Effective degradation of tetracycline via recyclable cellulose nanofibrils/polyvinyl alcohol/Fe3O4 hybrid hydrogel as a photo-Fenton catalyst

Ultrahigh Dispersion of Fe3O4 NPs on Cellulose Nanofibers: Unlocking Superior Visible-Light Photocatalysis

Constructing cost-effective and efficient photocatalysts is crucial for removing harmful contaminants from water sources, ensuring a greener and healthier environment. In this study, highly dispersed magnetic iron oxide (Fe3O4) nanoparticles (NPs) were successfully decorated on cellulose nanofibers (CNFs) by using a simple interfacial strategy. Four hybrid materials (Fe3O4-CNF1, Fe3O4-CNF2, Fe3O4-CNF3, and Fe3O4-CNF4) were systematically synthesized, with Fe3O4-CNF4 identified as the most efficient photocatalyst. The optimized Fe3O4-CNF4 hybrid exhibited a high surface area (54.12 m2/g), enhanced light utilization, and improved charge separation, leading to superior photocatalytic performance. It achieved a 95% removal rate of Rhodamine B (RhB) in 120 min and 99% removal rate of Methylene Blue (MB) in 150 min when exposed to visible irradiation. Moreover, Fe3O4-CNF4 demonstrated excellent recyclability, maintaining high efficiency over five reuse cycles with only ∼7% activity loss. Stability tests under varying catalyst concentrations and pH conditions further confirmed its robustness. Additionally, the primary active species, potential degradation pathways of MB, and the underlying reaction mechanism were systematically analyzed. These findings highlight Fe3O4-CNF4 as a promising visible-light-responsive and reusable photocatalyst for wastewater treatment.

Recent Progress on the Catalytic Application of Bimetallic PdCu Nanoparticles

Bimetallic PdCu nanoparticles with different Pd:Cu ratios and morphologies can be synthesized and immobilized on a variety of support materials. Accordingly, PdCu nanoparticles can be efficiently applied as heterogeneous catalysts in a large number of organic transformations including C-C coupling and cross-coupling reactions. As related to their favorable electronic and structural interactions, the catalytic performances of PdCu bimetallic nanoparticles may be superior to monometallic species. The heterogeneous catalysts can be recovered and reused, and the presence of copper tends to reduce the cost of the expensive Pd catalyst, which is beneficial for industrial applications.

Removal of tetracycline in aqueous solution by iron-loaded biochar derived from polymeric ferric sulfate and bagasse

In this study, the tetracycline (TC) removal performance of iron-loaded biochar (BPFSB) derived from sugarcane bagasse and polymerized iron sulfate was investigated, and the mechanism of TC removal was also explored by study of isotherms, kinetics and thermodynamics and characterization of fresh and used BPFSB (XRD, FTIR, SEM and XPS). The results showed that under optimized conditions (initial pH 2; BPFSB dosage 0.8 g·L-1; TC initial concentration 100 mg·L-1; Contact time 24 h; temperature 298 K), the removal efficiency of TC was as high as 99.03%. The isothermal removal of TC followed well the Langmuir, Freundlich, and Temkin models, indicating that multilayer surface chemisorption dominated the TC removal. The maximum removal capacity of TC by BPFSB at different temperatures was 185.5 mg·g-1 (298 K), 192.7 mg·g-1 (308 K), and 230.9 mg·g-1 (318 K), respectively. The pseudo-second-kinetic model described the TC removal better, while its rate-controlling step was a combination of liquid film diffusion, intraparticle diffusion, and chemical reaction. Meanwhile, TC removal was also a spontaneous and endothermic process, during which the randomness and disorder between the solid-liquid interface was increased. According to the characterization of BPFSBs before and after TC removal, H-bonding and complexation were the major interactions for TC surface adsorption. Furthermore, BPFSB was efficiently regenerated by NaOH. In summary, BPFSB had the potential for practical application in TC removal.

Heterogeneous Sono-Fenton like catalytic degradation of metronidazole by Fe3O4@HZSM-5 magnetite nanocomposite

In this research, Fe₃O₄@HZSM-5 magnetic nanocomposite was synthesized via a coprecipitation method for metronidazole (MNZ) degradation from aqueous solutions under ultrasonic irradiation which showed superb sonocatalytic activity. The synthesized magnetite nanocomposite was characterized by using field-emission scanning electron microscope-energy dispersive X-ray Spectroscopy, (FESEM-EDS), Line Scan, Dot Mapping, X-ray diffraction (XRD), vibrating sample magnetometer (VSM), and Brunauer-Emmett-Teller (BET). To investigate the sonocatalytic activity of the Fe₃O₄@HZSM-5 magnetite nanocomposite, the sonocatalytic removal conditions were optimized by evaluating the influences of operating parameters like the dosage of catalyst, reaction time, pH, the concentration of H₂O₂, MNZ concentration, and pH on the MNZ removal. The MNZ maximum removal efficiency and TOC at reaction time 40 min, catalyst dose 0.4 g/L, H₂O₂ concentration 1 mM, MNZ initial concentration 25 mg/L, and pH 7 were achieved at 98% and 81%, respectively. Additionally, the MNZ removal efficiency in the real wastewater sample under optimal conditions was obtained at 83%. The achieved results showed that using Langmuir-Hinshelwood kinetic model K_L-H = 0.40 L mg^-1, K_C = 1.38 mg/L min) can describe the kinetic removal of the process. The radical scavenger tests indicated that the major reactive oxygen species were formed by hydroxyl radicals in the Sono-Fenton-like process. Evaluation of the nanocomposite reusability showed an 85% reduction in the MNZ removal efficiency after seven cycles. Based on the results, it can be concluded that Fe₃O₄@HZSM-5 were synthesized as magnetic heterogeneous nano-catalysts to effectively degrade MNZ, and the observed stability and recyclability demonstrated that Fe₃O₄@HZSM-5 was promising for the treatment of wastewater contaminated with antibiotics.