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[Display omitted] • Fe 3 O 4 -SiO 2 /Polypyrrole Magnetic Nanocomposite Polymer Powder. • New application of magnetic powders. • Edible see salt purification. • Environmental protection. In this study, Fe 3 O 4 /SiO 2 /polypyrrole magnetic nanocomposite polymer powder was chemically synthesized. The structure of the prepared composite powders were studied using scanning electron microscopy, FTIR and XRD techniques. The results showed that the prepared composites have a nanometer structure. The FTIR results confirmed the electrostatic interactions between the composite components. XRD also showed the crystal structure of Fe 3 O 4 and its composites. Optimal nanocomposite powder was used to purify the salt of Lake Urmia. Salt samples were treated with powder and the chemical properties of salt were investigated before and after treatment. Qualitative tests performed on salt included COD, BOD, organic compounds, heavy metals, nitrate and nitrite, and color characteristics. Finally, the efficiency of the nanoparticle powder in the lake salt treatment was calculated. The results showed that the composite powder reduced BOD and COD as well as the heavy metal salts of the lake. Also, the organic compounds in the salt decreased and the color factors such as the white index of the salt increased. Under optimal conditions, Fe 3 O 4 /SiO 2 /PPy composite showed the best performance at 37 min of purification time. In general, Fe 3 O 4 /SiO 2 /PPy composite can be easily used to purify sea salts and also reduce environmental pollutants. [ABSTRACT FROM AUTHOR]

In this work intelligent and active films based on bacterial cellulose (BC) modified by polypyrrole-Zinc oxide nanocomposite (BC-PPy-ZnO) were provided. Chemical polymerization in the atmospheric condition was used for providing BC-PPy-ZnO film. Scanning electron microscopy (SEM) was used for studying BC-PPy-ZnO film morphology. The nanosized PPy-ZnO (50–150 nm) composites covered the BC surface. The BC-PPy-ZnO film was used for packaging of chicken thigh. The effects of storage time and storage temperature on the chicken thigh characteristics were studied based on a central composite design (CCD). The effects of BC-PPy-ZnO film on the chicken thigh characteristics, including pH, microbial property (Mesophilic and psychrophilic bacteria), color property, antioxidant and rheological properties were studied. The results showed that the BC-PPy-ZnO film could decrease the growth of microbial load in chicken thigh and could control the pH increasing. The BC-PPy-ZnO film could increase the shelf life and stabilize rheological properties of chicken thigh by increasing of antioxidant and antimicrobial activity as active packaging. According to the results there are good relations between film electrical resistance change and storage time-storage/temperature that this could help us to estimate the storage time and storage temperature of chicken thigh as intelligent packaging. • Novel films based on modified bacterial cellulose were synthesized. • BC-PPy-ZnO film exhibited a good antimicrobial and antioxidant activity. • Packaging of chicken thigh meat by BC-PPy-ZnO improves its shelf life. • There are good relations between film electrical resistance change and storage time-storage/temperature that this could help us to estimate the storage time and storage temperature of chicken thigh as intelligent packaging. • BC-PPy-ZnO film can be used as smart and active packaging system for meat controlling. [ABSTRACT FROM AUTHOR]

Purpose The purpose of this paper is to construct an array of sensors using polypyrrole–zinc oxide (PPy–ZnO) and PPy–vanadium (V; chemical formula: V2O5) fibers. To test responses of sensors, a central composite design (CCD) has been used. The results of the CCD technique revealed that the developed sensors are orthogonally sensitive to diacetyl, lactic acid and acetic acid. In total, 20 different mixtures of diacetyl, lactic acid and acetic acid were prepared, and the responses of the array sensors were recorded for each mixture.Design/methodology/approach A response surface regression analysis has been used for correlating the responses of the sensors to diacetyl, lactic acid and acetic acid concentrations during the gas phase in food samples. The developed multivariate model was used for simultaneous determination of diacetyl, lactic acid and acetic acid concentrations. Some food samples with unknown concentrations of diacetyl, lactic acid and acetic acid were provided, and the responses of array sensors to each were recorded.Findings The responses of each sensor were considered as target response in a response optimizer, and by an overall composite desirability, the concentration of each analyte was predicted. The present work suggests the applicability of the response surface regression analysis as a modeling technique for correlating the responses of sensor arrays to concentration profiles of diacetyl, lactic acid and acetic acid in food samples.Originality/value The PPy–ZnO and PPy–V2O5 nanocomposite fibers were synthesized by chemical polymerization. The provided conducting fibers, PPy–ZnO and PPy–V2O5, were used in an array gas sensor system for the analysis of volatile compounds (diacetyl, lactic acid and acetic acid) added to yogurt and milk samples. [ABSTRACT FROM AUTHOR]

