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The treatment of toxic organic pollutants is extremely important for the conservation of clean air, soil, and water. In this study, (reduced graphene oxide) NiCo _2 O _4 / rGO hybrid nanocomposite was prepared by a facile hydrothermal technique and employed for organic dye adsorption from wastewater. The synthesized NiCo _2 O _4 /rGO hybrid nanocomposite was studied using FTIR, XRD, SEM, TEM, BET, Raman spectroscopy, and UV–visible. The physical characterizations prove the deposition of NiCo _2 O _4 particles on the rGO surface. The transmission electron microscope image demonstrated that the NiCo _2 O _4 particles with an average size of ∼46 nm was dispersed on the rGO surface. The obtained nanoparticles show a higher specific surface area of 56.4 m ^2 g ^−1 . Adsorption dynamics as investigated by time and concentration variation show that the adsorption data follows pseudosecond order kinetics and the Langmuir isotherm model, with a maximum adsorption capacity of 106.2 mg g ^−1 , indicating homogeneous physiochemical adsorption of CR dye on the adsorbent surface. Besides, the catalytic effectiveness of synthesized nanocomposite towards Congo red (CR) dye reduction mediated by the electron (e ^− ) transfer route of BH _4 ^− ions was explained in detail. The electrostatic interaction used between the NiCo _2 O _4 /rGO hybrid composite and Congo red increased the adsorption ion effectiveness of the dye sample.

Industrial areas play an important role in the urban ecosystem. Industrial site environmental quality is linked to human health. Soil samples from two different cities in India, Jamshedpur and Amravati, were collected and analyzed to assess the sources of polycyclic aromatic hydrocarbons (PAHs) in industrial areas and their potential health risks. The total concentration of 16 PAHs in JSR (Jamshedpur) varied from 1662.90 to 10,879.20 ng/g, whereas the concentration ranged from 1456.22 to 5403.45 ng/g in the soil of AMT (Amravati). The PAHs in the samples were dominated by four-ring PAHs, followed by five-ring PAHs, and a small percentage of two-ring PAHs. The ILCR (incremental lifetime cancer risk) of the soil of Amravati was lower compared to that of Jamshedpur. The risk due to PAH exposure for children and adults was reported to be in the order of ingestion > dermal contact > inhalation while for adolescents it was dermal contact > ingestion > inhalation in Jamshedpur. In contrast, in the soil of Amravati, the PAH exposure path risk for children and adolescents were the same and showed the following order: dermal contact > ingestion > inhalation while for the adulthood age group, the order was ingestion > dermal contact > inhalation. The diagnostic ratio approach was used to assess the sources of PAHs in various environmental media. The PAH sources were mainly dominated by coal and petroleum/oil combustion. As both the study areas belong to industrial sites, the significant sources were industrial emissions, followed by traffic emissions, coal combustion for domestic livelihood, as well as due to the geographical location of the sampling sites. The results of this investigation provide novel information for contamination evaluation and human health risk assessment in PAH-contaminated sites in India.

The objective of this work is to develop cost-effective, reliable, and large-scale production of metallic nanoparticles (NPs) by adopting green chemistry principles for industrial applications. In that view, we have studied the phytochemical reducibility of silver nitrate by making use of Calotropis Procera (Ait.) R. Br root extract, and based on its medicinal properties, an attempt was made to evaluate the therapeutic potentials of silver (Ag) NPs containing this plant extract towards the clinical strains of bacteria. The optimization studies on reducing the potentials were done considering the concentration, pH, temperature, and reaction period of both the extract and the metal precursor. The nanoarchitecture elements were interpreted using visual, spectroscopic, and microscopic analyses cohorting the antibacterial potentials towards the clinically significant strains. The antimicrobial activity exercised by these Ag NPs towards 10 different strains of medically important bacteria at a given concentration was proved to be significant. The antimicrobial potential was further validated quantitatively, and the MIC/MBC concentration values were determined. Finally, the cytotoxicity of Ag NPs when tested against the HEPK cell line indicated that the metal-phytochemical moiety exhibited the maximum therapeutic efficacy and thereby paving the way for the development of disruptive technologies in the field of nanomedicine.

