Hoda S. Hafez

In this research, 0.5 wt% Pd plasmonic nanoparticles (5–8 nm) have been incorporated into TiO ₂ photoanode via a fast and low-cost microwave hydrothermal method at 210 °C, 300 psi, and 200 W. The physico-chemical characteristics of the photoanode have been examined by different techniques. Their analyses confirm the successful incorporation of Pd metal nanoparticles onto anatase TiO ₂ thin film electrode and show spherical shape nanoparticles of Pd metal and TiO ₂ . UV–Vis absorption spectrum reveals the visible light absorption capability of the photoactive electrode due to the localized surface plasmonic resonance (LSPR) behavior of Pd metal plasmonic nanoparticles. The XPS analysis confirms the metallic form of Pd metal plasmonic nanoparticles incorporated in TiO ₂ matrix. Plasmonic DSSC efficiency of 5.6% has been achieved with enhancement by 23%. The efficiency enhancement demonstrated by Pd plasmonic nanoparticles can be attributed to the tuned light absorptivity of the solar cell into visible region by the LSPR of Pd plasmonic nanoparticles.

Smart cement composites with CD-semiconductor nanocomposites (TiO ₂ , ZnO, SiO ₂ ) enhance CO ₂ capture and mechanical strength. Quantum-engineered CDs offer synergistic effects, with recyclable photocatalytic activity under solar light.

In this study, a facile, low cost and eco-friendly microwave-assisted hydrothermal method has been used and optimized for large-scale production of reduced graphene oxide (rGO) nanosheets. Different rGO samples have been prepared by the modified Hummers method, followed by microwave-assisted reduction at different MW temperatures of 190, 200, 210, 250 °C for 3, 10, 15, 17, 20 and 25 min irradiation time. The morphological, crystallographic and structural analyses of the different produced rGO samples have been investigated using surface area S_BET, TEM and XRD techniques. The HRTEM images confirm the formation of rGO nanosheets with few lots of wrinkles. The XRD confirmed the complete transformation of GO into rGO after only 15 min of microwave irradiation. The surface area analyses showed a remarkable increase in the S_BET and the total pore volume by reduction of GO into rGO (from 0.7 to 26.3 m².g^-1 and from 0.012 to 0.17 cm².g^-1). The produced rGO samples have been tested for dual adsorptive removal of Fe³⁺ metal ions and methylene blue (MB) dye pollutant. A high adsorptive removal efficiency of 95.5% and 99.5% for Fe³⁺ and MB has been achieved using rGO-17 min, 200 °C optimum sample. The Langmuir isotherm model highlighted adsorption capacities (qm values of 126.1 mg.g^-1 for Fe³⁺ and 27.24 mg.g^-1 for MB), confirming the effectiveness of the optimized rGO sample. Additionally, Form the practical point of view and for the first time, the optimized rGO sample has been tested on real wastewater sample. The removal efficiency of both Fe³⁺ and dye content was approximately 57% after 8 h and 49% after only 2 hours, respectively. This demonstrates an optimized low-cost and sustainable method for wastewater remediation. Graphical Abstract

With growing water scarcity worldwide, water recycling is now a vital component to save water and ensure sustainable water management. Boilers are extensively used in various industries to generate steam for industrial processes and heating. Boiler operation results in polluted wastewater, which has to be specially treated before it can be released into the environment. Effective treatment of boiler wastewater is indispensable to ensure environmental protection as well as regulatory compliance. In this study, a specially designed pre-treatment facility was used for treating boiler wastewater from a hydrochloric acid factory. The wastewater was mixed with reverse osmosis (RO) unit effluents that supplied the production line, followed by reusing the treated water in Hydraulic acid liquefaction process. As an inexpensive pretreatment technique, effective removal of inorganic contaminants, 20%—30% diminution in the level of sulfate, and the levels of phosphate also diminished, whereas metals (zinc and iron) were reduced to the extent of approximately 70%–80%. The Water Quality Index (WQI) indicates fair quality and demonstrates that the system was effective in improving water quality. Life Cycle Assessment (LCA) further revealed that integrating economic and environmental strategies is essential for sustainability. Consequently, 80% of the plant’s wastewater was successfully recovered and reused in a neighboring sulfuric acid production line, achieving a Minimal Liquid Discharge (MLD) outcome.

Plasmonic photocatalysis represents a highly promising area of research, as it enables the efficient exploitation of a broad spectrum of solar energy. Among the different photocatalysts, titanium dioxide (TiO₂) has emerged as a pre‐eminent photocatalyst owing to its remarkable catalytic attributes. Its abundant active sites and high surface‐to‐volume ratio enable synergistic interactions with plasmonic metal nanoparticles, including silver, gold, and palladium, leading to significantly enhanced photocatalytic activity. These hybrid nanostructured materials based on TiO₂ photocatalysts have many advances and challenges for many potential applications in environment and energy production. This phenomenon can be attributed to the efficient separation of charge carriers, coupled with the strategic tuning of the photocatalyst's optical response to extend into extended wavelength regions, specifically within the near‐infrared and visible spectra.

