Search Results (173)

In the Arabian Gulf region, saltwater desalination is considered to be a significant process in producing clean water. This paper presents a sustainable, combined process for upgrading a Doha reverse osmosis (RO) plant in Kuwait. A pilot-scale microbial desalination cell (MDC) stack is proposed as a pre-treatment unit prior to the RO process in order to improve plant performance. A cost–benefit analysis is conducted for the combined system to emphasize the significance of the MDC–RO process. In RO, the expected energy consumption is 2.6–13 kWh per m³ of desalinated water, whereas using MDC can reduce this to about 0.52–5.3 kWh/m³. Moreover, this new technology using catalytic MDCs can help in improving electric current production and reducing the amount of rejected brine and membrane fouling in the RO process. The electric current is improved by reducing MDCs’ internal resistance using a reduced graphene oxide/polyaniline composite-coated stainless steel mesh cathode electrode. Layer-by-layer electro-deposition can be applied to achieve these coatings. An intermediate zeolite filter is proposed to mitigate RO membrane fouling. The combined system’s natural zeolite-membrane filter improves water purification. In this study, we assessed the combined MDC–RO process for upgrading the Doha plant’s performance in terms of quality, cost, and time. The suggested catalytic MDC, using efficient, low-cost materials as cathode electrodes with an equivalent daily cost of 0.01 USD/m³ and a desalination efficiency of about 40%, acts as an alternative to high-cost platinum metal electrodes. The results also indicate that the equivalent daily cost of energy consumption using the MDC process is about 0.03 USD/m³, whereas the investment cost is about 0.4 USD/m³ daily for one year of cell operation. Full article

This study presents the rational design of a visible-light-responsive TiO₂/polyaniline (PANI) nanofiber heterostructure via in situ oxidative polymerization to overcome the limited visible-light absorption and rapid charge recombination of TiO₂. Comprehensive characterization using XRD, FT-IR, XPS, SEM, UV–Vis DRS, and EIS confirmed the successful integration of TiO₂ nanoparticles within a conductive polyaniline nanofiber network, enabling efficient interfacial charge transfer. The optimized TiO₂/PANI-30 composite exhibited outstanding photocatalytic performance, achieving ~99% degradation of Basic Fuchsin dye within 40 min under visible light, significantly outperforming pristine TiO₂. The enhanced activity is attributed to improved visible-light absorption, reduced bandgap energy, and suppressed electron–hole recombination, supported by optical and electrochemical analyses. Kinetic studies indicated pseudo-first-order behavior, with TiO₂/PANI-30 showing the highest rate constant. Radical trapping experiments identified superoxide and hydroxyl radicals as the main active species, with •OH playing a dominant role. A direct Z-scheme charge transfer mechanism was suggested, preserving strong redox potentials and promoting reactive oxygen species generation. Additionally, the photocatalyst demonstrated excellent stability and reusability. These findings highlight the suggested potential of TiO₂/PANI systems as efficient and sustainable photocatalysts for wastewater treatment. Full article

In the pursuit of sustainable and flexible electronics, polymer-based conductive films offer a promising solution due to their biodegradability, mechanical flexibility, and cost-effective fabrication. This study presents the development of a highly conductive and flexible nanocomposite material based on polyaniline-grafted chitosan (PANI-g-Chs) and Vinavil (Vi, a vinyl glue specifically designed for enhancing the sealability of textiles and paper), serving as a matrix for applications in flexible electronics. The PANI-g-Chs nanocomposite was synthesized via in situ oxidative polymerization, where chitosan nanoparticles (Chs) served as a stabilizing template to prevent PANI aggregation, reducing the particle size from 1700 nm (pristine PANI) to 180 nm (PANI-g-Chs). The resulting composite exhibited exceptional electrical conductivity (77.79 S/m at 25 wt% PANI-g-Chs). Hall effect measurements showed that the carrier mobility increased up to 1162.7 cm²/V·s and the carrier density rose to 6.5.1017 cm⁻³, confirming efficient charge transport and network formation. Mechanical analysis revealed a 300% increase in the storage modulus for PANI-g-Chs, and thermal studies confirmed stability up to 300 °C. Optical characterization showed a reduced bandgap (3.6 eV) and extended π-conjugation, which are critical for optoelectronic applications. Application tests demonstrated stable conductivity under mechanical deformation, highlighting the material’s potential for use in flexible electronics, sensors, and sustainable conductive coatings. This work offers a viable alternative to conventional conductive polymers. Full article

