Desalination, Vol.300, 58-63, 2012
The feasible study on the reclamation of the glyphosate neutralization liquor by bipolar membrane electrodialysis
Alkaline glyphosate neutralization liquor with high salinity is generated during the glyphosate production by glycine-dimethylphosphit process. It is not only a pollution problem but also a resource waste if the neutralization liquor is discharged directly. In this work, a zero discharge strategy that the bipolar membrane electrodialysis (BMED) is employed for the reclamation of the neutralization liquor, including desalinating glyphosate liquor for the subsequent concentration and recycling HCl and NaOH for the glyphosate production, is put forward. The lab-scale study based on the simulated feed solution and the domestic ion-exchange membranes indicates an acceptable current efficiency and energy consumption. For example, the current efficiency and energy consumption can reach 63% and 10.5 kWh/kg acid, respectively, at the 70 mA/cm(2). Also, almost no glyphosate leakage from the feed solution to acid and base compartments can be found. Furthermore, a preliminary economic feasibility is evaluated through the investigation on the process economics on the basis of the experimental results. There are good reasons to believe that, after the relevant process optimizations (including pretreatment), cyclic utilization of glyphosate neutralization liquor by bipolar membrane electrodialysis will bring significant social and economic benefits. (c) 2012 Elsevier B.V. All rights reserved.
Keywords:Bipolar membrane electrodialysis;Glycine-dimethylphosphit process;Glyphosate;Reclamation of neutralization liquor;Zero discharge process