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Benzotriazole loaded Cellulose reinforced 2 k polyamide coating system was developed to check the Corrosion inhibition performance of mild steel in 3.5 wt% nacl solution. Self-healing coatings were prepared utilizing cellulose nano fiber as a carrier for the Benzotriazole (BTA) with different loadings of 2, 4 and 6 wt%. Cellulose consists of hydroxyl groups and has sulphate and half ester groups on its surface that are acquired during Sulphuric acid hydrolysis of delignified sawdust. These hydroxyl and sulphate groups are negatively charged and provides anions to develop patina on the site of damaged coatings of mild steel for providing corrosion protection. TEM images confirmed the extracted cellulose nano fibres having cylindrical hallow shape with an average length of 176 nm and a lumen of 23 nm in size. The Electrochemical Impedance Spectroscopy (EIS) following 120 h of immersion proved that corrosion rate was decreased for BTA stacked cellulose reinforced coatings when compared to coatings without reinforcement. While Potentio dynamic examinations shows decrease in current density with increase in corrosion potential (Ecorr) for bare, standard, and for different compositions of CNB. It was also observed that the decrease in corrosion rate with respect to weight loss by reinforcement of encapsulated BTA in cellulose nano fibers implies better corrosion inhibition when compared to Bare and standard coatings of mild steel.

Halloysite nanotubes were used as nanocontainers to hold corrosion inhibitors such as Ce3+-Zr4+, 2-mercaptobenzothiazole and 8-hydroxyquinoline in their lumen. An acid assisted etching of the nanotubes was carried out with a view to increase the lumen diameter and thereby, increase the amount of loading of the corrosion inhibitor. The morphology of as-received and etched halloysite nanotubes was observed using TEM analysis. The loading of corrosion inhibitors was confirmed using SEM-EDS and BET analysis. Polymeric microcapsules were used as capping agents for the ends of the loaded HNTs following which, they were dispersed into a hybrid sol-gel silica matrix. Dip coating method was used to generate coatings on AZ91D substrates followed by heat treatment at 130 °C for 1 h. The release rate kinetics of corrosion inhibitors from as-received and etched nanotubes was investigated in buffer solutions of 3.5 wt% NaCl at different pH. The release mechanism of corrosion inhibitors from the HNT lumen was validated using various semi-empirical models. Coatings were also evaluated for their corrosion protection ability using electrochemical techniques after exposure to 3.5 wt% NaCl solution for 120 h. Coatings generated using Ce3+-Zr4+ loaded into as-received halloysite nanotubes have shown more effective corrosion protection when compared to other corrosion inhibitors after 120 h exposure to the corrosive medium.

Self-healing coatings were prepared for corrosion inhibition of mild steel by amino Silanization of lignin nano capsules. In-situ polymerization techniques through sonochemical approach was used for preparation of lignin nano capsules. Coatings have been developed using natural healing materials such as combination of lignin and safflower oil and coupling agents i.e APTES in water borne epoxy curing agent. Successful encapsulation of lignin and safflower oil was carried out via in-situ polymerization with the aid of urea–formaldehyde pre-polymer solution in presence of surfactant polyvinyl alcohol (PVA). Further Functionalization of lignin nanocapsules was done by amino Silanization. TEM and FE-SEM images confirm the encapsulation of nano particles and its histogram gives the average particle size distribution of the lignin nano particle and Capsuleas 106 and 146 nm. Total phenolic content of lignin extract were found to be 936 mg GAE/g. Potentio dynamic polarization studies revealed that the current density decreases to minimum of 3.703E-8A/cm2 with increase in weight percentage of lignin in nanocapsules (1.5 wt%) . Electrochemical Impedance spectroscopy showed a maximum impedance value as 6.44E6 for 1.5 wt% LNC coatings. Immersion studies give better corrosion rate for 1.5 wt% LNC coatings when compared to bare and standard coatings.

In this study, halloysite nanotubes polyaniline (HNT-PANI) nanocomposite was synthesized by using an ultrasound-assisted method. Because of high conductivity, ease of synthesis, low cost, nanosize tubular structure and improved structural/electrochemical properties, HNT-PANI had been used for the electrode fabrication of a supercapacitor. The dispersion of halloysite nanotubes in polyaniline was prepared by following an ultrasound approach. The structural and morphological studies of the HNT-PANI nanocomposite were investigated by X-ray diffraction, Fourier Transform Infrared Spectroscopy, Raman and transmission electron microscopy. The length of the halloysite nanotubes varied from 200 to 1000 nm and the composite nanoparticles possessed tubular hallow shaped structure. The electrochemical performance of the HNT-PANI nanocomposite electrode was analyzed after performing potentiodynamic and electrochemical impedance spectroscopic studies. The crystallite size of HNT-PANI composite was calculated and the average size ranged from 30 to 100 nm. HNT-PANI composite electrode exhibited the highest specific capacitance of 282.5 F/g at a current density of 0.5 A/g.

The fact that some of solid materials with suitable phases possess higher thermal conductivity than liquids gave rise to their utilization in heat transfer processes. Fluids that contain nanopartic...

This work deals with sonochemical synthesis of finely dispersed reduced graphene oxide–TiO2 (rGO/TiO2) nanocomposites with successful immobilisation of TiO2 nanoparticles on rGO. Structural and mor...

