Synthesis of bioinspired sorbent and their exploitation for methylene blue remediation

Synthesis of novel nanocomposite of g-C3N4 coated ZnO-MoS2 for energy storage and photocatalytic applications

Fabrication of heterostructures for energy storage and environmental remedial applications is an interesting subject of research that has been undertaken in this present investigation. The incorporation of g-C3N4 into ZnO:MoS2 heterojunction nanocomposite was accomplished by wet-chemical route and characterized by various techniques to ascertain its structure, morphology, and study its potential electro-optical characteristics. The g-C3N4@ZnO:MoS2 sample was investigated by x-ray diffraction (XRD) which reveals the co-existence of the ZnO, MoS2 and C3N4 phases linked to characteristic crystallographic planes in the spectrum, validating the formation of ternary nanocomposite. The XRD patterns of the pristine samples were also considered as reference to understand the structural evolution and phase transformations. Field emission scanning electron microscopy (FESEM) study states the formation of heterogeneous nanostructures having nanoparticles embedded on 2-D nanosheets like structures. Studies using energy dispersive spectroscopy (EDS) and elemental mapping show that all the elements that are linked to the above hybrid nanocomposite are present. Transmission electron microscopy (TEM) provided clear insights on the microstructure as we can identify the distribution of ZnO and MoS2 nanostructures on layered g-C3N4 nanosheets. The chemical composition and oxidation states of elements were elucidated by X-ray photoelectron spectroscopy (XPS) study, which added another layer of confirmation on the structural evolution of the ternary nanocomposite. Fourier transformed infrared (FTIR) study revealed the layered structure of sp2 hybridized bonding features of C and N in g-C3N4, besides Zn-O and Mo-S stretching vibrations. The nanocomposite demonstrated improved photodegradation efficacy and decomposed alizarin red and methylene blue dyes significantly with better stability and reusability. MoS2 as a co-catalyst acts as an electron acceptor/accelerator in the Z-scheme composite photocatalysis leading to improved photocatalytic efficiency. The resulting heterostructured material delivered a higher specific capacitance of 10.85 F/g with good capacitance retention. Electrochemical study revealed the energy storage capability of the hybrid system.

Sustainable remediation of dye-contaminated wastewater using novel cross-linked Hex-CCP-co-PPT microspheres

The presence of dyes in contaminated water poses substantial dangers to the health of both humans and aquatic life. A process called precipitation polymerization was used to create unique cross-linked hexa-chlorocyclotriphosphazene-co-phenolphthalein (Hex-CCP-co-PPT) microspheres for the purpose of this research. Advanced methods such as X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and differential thermogravimetry (DTG) were used to characterise these microspheres. In a simulated solution, the performance of Hex-CCP-co-PPTs as a sorbent for removing MB dye was investigated, and the results showed an unprecedentedly high removal rate of 88.4% for MB. Temperature of 25 °C, a Hex-CCP-co-PPTs dose of 40 mg, an MB concentration of 20 ppm, an MB solution volume of 20 mL, a contact time of 40 min, and a pH of 9 were found to be the optimal experimental conditions. According to the results of the kinetic and adsorption analyses, the PSO and Langmuir adsorption models are the best ones to use. These models favour the chemi-sorption nature and mono-layered adsorption of MB in comparison to Hex-CCP-co-PPTs. Importantly, the thermodynamic analysis demonstrated that the process of removing MB by utilizing Hex-CCP-co-PPTs was endothermic and occurred spontaneously. These findings highlight the potential application of Hex-CCP-co-PPT microspheres in Algal Membrane Bioreactors (AMBRs) for the efficient and sustainable removal of dye from wastewater. This would contribute to the protection of ecosystems as well as the public's health.