Orange peel magnetic activated carbon for removal of acid orange 7 dye from water

• Published in: Scientific reports 2024-01, Vol.14 (1), p.119-119, Article 119
• Main Authors: Khalil, Asmaa, Mangwandi, Chirangano, Salem, Mohamed A., Ragab, Safaa, El Nemr, Ahmed
• Format: Article
• Language: English
• Subjects: 639/638/169/896; 704/172/169/896; Activated carbon; Adsorption; Carbon; Dye concentrations; Dyes; Fruits; Humanities and Social Sciences; Isotherms; Magnetic fields; multidisciplinary; Pyrolysis; Science; Science (multidisciplinary); Surface area; Zinc chloride
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-023-50273-3

Magnetic activated carbon resources with a remarkably high specific surface area have been successfully synthesized using orange peels as the precursor and ZnCl 2 as the activating agent. The impregnation ratio was set at 0.5, while the pyrolysis temperature spanned from 700 to 900 °C. This comprehensive study delved into the influence of activation temperatures on the resultant pore morphology and specific surface area. Optimal conditions were discerned, leading to a magnetic activated carbon material exhibiting an impressive specific surface area at 700 °C. The Brunauer–Emmett–Teller surface area reached 155.09 m 2 /g, accompanied by a total pore volume of 0.1768 cm 3 /g, and a mean pore diameter of 4.5604 nm. The material displayed noteworthy properties, with saturation magnetization (Ms) reaching 17.28 emu/g, remanence (Mr) at 0.29 emu/g, and coercivity (Hc) of 13.71 G. Additionally, the composite demonstrated super-paramagnetic behaviour at room temperature, facilitating its rapid collection within 5 s through an external magnetic field. Factors such as absorbent dose, initial concentration of the adsorbate, contact time, and pH were systematically examined. The adsorption behaviour for acid orange 7 (AO7) was found to adhere to the Temkin isotherm models ( R 2  = 0.997). The Langmuir isotherm model suggested a monolayer adsorption, and the calculated maximum monolayer capacity ( Q m ) was 357.14 mg/g, derived from the linear solvation of the Langmuir model using 0.75 g/L as an adsorbent dose and 150–500 mg/L as AO7 dye concentrations. The pseudo-second order model proved to be the best fit for the experimental data of AO7 dye adsorption, with a high coefficient of determination ( R 2 ) ranging from 0.999 to 1.000, outperforming other kinetic models.