The Bmed Process For The Preparation Of Base And Acid:Taking The Raclamation Of Glypyosate Mother Liquor By BMED Process As An Example

Bipolar membrane electrodialysis (BMED) is an excellent electric-driven membrane separation technology with bipolar membrane and anion/cation membrane as the core. The BMED process is wildly used in the prepaprtion of inorganic acids/alkalis, organic acids/alkalis and the treatment of saline wasterwater, and so on. China is a major producer of glyphosate, where the so-called DMP process is the main synthesis process for about 60% enterprises. However, the glyphosate neutralization liquor containing high salinity(NaC1) in the industry poses a severe environmental pollution problem. In this study, the BMED process is applied for the production of NaOH and HC1 solution by transforming the NaCl in the glyphosate neutralization liquor.Firstly, the experiments for choosing bipolar membrane and anion/cation membranes were implemented using a three-compartents BMED process, in which a 10% NaCl solution was used as raw materials and the current efficiency, energy consumption, the concentration and purity of NaOH and HC1 solution were set as indexes. The results showed that:the process of acid/base production of BMED was under the combined impact of the water splitting efficiency and the performance againsting co-ion leakage of bipolar membrane and the permselsctivity of anion/cation membranes. The less the H+ and OH- uncorked through the ion exchange membranes, the higher concentration and purity of NaOH and HC1 solution would be obtained, which was conducive to the increase of current efficiency and the decrease of the energy consumption. The excellent performance of BPM, FKB, FAB during the BMED process indicated that they are suitable for the preparation of NaOH and HCl solution by the BMED process.The process of reclamation of glyphosate neutralization liquor by BMED was similar to the transformation of NaCl solution. The NaCl in the glyphosate neutralization liquor was removaled and transformed to NaOH solution with the concentration of about 2.3 mol/L, HCl solution with the concentration of about 1.8 mol/L, during which the current efficiency was above 50%. The highest current efficiency was 87.10% and the lowest energy consumption was 2.33 KW·h/kg, when the current density was 40 mA/cm2 and the flow rate of the feed was 100 L/h. Of all the experiments, the glyphosate yield and the rate of desalinization of the glyphosate neutralization liquor were above 97% and 90%. The nanofiltration permeate flux during the concentration of glyphosate neutralization liquor by nanofiltration was enhanced after treated by the BMED process, which was double of that without BMED treatment. And the decay rate of the permeate flux during the concentration process was 57.15% of that of the liquor without BMED treatment. All of this indicated that the fouling of nanofiltration membrane was reduced, which was conducive to the further concentrate of glyphosate neutralization liquor.It’s obvious that the BMED process for the preparation of base and acid will play an important role in the treatment of salina waterwater, such as the glyphosate neutralization liquor.