Study On Concentrating Hydrogen Peroxide Solution By Membrane Distillation

Membrane distillation is a new membrane separation technology which was developed in recent decades. It has been widely used in the field of desalination of sea water or brackish water, concentration of aqueous solution and the treatment of waste water because of its advantage of high evaporation efficiency and flexible design. The operation condition of membrane distillation is mild and the low-grade heat source can be utilized in the process of membrane distillation. The process can be operated under the condition of ambient temperature and pressure, so it is particularly suitable for the treatment of thermo-sensitive solution containing active substance, such as concentration of the traditional Chinese medicine extracting solution, the hyaluronic acid and the penicillin solution.Hydrogen peroxide is also thermo-sensitive, it will be decomposed into water and oxygen when heated. Especially the high temperature will accelerate its decomposition and even cause explosion. This research work is devoted to concentrate hydrogen peroxide solution by membrane distillation technology in order to provide a new method for concentrating hydrogen peroxide solution operated under mild conditions.Decomposition experiment of hydrogen peroxide solution was firstly studied in this work so as to determine the appropriate feed temperature. Five kinds of membranes which were chosen in the work were characterized, then used in the hydrogen peroxide solution membrane distillation process. Comparing the experiment results of the different membranes, PP membrane was the best choice, as the H2O/H2O2 separation factor was 20.28.The vacuum membrane distillation and the gas sweep membrane distillation were compared in which PP membrane was used and the feed was water. The results showed that PP membrane was easily damaged and the water infiltrated the membrane in the vacuum membrane distillation process, however it could be stabilized in the gas sweep membrane distillation.Finally the effect of operating variables on the gas sweep membrane of hydrogen peroxide solution was investigated. It was showed that the total flux, the water flux and the hydrogen peroxide flux increased with the increase of feed temperature. Also the separation factor and the concentration factor increased, the loss of hydrogen peroxide increased, so the hydrogen peroxide product yield decreased, above 80wt%. With the feed rate increasing, the total flux and water flux increased first then changed mildly, the hydrogen peroxide flux change was not obvious, the separation factor change was agree with the total flux, concentration factor increased, the hydrogen peroxide product yield change was not significant,above 95wt.%. With the feed concentration increasing, the total flux and water flux decreased, the hydrogen peroxide flux increased, both the separation factor and the concentration factor decreased, the hydrogen peroxide product yield was about 92%. With the gas sweeping rate increasing, the total flux and water flux increased, the hydrogen peroxide flux increased, the separation factor decreased, the concentration factor increased, the hydrogen peroxide product yield change was not significant,above 97wt.%. Prolonging the operation time, the total flux and water flux decreased, the hydrogen peroxide flux increased, both the separation factor and the concentration factor decreased.In the experiment, all the concentration factors were greater than 1, it was showed that the hydrogen peroxide solution could be concentrated by PP membrane gas sweep membrane distillation under the lower temperature safely.This work provides a newly safe method for concentration of hydrogen peroxide solution and enlarges the application field of membrane distillation.