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Abstract In this study, Washingtonia fibres (AW) and Kenaf fibres (KF) were utilized as environmentally friendly fillers to improve the quality of the resin matrix. The mechanical, morphological, and physical properties of the WA/KF biocomposites were assessed throughout this research. The mechanical tests (tensile strength and moduli, elongation at break, flexural strength along with moduli, and the impact properties) were carried out. The hybrid biocomposites (3AW/7KF) exhibited the highest tensile strength (16.05 MPa) and modulus (4.6 GPa) among pure and other hybrid biocomposites. The impact strength and resistance of hybrid biocomposites (1AW/1KF and 7AW/3KF) showed the highest impact strength (1694 J/m2) while the 3AW/7KF hybrid biocomposite, the impact strength value was 1630 J/m2 (17.2 J/m). SEM images indicated good distribution and bonding of hybrid biocomposites. The investigation using morphological tests (Scanning Electron Microscopy (SEM)) displays the longitudinal roughness on the surface, which acts as a very significant function in the adhesion between the AW/KF fibres and the resin. Furthermore, the results of SEM confirm better bonding in the biocomposites, fibre fracture, pull-out, fibre shearing, and tearing in the pure and hybrid composites. From the water absorption test, it was observed that, when increasing the immersion time of biocomposites, the WA percentage of KF biocomposite significantly increased (37%) compared to other biocomposites. However, the hybrid and pure biocomposites exhibited more resistance to increase the WA percentage after increasing the immersion times, compared to other biocomposites. Furthermore, the thickness swelling (TS) of hybrid biocomposites increased compared to pure biocomposites. The biocomposite sample (3AW/7KF) was thicker on the 7th day exhibiting the greatest increases in thickness swelling (4.98%) while the hybrid biocomposite exhibited greater WA value compared to other correspondence samples. Finally, the KF and AW hybrid blends can be appropriate for several applications, for example, textiles, machinery part production industries, medicine, and automobiles, and construction, specifically buildings, bridges, and structures such as boat hulls, swimming pool panels, racing car bodies, shower stalls, bathtubs, storage tanks. Overall, the findings exhibit that the hybridisation of natural fibres (KF/AW) is a sustainable approach for obtaining biocomposites with advanced mechanical and thermal performance. Hence, they could be used in numerous specific applications, including automobile panels, structural products, sporting goods and furniture tools.

The rising liability to suffer the environment eco-friendly covers the approach to the improvement of materials with bio-natural wastes. This research experimentally aims to study bamboo/oil palm reinforced bio-epoxy hybrid composite. Bamboo (B) and oil palm (O) reinforced bio-epoxy was fabricated as a control. The fabricated biocomposites were characterised by mechanical properties (tensile tests), physical characterisations (density, water absorption (WA) and thickness swelling (TS)), thermomechanical analysis (TMA), and morphological (scanning electron microscopy (SEM)). Among the hybrid composites, 5B5O has the highest tensile strength and modulus which is 35.66 MPa and 4.95 GPa, respectively. Based on the findings, the physical properties, WA and TS capacities (WA and TS) of B and 3B7O biocomposites were increased compared with all corresponding biocomposites while the O biocomposite exhibited lower TS and WA values compared to other samples. The hybrid 3B7O biocomposite sample was attributed to a higher void percentage (6.29%) and lower density (1.25 g/cm3) compared to other biocomposites. Generally, the SEM analysis of hybrid biocomposites confirms a valuable interaction between the filler and the matrix as further penetration for the matrix was permitted into the greatly porous structures of natural fibres. Furthermore, the SEM test of the fracture point confirmed the observations from the mechanical properties. The obtained findings confirmed that hybrid fibres improve the properties of the bio-epoxy matrix and can be utilised as sustainable and renewable biocomposites for several applications such as automotive tools, furniture and medical tools.

