The discharge of inorganic pollutants like phosphate and fluoride is a cause of mounting concern to the world due to the substantial environmental and human health risk. Adsorption is one of the most common and affordable technologies widely utilized for removing inorganic pollutants such as phosphate and fluoride anions. Investigating efficient sorbents for the adsorption of these pollutants is extremely important and challenging. This work aimed at studying the adsorption efficiency of the Ce(III)-BDC metal-organic framework (MOF) for the removal of these anions from an aqueous solution using a batch mode. Powder X-ray diffraction (XRD), Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), Brunauer-Emmett-Teller (BET), and scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDX) techniques evidenced the successful synthesis of Ce(III)-BDC MOF in water as a solvent without any energy input within a short reaction time. The outstanding removal efficiency of phosphate and fluoride was exhibited at an optimized pH (3, 4), adsorbent dose (0.20, 0.35 g), contact time (3, 6 h), agitation speed (120, 100 rpm), and concentration (10, 15 ppm) for each ion, respectively. The experiment on the effect of coexisting ions demonstrated that SO₄^2- and PO₄^3- ions are the primary interfering ions in phosphate and fluoride adsorption, respectively, while the HCO₃^- and Cl^- ions were found to have interfered less. Furthermore, the isotherm experiment showed that the equilibrium data fitted well with the Langmuir isotherm model and the kinetic data correlated well with the pseudo-second-order model for both ions. The results of thermodynamic parameters such as ΔH°, ΔG°, and ΔS° evidenced an endothermic and spontaneous process. The regeneration of the adsorbent made using water and NaOH solution showed the easy regeneration of the sorbent Ce(III)-BDC MOF, which can be reused four times, revealing its potential application for the removal of these anions from aqueous environment.

Plant-mediated synthesized materials are receiving more attention than conventional ones due to their wide availability, ease of access, simple preparation methods, environmental benign, and possess superior physicochemical properties. In this work, plant extract-mediated CuO, Bi₂O₃, and CuO/Bi₂O₃ nanocomposite samples were successfully synthesized using bamboo leaves extract as a capping agent. These materials were utilized for the photodegradation of Rhodamine B (RhB) dye, which served as a model organic dye pollutant. The physicochemical characterization techniques such as XRD, SEM-EDS, FTIR, and DRS-UV-vis spectrophotometry provide insight into the crystal structure, morphology, surface functional groups, and optical properties. These analyses confirm the effective formation of CuO, Bi₂O₃, and CuO/Bi₂O₃ materials. Surprisingly, upon calcination at 450 °C for 4 h, the color of the nanocomposite changed from pale green to gray greenish, providing evidence for the formation of the CuO in CuO/Bi₂O₃ nanocomposite. The photocatalytic optimization parameters such as pH (4), catalyst load (35 mg), irradiation time (180 min) and concentration of RhB (10 mg L⁻¹) dye were investigated. By coupling CuO with Bi₂O₃ nanoparticles resulted in an improved photocatalytic property for the degradation of RhB dye under optimal conditions. As a result, CuO/Bi₂O₃ nanocomposite exhibited a significantly boosted photocatalytic degradation efficiency (95.6%) compared to pure CuO (40.2%) and Bi₂O₃ (80.5%) photocatalysts, with good reusability. For comparison purpose, the photocatalytic degradation of RhB dye using selected photocatalyst was evaluated under dark and sunlight systems. This eco-friendly approach holds great potential for synthesis new nanocomposite with modified properties, thereby enabling the practical application of high-efficiency photocatalysts. The plausible mechanism of the electrons and holes transfer was proposed.

Nitrogen (N) and phosphorus (P) co-doped ZnO-CdO nanocomposites were synthesized from bioprecursors such as rice (O. Sativa L.), chickpea (Cicer arietinum L.), soybean (G. max (L.) Merr) and sesame (Sesamum indicum L.) through self-doping into the ZnO-CdO composite. The as synthesized composites were characterized using PXRD, XPS, TGA, SEM, Cs-corrected (S) TEM, EDS, FT-IR, AAS and UV-vis spectrophotometer. Effect of biogenic doping on the band structures of the binary heterojunction was also studied using Density Functional Theory (DFT). The theoretical results showed that NP co-doping in ZnO-CdO nanocomposite improves the absorption edge to longer wavelengths in line with the experimental finding obtained from UV-vis measurement. Biogenic NP co-doped ZnO-CdO nanocomposites showed greater photocatalytic activity compared to the undoped congeners under visible light irradiations. Comparatively, photocatalytic activity of biogenic NP co-doped ZnO-CdO samples showed the order: soybean-ZC > chickpea-ZC > rice-ZC > sesame-ZC at optimal conditions under visible light irradiation. The binary ZnO-CdO nanocomposite also showed better photocatalytic activity compared to the host crystal ZnO under the same experimental conditions. Highest photocatalytic degradation efficiency of biogenic NP co-doped ZnO-CdO could be attributed to the lower rate of recombination of the photogenerated electrons and holes as well as its lower band gap energy and good reusability.

