Paulownia is one of the most useful and sought-after trees worldwide. Various parts (flowers, fruits, leaves, wood, bark, and seeds) have found practical applications. The present study focuses on the characterization of paulownia fruits, flowers and shells, and their potential non-traditional application for pollutant adsorption. The fruits were found to contain higher amounts of flavonoids (1051.85 ± 10.32 µg mL⁻¹) compared to flowers (401.26 ± 5.48 µg mL⁻¹). This reflects the observed antioxidant activity of the fruits: two times higher than that of the flowers. Salicylic acid was the main phenolic acid (2729.96 ± 16.89 µg mL⁻¹) in the flowers, while quercetin (572.42 ± 10.32 µg mL⁻¹) and rosmarinic acid (352.84 ± 6.97 µg mL⁻¹) were present in higher amounts in the fruits. The lipids from the flowers were rich in linoleic (48.1%) and linolenic (20.0%) acids, while the fruit lipids were rich in linoleic (53.9%) and oleic (19.5%) acids. More than half of the fruits and flowers consisted of insoluble dietary fibers. The shells were rich in cellulose and lignin (42.96 ± 0.61 and 31.23 ± 0.34 g 100 g⁻¹ DW, respectively) and were applied as a natural biosorbent for Cu²⁺, Cd²⁺ and methyl orange removal (99.05%). Paulownia fruits were effective, removing 98.25% of Cu²⁺ (5000 mg L⁻¹). Hence, paulownia shells and flowers could potentially be utilized as non-traditional biosorbents for pollutant removal.

In this study, we employed one of the green synthesis methods utilizing water extracts prepared from solid industrial wastes of Rosa damascena Mill. (RD) and Oriental variety tobacco (Nicotiana tabacum)-mixed stems and leaves (O) as a natural reducing agent for PdCl₂ to obtain environmentally friendly Pd nanoparticles (PdNPs). Transmission electron microscopy (TEM), selected area electron diffraction (SAED), and energy-dispersive X-ray spectroscopy (EDX) in TEM were applied to determine the morphology, microstructure, phase, and elemental composition of PdNPs synthesized. The concentration of PdNPs in the suspensions was quantified by inductively coupled plasma optical emission spectroscopy (ICP-OES), which is essential for their intended application. Furthermore, the synthesized PdNPs were incorporated as dopant into a polymer matrix (PAZO) developed for optical applications. As will be demonstrated, doping PAZO with specific concentrations (0.1, 0.2, 0.25, 0.3, 0.4, 0.5, and 1 wt. %) of green PdNPs enhances the maximal value of the photoinduced birefringence by more than 50%. This improvement enables more efficient inscription of polarization-selective holographic optical elements in the resulting photoanisotropic nanocomposite materials with nearly 25% higher diffraction efficiency. Using a digital polarization holographic setup, the spatial modulation of polarization was recorded on thin nanocomposite films of the azopolymer PAZO, doped with certain concentrations of the green PdNPs.