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In this research, a tungsten oxide was prepared via a green (biogenic) synthesis route where sodium tungstate dihydrate and Punica granatum peel extract were used as a precursor and a reducing/capping agent, respectively. The characterization of the prepared tungsten oxide was performed through various spectroscopic and microscopic techniques. The characterization results revealed the preparation of highly crystalline and nanorod-shaped (length = 123 nm and width = 31.3 nm) tungsten oxide with a probable chemical formula of W5O14. Various functional groups on the W5O14 surface were also reported. The prepared nanorods were further used for the removal of Bismarck Brown R (BBR) dye from water in a batch manner. By varying the dose of nanorods (0.5–3.0 g L−1), BBR solution pH (2−10), contact time (15–120 min), BBR concentration in solution (10–60 mg L−1), and temperature of BBR solution (30, 40, and 50 °C), the optimized condition for maximum adsorption efficiency was measured. The results revealed that 2.0 g L−1 amount of nanorods of tungsten oxide were used to remove ~98% of BBR dye from its 10 mg L−1 at 30 °C and 7.0 pH. The temperature-dependent adsorption data were fitted to different types of non-linear isotherm models (e.g., Langmuir and Freundlich) to assess the adsorption potential and adsorption mechanisms in relation to temperature impacts. The synthesized nano-adsorbent fits the Langmuir as well as the Freundlich isotherm model with a maximum adsorption capacity of 17.84 mg g−1. Pseudo-first-order, pseudo-second-order, and Elovich kinetic models were used for the study of adsorption kinetics. BBR adsorption onto the W5O14 nanorods follows the pseudo-second-order rates. The present adsorption is governed by physico-chemical adsorption with predominant chemical interactions. [ABSTRACT FROM AUTHOR]

Hydrogen (H2) is a well-known renewable energy source that produces water upon its burning, leaving no harmful emissions. Nanotechnology is utilized to increase hydrogen production using sacrificial reagents. It is an interesting task to develop photocatalysts that are effective, reliable, and affordable for producing H2 from methanol and acetic acid. In the present study, CuO, CdWO4, and CuO–CdWO4 nanocomposite heterostructures were prepared using a cost-efficient, enviro-friendly, and facile green chemistry-based approach. The prepared CuO, CdWO4, and CuO–CdWO4 nanocomposites were characterized using X-ray diffraction pattern, Fourier-transform infrared spectroscopy, diffuse reflectance ultraviolet–visible spectroscopy, scanning electron microscopy, transmission electron microscopy, selected area electron diffraction (SAED) pattern, N2 physisorption, photoluminescence, and X-ray photoelectron spectroscopy techniques. The synthesized photocatalysts were utilized for photocatalytic H2 production using aqueous methanol and acetic acid as the sacrificial reagents under visible light irradiation. The influence of different variables, including visible light irradiation time, catalyst dosage, concentration of sacrificial reagents, and reusability of catalysts, was studied. The maximum H2 was observed while using methanol as a sacrificial agent over CuO–CdWO4 nanocomposite. This enhancement was due to the faster charge separation, higher visible light absorption, and synergistic effect between the CuO–CdWO4 nanocomposite and methanol. [ABSTRACT FROM AUTHOR]