Titanium oxide (TiO2) is one of the most scrutinized material because of its in-built fundamental properties and has been developed as an outstanding photo-catalytic material intended for many different industrial applications. In order to further explore the properties of TiO2, we prepared Copper-loaded TiO2 (Cu-TiO2) nanoparticles (NPs) for inhibiting the growth of bacterial cells and also to serve as a chemical sensor. The physico-chemical characteristics of the synthesized Cu-TiO2 NPs were characterized by many different techniques for the crystallinity, bonding and functionality, morphology, elemental composition, and absorption characteristics. From the results, we confirm for the formation of anatase phase of TiO2 having a tetragonal crystal system, while the morphology studies indicated that the Cu dope TiO2 has spherical morphology. The elemental analysis confirmed for the inclusion of Cu into TiO2 crystal lattice and the absorption spectroscopic analysis helped for the bandgap calculation and visible light absorption property of Cu-TiO2 NPs. The metal nanoclusters of Cu are observed to be deposited on different phases and sites of TiO2 resulting in the inter-band transitions. Further, the sensitivity of Cu-TiO2 as a chemical sensor is determined by fabricating the electrode at the FTO glass substrate where the ethanol sensitivity was found to be little increased/enhanced with Cu loading. Finally, the antibacterial activity of Cu-TiO2 NPs was confirmed by its activity against various bacterial cultures and are found to be efficient.

Due to the complexity of high temperature and cutting tool wear, most machined components are still facing problems in terms of harder functional fillers that reinforce aluminium matrix composites. Conversely, abrasive water jet machining (AWJM) incredibly useful for the cutting of anisotropic and non-homogeneous metal matrix composites. In this research article, silicon carbide (SiC) particulates were utilized as reinforcement in the AA6026 matrix material (AA6026/SiC) and machined using AWJM under different process parameters namely SiC loading, traverse speed and stand-off distance. Two different compositions of SiC (4, and 8 wt%) were considered to fabricate AA6026 composites using the stir casting. In addition, outputs have been examined, e.g., surface roughness, material removal rate, and kerf angle. An optical microscope, scanning electron microscope, Brinell hardness tester and universal testing machine have been used to characterize the matrix material AA6026 and its composites. Microstructural analysis revealed that the inclusion of SiC particulates in AA6026 affects the very fine grain size of the composite. Furthermore, the 8 wt% composite exhibits the evolution of the Al-Si eutectic phase during solidification. Processing of these composites was performed using the L _27 orthogonal geometry, successfully improving the parameters of the abrasive water jet process. The output response shows that reducing the SiC load improves the surface roughness under the key parameters of traverse speed and stand-off distance. However, increasing the SiC loading increases the material removal rate and kerf angle under the key parameters, namely traverse speed, and stand-off distance.

The objective of this research is to investigate the extraction and characterization of a particular kind of Indian bamboo family plant known as Bambusa bambos . The fibres were extracted from the bamboo plant in the form of strips using the retting process and separated as thin fibres after the stamping process. The extracted raw bamboo fibres were chemically modified in a 5% alkali solution. The thermogravimetric analysis (TGA), x-ray diffraction (XRD), and scanning electron microscopy (SEM) were used to investigate the thermal, crystalinity, and morphological properties of untreated and alkali (NaOH) treated bamboo fibres. The ASTM standard was followed for the chemical composition and tensile testing of raw and chemically treated bamboo fibres. In contrast to raw bamboo fibres, alkali-treated bamboo fibres had a 5% drop in hemicellulose concentration. In the alkali-treated state, weakly bonded containments were removed from the fiber's surface, exposing the cellulose over a wider surface area. As a result, the thermal stability of the alkali-treated fibres was enhanced as compared to raw bamboo fibres. The increased amount of cellulose content and decreasing aspect ratio of the alkali-treated bamboo fibers lead to increased tensile strength. A significant improvement in the crystallinity index (broad band width of the second peak) was observed in the alkali-treated condition, which may occur due to the removal of hemicelluloses. Based on their performance, the chemically treated bamboo fibres can be used as effective reinforcement elements for the development of polymer matrix composites in the automobile and construction industries.

In this present investigation, Sansevieria cylindrica fiber was used as a reinforcement in a natural rubber matrix. Various biocomposite samples with different fiber contents (lengths and loadings) were fabricated, using compression molding process and vulcanizing technique by maintaining the temperature around 150 °C. From the results obtained, mechanical properties: tensile strength, modulus elongation at break and tear strength of 10.44 MPa, 2.36 MPa, 627.59% and 34.99 N respectively, were obtained from the optimum composite sample with length and loading of 6 mm and 20 wt% composition, respectively. The maximum hardness was observed at 76.85 Shore A from the composite sample of 6 mm and 40 wt%. The optimum properties can be attributed to the presence of strong interfacial adhesion between the Sansevieria cylindrica fiber and the natural rubber matrix. The mechanisms of failure of the biocomposites at their interfaces were examined and analyzed, using scanning electron microscopy (SEM). The micrographs obtained from SEM further confirmed that the Sansevieria cylindrica fibers were surrounded with more amount of natural rubber which can exhibit strong interfacial bonding between fiber and matrix. The optimal composites of this work can be used in general, abrasion resistant conveyor belt.

