The current study focuses on the synthesis of Cerium oxide (CeO₂) nanocatalyst via Tragacanth Gum (TG) using the wet impregnation method and its application for sustainable biodiesel production from a novel, non-edible Descurainia sophia (L.) Webb ex Prantl seed oil. The D. sophia seed oil has higher oil content (36 wt%) and free fatty acid (FFA) value (0.6 mg KOH/g). Innovative analytical methods, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy, were used to characterize the newly synthesized, environmentally friendly, and recyclable CeO₂-TG phytonanocatalyst (FT-IR). The results show that the CeO₂-TG phytonanocatalyst was 22 nm in diameter with a spherical shape outer morphology, while the inner structure was hexagonal. Due to low FFA content, the D. sophia seed oil was pretreated and transesterified via a single step. Using varying parameters, the optimized process variables were determined via Response Surface Methodology (RSM). The optimum process values were 8:1 methanol to oil molar ratio, 0.3 wt% catalyst concentration, 90 °C temperature, and reaction time of 210 min with 98% biodiesel yield. The recently created phytonanocatalyst was reliable and effective, with three times reusability in the transesterification reaction. Thin layer chromatography (TLC), FT-IR, gas chromatography–mass spectroscopy (GCMS), and Nuclear magnetic resonance (NMR) analyses were used to characterize the synthesized biodiesel. Physico-chemical properties of D. sophia biodiesel, i.e., Kinematic viscosity (4.23 mm²/s), density (0.800 kg/m³), pour point (−7 °C), cloud point (−12 °C), and flash point (73.5 °C) agree well with international biodiesel standards (ASTM-6751, 951), (EU-14214), and China (GB/T 20828) standards. The results show that the synthesized nanocatalyst demonstrated remarkable stability, indicating a bright future for industrial biodiesel production from low-cost feedstock.

Membrane technology has been embraced as a feasible and suitable substitute for conventional time- and energy-intensive biodiesel synthesis processes. It is ecofriendly, easier to run and regulate, and requires less energy than conventional approaches, with excellent stability. Therefore, the present study involved the synthesis and application of a highly reactive and recyclable Titania-based heterogeneous nanocatalyst (TiO₂) for biodiesel production from nonedible Azadhiracta indica seed oil via a membrane reactor, since Azadhiracta indica is easily and widely accessible and has a rich oil content (39% w/w). The high free fatty acids content (6.52 mg/g KOH) of the nonedible oil was decreased to less than 1% via two-step esterification. Following the esterification, transesterification was performed using a heterogeneous TiO₂ nanocatalyst under optimum conditions, such as a 9:1 methanol–oil molar ratio, 90 °C reaction temperature, 2 wt.% catalyst loading, and an agitation rate of 600 rpm, and the biodiesel yield was optimized through response surface methodology (RSM). Azadhiracta indica seed oil contains 68.98% unsaturated (61.01% oleic acid, 8.97% linoleic acid) and 31.02% saturated fatty acids (15.91% palmitic acid, 15.11% stearic acid). These fatty acids transformed into respective methyl esters, with a total yield up to 95% achieved. The biodiesel was analyzed via advanced characterization techniques like gas chromatography–mass spectrometry (GC-MS), Fourier transform infrared spectroscopy (FT-IR), and nuclear magnetic resonance (NMR), whereas the catalyst was characterized via X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), and Fourier transform infrared spectroscopy (FT-IR). Due to its physicochemical properties, Azadirachta indica seed oil is a highly recommended feedstock for biodiesel production. Moreover, it is concluded that the Titania-based heterogeneous nanocatalyst (TiO₂) is effective for high-quality liquid fuel synthesis from nonedible Azadirachta indica seed oil in a membrane reactor, which could be an optional green route to cleaner production of bioenergy, eventually leading to sustenance, robustness, and resilience that will aid in developing a holistic framework for integrated waste management.

The green chemistry method for nanocatalyst synthesis along with environmentally feasible non-edible sources are promising alternatives to fossil fuels. The current study focuses on the synthesis of copper oxide phyto-nanocatalyst and the identification of a new renewable feedstock, Citrullus colocynthis, to reduce environmental pollution. The highest biodiesel yield (95%) was obtained under optimum conditions of a 1:8 oil-to-methanol ratio and reaction temperature of 85 °C for 120 min with a 0.365 wt% catalyst concentration. The phyto-nanocatalyst was synthesized using seed oil cake after extracting oil with the salt of copper (copper oxide). The catalyst was then subjected to various analyses, namely, EDX, FT-IR, SEM, and XRD. The catalyst was proved to be efficient and effective after being reused five times and still there was a very small difference in biodiesel yield. All the analyses also show sustainable and stable results. Thus, copper oxide phyto-nanocatalyst with non-edible Citrullus colocynthis proved to be highly effective, sustainable, and a better alternative source to the future biodiesel industry.

