ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Box–Behnken design to optimize Ni(II) adsorption using coffee husk-derived biochar compositing with MnFe₂O₄

Thuy Tien Do, Huu-Tap Van, The Duyen Nguyen, Lan Huong Nguyen, and Ngoc Bach Ta

Faculty of Chemistry, Hanoi Pedagogical University 2, Phuc Yen City, Vinh Phuc Province, Vietnam

E-mail: tapvh@tnus.edu.vn

Received: 31 December 2022  Accepted: 28 May 2023

Abstract:

The main objective of this research was to optimize Ni(II) adsorption using coffee husk-derived biochar composited with MnFe₂O₄ nanoparticles (MFO@BC). The MnFe₂O₄ nanoparticles (MnFe₂O₄–NPs) were synthesized by the co-precipitate method. Then, the MFO@BC nanocomposite was formed simultaneously through co-precipitation and hydrothermal processes. Box–Behnken experimental design in response surface methodology (Design Expert 11, Stat-Ease, USA) was used to carry the Ni(II) adsorption optimization onto MFO@BC. The effects of initial Ni(II) concentration, solution pH, contact time, and adsorption material mass were chosen as independent variables for Ni(II) adsorption processes on MFO@BC. The results indicated that the loaded mass ratio of 2.5 MnFe₂O₄–NPs (w/w) on the coffee husk-derived biochar was the most suitable for Ni(II) adsorption onto MFO@BC. The result of ANOVA analysis, where p values of 0.0005 were significant for the quadratic polynomial model. In addition, the proposed model was fitted with the actual values with the high R² and R²–adjusted (R²_adj) values of 0.8867 and 0.7647, respectively. Three factors, including initial Ni(II) concentration, solution pH and adsorbent mass, had the main effect on Ni(II) adsorption capacity by MFO@BC. Optimum conditions for Ni(II) adsorption onto MFO@BC were obtained at solution pH 7, 50 min of contact time, initial Ni(II) concentration of 4.0 mg/L and 0.025 g adsorbent/25 mL. Under these conditions, the maximum adsorption capacity of Ni(II) onto MFO@BC reached 5.51 mg/g. Five cycles of adsorption–desorption did not substantially decrease the adsorption capacities of MFO@BC.

Keywords: Box–Behnken design; Coffee husk-derived biochar; MnFe2O4-NPs; MFO@BC; Ni(II), Response surface methodology

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-023-02896-z

Chemical Papers 77 (10) 5773–5786 (2023)