Knoevenagel condensation and acetylation reactions play a critical role in organic synthesis by facilitating the formation of carbon-carbon bonds and the modification of functional groups; however, limitations like low efficiency and demanding reaction conditions and time underscore the necessity for developing better techniques to enhance their practical applications. In this study, a ternary nanocomposite of CdS/CeO₂/Ag₂CO₃ was synthesized by varying the molar ratio of CdS to CeO₂/Ag₂CO₃ using the precipitation method. This heterogeneous catalyst was developed for Knoevenagel condensation and acetylation reactions applications. The optical properties, functional groups, crystalline structure, morphology, and surface area of the synthesized catalysts were characterized using UV-Vis-DRS, FTIR, XRD, SEM, and N₂ adsorption-desorption isotherms, respectively. For the Knoevenagel condensation reaction between benzaldehyde and malononitrile, the optimal conditions were found to be the use of water as a solvent, at 10% w/w catalyst loading based on the total reagent mass, and room temperature (20 °C). Under these conditions, CdS/CeO₂/Ag₂CO₃ with a CdS: CeO₂/Ag₂CO₃ weight ratio of 3:1 gave high yields, 92.19 ± 0.41 in 33 min for Knoevenagel condensation and 93.8 ± 1.19 in just 3 min for the acetylation reaction. The reaction conditions were tested for different aromatic aldehydes with malononitrile, yielding high isolated products. The reusability of the CdS/CeO₂/Ag₂CO₃ (3:1) catalyst was assessed, with only a 6.4% decrease in yield after sixth consecutive runs under optimal reaction conditions. Furthermore, the optimized catalyst, CdS/CeO₂/Ag₂CO₃ (3:1), was evaluated for its catalytic activity in the acetylation of an aniline derivative. The structures of the synthesized products, 2-benzalidinemalononitrile and acetanilide, were confirmed by spectrometric techniques such as¹H-NMR,¹³C-NMR, and FTIR analysis.

UiO-type Zr-BDC MOFs have garnered the interest of the scientific community due to their exceptional diversity in composition, structure, and chemical environment, as well as their high thermal and chemical stabilities. This work demonstrates the sustainable synthesis of a series of nanocrystalline/semicrystalline UiO-66(Zr) metal–organic frameworks (MOFs) under facile conditions—specifically at room temperature, in water, with high yield, and without the use of modulators or toxic byproducts. The synthesis involves either deprotonating the linker or utilizing various ratios of water and DMF as solvents. The as-prepared materials obtained from both synthesis strategies share key structural features with conventional UiO-66(Zr) in their short- and medium-range physicochemical properties, while exhibiting significant differences in crystallinity and textural properties. Nonetheless, the materials generally lack long-range order (semicrystalline), in particular these synthesized following the deprotonation strategy. However, the materials prepared using mixed solvent strategy seem to exhibit characteristics of nanocrystalline UiO-66(Zr). Overall, both approaches successfully addressed various synthesis challenges related to the highly sought-after Zr-based metal–organic frameworks (MOFs). Some of these MOF materials were tested for the photodegradation of rhodamine B (RhB) under mercury light irradiation, evidencing high photocatalytic efficiency of up to 75 ± 0.078% within 120 min under the pseudo-first-order model. This suggests an interaction between the photocatalyst and the RhB dye, involving electron injection from RhB and the ability for ligand-to-metal charge transfer (LMCT), which enhances the efficient photocatalytic degradation of RhB. The trapping experiments indicated that superoxide radicals (•O₂⁻) and photogenerated holes (h⁺) are crucial in the photodegradation of RhB. Moreover, the materials showed good recyclability across five tested cycles. A plausible photocatalytic reaction mechanism has been proposed to explain these findings.