Facile bio-fabrication of ZnO@AC nanoparticles from chitosan: Characterization, hydrogen generation, and photocatalytic properties.

In this work, activated carbon-supported zinc oxide nanoparticles (ZnO@AC NPs) were studied using the thermal synthesis method. The activated carbon-supported zinc oxide catalyst was characterized by UV-Vis spectrometry techniques, Fourier Transform Infrared Spectrophotometer (FTIR), Transmissive electron microscopy (TEM), and X-ray diffraction (XRD) methods. XRD characterization measurements showed that the average size of the crystal NPs was 6.89 nm. According to the TEM analysis results, the nanoparticles' average size was 11.411 nm, and the particles had a spherical structure. The catalytic properties of the synthesized material were determined using the sodium borohydride methanolysis reaction. A kinetic study was performed regarding the effects of temperature, catalyst, and substrate concentration on the methanolysis reaction. Reusability experiments showed that the catalyst had excellent catalytic activity (85%), stability, and selectivity. As a result of the kinetic study, activation energy, enthalpy (ΔH), entropy (ΔS), and hydrogen production rate activation parameters were found to be 42.52 kJ/mol, 39.98 kJ/mol, -181.42 J/mol.K, 1257.69 mL/min. g, respectively. Also, the photocatalytic activity of ZnO@AC NPs was analyzed against Rhodamine B (RhB) dye, and the maximum degradation percentage was observed to be 76% at 120 min. This study aimed to develop the ZnO@AC NPs into an efficient photocatalyst to prevent industrial wastewater pollution and as a catalyst for hydrogen synthesis as an alternative energy source.

Anoxybacillus flavithermus loaded ɣ-Fe2O3 magnetic nanoparticles as an efficient magnetic sorbent for the preconcentrations of Cu(II) and Mn(II).

It was hypothesized that -iron( oxide nanoparticles (É£-Fe2O3 NPs) functionalized with Anoxybacillus flavithermus (A. flavithermus) as an effective magnetic sorbent for the preconcentrations of toxic metal ions. It is clear to conclude that the main novelty of this study is that É£-Fe2O3 NPs loaded with A. flavithermus is selective-specific for Cu(II), Mn(II). Structural functional groups of the samples were elucidated by FTIR, and SEM. Significant experimental parameters were investigated in detail. 0.2 mL min-1 of flow rate, 5 mL of 1 M of hydrochloric acid as eluent, 150 mg biogenic mass sample, and 150 mg É£-Fe2O3 NPs for supporting material were found as the best conditions. This developed method has been tested and verified using certified and standard reference materials. As a result of the studies, the pre-concentration factor of the Cu(II), Mn(II) metals was calculated as 40. All measurements showed that the developed solid-phase extraction (SPE) columns are available for 32 cycles. The use of É£-Fe2O3 NPs equipped with A. flavithermus as an effective magnetic sorbent for the first measurements of ions was thoroughly studied. In order of the biosorption capacities were calculated as 26.0, and 30.3 mg/g for Cu(II), Mn(II), respectively. The developed method for specifying the samples showed excellent to excellent results.