The increasing global need to achieve sustainability in product development demands the use of biodegradable materials from renewable resources in many engineering applications. Accordingly, various natural fibers were explored as suitable reinforcement in polymer matrixes due to their low density and biodegradability. Hence, in this present work, a novel fiber reinforcement was extracted from the stem of the Cryptostegia grandiflora (CG) plant through a retting process and manual intervention. The extracted Cryptostegia grandiflora fibers (CGFs) were chemically treated using NaOH and silane. Various properties like crystal structure, chemical composition, surface morphology, and thermal degradation were studied using x-ray diffraction (XRD, Fourier transform infrared spectroscopy (FTIR) Scanning electron Microscopy (SEM) and Thermogravimetric analysis (TGA). The increasing cellulose content and the removal of hemicellulose after the chemical treatment indicate the potential for this CG fiber as a better reinforcement element in polymers. The increasing trend of tensile strength was observed for the CG fiber in the following order: silane > NaOH > untreated conditions. Two-stage thermal degradation was observed in all the cases where the maximum thermal degradation was found at the silane-treated CG fibers. Based on their performance, the chemically treated CG fibres can be made into composites and used for structural applications.

In this study, we studied the DNA extraction capability of poly(4,4′-cyclohexylidene bisphenol oxalate) following the surface modification and composite formation with that of microcrystalline cellulose (MCC) and magnetic iron oxide nanoparticles (NPs). The physical characterization techniques like scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) spectroscopy, energy-dispersive X-ray analysis (EDX), and thermogravimetric analysis (TGA) were employed for the poly(bisphenol Z oxalate)-MCC-magnetite composite during different stages of its formation. The results confirmed the successful modification of the polymer surface. On testing in the presence of three types of binding buffers, a high value of 72.4% (out of 10,000 ng/μL) efficiency with a total yield of DNA at 2×106 ng and absorbance ratio of A260/A280 (1.980) was observed for the 2 M GuHCl/EtOH binding buffer. These results were compared against the other two buffers of phosphate-buffered saline (PBS) and NaCl. The lowest value of DNA extraction efficiency at 8125 ng/μL of 58.845% with absorbance ratios of A260/A280 (1.818) for PBS was also observed. The study has concluded an enhancement in the DNA extraction efficiency when the polymer is in the composite stage along with cellulose and magnetite particles as compared against the bare polymer.

Conducting polymers are gaining importance in recent years for their remarkable electrical and ionic properties and so, in order to further improve the fundamental properties, they are being integrated with iron oxide (Fe _3 O _4 ) nanoparticles (NPs). Therefore, in the present study, polypyrrole (PPy) doped with iron oxide NPs to form PPy@Fe _3 O _4 nanocomposite by adopting a simple chemical precipitation method of in situ polymerization. The various spectroscopic (UV–vis, FTIR, Raman, XRD, and XPS), and electron microscopic (FESEM and HRTEM) analysis were employed to study the effects of Fe _3 O _4 NPs onto the polymer mixture. The analysis of results revealed the successful doping of Fe _3 O _4 NPs onto the PPy polymer and also, the Raman spectral studies confirmed not only for the stabilization of doped nanocomposites in its polaronic form but also prevented from the auxiliary oxidation of polymer.

Photocatalysis provides excellent potentials for the complete removal of organic pollutants in environmentally friendly ways and sustainable means of technology. It has been noted that under UV-visible light irradiation, nanostructured semiconductor metal oxides photocatalysts can degrade different organic pollutants. Taking into consideration of the photocatalytic activity, the present study deals with the synthesis of cuprous oxide (Cu _2 O) nanoparticles (NPs) by the sonochemical method and characterized for their physicochemical, optical, and photocatalytic properties. The powdered X-ray diffraction (XRD) analysis confirmed for the cubic phase crystalline structure while the Field emission scanning electron microscopy (SEM) supported for the icosahedron morphology. The bandgap of the synthesized Cu _2 O NPs was found to be 2.26 eV, which is the suitable bandgap energy so as to achieve the enhanced photocatalytic degradation efficiency. On testing for the degradation of Malachite green (MG) as a model pollutant, the synthesized Cu _2 O NPs demonstrated a high degradation efficiency under visible light irradiation. The observed results suggest that the synthesized Cu _2 O NPs are attractive photocatalysts for the degradation of toxic organic wastes in the water under visible light. Further investigation confirmed for the photocatalytic reduction of 4-nitrophenol (4-NP) into 4-aminophenol (4-AP) under aqueous conditions with visible light.

