Sequential recycle of valuable phosphorus compounds of glyphosine, glyphosate, and phosphorous acid from glyphosate mother liquor by D301 resin through sorbent dosage control

Abstract

Glyphosate is the most widely used herbicide. Every ton of glyphosate produced would generate about 4.5 tons of toxic mother liquor containing glyphosate, glyphosine, phosphorous acid. Recycle of the valuable phosphorus compounds had great significance. In this study, glyphosate, glyphosine, and phosphorous acid were sequentially removed from glyphosate mother liquor by D301 resin through sorbent dosage control. Experiments including isotherm, kinetics, pH effect, regeneration, and competitive adsorption were carried out to test the performance of the D301 resin, and effects of sorbent dosage on the sequential recycle of the three compounds were investigated in detail. Results showed that D301 resin had wide pH use range, fast adsorption rate, and high adsorption capacity, and maximum amount of glyphosine, phosphorous acid, and glyphosate absorbed on the resin was 781.4, 603.5, and 392.2 mg/g, respectively. Regeneration experimental results showed that there was no obvious adsorption capacity loss (~ 7%) of the resin after five times five times regeneration. Competitive adsorption experiments illustrated that D301 resin showed much higher adsorption affinity toward glyphosine, and obvious competitive substitution reaction occurred between glyphosine and phosphorous acid or glyphosate. XPS illustrated that glyphosine was selectively absorbed mainly through ion exchange, electrostatic attraction and hydrogen bond. Mother liquor treatment experiment showed that glyphosine was selectively recycled by D301 resin at 3.0 g dosage, and glyphosate and phosphorous acid was efficiently recycled at 6.0 g dosage. D301 resin could be used in recycle of valuable phosphorous compounds from glyphosate mother liquor by sorbent dosage control.