Rod-Shaped Carbon Aerogel-Assisted CdS Nanocomposite for the Removal of Methylene Blue Dye and Colorless Phenol

Hydrothermal synthesis and photocatalytic application of ZnS-Ag composites based on biomass-derived carbon aerogel for the visible light degradation of methylene blue

A facile and cost-effective hydrothermal followed by precipitation method is employed to synthesize visible light-driven ZnS-Ag ternary composites supported on carbon aerogel (CA). Extensive studies were conducted on the structural, morphological, and optical properties, confirming the successful formation of ternary nanocomposites. The obtained results evidently demonstrate the successful loading of ZnS and Ag onto the surface of the CA. High-resolution transmission electron microscopy analysis revealed that ZnS and Ag nanoparticles (AgNPs) were uniformly distributed on the surface of the CA with an average diameter of 18 nm. The biomass-derived CA, containing a hierarchical porous nano-architecture and an abundant number of -NH2 functional groups on the surface, can greatly prevent the agglomeration, stability and reduce particle size. Brunauer-Emmett-Teller analysis results indicated specific surface areas of 4.62 m2 g-1 for the CA, 48.50 m2 g-1 for the CA/ZnS composite, and 62.62 m2 g-1 for the CA/ZnS-Ag composite. These values demonstrate an increase in surface area upon the incorporation of ZnS and Ag into the CA matrix. Under visible light irradiation, the synthesized CA/ZnS-Ag composites displayed remarkably improved photodegradation efficiency of methylene blue (MB). Among the tested samples, the CA/ZnS-Ag composites exhibited the highest percentage of photodegradation efficiency, surpassing ZnS, CA, and CA/ZnS. The obtained percentages of degradation efficiency for CA, ZnS, CA/ZnS, and CA/ZnS-Ag composites were determined as 26.60%, 52.12%, 68.39%, and 98.64%, respectively. These results highlight the superior photocatalytic performance of the CA/ZnS-Ag composites in the degradation of MB under visible light conditions. The superior efficiency of the CA/ZnS-Ag composite can be attributed to multiple factors, including its elevated specific surface area, inhibition of electron-hole pair recombination, and enhanced photon absorption within the visible light spectrum. The CA/ZnS-Ag composites displayed consistent efficiency over multiple cycles, confirming their stable performance, reusability, and enduring durability, thereby showcasing the robust nature of this composite material.

Strategic rationalization for improved photocatalytic decomposition of toxic pollutants: Immobilizing Bi2Te3 nanorods and V2O5 nanoparticles over MoS2 nanosheets

Researchers have become increasingly interested in solar energy based on semiconductor photocatalysts to remove hazardous pollutants and clean the environment. In this work, an efficient MoS2-Bi2Te3-V2O5 nanocomposite has been prepared through wet impregnation method. MoS2-Bi2Te3-V2O5 photocatalyst was utilized to decompose the MB and Rh B dyes. The photocatalytic efficiency (Rh B) of MoS2-Bi2Te3-V2O5 nanocomposite (95.19 %) was higher than 2.70 times of Bi2Te3 nanorods, 1.55 times of V2O5 nanoparticles, 1.68 times of MoS2 nanosheets, 1.50 times of MoS2-Bi2Te3, and 1.21 times of MoS2-V2O5 nanocomposite, respectively. Recycling tests conducted on the MoS2-Bi2Te3-V2O5 nanocomposite revealed its high stability and durability. The outcomes obtained from the scavenger test suggest that the photogenerated hydroxyl radicals play a chief role in the photocatalytic performance of Rh B dye in the MoS2-Bi2Te3-V2O5 nanocomposite, respectively. The enhanced photocatalytic performance of the MoS2-Bi2Te3-V2O5 nanocomposite is ascribed to the strong hybrid formation of Bi2Te3, V2O5, and MoS2 nanosheets, respectively. Consequently, the straightforward and readily synthesized MoS2-Bi2Te3-V2O5 nanocomposite can serve as an economical, highly effective material for environmental applications.

Green synthesis of fluorescent carbon nanodots from sage leaves for selective anticancer activity on 2D liver cancer cells and 3D multicellular tumor spheroids

Carbon nanodots, a family of carbon-based nanomaterials, have been synthesized through different methods from various resources, affecting the properties of the resulting product and their application. Herein, carbon nanodots (CNDs) were synthesized with a green and simple hydrothermal method from sage leaves at 200 °C for 6 hours. The obtained CNDs are well dispersed in water with a negative surface charge (ζ-potential = -11 mV) and an average particle size of 3.6 nm. The synthesized CNDs showed concentration-dependent anticancer activity toward liver cancer (Hep3B) cell lines and decreased the viability of the cancer cells to 23% at the highest used concentration (250 μg ml-1 of CNDs). More interestingly, the cytotoxicity of the CNDs was tested in normal liver cell lines (LX2) revealed that the CNDs at all tested concentrations didn't affect their viability including at the highest concentration showing a viability of 86.7%. The cellular uptake mechanisms of CNDs were investigated and they are thought to be through energy-dependent endocytosis and also through passive diffusion. The main mechanisms of endocytosis were lipid and caveolae-mediated endocytosis. In addition, the CNDs have hindered the formation of 3D spheroids from the Hep3B hepatocellular carcinoma cell line. Hence, it would be concluded that the synthesized CNDs from sage are more highly selective to liver cancer cells than normal ones. The CNDs' cancer-killing ability would be referred to as the production of reactive oxygen species.

