膜萃取邻甲酚废水的传质特性研究

Mass transfer characteristics of membrane extraction of o-cresol wastewater

构造了卷绕式及管束式两种膜组件,采用均质硅橡胶膜,以氢氧化钠溶液为萃取液来萃取邻甲酚废水。通过考察邻甲酚初始浓度、两相流动状态、两相压差(ΔP)和温度等因素对传质过程的影响,研究了邻甲酚废水的膜萃取过程与机制。结果表明,初始质量浓度为21.93g/L的邻甲酚废水很适合直接进行膜萃取;当ΔP<0.07MPa时,总传质系数(Kov)随ΔP的增大而略有减小,当ΔP>0.07MPa时,Kov随ΔP增大而显著增大;由实验数据拟合得到总的膜萃取传质模型,且该模型的实验值与理论值的相对误差在5%以内,满足工业设计要求。

Two membrane modules of spiral wound and single tubular non-porous silicone rubber membranes and 12.8% NaOH stripping solution were employed for extraction of the o-cresol wastewater. Many extraction runs were conducted to determine the effects of feed o-cresol concentration, flow status as represented by the Reynolds number （Ref）, pressure differential across the membrane, and system temperature （T） on the overall mass transfer coefficient （Kov） as well as to illustrate the mass transfer mechanism and o-cresol movement through the membrane. The experimental results indicated that the wastewater containing 21.93 g/L of o-cresol was suitable for the mem-brane extraction treatment. The Kov declined slightly with increasing pressure differential of d0.07 MPa; however, Kov increased notably with increasing pressure differential of 〉0.07 MPa. A model was developed to correlate Kov with Ref and T with a small relative error of 〈5% between the experimental and calculated Kov.