Enhanced Absorption Dominated Electromagnetic Interference Shielding Enabled by Carbon Nanotube and Graphene Reinforced Electrospun PVDF Nanocomposite Hisham Bamufleh, Usman Saeed, Abdulrahim Alzahrani, Aqeel Ahmad Taimoor, Sami-ullah Rather, Hesham Alhumade, Walid M. Alalayah, Hamad AlTuraif Polymers, 2026 The increasing density of wireless and wearable electronic devices necessitates the development of lightweight, flexible, and absorption-dominated electromagnetic interference (EMI) shielding materials. In this study, electrospun poly(vinylidene fluoride) (PVDF) composite mats reinforced with carbon nanotubes (CNTs) and graphene nanosheets at low filler loadings (1–3 wt.%) were fabricated and systematically investigated for X-band (8.0–12.5 GHz) EMI shielding performance. Raman, FTIR, and thermal analyses confirm enhanced electroactive β-phase formation and improved thermal stability upon nanofiller incorporation. The formation of interconnected conductive networks within the electrospun fibrous architecture leads to a significant increase in electrical conductivity from 10−7 S·cm−1 for pure PVDF to 10−2 S·cm−1 and 10−1 S·cm−1 for CNT/PVDF and Graphene/PVDF composites, respectively, at 3 wt.% loading. Consequently, the total EMI shielding effectiveness (SET) increases from 2.5 dB for pure PVDF to 40 dB for CNT/PVDF and 42 dB for graphene/PVDF composites at 3 wt.%. The shielding effectiveness arising from absorption (SEA) dominates the overall EMI shielding performance, contributing more than 85% of the total shielding effectiveness (SET), which clearly indicates an absorption-controlled shielding mechanism. The combination of high absorption-dominated EMI shielding, low filler content, and mechanical flexibility highlights these electrospun CNT/PVDF and graphene/PVDF composites as promising candidates for next-generation flexible, wearable, and biomedical EMI shielding applications.
Enhanced Removal of Hexavalent Chromium From Aqueous Solutions Using Locally Activated Saudi Bentonite Clay Saad Al-Shahrani, Aqeel Ahmad Taimoor Journal of Chemistry, 2026 Heavy metal contamination, particularly from chromium, poses significant health risks and environmental challenges due to its prevalence in industrial effluents. This study investigates the effectiveness of activated bentonite clay sourced from Saudi Arabian deposits for the removal of hexavalent chromium (Cr(VI)) in aqueous environments. We focus on optimizing removal efficiency based on key physicochemical parameters, including contact time, adsorbent dosage, and solution pH. Batch adsorption experiments were conducted using a prepared stock solution of chromium at a concentration of 1000 mg/L, diluted to prepare standard Cr(VI) solutions ranging from 20 to 100 mg/L. Results revealed rapid uptake of chromium ions by Saudi‐activated bentonite, achieving equilibrium within 30 min. However, higher initial chromium concentrations led to a decline in removal efficiency due to saturation of active sites on the bentonite surface. Additionally, the study demonstrated pH‐dependent adsorption behavior, with decreasing pH enhancing chromium removal. Equilibrium data fitted well with both the Langmuir and Freundlich isotherm models with maximum adsorption capacity q max ≈ 156 mg/g, while kinetic studies indicated that the adsorption process adhered to a pseudosecond‐order model with kinetic constant in order of hundredths.
Transforming Waste to Innovation: Sustainable Piezoelectric Properties of Pb(Ti0.52Zr0.48)O3with Recycled β-PbO Massicot Amna Idrees, Gwangseop Lee, Hamid Jabbar, Muhammad Siyar, Muhammad Zubair Khan, Farah Mumtaz, Aqeel Ahmad Taimoor, Awais Ahmad, Tauseef Ahmed, Jung-Hyuk Koh, Mohsin Saleem ACS Omega, 2025 High Resolution Image Download MS PowerPoint Slide In this study, we present an indigenous approach to enhancing the properties of Pb(Zr 0.52 Ti 0.48 )O 3 by synthesizing it from β-PbO obtained from spent lead-acid batteries. Initially, β-PbO, orthorhombic massicot, was produced by two-step heating, and 99.9% lead powder was derived from recovered lead-acid batteries at 700 °C. The synthesized β-PbO was thoroughly analyzed using X-ray diffraction, field emission scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy. Subsequently, the β-PbO precursor was utilized for the synthesis of PZT, offering a cost-effective alternative. The morphology of the sintered sample revealed the formation of homogeneous and uniform grains, indicative of significant densification (∼99%) of the ceramic. The sintered PZT exhibited an enhanced piezoelectric coefficient ( d 33 ) of 270 pC/N, a Q m factor of 30.94, and a dielectric constant of 1590 at ∼10 kHz. This study highlights the feasibility of using β-PbO derived from recycled lead ingots to synthesize materials, presenting a sustainable approach that contributes to technological progress and environmental conservation.
