| Abstract: | Aimed at developing new energy-efficient technology for the bromine extraction, continues bromine absorption in membrane air-blowing/absorption (MA-B/A) process was designed where Hydrophobic polyvinylidene fluoride (PVDF) hollow fiber membranes were used as aeration configurations. The compressed air was blown out of the aeration configurations (U-type PVDF membrane modules) in the form of small air bubbles, and flowed into respectively each membrane module which were in a series connection. Convective mass transfer happened between small air bubbles and the treating liquid (sea water simulated). Air flux carrying bromine molecules formed mixed gas made of air and bromine. Mixed gas permeated out of the membrane hole of hollow fiber hydrophobic membranes and reacted with absorption liquid to produced bromine compound, thus continues bromine extraction from the liquid was carried out. The effects of operation conditions in absorption process, such as the liquid height of absorption cell, fluid flow, concentration, pH, temperature of absorption solution, the thickness of membranes and the structure of modules in absorption process on membrane absorption process were investigated. The optimal parameters of continues bromine absorption with MA-B/A process were obtained. The experimental results show that bromine removal rate, recovery rate and absorption rate reaches 82%, 76.3% and 93.1% respectively when the membrane thickness in absorption process is 0.15 mm, the module is seaweed-type, the liquid height of absorption cell is 1.5 m, fluid flow is 0.5 L?h-1, the concentration is 0.1 mol?L-1, pH range is 6~7 and the temperature is 70 ℃ of absorption solution. |
