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Modification of carbon nanotubes (CNTs) and their incoporation in polymer matrix have attracted much attention of researchers. As maximum dispersion of CNTs could enhance the properties of matrix dynamically, researchers are trying to find new methodologies to obtain this target. However, maximum dispersion remains a great challenge and under the stage of progress. Here, we claimed the synthesis of composites with a highly uniform dispersion of the filler that results significantly improved electrical features. In this regard, composites of polymethylmethacrylate (PMMA) were fabricated by using pristine and zwitterionic surfactant (ZIS) modified CNTs (ZIS-CNTs). Characterization was done by using ultraviolet–visible (UV–Vis), Fourier transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermo gravimetric analysis (TGA) techniques. UV–Vis and FTIR spectroscopy confirmed the synthesis of ZIS-CNTs and composites. UV–Vis spectra showed an increase in wavelength with the decrease in optical band gap for CNTs-based (CNTs/PMMA) and ZIS-CNTs-based (ZIS-CNTs/PMMA) composites. SEM and XRD studies confirmed a significant homogenoeus and uniform dispersion of CNTs in ZIS-CNTs/PMMA composites. An increase in conductivity of PMMA from 10−9 to 10−2 and 10−1 S/cm was observed on addition of less than 1% (mass fraction) of CNTs without and with modification by ZIS, respectively. Low values of percolation threshold at 0.5% and 0.005% for CNTs/PMMA and ZIS-CNTs/PMMA composites were obtained, respectively. TGA analysis showed a slow rate of decomposition for composites than that for pure PMMA. Around 600 °C, 3% CNTs/PMMA and 7% ZIS-CNTs/PMMA composites were left in the end, which depicts the increase in thermal stability of PMMA. This work depicts a better dispersion of CNTs in PMMA matrix via slight modification in synthesis as well as by using ZIS as surfactant.

Methylene blue (MB) is a most commonly used synthetic dye in the textile industry. It is an extremely carcinogenic phenothiazine derivative and therefore needs to be removed from the water bodies. In the present study, a single-step hydrothermal novel synthesis of carbon quantum dots (CQDs) extracted from biomass of chicken feathers has been performed, and the synthesized CQDs were applied to remove MB present in the aqueous samples. A number of techniques such as ultraviolet-visible (UV-Vis) spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and X-ray diffraction (XRD) were used to characterize the samples for the conformity purposes. SEM and XRD analysis showed that CQDs are highly crystalline and have spherical structures with an average particle diameter of 35 nm. In the presence of 0.2 g of synthesized CQDs, MB dye degraded drastically under the sunlight. The rate of degradation was studied by determining the absorbance of the degraded sample with time relevant to untreated sample. The % degradation achieved during first 60 min of time was approximately 92% which increased minimally to a value of only 95% after 100 min of time. The ease of synthesis of carbon dots at low cost contributes hugely to their utilizations as an efficient photocatalyst for the degradation of aqueous pollutants. The opted approach to synthesize CQDs is cost-effective and eco-friendly and demonstrates excellent potential to remove MB from the aqueous samples.

Liquid chromatographic separation technique coupled with fluorescence detector (LC-FLD) has been one of the primary sensitive and selective analytical techniques in various science areas including environmental, food, biological, biomedicine etc. Its significance relies on several analytical advantages including cost-effectiveness, enhanced sensitivity, and selectivity performance. However, the desired applications of this technique and detection limits are not always possible without target analytes derivatization. When analytes manipulation is carried out by mere light, the mechanism is called photoderivatization or photochemical reaction. This addition of photochemical reactor has significantly enhanced the LC-FLD capability for selective, sensitive, and reproducible determination of variety of analytes such as pesticides, pharmaceutical drugs, flavonoids, vitamins etc. as compared to chemical pre/post-column derivatization. Herein, we have comprehensively and systematically summarized the development, instrumentation and applications of liquid chromatography-photoinduced fluorescence technique (LC-hv-FLD) to analyze a large number of analytes-residues in various matrices published between the years i.e., 2000 to 2022 along with some outstanding and important contributions before this time span. Moreover, the essential characteristic, advantages/disadvantages, challenges, and future prospects have also been highlighted. We expect this manuscript to be a useful key reference for the future development in fluorescence based chromatographic analysis and inspire new ideas and discoveries in the direction of reagent-less and online derivatization of intrinsically non-fluorescent analytes.

