Green synthesis of magnetic 3D bio-adsorbent by corn straw core and chitosan for methylene blue removal

ABSTRACT

In this work, a novel bio-adsorbent with a unique structure was prepared through one-step crosslinking in the emulsion using corn straw core (CSC), CoFe₂O₄ and chitosan (CS) as raw materials for adsorption of methylene blue (MB). The preparation method of the adsorbent was simple and environmentally friendly. In the adsorbent, the agricultural waste of CSC acted as scaffold and was wrapped with CS. CoFe₂O₄ was embedded in CS, giving magnetic property to the adsorbent, which was beneficial to the separation process. XRD, FTIR, SEM and TEM were utilized to characterize the adsorbent and the factors affecting adsorption removal efficiency were explored. The pseudo-second-order model and the Langmuir model described the adsorption behaviour well. The equilibrium adsorption capacity was 122 mg g⁻¹ for MB at 298 K. The thermodynamic studies suggested that the adsorption was a spontaneous, exothermic and randomness decrease process. MB loaded on the adsorbent could be desorbed by immersing in dilute acid solution, indicating that this kind of biomass adsorbent can be widely used in the field of adsorption.

GRAPHICAL ABSTRACT

KEYWORDS:

• Corn straw core
• chitosan
• CoFe₂O₄
• adsorption
• methylene blue

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Shanshan Liu http://orcid.org/0000-0002-4891-3023

Heyi Ge http://orcid.org/0000-0002-7107-6358

Shilin Cheng http://orcid.org/0000-0003-2485-1347

Yu Zou http://orcid.org/0000-0001-8685-8355

Additional information

Funding

This work is supported by National Key R&D Program of China (grant number 2016YFC0701005).