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We further simplify the most ‘user-friendly’ potentiometric sensor for waterborne analytes, the ‘extended-gate field effect transistor’ (EGFET). This is accomplished using a ‘bridge’ design, that links two separate water pools, a ‘control gate’ (CG) pool and a ‘floating gate’ (FG) pool, by a bridge filled with agar-agar hydrogel. We show electric communication between electrodes in the pools across the gel bridge to the gate of an LND150 FET. When loading the gel bridge with a sorbent that is known to act as a sensitiser for Cu2+ water pollution, namely, the ion exchanging zeolite ‘clinoptilolite’, the bridged EGFET acts as a potentiometric sensor to waterborne Cu2+. We then introduce novel sensitisers into the gel bridge, the commercially available resins PurometTM MTS9140 and MTS9200, which are sorbents for the extraction of mercury (Hg2+) pollution from water. We find a response of the bridged EGFET to Hg2+ water pollution, setting a template for the rapid screening of ion exchange resins that are readily available for a wide range of harmful (or precious) metal ions. We fit the potentiometric sensor response vs. pollutant concentration characteristics to the Langmuir–Freundlich (LF) model which is discussed in context with other ion-sensor characteristics.

In this study, polypyrrole-based activated carbon was prepared by the carbonization of polypyrrole at 650 °C for 2 h in the presence of four-times the mass of KOH as a chemical activator. The structural and morphological properties of the product (polypyrrole-based activated carbon (PPyAC4)), analyzed by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and thermogravimetric analysis, support its applicability as an adsorbent. The adsorption characteristics of PPyAC4 were examined through the adsorption of lead ions from aqueous solutions. The influence of various factors, including initial ion concentration, pH, contact time, and adsorbent dose, on the adsorption of Pb2+ was investigated to identify the optimum adsorption conditions. The experimental data fit well to the pseudo-second-order kinetic model (R2 = 0.9997) and the Freundlich isotherm equation (R2 = 0.9950), suggesting a chemisorption pathway. The adsorption capacity was found to increase with increases in time and initial concentration, while it decreased with an increase in adsorbent dose. Additionally, the highest adsorption was attained at pH 5.5. The calculated maximum capacity, qm, determined from the Langmuir model was 50 mg/g.

In the present work, a nitrogen-rich activated carbon (PAnAC) was prepared using polyaniline (PAn) as a precursor to represent one possible conversion of nitrogen-containing polymeric waste into a valuable adsorbent. PAnAC was fabricated under the chemical activation of KOH and a PAn precursor (in a 4:1 ratio) at 650 °C and was characterized using FTIR, SEM, BET, TGA, and CHN elemental composition. The structural characteristics support its applicability as an adsorbent material. The adsorption performance was assessed in terms of adsorption kinetics for contact time (0–180 min), methyl orange (MO) concentration (C0 = 50, 100, and 200 ppm), and adsorbent dosages (20, 40, and 80 mg per 250 mL batch). The kinetic results revealed a better fit to a pseudo-second-order, specifically nonlinear equation compared to pseudo-first-order and Elovich equations, which suggests multilayer coverage and a chemical sorption process. The adsorption capacity (qe) was optimal (405.6 mg/g) at MO C0 with PAnAC dosages of 200 ppm and 40 mg and increased as MO C0 increased but decreased as the adsorbent dosage increased. The adsorption mechanism assumes that chemisorption and the rate-controlling step are governed by mass transfer and intraparticle diffusion processes.

The adsorption of methyl orange (MO) from aqueous solutions onto a KOH-activated polypyrrole-based adsorbent (PACK) was investigated using batch and fixed-bed column techniques. The structural, thermal, and morphological properties of the PACK, analyzed by various methods, support its applicability as an adsorbent. An adsorption kinetic study revealed a preferably pseudo-second-order (R2 = 0.9996) and rate-limiting step controlled by both film and intra-particle diffusions. The thermodynamic adsorption tests resulted in negative ΔG°, ΔH°, and ΔS° values, which decreased as the temperature and concentration increased, indicating the spontaneous and exothermic adsorption over 25–45 °C. The adsorption isotherms fit the experimental data in the order of Langmuir ≈ Freundlich > Temkin, with evidence of adsorption operating well via the monolayer physical adsorption process, and maximum monolayer adsorption ranging from 520.8 to 497.5 mg/g. The breakthrough curve of the fixed-bed column experiment was modeled using the Thomas, Yoon–Nelson, and Hill models, resulting in an equilibrium capacity of 57.21 mg/g. A 73% MO recovery was achieved, indicating the possibility of column regeneration. Compared to other adsorbents reported, PACK had comparable or even superior capacity toward MO. For cost-effectiveness, similar nitrogen-containing polymeric wastes could be exploited to obtain such excellent materials for various applications.

