D113 resin in-situ loaded with Fe3+ to develop glyphosate adsorbent with the characteristics of salt-resistance and the remarkable saturated adsorption capacity

There are inorganic salts in glyphosate production liquor and natural water bodies coexisting with glyphosate. It is imperative to develop a salt-tolerant adsorbent for glyphosate in water. Industrial D113 resin undergone two-step transformation to optimize the preparation of D113 in-situ loaded with Fe 3+ (D113-Fe 3+ ) as salt-resistance glyphosate adsorbent. The loading amount of Fe 3+ on D113-Fe 3+ is 3.5 mmol/g. The adsorption mechanism revealed that Fe 3+ in D113-Fe 3+ formed Fe-O-P bond with the phosphonate group of glyphosate. At 293 K, the maximum complex ratio of the adsorbed glyphosate to Fe 3+ in D113-Fe 3+ was 2.4:1. At 293 K, the remarkable saturated glyphosate adsorption capacity of D113-Fe 3+ reached 1420.2 mg/g. In pK 2 state of glyphosate, D113-Fe 3+ featured its maximum adsorption capacity at the zero charge point 2.43 of D113-Fe 3+ and 293 K. In glyphosate solution coexisting 0–16 % NaCl, D113-Fe 3+ exhibited stable glyphosate adsorption capacity and salt-resistance compared with D201, D301 and 330 resin. The endothermic and spontaneous adsorption of glyphosate on D113-Fe 3+ can fit Freundlich model and pseudo-second-order model. 2 mol/L NH 3 ·H 2 O, 2 mol/L FeCl 3 and 2 mol/L H 2 SO 4 could all regenerate D113-Fe 3+ . The characteristics of salt-resistance and the remarkable saturated adsorption capacity made D113-Fe 3+ comparable to all reported glyphosate adsorbents.