The detection of human serum albumin (HSA) is of significant clinical importance in disease diagnoses. In this work, polymer-based synthetic receptors are designed by incorporating Ag-ZnS microspheres in molecularly imprinted poly(methacrylic acid-co-ethylene glycol dimethacrylate) (MIPs) for the gravimetric detection of HSA. Among different compositions of Ag-ZnS@MIPs, MIPs having methacrylic acid and ethylene glycol dimethacrylate volume ratio of 3:2 exhibit enhanced HSA sensitivity in the concentration range of 5–200 ng/mL. A remarkably low threshold limit of detection (LOD = 0.364 ng/mL) is achieved with quartz crystal microbalance (QCM) based gravimetric sensors. Furthermore, the Ag-ZnS@MIPs/QCM sensors show high selectivity for HSA compared to other proteins, e.g., bovine serum albumin (BSA), glycoprotein, ribonuclease, and lysozyme. Hence, the gravimetric quantification of HSA realizes a highly sensitive, selective, and label-free detection mechanism with a limit of quantification down to 1.1 ng/mL.

Abstract Electrically conductive polyorthochloroaniline/chromium nanocomposites (POC/Cr NCs) were prepared by in situ chemical oxidative polymerization of orthochloroaniline in the presence of Cr nanoparticles (Cr NPs). The load percentage of Cr nanofiller was varied in POC matrix to investigate the effect of Cr nanoparticles on the properties of the nanocomposites. The composition, structure, and morphology of POC and its composites were examined by Scanning electron microscopy, Fourier transform infrared spectroscopy, and UV–visible spectroscopic analysis. The antibacterial potential of POC and its composites was evaluated by the disc diffusion method against Escherichia coli and Bacillus subtilis. The results showed the improved antibacterial potential with the increase in the load percentage of nanofiller. The electrical conductivity of polymer and its composites was measured and correlated with the load percentage. The results showed that electrical conductivity of the composites was enhanced with the increase in load percentage of Cr nanoparticles.

Biomimetic hybrid particles based on amlodipine-imprinted poly(methacrylic acid-co-ethylene glycol dimethacrylate) (MIP) are developed by free radical polymerization of the monomers and crosslinkers in the presence of silica nanoparticles. Atomic force microscopy is used to study the distribution and surface morphology of MIP-silica hybrid particles. The responsive properties are studied by exposing the synthesized MIP-silica hybrid material to standard amlodipine drug solution and consequently monitoring the decrease in drug concentration. The control material, i.e., nonimprinted polymer- (NIP-) silica hybrid particles, exhibits much lower response during the drug rebinding assay suggesting the lack of functionality due to the absence of imprinting effects. The selectivity of MIP-silica hybrid particles is evaluated by examining the aspirin uptake that shows lower absorbance shifts for aspirin solution compared to amlodipine. It indicates a higher sensitivity of MIP-silica hybrid particles toward targeted pharmaceutical drug recognition and also exhibits their potential for drug assay in multiplex biological samples. Furthermore, MIP-silica hybrid particles used in the drug rebinding assay can be recovered and regenerated for subsequent tests without losing recognition properties.

