Composite Carbon-lignin/ Zinc Oxide Nanocrystalline Ball-like Hexagonal Mediated from Jatropha curcas L Leaf as Photocatalyst for Industrial Dye Degradation

Nanocomposite TiO2/ZnO/chitosan by method sol-gel for self-cleaning application

TiO2/ZnO/Chitosan coated cotton fabric as a self-cleaning, which has been synthesized by various concentrations of TiO2: 0.5 g, 1 g, and 2 g through the sol-gel method at pH 9. The self-cleaning test was conducted on TiO2/ZnO/Chitosan-coated cotton fabric samples by irradiating for 15 h using UVA-UVB lamps with clothing stain dye. TiO2/ZnO/Chitosan composite's structural properties were analyzed from X-ray diffraction (XRD) spectra, chemical bonding by Fourier Transform Infrared (FTIR), and bandgap by quantitative analysis from UV-visible spectroscopy. The XRD diffraction peaks showed a slight shift to the right, except for the sample with the highest TiO2 concentration, which showed a more significant shift. FTIR spectra showed the presence of Ti-O-Ti bonds at wavenumbers 500 cm-1 - 700 cm-1, which identified the presence of TiO2, and at wavenumber 3485 cm-1, which was used for stretching-OH and -NH2 of chitosan. The band gaps were 5.64 eV, 5.63 eV, and 5.58 eV for TiO2: 0.5 g, 1 g, and 2 g, respectively. The self-cleaning test showed that the best results were in the TiO2 sample with a concentration of 2 g at pH 9, where the dye successfully disappeared after exposure to UVA-UVB lamps for 15 h of irradiation.

Biosynthesis of JC-La2CoO4 magnetic nanoparticles explored in catalytic and SMMs properties

We have reported the synthesis of JC-La2CoO4 magnetic nanoparticles from Jatropha Curcas L. leaf extract in aqueous medium and potential application study in catalytic & Single Molecule Magnets (SMMs). Several techniques were used to investigate the structural, morphological, and elemental composition, particle size, optical properties, catalytic and magnetic properties by XRD, FTIR, SEM, EDAX, XPS, UV-visible and squid magnetic measurement. It was found that the crystallite sizes and grain sizes of JC-La2CoO4 NPs were 11.3 ± 1 and 24.1 ± 1 nm respectively and surface morphology of the nanoparticles looks spherical shape with good surface area. The band gap of JC-La2CoO4 was found to be 4.95 eV indicates good semiconductor in nature. XPS studies shows that La and Co present in + 3 and + 2 oxidation state respectively and suggest the composition formula is La2CoO4 with satisfied all the valency of metal ions. The photocatalytic efficiency of La2CoO4 shows good result against methylene blue (MB) compared to other dyes like MO, NO, RhB in presence of sunlight with rate constant 56.73 × 10-3 min-1 and completely degraded within 115 mints. The importance of JC-La2CoO4 has magnetic properties with antiferromagnetic coupling and SMMs properties with nature.

Bibliometric analysis of chitosan research for wastewater treatment: a review

Wastewater has negative impacts on the environment, such as destroying aquatic ecosystems and creating a shortage of clean water sources for consumption. In this paper, we provide a comprehensive bibliometric analysis of chitosan to better understand the evolution in degrading various pollutants as a wastewater treatment research limited only by photocatalyst system published in 2001-2021. The number of publications analyzed a total of 456 documents, which was conducted from the Scopus database. All data in this paper was visualized by using open-source software, VOSviewer and Tableau, to perform bibliometric analysis and scientific mapping. The reason for choosing chitosan is its ability to degrade various pollutants with high adsorption performance (from various sources: degradation Congo red 98.4%, methylene blue 99.36%, rhodamine B 95%, and Cd(II) 94%), non-toxicity, biodegradability, and abundantly available sources in nature. The analysis results show that the highest number of publications in 2016 was 66, and the highest number of citations was 2258. The network of keywords and innovations for wastewater treatment is USA and China as the most productive countries with many cooperative relations. This paper helps scholars understand the evolution of composite chitosan-based photocatalyst systems as research on wastewater treatment from a bibliometric point of view and inspires them to develop new efficient methods in synthesizing chitosan from fish by-products (waste) with high adsorption efficiency for various type of waste.

Enhanced Visible-Light Absorption of Fe2O3 Covered by Activated Carbon for Multifunctional Purposes: Tuning the Structural, Electronic, Optical, and Magnetic Properties

Visible-light absorption is a critical factor for photocatalyst activity and absorption of electromagnetic (EM) interference application. The band gap of Fe2O3 is 2 eV, which can be increased by doping with a high-band-gap material such as carbon from activated carbon (AC) with a band gap of 4.5 eV for increased visible-light absorption. The porosity decreases from 88 to 81.6%, and the band gap increases from 2.14 to 2.64 eV by increasing the AC from 10 to 25%, respectively. The photocatalytic activity takes 120 min to produce a harmless product for 10-20% AC, but 25% AC shows 89.5% degradation in only 90 min and the potential to attenuate the EM wave up to 99% due to the RL being below -20 dB. The second- and third-cycle degradation achieved by the composite Fe2O3-AC having 25% AC is 88.2 and 86.5% in 90 min, respectively. The pore of the surface state of AC contains a trapped charge, and interaction occurs between the charge (electron/hole) and O2 or H2O to produce OH and superoxide (O2 -) radicals. These radicals move inside the molecule of the pollutant (methylene blue (MB)) to break up the bond, with the final products being H2O and CO2. The X-ray photoelectron (XPS) spectra show that oxygen plays a key role in the interatomic bonding with Fe, C, and MB atoms. The best absorption of EM interference is -21.43 dB, with degradation reaching 89.51% in only 90 min for 25% AC due to its higher band gap and anisotropy constant. Fe2O3-carbon is a multifunctional material for the green environment because of its electromagnetic interference absorption and photodegradation of wastewater.