Application Of Composite Fe~0/C Micro-electrolysis Fillers On Treatment Of Acrylonitrile Wastewater

Two kinds of Fe0/C composite materials (sintered type and un-sintered type) were prepared in this study and physical properties of the composite materials (include bulk density, grain density, water absorption, voidage and specific surface area) were determined to explore the feasibility of using composite materials as micro-electrolysis fillers. Acrylonitrile wastewater was treated by two kinds of Fe0/C composite materials, respectively. Effects of influent pH, HRT and aeration rate on CODCr and acrylonitrile removal efficiency were investigated to determine the optimal conditions. The unhardened capacity of Fe0/C composite materials was studied by successive running of micro-electrolysis reactor. The optimal parameters and mode of operation was determined through pilot test. Conclusions were as follows:1. The preparation conditions of Fe0/C composite materials:(1) The optimum raw materials ratio of sintered type Fe0/C composite materials was obtained from clay 60%, Fe 32% and powdered activated carbon 8%. The optimum sintering temperature and time was 700℃ and 20min, respectively. The physical properties of the sintered type composite materials were as follows:bulk density was 997.2 kg/m3, grain density was 1675.0 kg/m3, water absorption was 18%, voidage was 41% and specific surface area was 30.52 m2/g. (2) The optimum raw materials ratio of un-sintered type Fe0/C composite materials was obtained from clay 20%, flyash 30%, cement 10%, Fe 32% and powdered activated carbon 8%. Natural curing was selected as best curing method and optimum curing time was selected as 7 days. The physical properties of the un-sintered type composite materials were as follows:bulk density was 956.2 kg/m3, grain density was 1608.4 kg/m3, water absorption was 14%, voidage was 42% and specific surface area was 32.82 m2/g. (3) The strength of two kinds of composite materials meet the water treatment fillers’ requirements. The performance of composite materials could be improved through addition 1-2%o Ni into composite materials.2. Fe0/C composite materials treated acrylonitrile wastewater, results were as follows:(1) Acrylonitrile wastewater was treated by improved sintered type Fe0/C composite materials at optimal operating conditions (influent pH of 3, HRT of 6h and aeration rate of 0.2L/min), the removal efficiency of CODcr and acrylonitrile was 68.8 and 73.9%. (2) Acrylonitrile wastewater was treated by improved un-sintered type Fe0/C composite materials at optimal operating conditions (influent pH of 3, HRT of 6h and aeration rate of 0.2L/min), the removal efficiency of CODCr and acrylonitrile was 65.8 and 70.4%. (3) During the successive running of micro-electrolysis reactor, the treatment effect of acrylonitrile wastewater was stable and two kinds of Fe0/C composite materials did not harden either.3. In the pilot test, the significance of each factor about acrylonitrile wastewater treatment was determined as influent pH> aeration rate> HRT through orthogonal experiment design. And the best parameters of operation were determined as influent pH of 3, HRT of 6h and aeration rate of 0.2L/min. The optimum operating mode of micro-electrolysis rector was determined as two reactors in series (adjusting first reactor effluent pH).