Efficient treatment of oily wastewater, antibacterial activity, and photodegradation of organic dyes using biosynthesized Ag@Fe3O4 nanocomposite.

A significant waste (e.g., high oil content and pollutants such as heavy metals, dyes, and microbial contaminants) in water is generated during crude oil extraction and industrial processes, which poses environmental challenges. This study explores the potential of Ag@Fe3O4 nanocomposite (NC) biosynthesized using the aqueous leaf extract of Laurus nobilis for the treatment of oily wastewater. The NC was characterized using ultraviolet-visible (UV-Vis) spectrophotometry, Scanning Electron Microscopy (SEM), Fourier Transformed Infrared (FTIR) and X-Ray Diffraction (XRD) spectroscopies. The crystalline structure of the NC was determined to be face-centered cubic with an average size of 42 nm. Ag@Fe3O4 NC exhibited significant degradation (96.8%, 90.1%, and 93.8%) of Rose Bengal (RB), Methylene Blue (MB), and Toluidine Blue (TB), respectively, through a reduction reaction lasting 120 min at a dye concentration of 10 mg/L. The observed reaction kinetics followed a pseudo-first-order model, with rate constants (k-values) of 0.0284 min-1, 0.0189 min-1, and 0.0212 min-1 for RB, MB, and TB, respectively. The fast degradation rate can be attributed to the low band gap (1.9 eV) of Ag@Fe3O4 NC. The NC elicited an impressive effectiveness (99-100%, 98.0%, and 91.8% within 30 min) in removing, under sunlight irradiation, several heavy metals, total petroleum hydrocarbons (TPH), and total suspended solids (TSS) from the oily water samples. Furthermore, Ag@Fe3O4 NC displayed potent antibacterial properties and a good biocompatibility. These findings contribute to the development of efficient and cost-effective methods for wastewater treatment and environmental remediation.

Enhanced photocatalytic activity and antiviral evaluation of CuO@Fe2O3NC for amoxicillin degradation and SARS-CoV-2 treatment.

Copper oxide nanoparticles (CuO NPs) and CuO NPs decorated with hematite (Fe2O3) nanocomposites (CuO@Fe2O3NC) were biosynthesized by a green method usingPortulaca oleracealeaves extract. The NC were characterized using various techniques, including x-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive x-ray spectroscopy, and UV-vis spectroscopy. The results showed that the synthesized CuO and CuO@Fe2O3NC were crystalline with a monoclinic crystal structure and contained functional groups responsible for catalytic activity. The size of the nanocomposites ranged from 39.5 to 45.9 nm, and they exhibited a variety of agglomerated or aggregated shapes. The CuO@Fe2O3NC showed improved photocatalytic activity for the degradation of antibiotics in water and wastewater and promising antiviral activity against SARS-CoV-2, indicating its potential for use in disinfection applications. The study investigated the impact of irradiation time on the photocatalytic degradation of Amoxicillin and found that increasing the irradiation time led to a higher degradation rate. The band gap energy (Eg) for pure CuO NPs was around 2.4 eV and dropped to 1.6 eV with CuO@Fe2O3NC. In summary, the CuO@Fe2O3NC has the potential to be an efficient photocatalyst and promising antiviral agent for environmental remediation. The CuO@Fe2O3nanocomposites have been found to possess a high degree of efficacy in inactivating SARS-CoV-2 infectivity. The results of the study indicate that the nanocomposites exhibit potent anti-viral properties and hold significant potential for use in mitigating the spread of the virus.

Impact of surface topography and hydrophobicity in varied precursor concentrations of tenorite (CuO) films: a study of film properties and photocatalytic efficiency.

