Dan Wang

The biodegradation of petroleum hydrocarbons has many potential applications and has attracted much attention recently. The hydrocarbon-degrading bacterium BL-27 was isolated from petroleum-polluted soil and was compounded with surfactants to improve biodegradation. Its 16S rDNA and rpoD gene sequences indicated that it was a strain of Bacillus subtilis. Strain BL-27 had extensive adaptability and degradability within a broad range of temperatures (25–50 °C), pH (4.0–10.0) and salinity (0–50 g/L NaCl). Under optimal conditions (45 °C, pH 7.0, 1% NaCl), the strain was able to degrade 65% of crude oil (0.3%, w/v) within 5 days using GC-MS analysis. Notably, strain BL-27 had weak cell surface hydrophobicity. The adherence rate of BL-27 to n-hexadecane was 29.6% with sucrose as carbon source and slightly increased to 33.5% with diesel oil (0.3%, w/v) as the sole carbon source, indicating that the cell surface of BL-27 is relatively hydrophilic. The strain was tolerant to SDS, Tween 80, surfactin, and rhamnolipids at a concentration of 500 mg/L. The cell surface hydrophobicity reduced more with the addition of surfactants, while the chemical dispersants, SDS (50–100 mg/L) and Tween 80 (200–500 mg/L), significantly increased the strain’s ability to biodegrade, reaching 75–80%. These results indicated that BL-27 has the potential to be used for the bioremediation of hydrocarbon pollutants and could have promising applications in the petrochemical industry.

BACKGROUND: The ammonia‐based wet flue gas desulfurization (FGD) system generates fluoride‐rich slurry, the concentration of which reaches several thousand mg L⁻¹. Therefore this slurry has to be treated to avoid damage to industrial equipment, human health and environment safety. This work aims at separating fluoride from high‐concentrated ammonia‐based wet FGD slurry and purifying the ammonium sulfate byproduct using electrodialysis (ED).RESULTS: The effects of experimental conditions such as applied potential, circular flow rate, pH and temperature were investigated for the ED process. The influence of competing ions such as Cl⁻ and SO₄²⁻ on the removal efficiency was also studied. The use of a homogeneous AMX membrane in the first stage of ED and an ACS monovalent anion selective membrane in the second stage of ED proved to be a feasible and cost‐effective strategy for F⁻ removal. The total recovery rate of F⁻ was 81.4%, while the content of NH₄F increased from 0.35 to 40.70%. The power consumption and current efficiency were also studied to evaluate the suitability of ED for the defluoridation of FGD slurry.CONCLUSION: The separation and recovery of F⁻ using the designed ED is cost‐effective and efficient, and the process can be extended to other FGD techniques. © 2019 Society of Chemical Industry