In this paper, tri-phase Fe 2 O 3 –MgO–CuO nanocomposites (NCs) and pure CuO, Fe 2 O 3 and MgO nanoparticles (NPs) were prepared using sol–gel technique. The physical properties of the prepared products were examined using SEM, XRD, and UV–visible. The XRD data indicated the formation of pure CuO, Fe 2 O 3 and MgO NPs, as well as nanocomposite formation with Fe 2 O 3 (cubic), MgO (cubic), and CuO (monoclinic). The crystallite size of all the prepared samples was calculated via Scherrer's formula. The energy bandgap of CuO, Fe 2 O 3 and MgO and Fe 2 O 3 –MgO–CuO NCs were computed from UV–visible spectroscopy as following 2.13, 2.29, 5.43 and 2.96 eV, respectively. The results showed that Fe 2 O 3 –MgO–CuO NCs is an alternative material for a wide range of applications as optoelectronics devices due to their outstanding properties.

The aim of this work was to biosynthesize SnO2-decorated ZnO (ZT) nanocomposites (NCs) of different Sn content (10, 20, and 30 mol%), namely, ZT10, ZT20, and ZT30, using Olea europaea leaf aqueous extract-based phytocompounds as nanoparticle facilitating agents for application as effective photocatalyst in the removal of dyes from polluted water. The obtained ZT NCs were characterized using various techniques, including FTIR, XRD, TGA, TEM, EDS, UV–Vis, PL, and BET surface area. X-ray diffraction patterns show that rutile SnO2 and hexagonal ZnO coexist in the composites, and their crystallite size (D) is affected by the SnO2 ratio; the obtained D-values were 17.24, 19.07, 13.99, 6.45, and 12.30 nm for ZnO, SnO2, ZT10, ZT20, and ZT30, respectively. The direct band gaps of the ZT heterostructure increase with increasing SnO2 ratio (band gap = 3.10, 3.45, 3.14, 3.17, and 3.21 eV, respectively). TEM spectroscopy revealed nanorod and spherical grain morphologies of the composites, while EDS confirmed the elemental composition, the element ratio, and the composite’s purity. All catalysts exhibit type III isotherm with macropore structure. The photocatalytic efficiency against cationic (methylene blue (MB), rhodamine B (RB)), and anionic (methyl orange (MO)) dyes, under sunlight, was optimal with ZT20. The results revealed almost complete degradation at 55, 65, and 55 min, respectively. Hence, it is evident that incorporating SnO2 improves the photocatalyst’s performance, with an apparent optimal enhancement at 20 mol% Sn decorating ZT NCs. More interestingly, the catalyst stability and activity remained unaffected even after four activating cycles.

The green synthesis of zinc sulfide nanoparticles (ZnS NPs)-mediated plant extract is gaining importance because of its simplicity, cost-effectiveness, and ecofriendly nature. In this work, ZnS NPs were synthesized using garlic extract as NPs facilitating agent, characterized by Fourier transform infrared, X-ray diffraction, scanning electron microscope, and UV–visible, then their antibacterial and hemocompatibility were assayed. Analysis revealed a cubic phase, 2.33 nm crystallite size, and a 3.75 eV optical bandgap. Bioactivity test against Staphylococcus aureus and Escherichia coli indicated dose-dependent potency closer to that of azithromycin standard drug and more efficient on S. aureus (Gram-positive) than E. coli (Gram-negative) bacteria. Biocompatibility test in terms of erythrocyte hemolysis, in reference to normal saline and water as minimal and maximal controls, confirmed nontoxic substance up to 100 μg/mL as the highest examined concentration and at which a lysis of 2.9% was detected. Therefore, it could be concluded that this biogenic method is effective in producing ZnS NPs with desirable properties for potential biomedical applications.

