This work describes the synthesis, characterization, and photocatalytic activity of new composite nanomaterials based on ZnO nanostructures impregnated by lipophlilic porphyrins derived from cashew nut shell liquid (CNSL). The obtained nanomaterials were characterized by X-ray diffraction (XRD), UV-Vis diffuse reflectance spectroscopy (DRS), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), and steady-state photoluminescence spectra (PL). The results confirm nanostructures showing average diameter of 55 nm and an improved absorption in the visible region. Further, the FTIR analysis proved the existence of non-covalent interactions between the porphyrin molecules and ZnO. The photocatalytic activity of prepared photocatalysts was investigated by degradation of rhodamine B (RhB) in aqueous solution under visible light irradiation and natural sunlight. It was demonstrated that the photocatalytic activity increases in the presence of the porphyrins and, also, depends on the irradiation source. The development of composite photocatalysts based on porphyrins derived from CNSL provides an alternative approach to eliminate efficiently toxic wastes from water under ambient conditions.
In the last decades, there is an increasing trend for replacing petro-based adhesives with sustainable and eco-friendly alternatives, especially in the wood industry. In this work it was developed and characterized novolac-type phenolic resins from the full use of the cashew nut shell liquid (CNSL), an agro-industrial residue and a rich source of phenolic compounds, sustainable alternative to petroleum-derived chemicals, to develop bio-based polymers. CNSL and paraformaldehyde were reacted, using oxalic acid as a catalyst, under a solvent-free methodology. A dark and viscous resin of high molar mass and thermally stable was obtained. The development of highly bio-based adhesives was proposed by combining CNSL-based novolac resin (CNSL-nov) with commercial epoxy resin (DGEBA), as an alternative to conventional hardeners. The use of the epoxy-novolac system proved to be efficient and promising in obtaining new highly cross-linked polymers with excellent thermal performance and with potential for wood industry, improving the bio-based content of high-performance adhesive.
K E Y W O R D Scashew nut shell liquid, diglycidyl ether of bisphenol A, phenolic resin, waste utilization, wood adhesive applications
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