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The intercalation of 2-methyl-4-chlorophenoxyacetic acid (MCPA) herbicide into the interlayer matrix of calcium–aluminium layered double hydroxide (CaAl LDH) host has been successfully done via the co-precipitation method to form CaAl-MCPA nanocomposite, proposing an eco-friendly alternative with an adjusted delivery system for herbicide application. The intercalation process is supported by powder X-ray diffraction analysis with an expanded interlayer spacing from 8.6 to 19.6 Å for nanocomposite pH 13, which is due to the inclusion of larger size anion in the interlayer. Next, the absence of a nitrate peak at 1,326 cm−1 and the presence of a newly formed peak at 1,416 cm−1 in the Fourier transformed infrared spectroscopy analysis also confirmed the process of the intercalation. The significant decrease in nitrogen content to 0.50% indicates the intercalation of MCPA using the carbon, hydrogen, nitrogen, sulphur analyser. The release rate of the MCPA anion in the aqueous solutions is initially rapid, followed by the slow release in the order of phosphate > carbonate > chloride and followed the pseudo-second-order kinetic model. Hence, the conducted studies exhibit the successful intercalation of the MCPA herbicide anion and its controlled release mechanism as a potential hybrid green herbicide.

Recently, the importance of sustainable environment has been engaged in many science practices and learning. This article intends to provide teachers in secondary school and research beginners with knowledge background on conducting polymers (CPs) for its application in environmental protection studies. A concise and straightforward discussion on the basic concept of CPs and its role as i) sensors for gas pollutants ii) photocatalyst are explained. A general workflow to guide readers in identifying and validating suitable sensors is included. In addition, the article provides a step-by-step guideline to assist readers in performing photocatalytic degradation experiments associated with CPs.

A simple, cost-effective, and novel chemical sensor for ammonia (N[H.sub.3]) gas detection was developed from polyaniline (PANI)/quail eggshell (QES) composites. QES is a natural waste enriched in calcium carbonate. In this work, pure PANI was synthesized from chemical oxidation method and PANI/QES composites were prepared from physical mixing of QES with the synthesized PANI at different mass ratio. A series of complementary techniques including Fourier transform infrared and ultraviolet-visible spectrometers, scanning electron microscope with energy dispersive detection coupled with mapping, thermogravimetric analysis, and X-ray diffractometer were used to characterize the physicochemical and textural properties of the biocomposites. From the results, PANI/QES composite with a mass ratio of 1 exhibited the lowest N[H.sub.3] detection limit of 5.24 ppm with a linear correlation coefficient ([R.sup.2]) of close to unity (0.9932) between the signal and N[H.sub.3] gas concentration. As a whole, the PANI/QES biocomposites synthesized from this work exhibited excellent selectivity toward N[H.sub.3] gas even in the presence of other gas impurities, such as acetone, ethanol, and hexane. For the sensor reusability, the PANI/QES biocomposites can be reused in the application of N[H.sub.3] gas detection for at least 4 cycles. KEYWORDS ammonia gas detection, polyaniline composite, quail eggshells, sensor, waste shells, 1 | INTRODUCTION The increasing generation rate of domestic waste products is the major contributor to the saturation of landfill waste disposal sites. Eggshells are one of the typical household [...]

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]

A simple, cost‐effective, and novel chemical sensor for ammonia (NH3) gas detection was developed from polyaniline (PANI)/quail eggshell (QES) composites. QES is a natural waste enriched in calcium carbonate. In this work, pure PANI was synthesized from chemical oxidation method and PANI/QES composites were prepared from physical mixing of QES with the synthesized PANI at different mass ratio. A series of complementary techniques including Fourier transform infrared and ultraviolet‐visible spectrometers, scanning electron microscope with energy dispersive detection coupled with mapping, thermogravimetric analysis, and X‐ray diffractometer were used to characterize the physicochemical and textural properties of the biocomposites. From the results, PANI/QES composite with a mass ratio of 1 exhibited the lowest NH3 detection limit of 5.24 ppm with a linear correlation coefficient (R2) of close to unity (0.9932) between the signal and NH3 gas concentration. As a whole, the PANI/QES biocomposites synthesized from this work exhibited excellent selectivity toward NH3 gas even in the presence of other gas impurities, such as acetone, ethanol, and hexane. For the sensor reusability, the PANI/QES biocomposites can be reused in the application of NH3 gas detection for at least 4 cycles. [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]

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]

Poly(phenyl-(4-(6-thiophen-3-yl-hexyloxy)-benzylidene)-amine) (P3TArH) was successfully synthesized and coated on the surface of Fe₃O₄ magnetic nanoparticles (MNPs). The nanocomposites were characterized by Fourier transform infra-red (FTIR), X-ray diffractometry (XRD), Brunauer-Emmett-Teller (BET) surface area analysis, analyzer transmission electron microscopy (TEM) and vibrating sample magnetometry (VSM). P3TArH-coated MNPs (MNP@P3TArH) showed higher capabilities for the extraction of commonly-used phthalates and were optimized for the magnetic-solid phase extraction (MSPE) of environmental samples. Separation and determination of the extracted phthalates, namely dimethyl phthalate (DMP), diethyl phthalate (DEP), dipropyl phthalate (DPP), dibutyl phthalate (DBP), butyl benzyl phthalate (BBP), dicyclohexyl phthalate (DCP), di-ethylhexyl phthalate (DEHP) and di- n -octyl phthalate (DNOP), were conducted by a gas chromatography-flame ionization detector (GC-FID). The best working conditions were as follows; sample at pH 7, 30 min extraction time, ethyl acetate as the elution solvent, 500-µL elution solvent volumes, 10 min desorption time, 10-mg adsorbent dosage, 20-mL sample loading volume and 15 g·L -1 concentration of NaCl. Under the optimized conditions, the analytical performances were determined with a linear range of 0.1⁻50 µg·L -1 and a limit of detection at 0.08⁻0.468 µg·L -1 for all of the analytes studied. The intra-day ( n = 7) and inter-day ( n = 3) relative standard deviations (RSD%) of three replicates were each demonstrated in the range of 3.7⁻4.9 and 3.0⁻5.0, respectively. The steadiness and reusability studies suggested that the MNP@P3TArH could be used up to five cycles. The proposed method was executed for the analysis of real water samples, namely commercial bottled mineral water and bottled fresh milk, whereby recoveries in the range of 68%⁻101% and RSD% lower than 7.7 were attained.