Nuclear Science and Techniques

《核技术》(英文版) ISSN 1001-8042 CN 31-1559/TL     2019 Impact factor 1.556

Nuclear Science and Techniques ›› 2013, Vol. 24 ›› Issue (S1): S010202

• LOW ENERGY ACCELERATOR, RAY AND APPLICATIONS • Previous Articles     Next Articles

A comparison of pilot scale electron beam and bench scale gamma irradiations of cyanide aqueous in solution

YE Longfei1,2,3,* HE Shijun1 YANG Chunping2 WANG Jianlong1,* YU Jiang3   

  1. 1Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, China
    2College of Environmental Science and Engineering, Hunan University, Changsha 410082, China
    3Jiangsu Dasheng Electron Accelerator Device Co., Ltd, Suzhou 215214, China
  • Contact: YE Longfei E-mail:yelongfei-2008@163.com
  • Supported by:

    Supported by Hi-Tech Research and Development Program of China (863 Plan) (No.2009AA063905), international cooperation project (2011DFR00110) and IAEA technical cooperation programme (CPR1008)

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YE Longfei, HE Shijun, YANG Chunping, WANG Jianlong, YU Jiang. A comparison of pilot scale electron beam and bench scale gamma irradiations of cyanide aqueous in solution.Nuclear Science and Techniques, 2013, 24(S1): S010202

Abstract:

Bench-scale gamma irradiation was conducted to investigate the influencing factors, such as initial cyanide concentration, absorbed dose, saturated gases, and pH value as well as water compositions on the γ radiolysis of cyanide in simulated aqueous solution. The decomposition rate of cyanide was observed as pseudo-first-order kinetic over the applied concentrations varied from 77 mg/L to 247 mg/L. Cyanide was decomposed more rapidly at a lower initial concentration than that at a higher initial concentration. However, the radical scavengers in natural waters, such as carbonate and bicarbonate, have negative effects on the remove of cyanide. This indicated that hydroxyl radical may play predominant role in the γ radiolysis of aqueous cyanide. Finally, ammonia and cyanate were identified as the main nitrogen-containing byproduct of γ radiolysis of cyanide. To remove toxic hydrogen cyanide (HCN) from carbon fiber industry waste gases, a pilot-scale experiment with a self-sheltered electron beam accelerator was demonstrated after two sprays of chemical absorption. The operating conditions for absorption and irradiation had been optimized. It was shown that after the first spray tower, HCN concentration decreased from (240±50) mg/m3 to 35 ± 15 mg/m3. While after the second spray tower, effluent HCN was reduced almost below the method detection limit. Then, the residual cyanide in aqueous solution was exposured to high energy electron beam (EB). Influent CN− concentration was controled at (15±2) mg/L with a water regulating tank. This treatment allows CN− to reach the regional limit (of 0.5 mg/L) for safe industrial wastewater discharge with a irradiation dose of 12 kGy. The obtained results showed that the combined process were effective for removing HCN from the waste gas.

Key words: Gamma irradiation, Electron beam, Wastewater treatment, Cyanide, Ozone, Advanced oxidation processes