 times that of the control. The abundance of toluene degrading bacteria, Pseudomonas sp. and Mycobacterium sp., significantly increased under β-CD with atomization. The addition of β-CD with atomization increased mass transfer, the relative hydrophobicity of biofilm, and the functional microbes so as to enhance treatment of toluene. This study may provide guidelines for the design and technological development of hydrophobic toluene control in industrial waste gas.