Enhanced Removal of Dissolved Humic Acid from Water Using Eco‐Friendly Phenylalanine‐Modified‐Chitosan Fe₃O₄ Magnetic Nanoparticles

Abstract

High-efficient adsorbents with eco-friendly and easy recycling features remain to be pursued in wastewater treatment. In this work, one green magnetic nano-composite, phenylalaninemodified-chitosan Fe 3 O 4 (Fe 3 O 4 @chitosan@Phe), was prepared and its adsorption behavior for humic acid from water was investigated. Our results showed that the modified phenylalanine could promote the maximum adsorption quantites of humic acid by Fe 3 O 4 @chitosan@Phe than Fe 3 O 4 @chitosan, and the adsorption processing followed the pseudo second-order kinetic model. Either the Langmuir or Freundlich isotherm model could not appropriately describe the adsorption proc-essing, implying the adsorption process is more complex than typical monolayer, or multilayer adsorption. The functional groups (amidogen, phenyl) of phenylalanine could strengthen the interaction between Fe 3 O 4 @chitosan@Phe and humic acid molecules through electrostatic interaction, π-π interaction, and hydrogen bonds. The Fe 3 O 4 @chitosan@Phe exhibited good reusability after running eight adsorption-regeneration cycles. This work proposes a new strategy to design eco-friendly magnetic adsorbents, which meets the requirement of modern green chemistry.