This study presents the successful electrodeposition of polyaniline (PANI) and TiO₂/PANI composites on boron-doped diamond (BDD) and fluorine-doped tin oxide (FTO) substrates via cyclic voltammetry. Using 20 scan cycles in 0.5 M H₂SO₄, we synthesized thin films with tailored electrochemical properties. The formation of PANI was confirmed by characteristic redox peaks in the voltammograms, while FTIR spectroscopy identified key functional groups and bonding interactions between TiO₂ and PANI. Morphological analysis via optical and scanning electron microscopy revealed uniform but cracked surfaces influenced by TiO₂ loading. Composite electrodes with molar ratios of 2:1, 4:1, and 6:1 (TiO₂:PANI) were compared, showing increased titanium content with higher ratios, as confirmed by EDS. This work offers a reproducible route for designing modified electrodes with enhanced interfacial properties. Full article

Magnesium-sulfur (Mg-S) batteries present a compelling energy storage solution, characterised by their remarkable theoretical energy density and economic viability. Nonetheless, challenges arise, including swift capacity degradation and suboptimal polysulfide (acting as an electronic and ionic insulator) utilisation, mainly due to a phenomenon known as the polysulfide “shuttle effect.” This effect also leads to a decline in battery performance. The Becke, 3-parameter, Lee-Yang-Parr (B3LYP) functional and 6-311G (d,p) basis set were used to examine the optoelectronic and charge-transfer properties of a polyaniline-pyrrole (PANIPyr) composite, emphasising interatomic and electronic interactions that enhance charge transport and oxidation of MgS₂. The findings demonstrate the presence of coordination bonding between hydrogen in pyrrole and the N⁻ ion in quinonediimine of polyaniline, significantly enhancing the electrical properties of PANI. The PANIPyr_P1 (P1-pyrrole attached at position one) configuration exhibits the lowest Ɛ_gap and the highest charge-transfer capacity, compared to other studied molecules in this work, thereby improving reactivity towards polysulfides in comparison to pure PANI. Significant electrical interactions at this site establish accessible electrophilic and nucleophilic regions that stabilise the ionic sides of the polysulfides, thus reducing the shuttle effect and improving charge transport at the interface. PANIPyr_P1 demonstrates viability for minimising polysulfide migration and enhancing cathodic efficiency in Mg-S batteries, thereby laying a foundation for future investigations into polymer-based cathode modifiers. Full article

Lead (Pb) contamination in water poses a significant threat to both human health and the environment as it is toxic even at very minimal concentrations. In the scope of this study, a novel magnetic composite material, AC/Fe₃O₄/PANI-SDS, was synthesized to efficiently eliminate Pb²⁺ ions from polluted water. Each component of the composite has a significant impact: the activated carbon provides a large surface area for adsorption, the magnetic iron oxide (Fe₃O₄) allows easy magnetic recovery from water systems using a magnet, and the polyaniline (PANI) and sodium dodecyl sulfate (SDS) improve the capability of the material to attract and hold onto Pb²⁺ ions. To assess the surface, magnetic, and structural properties of the prepared material, several characterization techniques were applied, such as FTIR, XRD, SEM-EDS, BET analysis, VSM, and zeta potential measurements. These tests confirmed that the composite has the right structure and functional groups to perform as a capable and efficient adsorbent. Batch adsorption studies were used to evaluate the effects of pH, interaction time, initial Pb²⁺ ion concentration, and temperature on removal efficiency. The findings highlight the composite’s remarkable adsorption efficiency after 220 min under optimal conditions, specifically at pH 6. Adsorption kinetic studies demonstrated strong agreement with the pseudo-second-order model, while isotherm analysis showed that the Langmuir model provided the highest correlation coefficient within the investigated concentration range. This fitting suggested apparent Langmuir-type adsorption behavior, with a maximum adsorption capacity of 348.39 mg/g. Thermodynamic assessment demonstrated that the elimination of Pb²⁺ ions is an endothermic and spontaneous process. In addition, the composite can be reused and recycled repeatedly without significantly reducing its effectiveness, offering an economical and ecologically sustainable approach. The findings of this research highlight the potential of the AC/Fe₃O₄/PANI-SDS composite as a new, efficient, and eco-friendly adsorbent for the elimination of Pb²⁺ ions from solutions. In real-world applications, its high capacity for adsorption, ease of separation, and reusability make it a promising treatment for heavy metal contamination. Full article