Chitosan and polyethylene glycol (PEG-600) membranes were synthesized and crosslinked with 3-aminopropyltriethoxysilane (APTES). The main purpose of this research work is to synthesize RO membranes which can be used to provide desalinated water for drinking, industrial and agricultural purposes. Hydrogen bonding between chitosan and PEG was confirmed by displacement of the hydroxyl absorption peak at 3237 cm−1 in pure chitosan to lower values in crosslinked membranes by using FTIR. Dynamic mechanical analysis revealed that PEG lowers Tg of the modified membranes vs. pure chitosan from 128.5 °C in control to 120 °C in CS-PEG5. SEM results highlighted porous and anisotropic structure of crosslinked membranes. As the amount of PEG was increased, hydrophilicity of membranes was increased and water absorption increased up to a maximum of 67.34%. Permeation data showed that flux and salt rejection value of the modified membranes was increased up to a maximum of 80% and 40.4%, respectively. Modified films have antibacterial properties against Escherichia coli as compared to control membranes.

Series of Cobalt nanoparticles incorporated polymethylmethacrylate composites in the presence and absence of dodecyl-benzene-sulphonic acid (DBSA-CoNPs/PMMA and CoNPs/PMMA, resp.) were synthesized by solution mixing methodology. UV-visible and FTIR techniques were used to confirm the formation of nanocomposite. UV-visible spectra of the composites showed the incorporation of filler particles in the polymer matrix. On the other hand, FTIR spectra indicated the physical interaction between the two phases of the composite. Moreover, the electrical nature of the composites was studied by plotting graphs between electrical conductivity (measured using LCR meter at 100 kHz) and contents of the filler particles as introduced in the polymer matrix. An increase in electrical conductivity was first observed with increasing filler concentration up to the critical percolation threshold value (0.5% for DBSA-CoNPs/PMMA and 1% for CoNPs/PMMA), which then dropped upon further increments in the filler content. However, at higher concentrations, a second jump in the conductivity was observed in case of DBSA-CoNPs/PMMA composites.

Molecular imprinting is a well-established technology to mimic antibody-antigen interaction in a synthetic platform. Molecularly imprinted polymers and nanomaterials usually possess outstanding recognition capabilities. Imprinted nanostructured materials are characterized by their small sizes, large reactive surface area and, most importantly, with rapid and specific analysis of analytes due to the formation of template driven recognition cavities within the matrix. The excellent recognition and selectivity offered by this class of materials towards a target analyte have found applications in many areas, such as separation science, analysis of organic pollutants in water, environmental analysis of trace gases, chemical or biological sensors, biochemical assays, fabricating artificial receptors, nanotechnology, etc. We present here a concise overview and recent developments in nanostructured imprinted materials with respect to various sensor systems, e.g., electrochemical, optical and mass sensitive, etc. Finally, in light of recent studies, we conclude the article with future perspectives and foreseen applications of imprinted nanomaterials in chemical sensors.

The study is intended to monitor the comparative degradation rates of acetaminophen in binary and ternary combinations by UV–vis spectroscopy. The drugs were exposed to UV-rays in blister packing. The exposition time was 24, 48 and 72 h for both shorter and longer wavelengths. The problem of overlapping UV bands of aspirin and caffeine with acetaminophen was solved by extracting them in diethylether, therefore, we developed a straightforward, rapid and accurate assay method for measuring acetaminophen concentration in binary and ternary mixtures and to monitor its degradation.

Catalysts play important rule in order to enhance the efficiency of the chemical processes. Catalysis being surface phenomena, catalytic activity mainly depends upon their total available surface area. Metals are often used as catalysts for electrochemical and chemical reactions. In this study, different techniques were employed to prepare or modify some of the metals in terms of particles and layers particularly from first row of transition metals to enhance the surface area of their given amount. Electrodes of copper and zinc are modified by electro chemical deposition. More importantly these modified electrodes are employed to check their catalytic activity for the oxidation of methanol and ethanol in basic environment. This is the one of the potential reactions occur in fuel cell. Secondly, hydrothermal method was adopted for the synthesis of the nanoparticles. To investigate the utility of the approach, synthesized materials under gone as catalysts for mineralization of the organic dye. Generally, enhanced catalytic activity is observed. Moreover, scanning electron microscopy is deployed for the investigation of the surface morphology of the prepared/modified materials.