In-situ development of boron doped g-C3N4 supported SBA-15 nanocomposites for photocatalytic degradation of tetracycline

In this study, versatile boron-doped graphitic carbon nitride (gCN) incorporated mesoporous SBA-15 (BGS) composite materials were prepared by thermal polycondensation method using boric acid & melamine as a B-gCN source material and SBA-15 as mesoporous support. The prepared BGS composites are utilized sustainably using solar light as the energy source for the continuous flow of photodegradation of tetracycline (TC) antibiotics. This work highlights that the photocatalysts preparation was carried out with an eco-friendly strategy, solvent-free and without additional reagents. To alter the amount of boron quantity (0.124 g, 0.248 g, and 0.49 g) have to prepare three different composites using a similar procedure, the obtained composites viz., BGS-1, BGS-2 and BGS-3, respectively. The physicochemical property of the prepared composites was investigated by X-ray diffractometry, Fourier-transform infrared spectroscopy, Raman, Diffraction reflectance spectra, Photoluminescence, Brunauer-Emmett-Teller and transmission electron microscopy (TEM). The results shows that 0.24 g boron- loaded BGS composites degrade TC up to 93.74%, which is much higher than the rest of the catalyst. The addition of mesoporous SBA-15 incresed the specific surface area of the g-CN, and heteroatom of boron increased the interplanar stracking distance of g-CN, enlarged the optical absorption range, reducing the energy bandgap and enhanced the photocatalytic activity of TC. Additionally, the stability and recycling efficiency of the representative photocatalysts viz., BGS-2 was observed to be good even at the fifth cycle. The photocatalytic process using the BGS composites demonstrated to be capable candidate for the removal of tetracycline biowaste from aquesous media.

Magnetically Recoverable Biomass-Derived Carbon-Aerogel Supported ZnO (ZnO/MNC) Composites for the Photodegradation of Methylene Blue

Hydrothermally assisted magnetic ZnO/Carbon nanocomposites were prepared using the selective biowaste of pomelo orange. Initially, the carbon aerogel (CA) was prepared hydrothermally followed by a freeze-drying method. Furthermore, the iron oxide nanoparticles were deposited onto the surface of carbon using the co-precipitation method and we obtained magnetic carbon nanocomposite, i.e., Fe3O4/C (MNC). Moreover, the ZnO photocatalysts were incorporated onto the surface of MNC composites using a hydrothermal process, and we obtained ZnO/MNC composites. The ZnO/MNC (55%), ZnO/MNC (65%) and ZnO/MNC (75%) composites were prepared by a similar experimental method in order to change the weight ratio of ZnO NPs. Using a similar synthetic procedure, the standard ZnO and Fe3O4 nanoparticles were prepared without the addition of CA. The experimental results were derived from several analytical techniques, such as: X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman and diffuse reflectance spectroscopy (DRS-UV). The synthesized carbon, ZnO, Fe3O4, ZnO/MNC (55%), ZnO/MNC (65%) and ZnO/MNC (75%) composites were examined through the photocatalytic degradation of methylene blue (MB) under visible-light irradiation (VLI). The obtained results revealed that the composites were more active than carbon, ZnO and Fe3O4. In particular, the ZnO/MNC (75%) composites showed more activity than the rest of the composites. Furthermore, the recycling abilities of the prepared ZnO/MNC (75%) composites were examined through the degradation of MB under identical conditions and the activity remained constant up to the fifth cycle. The synthetic procedure and practical applications proposed here can be used in chemical industries, biomedical fields and energy applications.

Optical properties and photoactivity of carbon nanodots synthesized from olive solid wastes at different carbonization temperatures

Carbon nanodots (CNDs) have many fascinating properties, such as optical properties (UV-Visible absorption and fluorescence emission), which make them good candidates in many applications, such as photocatalysts for the degradation of several organic pollutants. This study aims to synthesize CNDs from olive solid wastes at different carbonization temperatures from 300 to 900 °C and study the effect on the optical properties of the CNDs, such UV-Vis, fluorescence, quantum yield, and energy bandgap, in addition to the influence on the photoactivity of the CNDs as photocatalysts for the degradation of methylene blue (MB). CNDs were prepared from olive solid wastes (OSWs) by pyrolysis at different temperatures (300–900 °C) for conversion to carbonized material, and then oxidized chemically in the presence of hydrogen peroxide (H₂O₂). It was found that an increase in the carbonization temperature of the OSWs leads to an increase in the product yield with a maximum value at 500 °C, and it then decreased dramatically. On the other hand, a decrease in fluorescence due to the diminishment of oxygen groups and the destruction of the surface of the CNDs was observed. The higher quantum yield (5.17%) and bandgap (2.77 eV) were achieved for CNDs prepared from OSWs that carbonized at 300 °C. The rate and degradation efficiency of MB were studied with the different synthesized CNDs, and it was found that an increase in the carbonization temperature leads to a decrease in the rate and degradation efficiency of MB, with the highest degradation rate of 0.0575 min⁻¹ and degradation efficiency of 100% after 120 minutes of light irradiation being realized for the sample carbonized at 300 °C.

Carbon nanodots with different optical properties and photoactivity degrees as photocatalysts for the degradation of methylene blue are successfully synthesized from olive solid wastes at different carbonization temperatures.