A novel ternary nanocomposite, comprising reduced graphene oxide/polyaniline/gadolinium oxide (RGO-PANI-Gd₂O₃), was successfully synthesized using the Hummers method, followed by in situ emulsion polymerization of polyaniline. The final composite was produced by hydrothermally adding gadolinium nitrate. The composite was subjected to a systematic analysis that included optical, microstructural, physical, and Raman spectroscopic analysis, as well as current-voltage (J-V) measurements. The morphology of this composite material was investigated using scanning electron microscopy (SEM). The addition of Gd₂O₃ nanoparticles decreases the band gap energy from 3.5 eV (PANI) to 2.7 eV (RGO-PANI-Gd₂O₃). The UV–Vis spectra revealed a redshift in the π-π* transition peak from 318 nm (PANI) to 346 nm, indicating increased conjugation length and synergistic effects. This eco-friendly material has excellent catalytic activity for triiodide reduction. The manufactured counter-electrode (CE) demonstrated remarkable transparency and conversion efficiency comparable to platinum, with a current density of 11.7 mA·cm⁻² versus 8.2 mA·cm⁻² for platinum. Under simulated solar light (AM 1.5 G, 100 mW·cm⁻²), the RGO-PANI-Gd₂O₃ based nanocomposite CE achieved an excellent 4.3% photo conversion efficiency. These findings indicate that RGO-PANI-Gd₂O₃ nanocomposites have potential as efficient, platinum-free counter electrodes in dye-sensitized solar cells (DSSCs). Full article

Polyaniline (PANI), characterized by its proton-coupled redox mechanism and multicolor reversibility, is widely investigated for adaptive optical interfaces. Compared to inorganic oxides, PANI offers advantages in cost-effectiveness, mechanical flexibility, and molecular tunability; however, its practical implementation faces challenges related to kinetic limitations and environmental instability. This review presents a comprehensive analysis of PANI-based electrochromic materials, examining the intrinsic correlations among synthesis methodologies, microstructural characteristics, and optoelectronic performance. Synthesis strategies, including chemical oxidative polymerization, electrochemical deposition, and template-assisted techniques, are evaluated. Emphasis is placed on resolving the trade-off between optical contrast and switching kinetics by constructing high-surface-area porous nanostructures and inducing chain ordering via functional dopants to shorten ion diffusion paths and reduce charge transfer resistance. Fundamental electrochromic properties are subsequently discussed, with specific attention to degradation mechanisms triggered by environmental factors, such as pH drift, and stabilization strategies involving electrolyte engineering and composite design. Furthermore, the review addresses the evolution of applications from single-band monochromatic displays to dual-band smart windows for decoupled visible/near-infrared regulation and multifunctional integrated systems, including electrochromic supercapacitors and adaptive thermal management textiles. Finally, technical challenges regarding long-term durability, neutral color development, and large-area manufacturing are summarized to outline future research directions for PANI-based optical systems. Full article

The development of implantable neural interfaces is essential for enabling bidirectional communication between the nervous system and prosthetic devices, yet their evaluation still relies primarily on in vivo models which are costly, variable, and ethically constrained. Here, we report a bio-inspired artificial nerve simulator engineered as a reproducible ex vivo platform for pre-implantation testing of plug-type electrodes. The simulator is fabricated from a conductive hydrogel composite based on reduced graphene oxide (rGO), polyaniline (PANI), agarose, sucrose, and sodium chloride, with embedded conductive channels that replicate the fascicular organization and conductivity of peripheral nerves. The resulting construct exhibits impedance values of ~2.4–2.9 kΩ between electrode needles at 1 kHz, closely matching in vivo measurements (~2 kΩ) obtained in Sus scrofa domesticus nerve tissue. Its structural and electrical fidelity enables systematic evaluation of electrode–nerve contact properties, signal transmission, and insertion behavior under controlled conditions, while reducing reliance on animal experiments. This bio-inspired simulator offers a scalable and physiologically relevant testbed that bridges materials engineering and translational neuroprosthetics, accelerating the development of next-generation implantable neural interfaces. Full article