Batch scale studies for the adsorption potential of novel biosorbent Phragmites karka (Trin), in its natural and treated forms, were performed for removal of mercury ions from aqueous solution. The study was carried out at different parameters to obtain optimum conditions of pH, biosorbent dose, agitation speed, time of contact, temperature, and initial metal ion concentration. To analyze the suitability of the process and maximum amount of metal uptake, Dubinin-Radushkevich (D-R) model, Freundlich isotherm, and Langmuir isotherm were applied. The values of qmax for natural and treated biosorbents were found at 1.79 and 2.27 mg/g, respectively. The optimum values of contact time and agitation speed were found at 50 min and 150 rpm for natural biosorbent whereas 40 min and 100 rpm for treated biosorbent, respectively. The optimum biosorption capacities were observed at pH 4 and temperature 313 K for both natural P. karka and treated P. karka. RL values indicate that comparatively treated P. karka was more feasible for mercury adsorption compared to natural P. karka. Both pseudo-first-order and pseudo-second-order kinetic models were applied and it was found that data fit best to the pseudo-second-order kinetic model. Thermodynamic studies indicate that adsorption process was spontaneous, feasible, and endothermic.

Metal nanoparticles (NPs) have received significant attention in last decade because of their unique properties. In this work, two different metal NPs have been prepared and their catalytic activities are compared with conventional catalyst. In first case, Ag NPs were synthesized by chemical reduction method in ethanolic medium. Synthesized Ag NPs were characterized by scanning electron microscope (SEM) images which indicated an average particle size of Ag around 250 nm. The catalytic activity of Ag NPs was investigated for the oxidative mineralization of methylene blue dye. Comparative studies suggested that Ag NPs possess enhanced catalytic activity compared to bulk Ag. In second approach, supported Ni NPs were fabricated using Al2O3 as supporting surface; that is, Ni NPs get adsorbed on Al2O3 through in situ reduction reaction. Oxidative degradation of methylene blue indicated that catalytic activity of supported Ni/Al2O3 is about five times higher than simple Ni as catalyst.

A study was conducted in three successive seasons during 2004-06 on loam soil at three different sites in tehsil Faisalabad. The objective was to investigate the response of cotton (cv. NIAB-111) to different levels and times of K-application. The treatments comprised three potassium doses (0, 62.5 and 125 kg/ha) and its application on three times (full at sowing, full at first irrigation and ½ at sowing + ½ at first irrigation). The results indicated that potassium doses and application times significantly affected seed cotton yield. On an average, the highest seed cotton yield (2418.55 kg/ha) was obtained when crop was fertilized @ 125 kg K (full at sowing) closely followed by 62.5 kg (full at sowing) (2409.77 kg/ha). However, both these doses were statistically at par. The lowest yield was noted in control (2192.98 kg/ha) where no potassium fertilizer was applied. Hence application of K at economical dose of 62.5 kg per hectare is recommended in tehsil Faisalabad. [ABSTRACT FROM AUTHOR]

A study was carried out at Adaptive Research Farm, Sargodha, Punjab, Pakistan during 2006-07. The objective was to determine the most important factors affecting wheat production in mixed cropping zone of Punjab province. A sample of 200 wheat growing respondents was randomly selected from five villages of four district. i.e. Sargodha, Jhang, Faisalabad and Toba Tek Singh. Cobb Douglas type production function was employed to assess the effect of sowing time, seed rate, education, fertilizers application, irrigation, etc. on wheat yield. Sowing time, rotavator use, education, seed rate, weedicide cost and use of nitrogenous fertilizer were found as contributing factors towards higher wheat yield on sampled respondents farms with co-efficient values of -0.083, 0.07, 0.03, 0.418, 0.081 and 0.092, respectively. So, there is a need to educate the farmers on priority basis for adopting recommended practices. The extension staff can play a pivotal role in this regard. [ABSTRACT FROM AUTHOR]