This study addresses the critical need for effective dye removal in wastewater treatment by developing a chitosan/graphene oxide-ferric oxide (CS/GO-Fe2O₃) composite through a coprecipitation method. The primary objective was to evaluate its adsorption performance for methylene blue (MB), a model cationic dye, while optimizing key operational parameters. The composite was systematically characterized using X-ray diffraction (XRD), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), and Brunauer-Emmett-Teller (BET) analysis. XRD patterns confirmed the integration of crystalline Fe2O₃ nanoparticles with a crystallite size of 19.25 nm within the composite matrix, while SEM-EDS revealed a transformation from a dense chitosan morphology to a highly porous structure in the CS/GO-Fe2O₃ composite enriched with carbon, oxygen, nitrogen, and iron. BET analysis demonstrated a substantially higher surface area than that of conventional adsorbents, increasing from 7.036 m²/g for pure chitosan to 39.946 m²/g for the composite. Adsorption studies identified the optimal conditions at pH 9 and a contact time of 50 minutes. The composite exhibited superior adsorption capacity relative to many reported materials, following the Langmuir isotherm model, which has a maximum adsorption capacity (Qm) of 11.655 mg/g. These findings highlight the composite’s potential as a cost-effective and magnetically separable adsorbent for environmental remediation, offering insights into the design of hybrid materials for organic pollutant removal.
As illustrated in literature, T-OFDM achieved a lower clipping probability and reduces the side-lobe values of the autocorrelation function of the input vector then suppressing the high peak power of the transmitted samples with non-Gaussian distribution. Moreover, the high diversity features of the proposed structure led to substantial improvements in the system performance with frequency selective fading channel. Nevertheless, peak reduction is decreased with the Gaussian distribution of subcarrier numbers, as well as, the in-band distortion is susceptible to non-linearity of high power amplifiers (HPAs). Consequently, the smaller clipping probability and lower block error rate characteristics of T-OFDM are embedded with a new linear companding (LC) technique to construct a structure of T-OFDM-LC system. In the proposed T-OFDM-LC scheme, low-amplitude samples are enlarged, while high-amplitude samples are compressed linearly in the time domain. This linear amplitude transformation is designed to reduce the peak-to-average power ratio (PAPR) while preserving the average power of the transmitted signal. The proposed T-OFDM-LC system acquires preferable achievement in PAPR reduction and spectral regrowth decreasing comparable with the T-OFDM system when using under the negative ramification of HPAs.
The presence of synthetic dyes in industrial wastewater presents a serious environmental threat due to their high chemical stability, toxicity, and resistance to biodegradation. This review provides a comprehensive analysis of recent advancements in the use of modified biochar as a sustainable and cost-effective adsorbent for dye removal from wastewater. Various thermal conversion methods, such as pyrolysis, hydrothermal carbonization, gasification, and torrefaction, are discussed, as they affect biochar properties, including porosity, carbon content, and active functional groups. Furthermore, the review systematically examines physical (e.g., heat treatment and grinding), chemical (e.g., modification with acids, bases, and metals), and biological (e.g., using algae or microorganisms) modification methods to enhance the adsorption capacity and selectivity of biochar. Special attention is given to chemical modifications, such as chitosan and metal impregnation, which have been reported to significantly improve dye removal efficiencies, often exceeding 80%. Various adsorption mechanisms were also analyzed, including physical adsorption, ion exchange, and electrostatic interactions. Moreover, the review highlights the role of surface area, porosity, and functional group composition in improving sorption capacities, alongside recent efforts to model and optimize these processes using artificial intelligence and machine learning. Finally, the modified biochar is an environmentally sustainable option for treating industrial wastewater and achieving circular economy goals.
A miniaturized medical antenna with dual-band operation in the Industrial, Scientific, and Medical (ISM) bands is presented with a low specific absorption rate (SAR) for recommended safety limits. The proposed antenna with dimensions (27.6 mm × 28.2 mm × 0.32 mm) is considered suitable for medical applications. A fractal copper patch, Rogers 3010 biocompatible material, and full ground plane copper are used to get a miniature Antenna design. The research aims to design a compact, biocompatible, and low-SAR medical antenna for implantable and wearable applications. The dual-band antenna uses a fractal copper patch, simulating performance using CST Studio Suite, and optimizing SAR and gain for safety. Different configurations are analyzed for efficiency and medical applications. Low SAR levels were achieved for implantable and wearable designs equal to (0.487, and 0.141 W/kg) and (0.488, and 0.0392 W/kg) for dual bands 0.9 and 2.4 GHz respectively, and Negative gain for safety considerations. The design has been developed into three different forms: implantable, wearable, and capsule design for higher efficiency and more medical applications. The CST studio suite's simulations assessed the antenna's performance using design standards rules and efforts.
Integrated storage solar water heaters (ICS-SWH) are among the simplest and lowest-cost technologies for collecting and storing heat in a single vessel. In the present work, the impact of adding fins within the corrugated storage tank, between the absorber's lower surface and the tank bottom, was experimentally investigated. To increase the heat transfer between the water and the ICS-SWH absorber, an insulated reflective cover was installed on the top of the ICS-SWH to reflect sunlight towards the absorber during the day. At night, it was used as a cover to insulate the glass. The thermal performance of the ICS-SWH was studied under load and without load. The results showed that the highest recorded temperature of the stored water was 67 °C. In contrast, the system's thermal efficiency was 78.5% and 89%, respectively. This result is higher than previous works. A comparison between the present tank (12 cm depth) and the previous work (14 cm) regarding stored water temperature was conducted. The comparison showed that a decrease in the depth of the storage tank by 2 cm led to a 25% increase in the temperature difference.