The present study explores the comparative influence of reduced graphene oxide (rGO), silver nanowires (AgNWs), and their hybrid rGO–AgNWs on the electromagnetic interference (EMI) shielding performance of polyaniline (PANI)-based flexible films prepared using a polycaprolactone (PCL) matrix. The nanocomposites were synthesized through in situ oxidative polymerization of aniline in the presence of individual or hybrid fillers, followed by their dispersion in the PCL matrix and casting of the corresponding films. Morphological and structural characterization (SEM, Raman, and FTIR spectroscopy) confirmed a uniform PANI coating on both rGO sheets and AgNWs, forming hierarchical 3D conductive networks. Thermal (TGA) and thermomechanical (TMA) analyses revealed enhanced thermal stability and stiffness across all composite systems, driven by strong interfacial interactions and restricted polymer chain mobility. Tmax increased from 437.9 °C for neat PCL to 487.9 °C for PANI/PCL, 480.6 °C for PANI/rGO/PCL, 499.4 °C for PANI/AgNWs/PCL and 495.0 °C for the hybrid PANI/rGO–AgNWs/PCL film. The gradual decrease in contact angle following the order PANI/AgNWs/PCL < PANI/rGO–AgNWs/PCL < PANI/rGO/PCL < PANI/PCL < PCL clearly indicates a systematic increase in surface polarity and surface energy with the incorporation of conductive nanofillers. Electrical conductivity reached 60.8 S cm⁻¹ for PANI/rGO/PCL, gradually decreasing to 27.4 S cm⁻¹ for PANI/AgNWs/PCL and 22.1 S cm⁻¹ for the quaternary hybrid film. The EMI shielding effectiveness (SET) measurements in the X-band (8–12 GHz) demonstrated that the PANI/rGO/PCL film exhibited the highest attenuation (~7.2 dB). In contrast, the incorporation of AgNWs partially disrupted the conductive network, reducing SE to ~5–6 dB. The findings highlight the distinct and synergistic roles of 1D and 2D fillers in modulating the electrical, thermal, and mechanical properties of biodegradable polymer films, offering a sustainable route toward lightweight, flexible EMI shielding materials. Full article

We present a flexible pH sensor which leverages the unique properties of reduced graphene oxide/polyaniline (rGO/PANI) composite films through an efficient and scalable hybrid microfabrication approach, wherein the rGO/PANI films are conformally coated on flexible polyethylene terephthalate (PET) substrates via dip-coating and thereafter lithographically patterned into precise arrays of interdigitated electrodes (IDEs), serving both as the pH-active medium and the electrical interface. Upon dip-coating, a thermal reduction process is performed to yield uniform rGO/PANI composite layers on PET substrates, where the PANI content is adjusted to 20% to optimize conductivity and protonation-driven response. Composition optimization is first performed using inkjet-printed silver (Ag) contacts and a conductometric readout mechanism is employed to explore pH-dependent behavior. Subsequently, IDE arrays are defined in the rGO/PANI using photolithography and oxygen-plasma etching, demonstrating clean pattern transfer and dimensional control on flexible substrates. Eliminating separate contact metals in the final design simplifies the stack and reduces cost. A set of IDE geometries is evaluated through I–V measurements in buffers of different pH values, revealing a consistent, monotonic change in electrical characteristics with pH and geometry-tunable response. The present study demonstrated that the most precise pH measurement was achieved with an 80:20 rGO/PANI composition within the pH 2–10 range. These results establish rGO/PANI IDEs as a scalable route to low-cost, miniaturized, and mechanically compliant pH sensors for field and in-line monitoring applications. Full article