Multiwalled Carbon Nanotube Reinforced Electrospun Biodegradable Polybutylene Succinate: Electromagnetic Shielding, Thermal and Mechanical Properties Usman Saeed, Hisham Bamufleh, Abdulrahim Alzahrani, Aqeel Ahmad Taimoor, Sami Ullah Rather, Hesham Alhumade, Walid M. Alalayah, Hamad AlTuraif Polymers, 2025 An environmentally friendly biodegradable and flexible polymer with exceptional mechanical, thermal and electromagnetic interference shielding is urgently needed to reduce environmental pollutants and electromagnetic waves to preserve human health. The paper presents our study where we developed biodegradable electrospun nanocomposite by employing polybutylene succinate (PBS) with multiwalled carbon nanotubes (MWCNTs). The crystallization temperature Tc and melting temperature Tm of electrospun PBS/MWCNT composites with 3 wt% of MWCNTs was increased noticeably by 4 °C and 5 °C. The tensile strength increased by about 2.61 ± 0.15 MPA and the elastic modulus increased by about 0.72 ± 0.02 GPa with the addition of 3% MWCNT in polybutylene succinate. The increase in MWCNT content from 0.5 to 3 wt% led to an enhanced storage modulus and electrical properties 5 to 8 times higher in comparison to PBS. Moreover, the MWCNT was tested in different concentrations in PBS for electromagnetic interference shielding (EMI) and the most applicable results were obtained when the MWCNT was 3% which is capable of providing 25.5 db EMI shielding efficiency. The percolation threshold capability of PBS/MWCNT electrospun nanocomposites was 0.94 wt% and has significant entanglement of the MWCNTs and MWCNT network in the PBS matrix for conductive pathways. The study offers a viable process for creating an electrospun PBS/MWCNT composite that is lightweight, biodegradable and has exceptional electromagnetic shielding capabilities.
Evaluating the ionic liquids, commercial solvents, and pressure-swing for efficient azeotropic separation Ammar Abbas Ali Saif, Aqeel Ahmad Taimoor, Saad Al-Shahrani, Usman Saeed, Sami-Ullah Rather, Majed A. Alamoudi Chemical Product and Process Modeling, 2025 Techniques like extractive distillation and pressure swing distillation (PSD) have been commercially developed to separate azeotropic mixtures. Extractive distillation using conventional solvents offers advantages in achieving high purity levels, but challenges include difficulty in solvent recovery, increased energy consumption, higher costs, and potential negative environmental impact. Selecting appropriate solvents is a challenging task with potential compromises. PSD manipulates pressure to overcome azeotropic points without an entrainer, offering solvent-free operation. Ionic liquids may provide an alternative to conventional solvents in extractive distillation. Five imidazolium, ammonium and pyridinium based ILs have been chosen to investigate their impact on the separation of the selected azeotropic mixtures. The three techniques are employed for seven different (model) azeotropic mixtures to evaluate the commercial feasibility of each process by comparing energy requirements and Total Annual Cost (TAC). Aspen Plus software has been employed to perform a comparison simulation among the processes. This benchmark analysis and process simulation can aid in evaluating the efficacy and feasibility of the possible optimum commercial process in separation. There is no one-size-fits-all technique that provides the best cost-effective and energy-efficient process for every azeotropic separation.
