Nanofiltration process of glyphosate simulated wastewater.

Nanofiltration separation of glyphosate simulated wastewater was investigated using a DK membrane. The effects of operating parameters and the addition of impurities on membrane performance were studied in detail. It was found that at 20 °C, with a glyphosate concentration of 500 mg/L and pH of 2.96, the glyphosate retention rate and the membrane permeate flux increased slightly with increasing transmembrane pressure. With an increase in operating temperature, the permeate flux increased linearly while the retention rate decreased. The permeate flux and glyphosate retention rate decreased with increasing feed concentration. Within the pH range of 3-5, the glyphosate retention rate decreases with increasing pH and reaches a minimum at the isoelectric point of the membrane, while the permeate flux reaches a maximum level at this point. In the pH range of 5-11, with the increases of pH, the glyphosate retention rate increases and the permeate flux decreases. Glyphosate retention decreases slightly with increasing NaCl and phosphite concentrations. This can be explained in terms of the shielding phenomenon.