Facile synthesis of CoFe2O4@MIL–53(Al) nanocomposite for fast dye removal: Adsorption models, optimization and recyclability

The global occurrence of textile dyes pollution has recently emerged, posing a serious threat to ecological systems. To abate dye contamination, we here developed a novel magnetic porous CoFe 2 O 4 @MIL–53(Al) nanocomposite by incorporating magnetic CoFe 2 O 4 nanoparticles with MIL–53(Al) metal–organic framework. This nanocomposite possessed a surface area of 197.144 m 2  g −1 and a pore volume of 0.413 cm 3  g −1 . The effect of contact time (5–120 min), concentration (5–50 mg L −1 ), dosage (0.1–1.0 g L −1 ), and pH (2–10) on Congo red adsorption was clarified. CoFe 2 O 4 @MIL–53(Al) could remove 95.85% of Cong red dye from water with an accelerated kinetic rate of 0.6544 min −1 within 10 min. The kinetic and isotherm models showed the predominance of Bangham and Temkin. According to Langmuir, the maximum uptake capacities of CoFe 2 O 4 @MIL–53(Al), CoFe 2 O 4 , and MIL–53(Al) adsorbents were 43.768, 17.982, and 15.295 mg g −1 , respectively. CoFe 2 O 4 @MIL–53(Al) was selected to optimize Cong red treatment using Box–Behnken experimental design. The outcomes showed that CoFe 2 O 4 @MIL–53(Al) achieved the highest experimental uptake capacity of 35.919 mg g −1 at concentration (29.966 mg L −1 ), time (14.926 min), and dosage (0.486 g L −1 ). CoFe 2 O 4 @MIL–53(Al) could treat dye mixture (methylene blue, methyl orange, Congo red, malachite green, and crystal violet) with an outstanding removal efficiency of 81.24% for 30 min, and could be reused up to five cycles. Therefore, novel recyclable and stable CoFe 2 O 4 @MIL–53(Al) is recommended to integrate well with real dye treatments systems.