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[Display omitted] • PANI-CHT SPCE was prepared for electrochemical sensing of PFOA. • An excellent electro-oxidation activity towards the detection of PFOA was accomplished. • Highly sensitive and selective determination of PFOA with LOD in ppb range was recorded. • This electrochemical sensor was successful for determination of PFOA in water sample. The overwhelming utilisation of perfluorooctanoic acid (PFOA) for household and industrial applications has posed a severe risk to human health and environmental pollution. Therefore, this study was performed to fabricate a polyaniline-chitosan (PANI-CHT) composite using CHT extracted from crab shells and modified with Screen-Printed Carbon Electrode (SPCE) for the development of an electrochemical sensor to detect PFOA. The physicochemical properties of CHT, PANI, and PANI-CHT were characterised using ATR-FTIR, XRD and SEM-EDX. In addition, the electrochemical performance of the SPCE-modified PANI-CHT 1:1 composite was evaluated through cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Based on the results, PANI-CHT 1:1 showed a linear correlation coefficient of R2 = 0.9954 with a LOD of 1.08 ppb in a linear range of 5–150 ppb. The physicochemical analyses demonstrate the successful blending of CHT with PANI, which enhanced the effective active sites on the surface of SPCE. Upon the practical assessment of the fabricated composite using spiked water samples, the sensor recorded an acceptable recovery percentage range of 96–103 %. Overall, the proposed sensor exhibited great sensitivity, excellent reproducibility, and good stability for the detection of PFOA and with a promising performance. [ABSTRACT FROM AUTHOR]

In this work, activated carbon (referred to as MCAC) was produced by microwave radiation assisted ZnCl2 activation using Malaysian coal (MC) as a precursor. The Brunauer–Emmett–Teller findings indicate that the MCAC has a relatively large surface area (798.18 m2/g) and a mesoporous structure (average pore diameter of 3.67 nm). The removal of Methylene Violet (MV 2B) a cationic dye model, was employed to investigate the adsorption properties of MCAC. A numerical desirability function in the Box–Behnken design (BBD) was employed to optimize the independent crucial adsorption variables as follows: A: MCAC dose (0.02–0.1 g); B: pH (4–10); and C: time (5–25 min). The results of equilibrium and dynamic adsorption showed that the adsorption of MV 2B followed Freundlich and pseudo-second order models, respectively. The maximum amount of MV 2B dye that the MCAC could adsorb (qmax) was 134.1 mg/g. Electrostatic interactions, π-π stacking, H-bonding, and pore diffusion contribute to the adsorption of MV 2B dye onto the MCAC surface. This study demonstrates the potential to utilize MC as a low-cost precursor for the efficient synthesis of MAC and its utility for the removal of pollutants. [ABSTRACT FROM AUTHOR]

Once widely utilised in both human and veterinary medicine, tetracycline antibiotics are now recognised as major environmental pollutants with detrimental effects on the environment and human health. Concerns regarding allergic responses, gastrointestinal problems, and diseases resistant to antibiotics are raised by their persistence in soil, groundwater, and surface water. The production of a tungsten disulfide-graphene oxide nanocomposite for tetracycline degradation under varied light sources is presented in this work. The successful incorporation of tungsten disulfide on graphene oxide structures was confirmed by characterization using Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR) and X-ray Diffraction (XRD). This revealed characteristic peaks for hydroxyl (3328 cm-1), carbonyl (1732 cm-1), alkene (1583 cm-1), and ether (1044 cm-1) bonds, as well as sulphur bonding (500 to 739 cm-1). With a D-spacing of 2.24 nm, the tungsten disulphide-graphene oxide nanocomposite had a strong peak at 2θ = 15.5°corresponds to the (002) plane, as shown by X-ray diffraction. A distinctive GO peak was found at 2θ = 10.1°, which corresponds to the plane (002). With light emitting diodes (95.67%), fluorescent lights (81.28%), and ultraviolet-visible light (88.09%), the nanocomposite in a photoreactor showed excellent photocatalytic efficiency. The better performance of the tungsten disulfide-graphene oxide nanocomposite under varying illumination circumstances, as determined by the Langmuir-Hinshelwood (LH) model, presents a viable and sustainable option for tetracycline degradation in water purification. This technique tackles a long-term strategy for tetracycline photocatalytic degradation in water purification under different illumination scenarios. [ABSTRACT FROM AUTHOR]