Graphene and graphene oxide based nanomaterials have attained immense significance in research because of their matchless physiochemical characteristics. Although potential biomedical applications of graphene have been extensively studied, however, dentistry related applications were rarely explored. This study aimed to investigate the effect of various percentages of surface modified reduce graphene oxide (S-rGO) in combination with SiO2 nanoparticles (bulk filler) on numerous physio-mechanical characteristics of acrylate-based (BisGMA/TEGDMA: 1:1 by wt.) composites. BisGMA/TEGDMA reinforced with 30 wt.% surface modified fumed-silica (S-A200) was considered as control group (base composite). Various concentrations (0, 0.5, 1, 2, 4 wt.%) of S-rGO were incorporated into the base composite via solution casting and high-speed mixing. The obtained composites were characterized for rheological properties before curing by using Rheometer (Anton Paar, USA) in the oscillatory mode under a frequency sweep over a range of angular frequency of 0.1–100 rad/s at 25 °C. The degree of conversion (DC) was measured by using Fourier transform infrared spectroscopy (FTIR). A Nano-indentation test was carried out to obtain nano-hardness and elastic modulus. The surface roughness was measured by optical microscope (Bruker®), 3D non-contact surface profilometer. The structural and morphological properties were studied by using Scanning Electron Microscopy (SEM). The mean and standard deviation were calculated and a simple mean comparisons test was performed for comparison using SPSS. The results revealed that the addition of a tiny proportion of S-rGO considerably increased the nano-indentation hardness, elastic modulus and DC. Conversely, a gradual reduction in viscosity was observed with increasing S-rGO concentration. The study demonstrates that a small fraction of S-rGO in combination with SiO2 could enhance physical, mechanical and rheological properties of acrylate based composites. Thus S-rGO/SiO2 combination could be used as a potential hybrid filler for dental nanocomposites.

This study aimed to assess the role of polymeric sources (polypyrrole, polyaniline, and their copolymer) of nitrogen (N)-doped activated carbons (indexed as PAnAC, PPyAC, and PnyAC, respectively) on their adsorption efficiency to remove methyl orange (MO) as a model cationic dye. The adsorbents were characterized using FTIR, SEM, TGA, elemental analysis, and surface area. The kinetic experiments were performed in batches at different MO concentrations (C0) and adsorbent dosages. The adsorption kinetic profiles of pseudo-first-order, pseudo-second-order (PSO), Elovich, intraparticle diffusion, and liquid film diffusion models were compared. The results showed a better fit to the PSO model, suggesting a chemisorption process. The adsorption capacity (qe, mg/g) was found to have increased as MO C0 increased, yet decreased as the adsorbent quantity increased. At the adsorption operating condition, including MO C0 (200 ppm) and adsorbent dose (40 mg), the calculated qe values were in the order of PAnAC (405 mg/g) > PPyAC (204 mg/g) > PnyAC (182 mg/g). This trend proved the carbon precursor’s importance in the final properties of the intended carbons; elemental analysis confirmed that the more nitrogen atoms are in the activated carbon, the greater the number of active sites in the adsorbent for accommodating adsorbates. The diffusion mechanism also assumed a rate-limiting step controlled by the film and intraparticle diffusion. Therefore, such an efficient performance may support the target route’s usefulness in converting nitrogenous-species waste into valuable materials.

This investigation delves into the potential use of halogen bonding to enhance both the short-circuit current (JSC) and overall efficiency of dye-sensitized solar cells (DSSCs). Specifically, we synthesized two distinct dyes, SQI-F and SQI-Cl, and characterized them using FT-IR, 1HNMR, 13C NMR, and mass spectroscopy. These dyes are based on the concept of incorporating halogen atoms within unsymmetrical squaraine structures with a donor–acceptor–donor (D-A-D) configuration. This strategic design aims to achieve optimal performance within DSSCs. We conducted comprehensive assessments using DSSC devices and integrated these synthesized dyes with iodolyte electrolytes, denoted as Z-50 and Z-100. Further enhancements were achieved through the addition of CDCA. Remarkably, in the absence of CDCA, both SQI-F and SQI-Cl dyes displayed distinct photovoltaic characteristics. However, through sensitization with three equivalents of CDCA, a significant improvement in performance became evident. The peak of performance was reached with the SQI-F dye, sensitized with three equivalents of CDCA, and paired with iodolyte Z-100. This combination yielded an impressive DSSC device efficiency of 6.74%, an open-circuit voltage (VOC) of 0.694 V, and a current density (JSC) of 13.67 mA/cm2. This substantial improvement in performance can primarily be attributed to the presence of a σ-hole, which facilitates a robust interaction between the electrolyte and the dyes anchored on the TiO2 substrate. This interaction optimizes the critical dye regeneration process within the DSSCs, ultimately leading to the observed enhancement in efficiency.