Recently, intensifying energy crises accompanying ecological crises due to the decline in fossil-fuel reserves and extensive greenhouse gas emissions have triggered the exploration of renewable substitutes for petro-diesel. In this scenario, biodiesel is the best alternative to non-renewable finite conventional fuels due to its cost-effectiveness, sustainability, renewability, biodegradability, and eco-friendly nature. Hence, the current research was designed to utilize scanning electron microscopy to investigate and identify the micro-morphological characteristics of selected seed-bearing crops. Light-microscopy (LM) indicated discrete variations in macro-morphological characters such as seed shape (ovoid, ovate, oblong, semi-spheroid, or discoid), seed size (3.5–14 mm in length and 2.25 to 6.5 mm in width), seed color (yellow to black), and number of seeds per kilogram (from 6000 to 260,000). Chemical extraction via Soxhlet apparatus resulted in the estimation of oil content within the range of 20.3–48.0% (wt./wt.), FFA content (0.63–6.91 mg KOH/g), and maximum product, i.e., 98% biodiesel yield was achieved. Multivariate analysis via principal component analysis (PCA) was done using PAST 3 software to investigate similarities and differences among factors/variables. SEM examination exhibited ultra-morphological characters and distinct variation in cell-wall ornamentation; hilum occurrence, position, and level; wall-sculpturing variations such as ruminate, verrucate, wrinkled, or striate; cell arrangement (anticlinal or periclinal); and cell shape and margins. To conclude, SEM could be an advanced technique to disclose the ultra-micromorphological characteristics of oil-bearing energy crops providing a convenient way for scientists to determine correct identification, authentication, and classification.

The objective of the study was a pre-screening of the microplastic (MP) content in surface water and benthic sediments of Kara Darya and Chirchiq rivers, the first-order tributaries of the Syr Darya River (Uzbekistan). For the first time, surface water and benthic sediment samples were taken from this region, and quantitative screening of MPs 0.15–5.00 mm in size was performed. A combined visual and μRaman-based methodology was used to quantify and characterize artificial polymer microparticles from the surface water and bottom sediments of two rivers. The average abundance of MPs in the Kara Darya River and Chirchiq River waters was found to be 4.28 ± 0.09 and 0.95 ± 0.36 items per m³, and that in benthic sediments attained 244 ± 28.9 and 333 ± 11.5 items per kg of dry soil, respectively. MP concentration in surface water and benthic sediments of the Kara Darya River significantly exceeded (p-value < 0.01) that in the Chirchiq River. Microfibers were most abundant; the proportion of MP fibers in the water of the Kara Darya and Chirchiq rivers amounted to 89 and 95%, respectively, and that in benthic sediments of the rivers was 86 and 84%, respectively. The dominance of microfibers may indicate the route of entry to the rivers through domestic wastewater treatment plant discharges. The polymer microparticles in the surface water and benthic sediments of the Kara Darya and Chirchiq rivers were mainly represented by polyethylenterephtalate (PET), which accounted for half of all MPs detected in the Kara Darya River. Microparticles of textile origin were particularly abundant in the Kara Darya River, where viscose and nylon fibers were also found, which suggests the leading role of synthetic textiles in the pollution. The reported data are the first experimental evidence of MP pollution of the Syr Darya tributaries, but the distribution and circulation of MPs in surface water in Central Asia requires further comprehensive studies.

This study examines the role of light microscopic (LM) and scanning electron microscopic (SEM) micromorphological traits of the epidermis in identifying and classifying invasive plants. SEM was conducted to increase our understanding of microscopic qualities that are not visible in light microscopy and to elucidate unclear affinities among invasive species. The study examines invasive species’ morphological and anatomical characteristics from the Pothohar Plateau of Pakistan for the first time. The results showed that various micromorphological features are very useful for species’ accurate identification. Adaxial and abaxial surfaces of leaves showed variations in subsidiary cells, glands, anticlinal wall patterns, stomata, and epidermal cells. Epidermal cell shapes observed were irregular, elongated, rectangular, and polygonal. Epidermal cells having maximum length were calculated in Stellaria media (126.3 μm) on adaxial side. On the abaxial surface, the minimum length was noticed in Eucalyptus camaldulensis (28.5 μm). Both glandular and nonglandular trichomes were examined, ranging from unicellular to multicellular. Most of the investigated specimens of leaves were amphistomatic, while some were hypostomatic, like Alternanthera pungens, Calotropis procera, Cannabis sativa, Lantana camara, and Thevetia peruviana. Leaf epidermal morphology contains numerous useful systematic features for accurate identifications of plant species. The micromorphological attributes under observation provide a standard criterion to the researcher for identifications of invasive flora in future morpho-taxonomic studies.