Mechanisms of N, N-dimethylacetamide-facilitated n-hexane removal in a rotating drum biofilter packed with bamboo charcoal-polyurethane composite

n-Hexane and N, N-dimethylacetamide (DMAC) are two major volatile organic compounds (VOCs) discharged from the pharmaceutical industry. To enhance DMAC-facilitated n-hexane removal, we investigated the simultaneous removal of multiple pollutants in a rotating drum biofilter packed with bamboo charcoal-polyurethane composite. After adding 800 mg·L^-1 DMAC, the n-hexane removal efficiency increased from 59.4 % to 83.1 % under the optimized conditions. The maximum elimination capacity of 10.0 g·m^-3·h^-1n-hexane and 157 g·m^-3·h^-1 DMAC were obtained. The biomass of bamboo charcoal-polyurethane and the ratio of protein-to-polysaccharide in extracellular polymeric substances were significantly increased compared with the non-DMAC stage, which is attributed to increased carbon utilization. In addition, Na⁺ K⁺-ATPase was positively correlated with increasing electron transport system activity, which was 1.98 and 1.36 times greater. Hydrophilic DMAC improved the bioavailability of hydrophobic n-hexane and benefited bacterial metabolism. Co-degradation of n-hexane and DMAC system can be used for other volatile organic pollutants.