Synthesis and characterization of antibacterial chromium iron oxide nanoparticle-loaded activated carbon for ultrasound-assisted wastewater treatment

Innovations and challenges in adsorption-based wastewater remediation: A comprehensive review

Water contamination is an escalating emergency confronting communities worldwide. While traditional adsorbents have laid the groundwork for effective water purification, their selectivity, capacity, and sustainability limitations have driven the search for more advanced solutions. Despite many technological advancements, economic, environmental, and regulatory hurdles challenge the practical application of advanced adsorption techniques in large-scale water treatment. Integrating nanotechnology, advanced material fabrication techniques, and data-driven design enabled by artificial intelligence (AI) and machine learning (ML) have led to a new generation of optimized, high-performance adsorbents. These advanced materials leverage properties like high surface area, tailored pore structures, and functionalized surfaces to capture diverse water contaminants efficiently. With a focus on sustainability and effectiveness, this review highlights the transformative potential of these advanced materials in setting new benchmarks for water purification technologies. This article delivers an in-depth exploration of the current landscape and future directions of adsorbent technology for water remediation, advocating for a multidisciplinary approach to overcome existing barriers in large-scale water treatment applications.

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.

Chitosan-Grafted Polyacrylic Acid-Doped Copper Oxide Nanoflakes Used as a Potential Dye Degrader and Antibacterial Agent: In Silico Molecular Docking Analysis

This study examined the catalytic and bactericidal properties of polymer-doped copper oxide (CuO). For this purpose, a facile co-precipitation method was used to synthesize CuO nanostructures doped with CS-g-PAA. Various concentrations (2, 4, and 6%) of dopants were systematically incorporated into a fixed amount of CuO. The prepared samples were analyzed by different optical, structural, and morphological characterizations. Field emission scanning electron microscopy and transmission electron microscopy micrographs indicated that doping transformed CuO's agglomerated rod-like surface morphology to form nanoflakes. UV-vis spectroscopy revealed that the optical spectra of the samples exhibit a redshift after doping, leading to a decrease in band gap energy from 3.3 to 2.5 eV. The purpose of the study was to test the catalytic activity of pristine and CS-g-PAA doped CuO for the degradation of methylene blue in acidic, basic, and neutral conditions using NaBH4 as a reducing agent in an aqueous medium. Furthermore, antibacterial activity was evaluated against Gram-positive and Gram-negative bacteria, namely, Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Overall, enhanced bactericidal performance was observed upon doping CS-g-PAA into CuO, i.e., 4.25-6.15 and 4.40-8.15 mm against S. aureus and 1.35-4.20 and 2.25-5.25 mm against E. coli at the lowest and highest doses, respectively. The relevant catalytic and bactericidal action mechanisms of samples are also proposed in the study. Moreover, in silico molecular docking studies illustrated the role of these prepared nanomaterials as possible inhibitors of FabH and FabI enzymes of the fatty acid biosynthetic pathway.

Innovative method for minimization of waste containing Fe, Mn and Ti during comprehensive utilization of vanadium slag

More than 1.2 million tons of tailings containing approximately 30 wt% of Fe from traditional vanadium extraction processes are discarded every year as solid waste, which waste resources. In order to achieve effective and green utilization of waste, a novel process was proposed to keep Cr and V at Cr³⁺ and V³⁺ during extraction by using AlCl₃-NaCl-KCl molten salt in Ar gas atmosphere to control the valuable elements (Cr, V, Mn and Fe) from oxidized. The morphological features of vanadium slag reacted in the temperature range from 200 °C to 800 °C and volatilization of samples under different AlCl₃/slag ratios were analyzed. Meanwhile, the chlorinated kinetics of V, Cr, Mn and Fe in vanadium slag were systemically investigated in temperature range of 850 °C-950 °C. The kinetics investigation indicated that the chlorination processes of Fe and Mn were restricted by mass transfer in product layer (Al-Si-O mixture) and the chlorination processes of V and Cr were controlled by surface reaction. The apparent activation energies for Fe, Mn, V, and Cr are 105.28 kJ/mol, 94.26 kJ/mol, 64.64 kJ/mol, and 63.30 kJ/mol, respectively. After chlorination, the separation of metal chlorides was achieved. TiCl₄ is hydrolyzed to obtain TiO₂. Mn can be separated from VCl₃, CrCl₃, FeCl₂, and MnCl₂ by controlling the electrolytic voltages. Fe-V-Cr alloy was obtained by electrolysis at 2.3 V.