Co3O4 nanocube polyaniline nanocomposites have been successfully synthesised. They show enhanced surface properties and a greater adsorption capacity to remove MO efficiently within a short duration of time.

Superparamagnetic nanosorbent poly(phenyl(4-(6-thiophen-3-yl-hexyloxy)-benzylidene)-amine)/Fe3O4 nanoparticles (Fe3O4@P3TArH) were successfully synthesized via a simplistic method for the enhanced extraction of potent endocrine disruptor, di-(2-ethylhexyl)phthalate (DEHP).

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.

Polyaniline (PANI) is one of the unique conducting polymers due to tunable conductivity, acid-base chemistry and optical properties. In this study, commercial PANI was used to prepare PANI/shell composites to enhance the sensitivity of PANI in ammonia (NH3) gas detection. Three types of waste shells were utilized to incorporate into the PANI matrix such as egg shells (ES), crab shells (CS) and mussel shells (MS). The characterizations were done by Fourier transform infrared (FTIR) and ultraviolet-visible (UV-Vis) spectrophotometer. FTIR spectra confirmed the presence of CaCO3 in the PANI/shell composites’ backbone. Whereas, UV-Vis spectra further confirmed the PANI/shell composites were in the doped state by exhibiting a characteristic peak at ~790-820 nm. Sensor performance of commercial PANI and PANI/shell composite films were studied in terms of sensor measurement and sensor performances (selectivity, reusability and long-term stability). The sensor performances of commercial PANI, PANI/ES and PANI/CS exhibited correlation coefficient of >0.95. In addition, commercial PANI and PANI/CS films exhibited good selectivity for NH3 gas detection in the presence of interfering gases. In conclusion, PANI/shell composites were successfully prepared for NH3 gas detection and PANI/CS exhibited the highest sensitivity compared to other films.

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Poly(phenyl-(4-(6-thiophen-3-yl-hexyloxy)-benzylidene)-amine) (P3TArH) was successfully synthesized and coated on the surface of Fe 3 O 4 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.

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