Effects Of Membrane Structrues On The Mass Transfer Of Hollow Fiber Renewal Liquid Membrane

Hollow fiber renewal liquid membrane (HFRLM) techniques is a new type of simultaneous extraction and stripping processes in the same stage. It has many advantages, such as low mass transfer resistance, high mass transfer rate, simply operate, non secondary pollution, long-term stability, etc. It has great application potential in the following industrial field, including heavy metal wastewater treatment and in-situ fermentation product recovery, etc. In HFRLM process, the core part is the membrane module. Moreover, the hollow fiber in the module play an imoprtant role in the whole process, because the hollow fiber membrane structures and the fluid flow in the fiber have great influence on the mass transfer performance.In this work, copper sulfate solution was used as feed phase, LIX984N dissolved in kerosene was choosen as membrane phase and sulfuric acid is used as stripping phase. Effects of inner diameter and thickness of hollow fiber membrane, tube side and shell side velocity, oil-water ratio on the HFRLM process performance were investigated. Results indicated that the better performance of HFRLM in our study could be obtained in case of the thinner fiber thickness, the larger fiber inner diameter, the larger oil-water ratio and the larger tube velocity. Besides, the mass transfer enhancement increased with increasing hollow fiber inner diameter and oil-water ratio.The visualization research on oil-water flow in horizontal PVDF hollow fiber with different inner diameter was done by using microscope and high speed camera. Experimental results indicated that the mean and variance of droplet size distributions increased with increasing fiber inner diameter and velocity. The correlation for calculating the Sauter mean diameter of various hollow fiber inner diameter and velocity has been established. And, the flow pattern of the system of LIX984N dissolved in kerosene and deionized water was obtained.Based on the resistance in series model and assuming the renewal mass transfer and extract mass transfer exist in the tube, the mass transfer model of HFRLM process was founded. The model results were in good agreement with the experimental data.