3. Results and discussion
3.1. Bioelectrochemical treatment of p-FNB
3.1.1. p-FNB removal
Fig. 1. p-FNB removal in CGP 41251 TBES, TBS, TECS, MBES, MBS and MECS. The respective p-FNB removal rate (k) and half-lifetime (t1/2) under different conditions were: TBES: k = 0.2345, t1/2 = 2.96, R2 = 0.9951; MBES: k = 0.1313, t1/2 = 5.28, R2 = 9887; TBS: k = 0.0081, t1/2 = 85.57, R2 = 0.9319; MBS: k = 0.0202, t1/2 = 34.31, R2 = 0.9765; TECS: k = 0.0632, t1/2 = 10.97, R2 = 0.8478; MECS: k = 0.0419, t1/2 = 16.54, R2 = 0.9769. p-FNB removal kinetics were characterized by fitting p-FNB concentrations measured in batch experiments as a function of time.Figure optionsDownload full-size imageDownload as PowerPoint slide
Further fitting results revealed that the rate constant for p-FNB removal (kp-FNB) in the TECS was 50.8% higher than that in the MECS ( Fig. 1), which was attributed to the thermophilic benefit of reduced activation resistance, mass-transfer limitation, and ohmic potential loss ( Ha et al., 2012). However, elevation of the p-FNB removal rate constant owing to temperature increase was greater in the BES (78.6%). Considering the inactivation of the microbial metabolism in the TBS, the greater elevation of p-FNB removal in the TBES likely resulted from the successful evolution of specific thermophilic biocatalysis for the efficient metabolism of p-FNB degradation.