Adsorption of 2,4‐D on 3‐Aminopyridine Functionalized Polystrene Adsorbent With Double Pore Structure

ABSTRACT 2,4‐Dichlorophenoxyacetic acid (2,4‐D) is a common pesticide, which is often detected in groundwater and surface water. Half of the benzyl chloride in chloromethylpolystyrene was formed the hypercrosslinked pore structure, while the other half was functionalized by 3‐aminopyridine to tailor the macroporous structure. This double pore structure adsorbent (JX‐02) was fabricated to investigate its adsorption performance for 2,4‐D. The micropore area of JX‐02 accounted for 54.04%. At pH 2.97 (without pH adjustment) and 298 K, the maximum adsorption capacity of 2,4‐D on JX‐02 is 370.4 mg/g, exceeding the corresponding adsorption capacities of the referred macroporous XAD‐4 and the hypercrosslinked adsorbent. The adsorption of 2,4‐D on JX‐02 conformed to the pseudo‐first‐order equation, Langmuir equation, and Temkin equation. JX‐02 exhibited a maximum absorptive capacity of 540.5 mg/g for 2,4‐D at 298 K, which was larger or comparable to 18 adsorbents in the literature. The adsorption of 2,4‐D on JX‐02 was spontaneous and endothermic. Corresponding to its double pore structure, JX‐02 demonstrated a synergistic multiple adsorption mechanism for 2,4‐D, including micropore filling, hydrophobic interaction, π – π interaction, and anion exchange. JX‐02 could be regenerated with the binary complex of 3% NaCl‐60% C 2 H 5 OH. Five adsorption–regeneration cycles exhibited constant adsorption capacities of 367.7–372.4 mg/g for 2,4‐D on JX‐02.