Semiconductor films are crucial in photocatalysis applications, yet their controlled production remains challenging. Previous studies have mainly focused on deposition processes, heating rates, and doping of semiconductor oxides. In this paper, we introduce a novel method for fabricating tenorite (CuO) semiconductor films with varying precursor concentrations (0.01, 0.02, 0.04, 0.06, and 0.1 g/ml) using a dip-coating technique. We explore the impact of contact angles, 3D surface topography, and film thickness on photoactivation properties, areas with limited previous research focus. The results demonstrate that higher-concentration tenorite films (0.1 g/ml) exhibit rougher surfaces (77.3 nm), increased hydrophobicity (65.61°), improved light-harvesting ability, enhanced charge separation, and higher active oxygen output. The crystal sizes were within the range of 7.3-44.1 nm. Wettability tests show a 21.47% improvement in the 0.1 g/ml film surface under indirect sunlight compared to darkness. Transmittance rates in the 600 nm range were from 0.02 to 90.94%. The direct optical band gaps were 1.21-2.74 eV, while the indirect band gaps remained unaffected (0.9-1.11 eV). Surface morphology analysis reveals an increased presence of grains with higher concentrations. Regarding photocatalysis's impact on film morphology and copper content, SEM images reveal minimal changes in film structure, while copper content remains stable with slight variations. This suggests strong adhesion of tenorite to the film after photocatalysis. Tenorite thin films display exceptional photocatalytic efficiency, making them suitable for practical applications.

Nanostructured Mn@NiO composite for addressing multi-pollutant challenges in petroleum-contaminated water.

Efficient catalysts play a pivotal role in advancing eco-friendly water treatment strategies, particularly in the removal of diverse organic contaminants found in water-petroleum sources. This study addresses the multifaceted challenges posed by contaminants, encompassing a spectrum of heavy metals such as As, Cd, Cr, Mn, Mo, Ni, Pb, Sb, Se, and Zn alongside pollutants like oily water (OIW), total suspended solids (TSS), chemical oxygen demand (COD), dyes, and pharmaceuticals, posing threats to both aquatic and terrestrial ecosystems. Herein, we present the synthesis of biogenically derived Mn@NiO nanocomposite (NC) photocatalysts, a sustainable methodology employing an aqueous Rosmarinus officinalis L. extract, yielding particles with a size of 36.7 nm. The catalyst demonstrates exceptional efficacy in removing heavy metals, achieving rates exceeding 99-100% within 30 min, alongside notable removal efficiencies for OIW (98%), TSS (87%), and COD (98%). Furthermore, our photodegradation experiments showed remarkable efficiencies, with 94% degradation for Rose Bengal (RB) and 96% for methylene blue (MB) within 120 min. The degradation kinetics adhere to pseudo-first-order behavior, with rate constants of 0.0227 min-1 for RB and 0.0370 min-1 for MB. Additionally, the NC exhibits significant antibiotic degradation rates of 97% for cephalexin (CEX) and 96% for amoxicillin (AMOX). The enhanced photocatalytic performance is attributed to the synergistic interplay between the Mn and NiO nanostructures, augmenting responsiveness to sunlight while mitigating electron-hole pair recombination. Notably, the catalyst demonstrates outstanding stability and reusability across multiple cycles, maintaining its stable nanostructure without compromise.

A novel biosynthesis of MgO/PEG nanocomposite for organic pollutant removal from aqueous solutions under sunlight irradiation.

The novel synthesis of MgO from Laurus nobilis L. leaves was prepared using the green synthesis method. It is using direct blending process to decorate MgO/PEG nanocomposite to enhance the photodegradation properties and examine its physical properties using diverse characterization techniques, including XRD, FTIR, SEM, EDX, and UV-Vis. X-ray diffraction reveals a cubic phase of MgO with a 37-nm grain size. SEM images confirm spherical nanoparticles with a diameter size of 22.9 nm. The optical energy gap of MgO NPs was 4.4 eV, and the MgO/PEG nanocomposite was 4.1 eV, which made it an efficient catalyst under sunlight. The photocatalytic activity of Rose Bengal (RB) and Toluidine Blue (TB) dyes at 5 × 10-5 mol/l dye concentration indicates excellent degradation efficiencies of 98% and 95% in 120 min, respectively, under sunlight irradiation. MgO/PEG is an excellent candidate nanocomposite for applications of photodegradation and could be used for its potential capability to develop conventionally used techniques.