Abstract: A selective dimethyl sulfoxide (DMSO) gas sensor based on nanostructured conducting polypyrrole doped with sulfonate anion was constructed. Five sulfonate anions, including HSO3 −, para toluene sulfonate (PTS), dodecyl benzene sulfonate (DBS), dodecyl sulfonate (DS) and 5-sulfo salicylate (SS) were used to dope polypyrrole film. Sulfonated doped polypyrrole samples (PPy-S) have been prepared by polymerization of pyrrole on surfaces of the polyester fibers in the presence of an oxidizing agent. The presence of the dopants in the conducting polymer matrix was verified by FT-IR spectroscopy and the morphology of the resulting PPy-S was analyzed by scanning electron microscopy (SEM). The effects of the dopant type and concentrations on the conductivity and response patterns of the PPy-S as a gas sensor to the different gases were studied. The PPy-S gas sensors had demonstrated fast response time (<1s). The responsivity of the PPy-S gas sensors for various volatile organic compounds (VOCs) was also reported. The PPy-HSO3 exhibit a lowest detection limit to the DMSO and could also be successfully applied as a highly selective sensor for detection of DMSO (DL=30ng). Linearity of calibration curve was observed at the range of 0.1–500μg. [Copyright &y& Elsevier]

Abstract: Polypyrrole (PPy) gas sensor has been prepared by polymerization of pyrrole on surfaces of commercial polymer fibers in the presence of an oxidizing agent. The sensing behavior of PPy gas sensor was investigated in the presence of pyridine derivatives. The resistive responses of the PPy gas sensor to pyridine derivatives were in the order of quinoline>pyridine>4-methyl pyridine and 2-methyl pyridine. The PPy gas sensor was used as gas chromatography (GC) detector and exhibited linear responses to pyridine derivatives in the ranges 40–4000ng. Dispersive liquid–liquid microextraction (DLLME) combined with GC/PPy gas sensor has been developed for simultaneous determination of pyridine derivatives and quinoline. The purposed method was used for determination of pyridine derivatives from cigarette smoke. The GC runs were completed in 4min. The reproducibility of this method is suitable and good standard deviations were obtained. RSD value is less than 10% for all analytes. [Copyright &y& Elsevier]

Abstract: In this work, electrically conductive polymers have been prepared by polymerization of pyrrole on surfaces of commercial polymer fibers in the presence of an oxidizing agent. The resistance of polypyrrole-coated fibers was investigated and related to coating conditions, which was controlled by adjusting the reactant concentrations. The effect of initial treatment with monomer or oxidant prior to polymerization reaction with regards to resistance of sensor was optimized. The morphology of the conducting film on the surface of the fibers was examined by scanning electron microscope (SEM), indicating a strong dependence of the processing conditions. The sensing behavior of polypyrrole-coated fiber in the presence of different volatile organic compounds (VOCs) is studied experimentally. Effects of functional group and polarity of organic molecules on responses of the PPy-coated fiber sensor (PPy-CFS) were investigated. The PPy-CFS had demonstrated fast response time (<1s), high sensitivity for various polar molecules and good reproducibility when reused. The sensitivity of the PPy-CFS for various molecules was in the following order: pyridines>acetonitrile>DMSO>ROHs>aldehydes>ketone>benzene derivatives≫alkanes. [Copyright &y& Elsevier]

In this work, the electrical conductive polymer is formed by vapor phase polymerization of pyrrole on the copper interdigital electrodes (Cu-IDEs) in the presence of Fe(III) as an oxidant at room temperature under atmospheric condition. Electrical resistance of IDEs covered with polypyrrole (PPy) layer was investigated and the relationship between the normalized electrical resistances ( R − R/ R), experimental conditions of vapor-phase coating (amount of oxidant and time coating) and response behavior of sensors to the volatile organic compounds were studied. The results showed that the pattern of response and selectivity of the sensor is affected by vapor phase polymerization conditions. The prepared PPy gas sensors were used at different conditions for detection and measurement of volatile organic compounds in the gas phase. The PPy gas sensors had demonstrated fast response time (<1 s). Morphological study of the PPy coated layer by scanning electron microscope (SEM) showed that the conducting polymer prepared with nanotube shape. One of the sensors showed selective response toward of n-butylamine (PPy) with the detection limit of 1 µg and linear range of 2-74 µg. The PPy gas sensor was used to measure n-butylamine in well water sample. Disperse liquid-liquid microextraction (DLLME) method was used for extraction and pre-concentration of n-butylamine from aqueous solutions. The extraction recovery of the proposed method was founded 93-105 %. [ABSTRACT FROM AUTHOR]

• Synthesize new conducting/nano-based composite film based on BC/PPy/TiO 2 -Ag. • The conducting BC/PPy/TiO 2 -Ag film had sensing ability of pathogenic bacteria. • The BC/PPy/TiO 2 -Ag film could be used in food packaging to show bacterial count. • The BC/PPy/TiO2-Ag film as a sensor has the potential to improve biological safety as diagnostic tools. The aim of this study was to use of bacterial cellulose/polypyrrole/TiO 2 -Ag (BC/PPy/TiO 2 -Ag) nanocomposite film to detect and measure the growth of 5 pathogenic bacteria. For this purpose, at first, 13 BC/PPy/TiO 2 -Ag films were fabricated, then bacterial suspensions were prepared according to McFarland standard. The results showed that by increasing the bacterial concentration, the electrical resistance of sensors was decreased and there was a relation between bacterial concentration and bacterial type with electrical resistance change of sensors. The obtained data showed that the sensitivity of the sensors was increased with increasing the concentration of polypyrrole and TiO 2 -Ag. FT-IR and SEM tests were performed to investigate the interaction between nanoparticles and determine the size of nanoparticles. The BC/PPy/TiO 2 -Ag biosensors are portable and the response time of these sensors is very short for target analysis. Therefore, these sensors have the potential to improve biological safety as diagnostic tools. [ABSTRACT FROM AUTHOR]