Bipolar Membrane Introduction
Bipolar membrane (BPM) is a new membrane, which is usually a composite ion exchange membrane composed of an anion exchange layer and a cation exchange layer. It can also be added with a third layer of substance between the anion membrane and the cation membrane to promote water dissociation, which can be called as a three-layer structure of anion exchange layer, cation exchange layer and medium reaction layer. Under the action of the DC electric field, the bipolar membrane can dissolve water, and H+ and OH- are generated on both sides of the anion and cation membranes.
● Treatment of fluorine-containing waste liquid and recovery of fluorine with valence
In the production of fluorocarbon industry and uranium industry (UF6), the mass fraction of fluorine and organic acid contained in the waste gas and waste water discharged is 50-500×10-6, which usually needs KOH neutralization to remove them completely, the resulting KF solution contains many heavy metals (such as uranium, arsenic, etc.) and trace radioactive materials. It also needs Ca(OH)2 to react with KF to regenerate KOH and produce insoluble wastes. This method leads to the loss of fluorine with valence, and leaves the user with the problem that how to deal with the Ca(OH)2 waste containing radioactive substances. If the bipolar membrane electroosmotic dissociation technology is used, not only can it be converted into HF and KOH, but also the high-value fluorine can be recycled, while avoiding the use of lime and reducing the amount of waste disposal.
● Bipolar Membrane Used in the Purification and Recycling of Acid and Alkali Wastewater
Industrial production will produce a lot of acid and alkali waste liquid, such as all kinds of waste liquids from ion exchange resin regeneration, pickling, lead storage battery, paper mill and so on. In order to reduce the pollution to the environment, these waste liquids must be treated and then discharged, but the treatment processes are complicated and the capital expenditure is large. The bipolar membrane electrodialysis process provides a good solution for the treatment of such waste liquids.
● Treatment of Domestic Sewage Treatment
Domestic sewage is generally treated by the combination of biodegradation and chemical oxidation, but the amount of oxidant is too large and there are many residues. If a nanofiltration step is added between them, small molecules that can be degraded by microorganisms (relative molecular mass <100) are passed, while macromolecules (relative molecular mass > 100) that cannot be degraded by microorganisms are intercepted. The macromolecular substance is biodegraded after being treated by a chemical oxidizer, so that the biodegradability can be fully utilized, the amount of the oxidant and the activated carbon can be saved, and the final residue content can be reduced.
● Drinking Water Purification
As water pollution intensifies, people are increasingly concerned about the quality of drinking water. Tests have shown that bipolar membrane nanofiltration can remove microtoxic by-products, traces of herbicides, pesticides, heavy metals, natural organic matters, hardness, sulfates and nitrates etc produced in the disinfection process. At the same time, it has the advantages of good and stable water quality, less chemical dosage, less land occupation, energy saving, easy management and maintenance.
● Wastewater Treatment Containing Heavy Metals
In electroplating and alloy production, it is often necessary to be rinsed with a large amount of water containing a relatively high concentration of heavy metals, such as nickel, iron, copper and zinc. In order to meet the emission requirements of wastewater containing these heavy metals, the general measure is to treat these heavy metals into hydroxide precipitates for removal. If the nanofiltration membrane technology is adopted, not only can 90% of the wastewater be recovered and then purified, but also the heavy metal ion content can be concentrated by 10 times, and the concentrated heavy metals have the value of recycling.
● Wastewater Treatment of Food industry
The N-P composite bipolar nanofiltration membrane has obvious separation effect on monovalent salts and divalent salts, and significantly reduces the COD content in the wastewater to meet environmental protection requirements.
● Bipolar Membrane Prospect
As a new type of membrane, the bipolar membrane provides many new ideas and solutions for solving some of the long-standing technical problems in environmental engineering by means of its unique advantages. Continue to develop high-performance bipolar membranes, improve membrane preparation process, reduce membrane production cost, conduct in-depth mechanism research, study the mechanism of ion migration and water transfer in membranes, study high-performance bipolar membrane materials and preparation, and broaden application fields , the above have far-reaching significance.
Phone
Product
Contact us