Fabrication of conductive cross‐linked polyaniline/ G‐MWCNTS core‐shell nanocomposite: A selective sensor for trace determination of chlorophenol in water samples

Electrodeposited histidine-(CuCr)layered double hydroxides/carbon dots for in-tube solid-phase microextraction of chlorophenols from water, juice, and honey samples followed by HPLC-UV

A novel adsorbent consisting of a composition of carbon dots and CuCr-layered double hydroxides intercalated with l-histidine (C-dots@His/LDHs) was introduced. This adsorbent was electrochemically deposited on the inner surface of a capillary copper tube. It was used as an adsorbent for in-tube solid-phase microextraction of chlorophenols (CPs). Separation and measurement of CPs were done by high-performance liquid chromatography-ultraviolet detector. The main parameters which had the most impact on the extraction efficiency and time such as extraction time and flow rate, desorption time and flow rate, ionic strength (salt concentration) and pH were optimized. Calibration curves (0.5-1000 μg L-1) were plotted in real sample (tap water) under optimal conditions which coefficients of determination better than 0.9893 and relative recoveries in the range of 88-120 % were obtained. The limits of detection (S/N = 3) and limits of quantification (S/N = 10) were obtained in the range of 0.1-1.0 μg L-1 and 0.3-3.0 μg L-1, respectively. The intra- and inter-assay precisions (RSD%, n = 3) were better than 5.9 and 8.8 %, respectively.

Enhancement of integrated nano-sensor performance comprised of electrospun PANI/carbonaceous material fibers for phenolic detection in aqueous solutions

The detection of trace levels of organic residue in water samples is a key health issue. This manuscript describes the fabrication of integrated nano-sensors composed of electrospun microfibers consisting of a nanocomposite of carbonaceous materials (CNMs) containing polyaniline (PANI) and polycaprolactone (PCL) for phenolic detection in aqueous solutions. The morphology of the resulting microfiber composite was characterized by scanning electron microscopy. It revealed elongated fibers with a highly interconnected web-like pattern in the presence of reduced graphene oxide (rGO). Shorter microfibers were observed in the composite filled with multi-walled carbon nanotubes (MWCNTs), whereas large agglomerates were formed upon the incorporation of single-walled CNTs (SWCNTs) and graphene 300 (G300). Comparative analysis showed that the PANI/CNM sensors exhibited the best electrochemical properties, in particular in the presence of rGO and MWCNTs, where greater electrical conductivity was achieved, i.e., 4.33 × 10-3 and 7.22 × 10-4 S/cm, respectively, as compared to the PANI-PCL sensor (3.79 × 10-4 S/cm). All the PANI/CNM sensors exhibited high sensitivity. Notably, PANI/rGO was found to have a detection limit of 8.34 × 10-3 µM for aminophenol. All the sensors exhibited good selectivity in the presence of interference to detecting phenolic compounds in aqueous solutions, thus confirming their value for industrial applications.

Polymer based nanocomposites: A strategic tool for detection of toxic pollutants in environmental matrices

A large fraction of population is suffering from waterborne diseases due to the contaminated drinking water. Both anthropogenic and natural sources are responsible for water contamination. Revolution in industrial and agriculture sectors along with a huge increase in human population has brought more amount of wastes like heavy metals, pesticides and antibiotics. These toxins are very harmful for human health, therefore, it is necessary to sense their presence in environment. Conventional strategies face various problems in detection and quantification of these pollutants such as expensive equipment and requirement of high maintenance with limited portability. Recently, nanostructured devices have been developed to detect environmental pollutants. Polymeric nanocomposites have been found robust, cost effective, highly efficient and accurate for sensing various environmental pollutants and this is due to their porous framework, multi-functionalities, redox properties, great conductivity, catalytic features, facile operation at room temperature and large surface area. Synergistic effects between polymeric matrix and nanomaterials are responsible for improved sensing features and environmental adaptability. This review focuses on the recent advancement in polymeric nanocomposites for sensing heavy metals, pesticides and antibiotics. The advantages, disadvantages, operating conditions and future perspectives of polymeric nanocomposites for sensing toxic pollutants have also been discussed.

Network structure-based decorated CPA@CuO hybrid nanocomposite for methyl orange environmental remediation

A unique network core-shell hybrid design-based cross-linked polyaniline (CPA), which was coated with CuO nanoparticles (NPs) and decorated with nitrogen-doped SWCNT/GO/cellulose N-SWCNTS-GO-CE, has been fabricated using the oxidative polymerization technique. This hybrid nanocomposite shows excellent photocatalytic degradation and an acceptable adsorption capability for Methyl Orange (MO) dye in aqueous solutions with a very slight effect for the N-SWCNTS-GO-CE CuO component. The prepared nanocomposites were used for the removal of a carcinogenic and noxious dye, Methyl Orange, from aqueous samples under various adsorption conditions. Approximately 100% degradation of 10 mg/L of Methylene orange dye was observed within 100 min at pH 6.0 using 50 mg/L CPA/N-SWCNTS-GO-CE/CuO nanocomposite under UV radiation. Additionally, significant factors were investigated on the degradation process including the contact time, MO initial concentration (Ci), solution pH, and dosage of the CuO nanocomposite. All investigated experiments were performed under UV radiation, which provided significant data for the MO degradation process. Furthermore, the recovery of the nanocomposite was studied based on the photocatalytic process efficiency. The obtained data provide the high opportunity of reusing CPA/N-SWCNTS-GO-CE/CuO nanocomposite for numerous photocatalytic processes. The CPA/N-SWCNTS-GO-CE/CuO nanocomposite was prepared via chemical oxidative copolymerization of polyaniline (PANI) with p-phenylenediamine (PPDA) and triphenylamine (TPA) in the presence of N-SWCNTS-GO-CE and CuO NPs. The morphology, structure and thermal properties of the CPA/N-SWCNTS-GO-CE/CuO nanocomposite were investigated using various techniques, including FTIR, XRD, RAMAN, SEM, MAP, EDX, TEM, TGA and DTG. Therefore, CPA/N-SWCNTS-GO-CE/CuO nanocomposite can be effectively used as a convenient and reusable adsorbent to remove hazardous dye from wastewater.