Recyclable magnetic composites prepared by a novel reverse encapsulation reaction to increase benzene rings reactive sites for enhanced removal of 3,4-diaminotoluene: Theoretical prediction with experimental statistics

The widespread distribution of organic amine reagent in the aquatic environment has severely constrained ecological health, and mitigating its potential environmental hazards is imperative. Herein, the recyclable magnetic composite (Fe3O4-3-Amino-Tereph-acid) with abundant homogenous reaction sites and excellent removal efficacy (34.72 mg/g) towards 3,4-diaminotoluene (UENE) contaminant was fabricated via the reverse direction layer-by-layer reaction. This reaction method greatly solved the difficulty of the newly introduced reaction sites being limited by the traditional grafting reactions methods. The effectiveness of the reverse direction layer-by-layer reaction was proved via multiple characterization techniques. More importantly, the necessity of the reverse direction layer-by-layer reaction, the occupation preference of reaction active sites and the removal pathway of contaminant molecules in complex removal reaction systems were studied from the DFT calculations prediction perspectives. Furthermore, the environmental behaviours of Fe3O4-3-Amino-Tereph-acid towards UENE in different environmental systems were comprehensively studied, contributing to comprehending the capturing process existing in liquid-solid phases. Overall, multiple driving forces, microscopic and macroscopic forces were mutually involved in the complex chemisorption reaction. The possible environmental application prospects of Fe3O4-3-Amino-Tereph-acid were discussed via the Requirement-Difficulty-Methodology-Extend framework. This work proposed a feasible strategy to massively increase the reactive active sites on the surface of magnetic composite, which could greatly facilitate its environmental applications, especially in eliminating organic amine contaminants fields, and theoretical prediction deeply assessed the underlying microscopic bonding modes and mechanisms in environmental systems.