Fluoborate poses a problem to electroplaters when discharged in their wastestreams. Therefore, a method for removing fluoborate from rinse waters is necessary. An ion floatation technique using a surfactant was developed at N.J.I.T. to perform this job. However, this technique requires long time periods therefore other methods were investigated.
Ultrafiltration was investigated as a replacement for the ion floatation technique. It would cut down the time required for the fluoborate removal. Also, electrolysis and the addition of excess acetic acid were tried in an attempt to separate the fluoborate and the surfactant in the ultrafiltration retentate. This system was evaluated using dilute rinse solutions. For concentrated rinses, electrodialysis was employed.
Results showed that when using a 1,000 molecular weight cut-off membrane, ultrafiltration succeeded in removing the surfactant-fluoborate complex from solution. Therefore, ultrafiltration can replace the ion floatation technique. Also, the results achieved using electrolysis to separate the surfactant-fluoborate complex were encouraging. However, further experimentation should be done in this area.
In utilizing electrodialysis as a means of removing fluoborate from concentrated rinse waters, positive results were achieved. Also, electrodialysis can be employed to recover plating solutions from the rinse waters.
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