Adsorption mechanism and removal efficiency of magnetic graphene oxide-chitosan hybrid on aqueous Zn(II)

Magnetic architecture incorporating graphene-chitosan has demonstrated encouraging application in wastewater purification. Herein, a ternary hybrid based on Fe3O4-graphene oxide-chitosan (MGOCS) was fabricated and employed as adsorbent to remove aqueous Zn(II). The adsorption mechanism was intensively inspected based on the hard and soft acid base (HSAB) theory. Results present, MGOCS removes 96.73 % of Zn(II) in 38 min, with adsorption quantity 386.92 mg center dot g(-1). Electron transfer and energy lowering determined by the HSAB theory illuminate the plausible adsorption sites in each component of MGOCS: O-2(-) in Fe3O4, -C(=O)NH-, -NH2 in chitosan and -OH in graphene oxide. The exploration was upheld by spectroscopic analyses. Thereby, following adsorption mechanism was proposed. (1) Zn-O bond was formed featured by electron donation. (2) The -C(=O) NH- group formed via amidation between graphene oxide and chitosan contributes to Zn(Pi) uptake. This work may inspire the development of efficient adsorbent based on magnetic graphene-chitosan for wastewater remediation.

Automated summary

The magnetic architecture incorporating graphene-chitosan has shown promising potential in wastewater purification. In this study, a Fe3O4-graphene oxide-chitosan (MGOCS) ternary hybrid was fabricated and used as an adsorbent for the removal of aqueous Zn(II) ions. The adsorption mechanism was investigated based on the hard and soft acid base (HSAB) theory, and the results showed that MGOCS was able to remove 96.73% of Zn(II) ions within 38 minutes, with an adsorption quantity of 386.92 mg•g(-1). Spectroscopic analyses supported the proposed adsorption mechanism, suggesting the potential for the development of efficient adsorbents based on magnetic graphene-chitosan for wastewater remediation.