Extraction of nitrobenzene from aqueous solution in impinging stream rotating packed bed

A liquid-liquid extraction of nitrobenzene (NB) in impinging stream-rotating packed bed (IS-RPB) was proposed using cyclohexane as an extractant, presented for its improvement of micromixing and mass transfer performance. The effects of pH, phase ratio (the flow rate of organic phase/aqueous phase) and rotating speed of ISRPB on removal efficiency and extraction stage efficiency of NB were investigated experimentally in IS-RPB. The experimental result showed that the removal rate of NB reached 94.93%, and extraction stage efficiency was 99.99% in IS-RPB, respectively, under the following experimental conditions including: a pH of 6.4, a temperature of 25 degrees C, a phase ratio of 1:1, a liquid flow rate of 50 L/h, a rotating speed for IS-RPB of 400 r/min, and an initial impinging velocity of 7.88 m/s. Besides, IS, RPB and IS-RPB were compared based on the removal rate of NB and extraction stage efficiency in the same experimental conditions. Compared with other mixing devices, IS-RPB has better extraction stage efficiency and shorter extraction time than other extraction devices, proving that high gravity technology can be utilized to effectively improve the extraction stage efficiency and has a good application prospect.