The mesoporous silica nanoparticles (MSNs), because of the synthesis, ease of surface functionalization, tunable pore size, large surface area, and biocompatibility, are being useful in many of the biomedical applications like drug delivery, theranostics, stem cell research, etc. It has been a potent nanocarrier for many different therapeutic agents, i.e., the surface functionalization of silica nanoparticles (SNs) with chemical agents, polymers, and supramolecular moieties enable the efficient delivery of therapeutic agents in a highly controlled manner. Also, the toxicity, biosafety, and in vivo efficiency involving biodistribution, pharmacokinetics, biodegradation, and excretion of MSNs play an important role in its involvement in the clinical applications. A coherence between chemistry and biological sciences extends its opportunities to a wide range in the field of nanomedicine such as smart drug delivery systems, functionalization and gating approach, controlled drug delivery systems, diagnostic and targeted theragnostic approach etc. Thus, taking advantage of the inbuilt properties of the MSNs applicable to the biomedical sector, the present review describes a panorama on the SNs which are presently used for the development of theragnostic probes and advanced drug delivery platforms.

In the present study, a beneficial approach for the ultrasensitive and affordable naked eye detection and diagnosis of tuberculosis (TB) by utilizing plasmonic enzyme-linked immunosorbent assay (ELISA) via antibody-antigen interaction was studied. Here, the biocatalytic cycle of the intracellular enzymes links to the formation and successive growth of the gold nanoparticles (GNPs) for ultrasensitive detection. The formation of different colored solutions by the plasmonic nanoparticles in the presence of enzyme labels links directly to the existence or non-existence of the TB analytes in the sample solutions. For disease detection, the adapted protocol is based mainly on the conventional ELISA procedure that involves catalase-labeled antibodies, i.e., the enzymes consume hydrogen peroxide and further produce GNPs with the addition of gold (III) chloride. The amount of hydrogen peroxide remaining in the solution determines whether the GNPs solution is to be formed in the color blue or the color red, as it serves as a confirmation for the naked eye detection of TB analytes. However, the conventional ELISA method only shows tonal colors that need a high concentration of analyte to achieve high confidence levels for naked eye detection. Also, in this research, we proposed the incorporation of protein biomarker, Mycobacterium tuberculosis ESAT-6-like protein esxB (CFP-10), as a means of TB detection using plasmonic ELISA. With the use of this technique, the CFP-10 detection limit can be lowered to 0.01 µg/mL by the naked eye. Further, our developed technique was successfully tested and confirmed with sputum samples from patients diagnosed with positive TB, thereby providing enough evidence for the utilization of our technique in the early diagnosis of TB disease.

A semiconducting water-soluble core-shell quantum dots (QDs) system capped with thiolated ligand was used in this study for the sensitive detection of glucose in aqueous samples. The QDs selected are of CdSe-coated ZnS and were prepared in house based on a hot injection technique. The formation of ZnS shell at the outer surface of CdSe core was made via a specific process namely, SILAR (successive ionic layer adsorption and reaction). The distribution, morphology, and optical characteristics of the prepared core-shell QDs were assessed by transmission electron microscopy (TEM) and spectrofluorescence, respectively. From the analysis, the results show that the mean particle size of prepared QDs is in the range of 10–12 nm and that the optimum emission condition was displayed at 620 nm. Further, the prepared CdSe/ZnS core shell QDs were modified by means of a room temperature ligand-exchange method that involves six organic ligands, L-cysteine, L-histidine, thio-glycolic acid (TGA or mercapto-acetic acid, MAA), mercapto-propionic acid (MPA), mercapto-succinic acid (MSA), and mercapto-undecanoic acid (MUA). This process was chosen in order to maintain a very dense water solubilizing environment around the QDs surface. From the analysis, the results show that the CdSe/ZnS capped with TGA (CdSe/ZnS-TGA) exhibited the strongest fluorescence emission as compared to others; hence, it was tested further for the glucose detection after their treatment with glucose oxidase (GOx) and horseradish peroxidase (HRP) enzymes. Here in this study, the glucose detection is based on the fluorescence quenching effect of the QDs, which is correlated to the oxidative reactions occurred between the conjugated enzymes and glucose. From the analysis of results, it can be inferred that the resultant GOx:HRP/CdSe/ZnS-TGA QDs system can be a suitable platform for the fluorescence-based determination of glucose in the real samples.