Search

This study introduces a novel Fe3O4@SiO2/Ag/AgCl/CdS nanocomposite, designed for the efficient photocatalytic degradation of methyl orange (MO), serving as a proxy for synthetic water pollutants under visible light. A combination of co-precipitation, sol-gel, and photodeposition techniques was used to synthesize the desired nanocomposite. Leveraging the response surface methodology (RSM), we optimized the degradation process, achieving an unprecedented near-complete degradation efficiency of 99% within 90 min. The nanocomposite, characterized by an average diameter of 25 nm and uniform size distribution, demonstrated significant photocatalytic activity and stability, maintaining effectiveness over multiple usage cycles. Notably, the incorporation of Ag/AgCl alongside CdS not only extends the light absorption range but also facilitates charge separation, enhancing photocatalytic performance. Additionally, mineralization was confirmed by measuring the Chemical Oxygen Demand (COD) values. This work not only presents a significant advancement in the field of photocatalyst for water purification but also introduces a scalable and effective approach for the development of next-generation photocatalysts. Our findings highlight the potential of magnetic nanocomposites in environmental remediation, offering a sustainable solution for the degradation of organic pollutants. Highlights: Developed a Fe3O4@SiO2/Ag/AgCl/CdS nanocomposite optimized for visible-light photocatalysis. Achieved 99% methyl orange degradation under visible light in 90 min. Enhanced water purification via magnetic nanocomposites for pollutant degradation. Confirmed stability and sustained efficiency of the photocatalyst over multiple use cycles. Used response surface methodology to optimize photocatalytic conditions efficiently. [ABSTRACT FROM AUTHOR]

The type of surface active agent (surfactant) has been known to significantly influence chemical and physical properties of ferrite nanoparticles (FNPs). Nevertheless, no comparison has been made so far between the surfactant type and hyperthermia properties of cobalt FNPs. Here, by using a co-precipitation approach, CoFe2O4 FNPs are synthesized in the absence (free) and presence of different surfactants such as cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulfate (SDS), and polyvinylpyrrolidone (PVP). The use of surfactant causes FNP size to be reduced in such a way that it decreases coercivity and enhances superparamagnetic contribution significantly, making CoFe2O4 FNPs suitable for magnetic hyperthermia applications. First-order reversal curve (FORC) analysis indicates that the free surfactant synthesis leads to a mixture of single domain and superparamagnetic FNPs, whereas the PVP surfactant reduces the formation of single domain FNPs with less uniformity. For hyperthermia measurements, ferrofluids of the FNPs with different concentrations (0.5‒6 mg mL−1) are prepared and examined under a frequency of 400 kHz and magnetic field intensities in the range between 100 and 400 Oe. The maximum specific absorption rate (SAR) value is obtained to be 781 W g−1 for FNPs synthesized using PVP surfactant. [ABSTRACT FROM AUTHOR]

Developing a quick and precise technique for hydrogen peroxide (H2O2) detection would open up a new class of technologies for biological, medical and chemical applications. Herein, using a polyol method, we report the synthesis of a reduced graphene oxide (RGO)/Au/Fe3O4/Ag nanocomposite with high electrocatalytic efficiency, involving a modified glassy carbon electrode for non-enzymatic trace analysis of H2O2. The resulting nanocomposite showed an inherently high specific surface area and fast electron transfer characteristics of graphene, and Au, Fe3O4 and Ag nanoparticles (NPs). With a detection limit of 1.43 μM at a signal-to-noise ratio of 3 and a response time of 2 s, H2O2 concentrations ranging from 2 μM to 12 mM can be detected by the nanocomposite sensor. By investigating non-enzymatic H2O2 detection in the presence of other biomaterials including ascorbic acid, uric acid, glucose and sucrose, the selectivity of the sensor was evaluated. Furthermore, we test our nanocomposite sensor for practical applications in detection of H2O2, indicating good recoveries for a hair dye cream as a pharmaceutical sample. Our results on the electrocatalytic efficiency of the RGO/Au/Fe3O4/Ag nanocomposite were compared with those of the RGO/Fe3O4 nanocomposite, revealing the role of Au and Ag NPs in the sensing performance improvement. [ABSTRACT FROM AUTHOR]