New magnetic iron oxide (Fe₃O₄)/activated charcoal (AC)/β-cyclodextrin (CD)/sodium alginate (Alg) polymer nanocomposite materials were prepared by direct mixing of the polymer matrix with the nanofillers. The obtained materials were utilized as nano-adsorbents for the elimination of methylene blue (MB), a hazardous water-soluble cationic dye, from aqueous solutions, and showed excellent regeneration capacity. The formation of the nanocomposites was followed by high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectrometry (EDX), Fourier-transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM), X-ray diffraction (XRD) and adsorption of N₂ at −196 °C. The rate of adsorption was investigated varying several factors, namely contact time, pH, amount of adsorbent and MB concentration on the adsorption process. Studies dealing with equilibrium and kinetics were carried out in batch conditions. The obtained results indicated that the removal rate of MB was 99.53% in 90 min. Langmuir’s isotherm fitted better to the equilibrium data of MB. Fe₃O₄/AC/CD/Alg polymer beads shows amazing adsorption capacities in the elimination of cationic dyes (2.079 mg/g for polymer gel beads and 10.63 mg g⁻¹ for dry powder beads), in comparison to other adsorbent materials. The obtained adsorbent is spherical with hydrophobic cross-linked surface properties that enable an easy recovery without any significant weight loss of in the adsorbent used.

Hydrogels have emerged as important soft materials with numerous applications in fields including biomedicine, biomimetic smart materials, and electrochemistry. Because of their outstanding photo-physical properties and prolonged colloidal stability, the serendipitous findings of carbon quantum dots (CQDs) have introduced a new topic of investigation for materials scientists. CQDs confined polymeric hydrogel nanocomposites have emerged as novel materials with integrated properties of the individual constituents, resulting in vital uses in the realm of soft nanomaterials. Immobilizing CQDs within hydrogels has been shown to be a smart tactic for preventing the aggregation-caused quenching effect and also for manipulating the characteristics of hydrogels and introducing new properties. The combination of these two very different types of materials results in not only structural diversity but also significant improvements in many property aspects, leading to novel multifunctional materials. This review covers the synthesis of doped CQDs, different fabrication techniques for nanostructured materials made of CQDs and polymers, as well as their applications in sustained drug delivery. Finally, a brief overview of the present market and future perspectives are discussed.

In this work, we report the synthesis of graphene oxide nanosheets (GO NS) using four different oxidants, namely, chloramine-T (CAT), FeCl₃, N-bromosuccinimide (NBS), and KIO₃. Fourier transform infrared spectroscopy (FTIR) was used to characterize the functional groups present in the synthesized GO. The microstructure analysis was performed using X-ray diffraction (XRD) and scanning electron microscopy (SEM) to investigate the morphology of GO. High-resolution transmission electron microscopy (HRTEM) studies demonstrated the nanostructure and crystalline phases of GO. The antibacterial activity of the prepared GO NS was investigated against pure cultures of Pseudomonas pneumonia and Staphylococcus aureus. The synthesized GO NS with CAT-GO (C-GO) exhibited very good antibacterial activity towards pathogens.

This work investigates the degradation of the azo dye solochrome dark blue (SDB) by measurement of the photocatalytic, sonocatalytic and sonophotocatalytic activities, under low ultrasonic frequency (40 kHz) and UV-C (254 nm) light, using Mn-doped ZnS semiconductor quantum dots (Mn²⁺:ZnS Qds) as catalysts, prepared by a simple chemical precipitation procedure. In order to study the different morphological and optical crystal properties, various characterization techniques were used, such as high resolution transmission electron microscopy, scanning electron microscopy, energy dispersive X-ray analysis, X-ray diffraction, N₂ adsorption-desorption at −196 °C and ultraviolet-visible spectroscopy. The average particle size of the semiconductor Qds was in the range of 3–4 nm. The optimal parameters affecting dye degradation, such as the catalyst loading, solution pH, time of irradiation, initial concentration of dye, dopant concentration, ultrasonic power and frequency effect were evaluated. The synthesized catalytic material exhibited a high activity for sonophotocatalytic degradation of SDB (89%), larger than that observed for sonocatalysis (69.7%) or photocatalysis (55.2%) alone, which was due to the improved electron-holes separation, formation of more reactive radicals and enhancement of the active surface area. Qds showed good stability and reusability after five repeated cycles. Finally, the degradation products were identified by liquid chromatography-mass spectrometry (LC-MS).

Zinc molybdate nanoparticles with molybdate are synthesized through green method with different salt precursors using Moringa oleifera leaf extract. Those nanoparticles had structural, vibrational, and morphological properties, which were determined by X-ray diffraction (XRD). The crystalline size of synthesized zinc molybdate was 24.9 nm. Fourier transform infrared (FTIR) spectroscopy and field emission scanning electron microscopy (FE-SEM) clearly showed the attachment of molybdate with ZnO. The synthesized nanomaterial was also characterized through UV-visible spectroscopy which had 4.40 eV band gap energy. Those nanoparticles were also characterized via thermogravimetric analysis (TGA-DTA) and photoluminance spectroscopy (PL). ZnMoO₄ had photocatalytic property via methylene blue dye. After 190 minutes, the dye changed to colourless from blue colour. The degradation efficiency was around 92.8%. It also showed their antibacterial effect via Escherichia coli and Staphylococcusaureus bacterial strains. In the presence of light and air, nanoparticles of ZnMoO₄ inhibit the growth of cells of E. coli and S. aureus bacterial strains because of ROS (reactive oxygen species) generation. Because of the formation of singlet oxygen (), hydrogen oxide radical (), and hydrogen peroxide (H₂O₂), ZnMoO₄ showed photodegradation reaction against aq. solution of methylene blue dye at 6 pH with constant time interval. With time, the activity of ZnMoO₄ also decreased because of the generation of a layer of hydrogen oxide (-OH) on nanomaterial surface, which could be washed with ethanol and distilled water. After drying, the catalytic Zinc molybdate nanoparticles could be reused again in the next catalytic reaction.

Textile industries discharge wastewater in huge amount that contains several toxic contaminants, especially organic dyes. Organic dyes present in wastewater have many adverse effects on environment as well as on living organisms including human beings. The generation of a nanocomposite to trap the toxic organic dyes from wastewater is highly recommended. Herein, we report the preparation of graphene-iron-titanium oxide (GFT) nanocomposite using simple, practical, and cost-effective protocol. The prepared tri-nanocomposite was successfully recognized by employing several analytical techniques. Morphology of the prepared nanocomposites was assessed by SEM coupled with EDS (energy dispersive spectroscopy). HRTEM was used to measure the size of the nanocomposites with shape and morphology. The UV-visible absorption spectra of the nanocomposites were recorded by a UV-visible spectrophotometer. Finally, the crystal structures of the nanocomposites were confirmed by XRD. Moreover, we proposed a plausible mechanism to demonstrate the catalytic activity of GFT oxide nanocomposite for the degradation auramine (AM) dye via a heterogeneous Fenton process.