| In this paper, 4-fluorocinnamic acid was selected as research object. Photosynthetic bacteria with high degradation efficiency for 4-fluorocinnamic(4-FCA) was obtained by acclimation of gradual increase of 4-FCA concentration and multiplication, and their cells morphological and some physiological and biochemical characteristics were identified. Toxic effect of 4-FCA to PSB-DR and the biodegradation characteristics of PSB-DR for 4-FCA were investigated.First, PSB-DR dehydrogenase activity under different concentration of 4-FCA was studied. 4-FCA produced inhibitory for dehydrogenase activity of PSB-DR, and with the increase of the concentration of 4-FCA, the dehydrogenase activity was decreased gradually. A standard method of algal bioassay for evaluating the toxicity of toxic chemicals was applied. The lowest observed effect of concentration(LOEC) on the growth was 50mg/L, and the 24h-EC50 of 4-FCA on the inhibition of growth was 513mg/L.Next, biodegradation characterizations of 4-FCA by PSB-DR at different 4-FCA concentration, inoculum size, the addition of sodium acetate, initial pH, in the presence or absence of light and NaCl concentration under aerobic condition were investigated. The optimal condition was as follows: under dark-aerobic condition, inoculum size10%, pH 7.0, and without the addition of sodium acetate, respectively, and above 90% of 4-FCA(200 mg/L) was removed after 96 h.Release of fluoride occurred during the degradation process. The concentration of fluoride ion was 12mg/L at a concentration of 200mg/L, and the defluorination rate was 52%.Biodegradation kinetics was in accordance with the Haldane’s equation. And the kinetic parameter values were rmax=0.066 h-1, Km=425.1 mg/L, and Ki=89.25 mg/L. Moreover, biodegradation of simulated 4-FCA containing wastewater was scaled-up at a batch bioreactor under dark-aerobic condition. For the 7d HRT, TOC removal rate was 73.4% when the initial 4-FCA concentrations of 200 mg/L. |
PDF Full Text Request