| Apilot apparatus with electrodialysis(ED) and bipolar membrane electrodialysis (EDBM)modules was used for concentrating pretreated butyl-acrylate wastewater and recoveringorganic from the concentrate. Influence of liquid temperature and operation voltage onelectrodialysis was investigated. Cost for organic acid recovery at different operation voltagewith EDBM was analysis. Operation parameters were optimized. The conclusions are asfollows.(1)ED could concentrate butyl-acrylate wastewaster from0.322mol/L to2.02mol/Lunder optimized conditions (25℃～30℃，40V，flow velocity across membrane3.3cm/s).(2)Operation temperature has significant influence on average current density, currentefficiency and energy consumption.25℃was more suitable for EDBM operation than20℃.(3)Increase of initial acid concentration to COD of50000mg/L or100000mg/L has littleeffect on recovered acid concentration.(4)Increase of initial volume ratio of feed and acid solution is an effective method toachieve high acid concentration. As the ration increased from2:1to5:1, average currentdensity increased from30.82mA/cm2to36.98mA/cm2. Current efficiency increased from75%to46%. Energy consumption for organic acid production increased from0.11kWh/molto0.16-0.18kWh/mol. Recovered organic acid concentration increased from1.45mol/Lto2.74mol/L.(5)As operation voltage of EDBM increased from50V to100V, average current densityincreased linearly from16.91mA/cm2to55.22mA/cm2, and duration required was shortened.Current efficiency maintained at64%-66%, while energy consumption for organic acidincreased from0.10kWh/mol to0.20kWh/mol linearly. Cost for organic production decreasedfrom0.713yuan/mol to0.378yuan/mol. |
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