Superparamagnetic cobalt ferric nanoparticles incorporated biopolymers extracted from dragon fruit (hylocereus undatus) peels for nickel(II) removal

Low-cost adsorbents derived from agricultural by-products incorporated magnetic nanoparticles (NPs) are promising and novel adsorbents for water/wastewater treatment due to their outstanding performance and easy separation. This study reports a nanocomposite of cobalt superparamagnetic (CoFe2O4) NPs incorporated biopolymers extracted from a dragon fruit (hylocereus undatus) peel, called bp-CoFe2O4, to potentially remove Ni(II) ions from aqueous solutions. Morphologic and structural properties of the bp-CoFe2O4 were successfully characterized using a scanning electron spectrometry, X-ray diffraction, Fourier transform infrared spectrometry, and vibrating sample magnetometer (VSM). The bp-CoFe2O4 particles exhibited soft and superparamagnetic properties, which can be easily recycled using an external magnet. Ni(II) adsorption on the bp-CoFe2O4 was attributed to both the components including CoFe2O4 particles and coated biopolymers. Indeed, the bp-CoFe2O4 adsorbing Ni(II) ions reached optimal at pH similar to 6 (similar to 88% of Ni(II) removal at an adsorbent dose of 1 g/l and Ni(II) concentration of 171.1 mg/l). The bp-CoFe2O4 can maintain the effective treatment of Ni(II) ion (only similar to 10% of efficiency loss) up to three cycles of the regeneration. Owing to retaining the magnetic property through the regeneration cycles, this bio-adsorbent would promise a high potential for long-term treatment of Ni(II) ions from polluted waters with easy separation. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

Low-cost adsorbents incorporating magnetic nanoparticles derived from agricultural by-products show great potential for water/wastewater treatment. The nanocomposite of bp-CoFe2O4, made from dragon fruit peel biopolymers and cobalt superparamagnetic NPs, exhibits excellent Ni(II) ion removal efficiency and recyclability. With optimal performance at pH around 6 and ability to maintain high Ni(II) ion treatment efficiency through multiple regeneration cycles, this bio-adsorbent holds promise for long-term treatment of Ni(II) ions from polluted waters.