In this work, the effect of aqueous dispersions of graphene oxide (GO) and nanosized graphene oxide (nGO) on the enzymatic polymerization of polyaniline (PANI) was studied. The enzymatic polymerization of PANI was carried out in aqueous medium using toluenesulfonic acid (TSA) as the dopant, horseradish peroxidase (HRP) as the catalyst, and hydrogen peroxide (H₂O₂) as the oxidant, using 1.0, 2.5, and 5.0 wt% of GO and nGO. The morphology of PANI-GO/nGO composites was studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Further characterization was performed by thermogravimetric analysis (TGA) and spectroscopic techniques such as ultraviolet–visible (UV–Vis), Fourier-transform infrared (FTIR), Raman and X-ray photoelectronics (XPS). SEM images showed that during enzymatic polymerization, PANI completely covers the GO/nGO sheets. Furthermore, physicochemical results confirmed the production of a hybrid PANI-GO/nGO material with Van der Waals-type interactions between the oxygen-based functional groups of GO and the secondary amino bond (-NH-) of PANI. Also, cyclic voltammetry experiments were carried out in situ during the polymerization of PANI-GO/nGO films. The electrochemical response of PANI-GO/nGO composites reflects two broad oxidation peaks around 300 mV and 500 mV during anodic scanning, with reversible oxidation during cathodic scanning. Classical molecular dynamics simulations were used to understand the mechanism of the composite film’s growth. Full article

Polyaniline (PANI), as a classical conducting polymer, has attracted significant attention in the field of energy storage due to its low cost, facile synthesis, environmental stability, and unique dual electronic/ionic conductivity. Particularly, one-dimensional (1D) nanostructures of PANI, such as nanowires and nanorods, exhibit superior electrochemical performance and cycling stability, attributed to their high surface area and efficient charge transport pathways. This review provides a comprehensive summary of recent advances in 1D PANI-based anode materials for lithium-ion, sodium-ion, and other types of rechargeable batteries. The specific capacity, rate performance, and long-term cycling behavior of these materials are discussed in detail. Moreover, strategies for performance enhancement through combination with carbon materials, metal oxides, and silicon, as well as chemical doping and structural modification, are systematically reviewed. Key challenges including electrochemical stability, structural durability, and large-scale fabrication are analyzed. Finally, the future directions in structural design, composite engineering, and commercialization of 1D PANI anode materials are outlined. This review aims to provide insight and guidance for the further development and practical application of PANI-based energy storage systems. Full article

Effective glucose monitoring is paramount for patients with diabetes to effectively manage their condition and prevent health complications. Electrochemical sensors for glucose monitoring have key advantages over other systems, including cost-effectiveness, miniaturisation and portability, enabling the design of compact and wearable devices. Typically, enzymes are used in these sensors, with the limitations of poor stability and high cost. In alternative, this study reports the development of a gold and platinum composite nanostructured electrode and its testing as an abiotic (enzyme-free) electrocatalyst for glucose oxidation. The electrode consists of a film of highly porous gold electrodeposited onto gold-plated electrodes on a printed circuit board (PCB), which is coated with polyaniline decorated with platinum nanoparticles. The resulting nanocomposite structure shows a sensitivity towards glucose as high as 95.12 ± 2.54 µA mM⁻¹ cm⁻², nearly twice that of the highly porous gold electrodes, and excellent stability in synthetic interstitial fluid over extended testing, thus demonstrating robustness. Accordingly, this study lays the groundwork for the next generation of durable, selective, and affordable abiotic glucose biosensors. Full article

This study focuses on developing FeNiS/PANI composites for supercapacitor applications, leveraging the individual benefits of iron–nickel sulfide (FeNiS) and polyaniline (PANI). FeNiS offers high electrical conductivity and energy density, while PANI contributes enhanced flexibility and pseudocapacitive behavior. The goal is to create a composite with superior electrochemical performance. Synthesis involved chemical oxidative polymerization for PANI and an in situ method for FeNiS, followed by integration. Characterization techniques like XRD, SEM, and EDS confirmed the successful formation and homogeneous elemental dispersion of the composite, showing that PANI formed an interconnected network that improved charge transport. Electrochemical analysis demonstrated significant improvements. Cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) tests revealed that the FeNiS/PANI composite exhibited a doubled discharge time (159 s vs. 72 s for FeNiS) and a higher specific capacitance (113.5 F/g vs. 51.42 F/g). These results highlight the promise of FeNiS/PANI as an advanced material for efficient and sustainable energy storage. Full article