Recycling of mining waste in the synthesis of magnetic nanomaterials for removal of nitrophenol and polycyclic aromatic hydrocarbons

Research Progress and Prospects of Spinel Ferrite Nanostructures for the Removal of Nitroaromatics from Wastewater

“…3 The specific characteristics of CDs@CuFe 2 O 4 and higher synergy contributed to higher catalytic activity than those of other tested spinel ferrite NS, which followed the order CuFe 143 Co-doped CuFe 2 O 4 showed the highest catalytic activity and recyclability up to six cycles along with high stability. 143 Hybrid CoFe 2 O 4 exhibited high catalytic efficiency toward 4-NP reduction with 99% conversion efficiency in just 50 s. 63 Highly efficient reduction of 4-nitroaniline is reported using MnFe 2 O 4. The electron-donating nature of the amino group and the electron-withdrawing effect of the nitro group lead to a resonating structure and strong interaction with MnFe 2 O 4 , which as a consequence achieves a highly efficient reduction even under dark conditions (Figure 14a).…”

“…Kumar et al adopted a solution combustion route for the green and energy-efficient synthesis of a GO–CuFe 2 O 4 nanocomposite . Pioneering work from Cruz et al shows an approach for the utilization of hazardous mining waste to fabricate a hybrid composite of CoFe 2 O 4 enriched with natural organic material (NOM) (CoFe 2 O 4 /NOM), which can be used as both catalyst and adsorbent . Attempts also have been made to decrease the environmental impact of spinel ferrite NS by making a composite or coating with biocompatible material/polymer. , MgFe 2 O 4 –bentonite clay nanocomposites offer an eco-friendly substitute to enhance surface area and porosity …”

“…Co-doped CuFe 2 O 4 showed the highest catalytic activity and recyclability up to six cycles along with high stability . Hybrid CoFe 2 O 4 exhibited high catalytic efficiency toward 4-NP reduction with 99% conversion efficiency in just 50 s …”

“…At first, the nitroaromatics and BH 4 – are adsorbed onto the surface of the catalyst. The electron transfer from BH 4 – to nitroaromatics (oxidation sites or reduction sites) takes place, which leads to the formation of aminoaromatics . The aqueous medium provides H + ions required for reduction .…”

“…In general, the reduction of nitroaromatics is modeled by the Langmuir−Hinshelwood − to nitroaromatics (oxidation sites or reduction sites) takes place, which leads to the formation of aminoaromatics. 63 The aqueous medium provides H + ions required for reduction. 3 The reduction process is monitored by monitoring the change in intensity of the characteristic absorption peak of nitroaromatics and the appearance of the aminoaromatics peak.…”