Nano Molybdenum trioxide (α-MoO₃) was synthesized in an easy and efficient approach. The removal of methylene blue (MB) in aqueous solutions was studied using this material. The effects of various experimental parameters, for example contact time, pH, temperature and initial MB concentration on removal capacity were explored. The removal of MB was significantly affected by pH and temperature and higher values resulted in increase of removal capacity of MB. The removal efficiency of Methylene blue was 100% at pH = 11 for initial dye concentrations lower than 150 ppm, with a maximum removal capacity of 152 mg/g of MB as gathered from Langmuir model. By comparing the kinetic models (pseudo first-order, pseudo second-order and intraparticle diffusion model) at various conditions, it has been found that the pseudo second-order kinetic model correlates with the experimental data well. The thermodynamic study indicated that the removal was endothermic, spontaneous and favorable. The thermal regeneration studies indicated that the removal efficiency (99%) was maintained after four cycles of use. Fourier Transform Infrared (FTIR) and Scanning Electron Microscopy (SEM) confirmed the presence of the MB dye on the α-MoO₃ nanoparticles after adsorption and regeneration. The α-MoO₃ nanosorbent showed excellent removal efficiency before and after regeneration, suggesting that it can be used as a promising adsorbent for removing Methylene blue dye from wastewater.

Perovskite solar cells (PSCs) have emerged as potential substitutes to conventional photovoltaic devices due to their outstanding performance, affordability, and simplicity of construction. This study focuses on optimizing rubidium-based halide perovskite solar cells using numerical simulation tools, specifically SCAPS-1D (Solar Cell Capacitance Simulator), with rubidium germanium bromide (RbGeBr3) as the absorber material. The aim is to improve both efficiency and durability, addressing challenges in creating sustainable and cost-effective photovoltaic technologies. The performance of the proposed solar cell configuration was evaluated by examining various parameters such as the thickness of the absorber, the thickness of the electron transport layer and hole transport layer (HTL), defect densities, temperature, etc. Various hole transport layer materials, including Copper Barium Tin Sulfide (CBTS), Copper Iodide (CuI), PEDOT: PSS, and Spiro-MeOTAD, were analyzed to evaluate their impact on open-circuit voltage, short-circuit current, fill factor, and power conversion efficiency. The findings indicate significant potential for RbGeBr3-based solar cells, with the CBTS HTL yielding the highest efficiency. Among the structures, the ITO/WS2/RbGeBr3/CBTS/Au structure was found to be optimal, achieving a power conversion efficiency of 31.48%, a current density of 26.27 mA/cm2, a voltage of 1.39 V, and a fill factor of 85.76%. This research provides valuable insights for designing and optimizing future perovskite solar cells, contributing to the advancement of renewable and sustainable energy technologies.

Solid-state dye-sensitized solar cells (SSDSC) have been fabricated using two different metal oxide materials, graphene oxide and titanium oxide, are used as hole and electron transport materials, respectively. The N719 dye ruthenium between the hole and electron transport materials to act as an absorber layer in your Go/N719dye/TiO2 solar cells. Through the SCAPS-1D simulation, it was found that the Go/N719dye/TiO2 solar cells have significantly improved the performance of the solar cells compared to the Go/TiO2 solar cells. Specifically, the short circuit current (Jsc) has increased from 0.17 mA/cm2 to 1 mA/cm2, the open circuit voltage (Voc) has increased from 0.2 V to 1 V, and the power conversion efficiency (η) has increased from 0.02% to 2.5%. Additionally, Various factors that can affect the performance of Go/N719 dye/TiO2 solar cells. It was found that the optimal dye thickness for achieving high short circuit current density, high power conversion efficiency, and high open circuit voltage is between 200nm and 300nm. Furthermore, the operating temperature of the solar cells also affects their performance. Increasing the operating temperature negatively affects the open circuit voltage and power conversion efficiency of the cells, while the short circuit current density is slightly enhanced. Finally, the efficiency of a solar cell can be affected by the type of metal used for the electrode and the type of semiconductor material used in the cell. In Ni and Cu electrodes solar cells ohmic contacts allow for efficient transfer of electrons, whereas Schottky barriers can impede electron flow and reduce efficiency in Mo and Ag electrodes solar cells .

The aim of this work was to investigate the use of modified nigella sativa seeds (MNS) for removing of methylene blue (MB) dye from aqueous solution. The nigella sativa (NS) seeds have been pre-treated at different temperatures and periods of time. The maximum adsorption of MB was achieved using NS sample washed with distilled water pre-heated at 65 °C for one hour, then ground to 250 µm particle size (MNS-4). Different parameters were modified to optimize the removal process of MB using MNS-4, such as contact times, temperatures, initial dye concentrations, adsorbent doses, and pH of the solution. MNS-4 exhibited a removal efficiency of 99% for initial dye concentrations greater than 800 ppm at pH value of 11. The kinetic study indicated that the removal process follows the pseudo second order model. The removal was spontaneous, endothermic and favorable, and this was indicated by the thermodynamic study. Maximum removal capacity was 194 mg/g as deduced from Langmuir model. The removal efficiency was maintained after four recycle uses. The modified nigella sativa seeds were characterized before, and after adsorption and regeneration by Fourier Transform infrared (FTIR) and scanning electron microscopy (SEM). The data suggested that nigella sativa seeds could be a prospective agent for removing MB from wastewater.

The removal of Basic Blue-41 dye molecules was carried out by using two doped porous clay heterostructures by aluminum (Al) or zirconium (Zr) species. The proposed method of synthesis showed its efficiency, starting from Al or Zr intercalated hydrolyzed species, prior to its reaction with dodecylamine (C₁₂ amine) and tetraethyl orthosilicate (TEOS) as a silica source. The intercalated precursors and their porous clay heterostructures (PCH) derivatives were characterized by different techniques. Solid NMR technique proved the presence of Al species into the intercalated silica between the clay sheets, and in addition to Si in different environments within the PCH materials. The Zr-PCH material exhibited a higher surface area and pore volume compared to its Al-PCH counterpart, with a mesoporous character for both materials. A maximum removed amount of 279 and 332 mg/g was achieved and deduced from the Langmuir equation. The regeneration tests revealed that the removal efficiency of Zr-PCH was retained after five regeneration runs, with a loss of 15% of the original value; meanwhile, the Al-PCH lost 45% of its efficiency after only three cycles. A single-stage batch design was proposed based on the Langmuir isotherm parameters. The increase of the removal capacity of Zr-PCH led to the reduction of the required amounts for the target removal of BB-41 dye compared to Al-PCH.