This review article provides useful information on TiO2 and ZnO photocatalysts and their derivatives in removing organic contaminants such as dyes, hydrocarbons, pesticides, etc. Also, the reaction mechanisms of TiO2 and ZnO photocatalysts and their derivatives were investigated. In addition, the impact of adding metallic (e.g., Ag, Co, Pt, Pd, Cu, Au, and Ni) and non-metallic (e.g., C, N, O, and S) cocatalysts to their structure on the photodegradation efficiency of organic compounds was thoroughly studied. Moreover, the advantages and disadvantages of various synthesis procedures of ZnO and TiO2 nanocatalysts were discussed and compared. Furthermore, the impact of photocatalyst dosage, photocatalyst structure, contaminant concentration, pH, light intensity and wavelength, temperature, and reaction time on the photodegradation efficiency were studied. According to previous studies, adding metallic and non-metallic cocatalysts to the TiO2 and ZnO structure led to a remarkable enhancement in their stability and reusability. In addition, metallic and non-metallic cocatalysts attached to TiO2 and ZnO demonstrated remarkable photocatalytic efficiency in removing organic contaminants.

The application of hybrid natural fibres incorporated with bio phenolic composites is significant due to their sustainability and low-cost rates. In this paper, two natural fibres composites were prepared using a hand lay-up technique. The thermal stability, dynamic-mechanical, and thermo-mechanical characterisations of kenaf fibre (KF)/Washingtonia Leaf Stalk Fibres (AW)/epoxy biocomposite were investigated in this paper. Thermomechanical analysis (TMA) and dynamic mechanical analysis (DMA), respectively, were used to examine the thermal stability and the coefficient of thermal expansion (CTE) and the dynamic mechanical properties of composites, respectively. The Thermogravimetric (TG) analyses showed that the addition of KF and AW enhanced the thermal stability of the epoxy composites. 7AW/3KENAF showed the most significant improvement in thermal stability (Tonset; 284.52 °C and Tmax; 368.25. Furthermore, the hybrid biocomposite exhibited the highest storage modulus (2668.9 MPa) among all other pure and hybrid biocomposites. On the other hand, the TMA findings illustrated that the 50% AW sample exhibited the highest value of CTE (242 μm/m °C) at the maximum temperature (175 °C) among all samples. Briefly, it is obvious that the combination of WA with KENAF enhanced the potential in improving thermal, dimensional and dynamic mechanical characterisations of epoxy composites and can be utilised in building applications that dictate elevated dimensional stability. It was proven that the hybrid biocomposites prepared in this work supported by hybrid natural fibres as strengthened bio fillers might benefit the performance of epoxy composites, which could broaden the application range of industrial and engineering applications and provide novel ways for its effective uses.

In this study, an eco-friendly procedure was established by vortex-assisted liquid-phase microextraction based on deep eutectic solvent (VA−LPME−DES) combined with graphite furnace atomic absorption spectroscopy (GFAAS). The performance of this method was demonstrated by the extraction and analysis of lead (Pb), cadmium (Cd), and mercury (Hg) in fish samples. The hydrophobic DES is considered as a green extractant (environmentally friendly and less toxic than common organic solvents) and is a suitable alternative to common toxic organic solvents and is made of l-menthol and ethylene glycol (EG) with a molar ratio of 1:1. Under optimized conditions, the method linearity was in the ranges of 0.15–150 µg kg−1 with the coefficient of determinations (r2) higher than 0.996. Accordingly, the detection limits for Pb, Cd, and Hg were 0.05, 0.05, and 0.10 µg kg−1, respectively. The analysis of fish samples showed that the concentration of toxic elements in fish caught from the Tigris and Euphrates Rivers is much higher than the concentration of these elements in locally farmed trout fish. Also, the analysis of fish-certified reference materials with presented procedure produced results that were in good agreement with the certified values. The results showed that VA−LPME–DES is a very cheap, fast, and environmental-friendly procedure for the analysis of toxic elements in different types of fish species.