The present study demonstrates the self-assembly method of chemical oxidative polymerization of polypyrrole (PPy), polypyrrole/boron nitride (PPy/BN), and polypyrrole/dodecylbenzene sulfonic acid/boron nitride (PPy/DBSA/BN) thin films for ammonia (NH3) gas detection. The PPy, PPy/BN, and PPy/DBSA/BN thin films were comprehensively characterized using Attenuated Total Reflectance Fourier-Transform Infrared Spectroscopy (ATR-FTIR), Scanning Electron Microscopy (SEM), X-ray diffractometry (XRD) and conductivity measurement. ATR-FTIR revealed all the pertinent peaks of PPy, BN, and DBSA present in the PPy/DBSA/BN. SEM images of PPy/DBSA/BN depict well-organized morphology. PPy/DBSA/BN recorded the highest conductivity of 4.771 x 10-6 S cm-1 among the prepared polymer thin films. The obtained characterization results are in good agreement with the NH3 gas sensor measurements conducted on the PPy/DBSA/BN composite. The linear correlation coefficient between the two was found to be R² = 0.9916, indicating a strong relationship. Furthermore, the PPy/DBSA/BN thin film demonstrated a low limit of detection (LOD) of 5.8 ppm, surpassing the OSHA threshold value for NH3 gas. This suggests that the sensor is highly sensitive to trace amounts of NH3 gas. Moreover, the PPy/DBSA/BN thin film exhibited exceptional reusability, with the ability to be used for up to 10 cycles without a significant decrease in performance. The sensor also demonstrated selectivity towards NH3 gas in the presence of common interfering species. Additionally, it exhibited long-term stability, maintaining its performance over a period of 7 days. The proposed self-assembled gas sensor has showcased remarkable performance in detecting NH3 gas at room temperature, making it a promising candidate for industrial applications. [ABSTRACT FROM AUTHOR]

In this work, chitin (Ch) was chemically extracted from wild mushrooms and then grafted to polyaniline (PANI) to form a composite (Ch-g-PANI) to detect ammonia (NH 3) gas. The Ch-g-PANI was comprehensively characterized using Scanning electron microscopy (SEM), elemental mapping, thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR) and UV–Vis spectroscopy. The NH 3 gas detection optimization was evaluated using Box-Behnken Design. Typically, physical factors such as (A)film layer, (B)loading %, and (C)contact time were investigated and validated through the analysis of variance (ANOVA). The ANOVA revealed that dual interactions between (A)film layer - (C)contact time, and (B)loading % - (C)contact time are among the significant factors. By considering these significant interactions, the highest sensitivity was obtained when (A)film layer (3), (B)loading (5 %), and (C)contact time (10 min) in NH 3 gas detection. Then, the optimized Ch-g-PANI was tested in the linear range of NH 3 gas concentration from 10 to 50 ppm, which resulted in a linear calibration curve with R2 = 0.994 and a detection limit of 15.03 ppm. Sensor performances showed that Ch-g-PANI films possess high selectivity for NH 3 gas among the common interfering gases and the film can be reused for up to 6 cycles. Therefore, the new mushroom-sourced Ch-g-PANI is an inexpensive and economical sensor in the NH 3 gas sensor field. [ABSTRACT FROM AUTHOR]

[Display omitted] • Recent trends in the development of electrochemical sensor technology for antioxidants in food applications. • Integrating deep eutectic solvents with electrochemical sensors that align with green chemistry principles. • Applications of deep eutectic solvents in the detection of specific antioxidants. • Challenges and limitations in the development deep eutectic solvents-based electrochemical sensors are addressed. Antioxidants are commonly found in both natural and synthetic forms. Recent years have witnessed significant efforts directed towards the identification of natural antioxidants. This review focuses on the recent advancements in electrochemical sensors constructed using deep eutectic solvents for electrode modification, emphasizing their role in detecting natural antioxidants such as ascorbic acid, phenolic acids, flavonoids, tryptophan, and citric acid. The term 'green' denotes the progression of electrochemical sensing platforms employing biodegradable and sustainable materials, particularly those utilizing green solvents, e.g., deep eutectic solvents (DES). The electrochemical performance of these green sensors and their associated benefits, including biodegradability, non-toxicity, sustainability, and low cost, are discussed. Furthermore, the review outlines the limitations of existing DES-based modified electrode sensing technology, current development trends, and the potential applications for various natural antioxidant substances. The objective of this review is to offer insights for researchers engaged in the field of electrochemical sensors DES-modified electrodes. [ABSTRACT FROM AUTHOR]

Confiscation of organic pollutants from the environment is one the most important topics recently. The contamination of our water body that comes from several pollutants lead to several serious effects to the environment. The development of green and economical method in reducing the contamination is well discussed. The main aim of this research is to characterize and investigate the solar driven photocatalytic degradation of 2-chlorophenol (2-CP) from aqueous solution with the aid of polyaniline (PANI) incorporated graphene oxide (GO) composite (PANI/GO). PANI was incorporated with GO via in-situ oxidation polymerization method using ammonium persulfate (APS) as oxidizing agent to form composite. Three compositions of PANI/GO composites were synthesized with the ratio of PANI and GO of 1:1, 1:4 and 9:1. PANI, GO and PANI/GO composites were characterized comprehensively using Fourier transform infrared (FTIR), UV-visible (UV-VIS) and XRD spectroscopy analysis. Morphology was analyzed by capturing the images using Scanning electron microscope (SEM) with Energy Dispersive X-ray (EDX) analysis setup. The characterization studies revealed that, the PANI/GO composites have been successfully synthesized. Degradation of 2-CP was conducted using PANI/GO composites under solar irradiation for 3 hours. The degradation results disclosed that, PANI/GO composite with composition ratio of 1:1 possessed the highest degradation percentage with 75 % at degradation time of 150 minutes. Therefore, PANI/GO composites are one of the ideal catalysts in order to degrade 2-CP. [ABSTRACT FROM AUTHOR]