An Experimental and Theoretical Carbon Dioxide Capture-Based Investigation of Methyltrioctylammonium Trifluoromethanesulfonate Ionic Liquid Hisham S. Bamufleh, Sami-ullah Rather, Aqeel Taimoor, Usman Saeed, Faheem A. Sheikh, Arshid M. Ali, Yahia A. S. AlHamed, Walid M. Alalayah, Ayaz Mohamad Nawaz International Journal of Energy Research, 2025 An alarming elevation of anthropogenic carbon dioxide (CO2), primarily responsible for global warming and its drastic effects on climatic conditions, must be challenged on a priority basis. Various types of absorbents capture as much CO2 as possible to minimize the harsh effects of environmental and climatic changes. In this study, one such compound, methyltrioctylammonium trifluoromethanesulfonate ionic liquid (IL), was analyzed experimentally and theoretically. The COSMO‐RS, a type of conductor‐like screening model, is an advanced fast method to predict the thermo‐physical properties of IL. It depends upon unimolecular, statistical thermodynamics, molecular structure, and conformation, which provides the required information for estimating interactions in ILs. The COSMO‐RS, not dependent on data, coefficients, or parameters, was used to calculate the sigma surface, profile, and potential. These parameters are crucial for predicting high‐absorbing CO2 materials, such as ILILs. Spectroscopic methods, such as Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1H NMR), and carbon‐13 NMR (13C NMR), verified the structure confirmation. In addition, spectrochemical characterization of the IL was performed using FTIR, NMR, ultraviolet–visible (UV–Vis) spectroscopy, and fluorescence. The thermal integrity of IL was measured by thermogravimetric–differential thermal analysis (TGA‐DTA) over the temperature range of 323–773 K in an oxygen ambiance with a ramp rate of 283 K/min. Due to its high potential for gas absorption, as confirmed by COSMO‐RS calculations, IL was investigated for CO2 absorption and desorption studies at 298 K and 4.5 MPa. The maximum CO2 absorption obtained was ~ 6.0 mmol/g, performed at similar experimental conditions. The high uptake of CO2 might be due to fluorinated anions, as CO2 has a high affinity for fluoroalkyl groups. According to a hysteresis‐based classification, the hysteresis formation during CO2 absorption and desorption follows type H3, indicating the presence of both microporous and mesoporous characteristics in the sample. A detailed study of the excess Gibbs energy of sorption and the activity coefficient of the IL indicates a strong sorption capacity under moderate conditions.
Carbon Dioxide Capturing in Temperature/Pressure Swing-Commercial Processes Using Ionic Liquids Sami‐ullah Rather, Aqeel Ahmad Taimoor, Usman Saeed, Muhammad Ehtisham Siddiqui, Hisham S. Bamufleh Chemical Engineering and Technology, 2024 Capturing carbon dioxide is vital for mitigating global warming and supporting chemical processes. Ionic liquids (ILs) have emerged as promising solvents for CO2 capture. Using ASPEN simulation software, this study explores three specific ILs: [emim][triflate], [bmim][MeSO3], and [bmim][NTf2]. Their selection is based on exploitable differences in energy. The study models CO2 solubility and validates it against published data. It also considers the decomposition of ILs using a more accurate vapor loss model. Simulated equations predict CO2 and IL behavior more accurately than published ASPEN studies, optimizing the process for minimal energy consumption. Commercial considerations and rigorous engineering calculations guide the analysis, encompassing energy and economic factors.
Selection of Organic Fluid Based on Exergetic Performance of Subcritical Organic Rankine Cycle (ORC) for Warm Regions Muhammad Ehtisham Siddiqui, Eydhah Almatrafi, Usman Saeed, Aqeel Ahmad Taimoor Energies, 2023 The organic Rankine cycle (ORC) exhibits considerable promise in efficiently utilizing low-to-medium-grade heat. Currently, there is a range of organic fluids available in the market, and selecting the appropriate one for a specific application involves considering factors such as the cycle’s thermodynamic performance, plant size, and compatibility with turbomachinery. The objective of our study is to examine the exergetic performance of the ORC with internal heat regeneration. We analyze 12 different organic fluids to evaluate their suitability based on parameters like exergy efficiency and heat exchange area requirements. Additionally, we investigate the need for internal heat regeneration by comparing the overall exergy performance with a simpler ORC configuration. To ensure broad applicability, we consider source temperatures ranging from 150 to 300 °C, which are relevant to industrial waste heat, geothermal sources, and solar energy. For each case, we calculate specific net power output and the UA value (heat exchanger conductance) to gain insights into selecting the appropriate organic fluid for specific source temperatures. Cyclohexane, benzene, isopropyl alcohol, and hexafluorobenzene show poor exergy efficiency due to their high boiling points. Pentane and cyclopentane provides the highest exergy efficiency of 62.2% at source temperature of 300 °C, whereas pentane is found to be the most suitable at source temperatures of 200 and 150 °C with exergy efficiency of 67.7% and 61.7%, respectively. At 200 °C source temperature, RE347mcc achieves 65.9% exergy efficiency. The choice of organic fluid for a given heat source is highly influenced by its critical properties. Moreover, the normal boiling temperature of the organic fluid significantly impacts exergy destruction during the condensation process within the cycle.
Electrocatalytic Hydrogenation of CO2 to Hydrocarbons on Gold Catalyst in the Presence of Ionic Liquid Journal of the Chemical Society of Pakistan, 2021