The main focus of this research is on energy production by clean photocatalytic technology. By using the sol–gel process, yttrium titanate nano‐photocatalysts modified with europium (x mol. Eu³⁺:Y₂Ti₂O₇) have been created and used to produce photocatalytic biogas and hydrogen using acetic acid. X‐ray powder diffraction (XRD) confirms the formation of cubic Y₂Ti₂O₇ phase. Microscopic study has indicated that Eu doping improved the shape, size, and dispersity of Y₂Ti₂O₇ photocatalyst. Different crystal defects, including oxygen vacancies (OVs) and Ti³⁺ species, are demonstrated by X‐ray photoelectron spectroscopy (XPS) studies. Compared with pure Y₂Ti₂O₇, 0.03 mol. Eu³⁺:Y₂Ti₂O₇ has the highest proportion of lattice defects. The band gap energies have increased as a result of doping on Y₂Ti₂O₇ size. Urbach energy calculations confirm that Eu³⁺:Y₂Ti₂O₇ nano‐photocatalyst has the highest degree of distortion. The photoluminescence (PL) measurements have shown that 0.03 mol. Eu³⁺ dopant can effectively separate the active charge carriers. Electron spin resonance proved the progressive increase of defect states (OV and Ti³⁺) by doping, which promoted the photocatalytic activity of the nano‐photocatalyst. These photocatalysts have generated biogas and hydrogen gas via photocatalytic oxidation of acetic acid under inert conditions. The maximum photocatalytic activity for the generation of biogas and hydrogen is found in 0.03 mol. Eu³⁺:Y₂Ti₂O₇. The maximum photocatalytic activity of 0.03 mol. Eu³⁺:Y₂Ti₂O₇ is correlated with higher lattice defects (OV, Ti³⁺) and reduced charge carrier recombination. The proposed photocatalytic mechanism has been discussed. According to the findings, Eu³⁺:Y₂Ti₂O₇ nano‐photocatalyst is a promising nanomaterial for the generation of energy.

Plasmonic Pd–ZnO nano photocatalysts synthesized via a green chemistry approach represent an innovation of visible‐light‐induced photocatalysis that can be applied for photobiogas production from organic dye pollutants. Different plasmonic Pd–ZnO nanophotocatalysts have been synthesized via green microwave‐assisted methods using orange peel extract as a capping agent by adding different proportions (3, 5, and 7 wt%) from Pd‐metal plasmons. This fast and green innovative method anchored well distribution of Pd‐metal plasmons (2‐5 nm) on the surface of ZnO (17–27 nm). XRD has investigated the nanostructures' crystallographic, morphological, and optical characteristics, XPS, TEM, UV–Vis DRS, and a_s.BET surface area analysis. A higher surface area data have been achieved by incorporating Pd plasmons from 9.2 m² g⁻¹ in pure ZnO to 16.9 m² g⁻¹ in 7% Pd–ZnO. The analysis of XPS spectra shows an increase of the lattice oxygen (O_L) from 62.36% to 65.08%, suggesting an increase in the number of oxygen vacancies on the surface of the Pd–ZnO plasmonic photocatalysts that leads to enhancing its photocatalytic performance. UV–Vis optical spectra of the different Pd–ZnO photocatalysts reveal the visible light absorption capability due to the localized surface plasmonic resonance effect (LSPR). The photocatalytic activity of the obtained Pd–ZnO nanomaterials has been tested on the photobiogas production during the photocatalytic destruction of Reactive Yellow 15 (R.Y.) in two prototype photobiogas reactors, cylindrical UV reactor and a pilot‐scale CPC solar reactor, under nitrogen atmosphere. A higher yield of biogas (CH₄) and hydrogen (H₂) gases have been achieved by the effect of Pd plasmons on the ZnO photocatalyst.

Lanthanide-doped nanoparticles exhibit unique optical properties and have been widely utilized for different sensing applications. Herein, the Eu³⁺:SrSnO₃@APTS nanosensor was synthesized and its optical properties were analyzed using UV-Vis and photoluminescence spectroscopy. The TEM images of the synthesized nanophosphor Eu³⁺:SrSnO₃@APTS exhibited peanut-like morphology, composed of two or more spherical nanoparticles with an average diameter ∼33 nm. Effects of environmental pH values and doping concentrations as well as amino functionalization on the structure of Eu³⁺:SrSnO₃ were investigated. The as-synthesized optical nanosensor was used for determination of copper ions based on a fluorescence quenching approach. Red emission with a long lifetime was obtained in the case of the 0.06 mol Eu³⁺:SrSnO₃@APTS sample. Under the optimal experimental conditions, a Stern–Volmer plot exhibited a good linearity for copper ions over the concentration (0.00–10.8) × 10⁻¹¹ mol L⁻¹ with a correlation efficient of 0.996 and a limit of detection 3.4 × 10⁻¹² mol L⁻¹. The fluorescent sensor was dynamically quenched via a coulombic interaction mechanism between the Eu³⁺ (⁵L₆) and Cu²⁺. The Eu³⁺:SrSnO₃@APTS nanosensor with the optimal Eu³⁺ dopant concentration of 0.06 mol was applied for copper determination in food and real drink water samples with high recovery values. We believe that the developed nanosensor probe can also be used for the detection of other toxic compounds, with high selectivity and sensitivity.