Halloysite nanotubes are inorganic clay minerals of kaolin group. Halloysite possess unique morphology, chemical composition, cation exchange capacity and charge properties making them ideal candidate for various industrial application. In the present study, an attempt was made to functionalize the exterior surface of halloysite nanocontainer. The surface of halloysite nanocontainer was modified using tetrabutylammonium chloride (TBAC). Further an attempt was made to employ these functionalized nanocontainers to uptake and release the active molecule (dye Acid Red1). TBAC-modified nanocontainer indicated higher adsorption capacity of 4.54 mg/g as compared to unmodified nanocontainer (3.08 mg/g). The release behaviour of active molecule from loaded nanocontainers was found with change in pH and temperature. Since the loading characteristics of functionalized nanocontainers were found to be adsorption dependent, parameters such as effect of time, loading, pH, initial concentration were studied for analysing the loading characteristics. The dye release from 0.5 g dye-loaded TBAC-modified nanocontainers at pH 11 and at 32 °C was found to be 92%. Lastly, the release readings were analysed for the best fit (97%) using permeation kinetic model (Peppa’s model).

In the present work, the synthesis of ternary chitosan/zinc oxide/titanium dioxide (CTS-ZnO-TiO2) nanocomposite was carried out with the use of mechanical stirring (conventional) and ultrasound assisted method. The characterization of prepared CTS-ZnO-TiO2 adsorbent was carried out using XRD, TEM, FTIR and the results of these analysis methods proved the successful preparation of ternary nanocomposite. Crystal violet (CV) dye was used as a pollutant to observe the adsorption ability of the prepared nanocomposite and the nanocomposite prepared by ultrasonic-assisted method proved to be a better adsorbent. The CV dye adsorption was significant for CTS-ZnO-TiO2 nanocomposite synthesized with the use of ultrasound assisted method compared to that prepared by conventional method. It is due to the physical effects of the ultrasonic irradiations due to which formation of finely dispersed nanocomposite takes place than that by conventional method. For batch adsorption the effect of various operating parameters such as initial dye concentration, time, temperature and adsorbent dose has been evaluated. The obtained data were processed using isotherm models, adsorption kinetics and the thermodynamic behavior of the cationic dye adsorption was also studied. The isotherm data was correlated reasonably well by the Temkin adsorption isotherm. Pseudo-second-order kinetic model provided a better correlation for the experimental data compared to pseudo first order, Elovich model and power function kinetics model. Thermodynamic parameters for adsorption indicated that the dye adsorption was spontaneous and endothermic in nature.

Peroxypropionic acid (PPA) is an important organic chemical compound. Due to its versatile oxidizing properties, it is used in the oil, chemical and other industries. In this article, an attempt was made for the production of PPA in a Teflon helical capillary microreactor without and with homogeneous catalyst. The article reports the perhydrolysis of PPA with the effect of various parameters such as concentration of hydrogen peroxide, molar ratio of reactants, radius of curvature of the microreactor, concentration of catalyst and temperature. The reaction is slow, as the PPA equilibrium was found to be reached within 10 min at a temperature of 50 °C and at 10 mol % catalyst loading based on propionic acid. The reaction was carried out in 13.25 and 23.25 mm radius of curvature of the microreactor in which 4.0375 and 3.488 mol/L concentrations of PPA respectively were obtained at 50 ºC and 10 mol % catalyst. It indicates that as radius of curvature decreases, better mixing was provided among the reactants for the reaction to give enhanced yield and selectivity. From the experimental data and the kinetic expressions, the expressions of activation energies and reaction rate constants were determined. For PPA synthesis and hydrolysis, the activation energies were 43.897 and 20.658 kJ/mol respectively without catalyst, while the activation energies for both the cases were 42.314 and 17.514 kJ/mol respectively with catalyst of 10 mol% based on propionic acid. The dean number, curve tube friction factor and pressure drop also determined for the helical capillary microreactor.

In this work, decolorization of rhodamine-B (Rh-B) dye was investigated by using a hybrid treatment technique involving hydrodynamic cavitation (HC) and hydrogel adsorption. Halloysite nanoclay embedded poly-acrylic acid (PAA) nanocomposite hydrogel was prepared by using the ultrasound polymerization technique. Halloysite nanoclay and the synthesized hydrogels were further characterized by using TEM analysis were carried out in order to confirm the structure and morphology of the respective materials. Decolorization of Rh-B dye was carried out by HC followed by adsorption of dye molecules on the hydrogel nanocomposite. Effect of different operating parameters such as inlet pressure to the cavitation device, effect of clay content in the hydrogel, effect of hydrogel loading in adsorption column, the effect of pH on Rh-B dye removal was tested. The individual effects of HC and hydrogel adsorption on Rh-B dye removal were also studied. It was found that the HC assisted hydrogel nanocomposite adsorption shows the decolorization of 65% at the optimized operating conditions such as, pH 7.62, 0.5 g clay loaded nanocomposite hydrogel, and 25 g of hydrogels loading in adsorption column. Addition of H2O2 into the hybrid system further enhances the decolourization of Rh-B dye to 72.85% with 45% of total organic carbon removal at the optimum conditions.

Highlights • Cellulose nanocrystals (CNCs) were produced from cotton using ultrasound treatment. • The structural and thermal properties of the CNCs were enhanced. • The crystallinity of CNCs has been increased due to the combined effect. • TEM images shows the acid concentration had a significant effect on the shape of CNCs. • The synthesized CNCs can potentially be used for various applications., This present work reports the synthesis of Cellulose nanocrystals (CNCs) from cotton using an ultrasound-assisted acid hydrolysis. Further, the synthesized CNCs was comprehensively characterized using Fourier Transform Infrared Spectroscopy (FTIR) to analyze surface functional groups and X-ray diffraction (XRD) in studying structural characteristics. Differential Thermal Analysis (DTA) and Thermogravimetric Analysis (TGA) have been used to study the thermal properties of CNCs. Morphology of CNCs was studied using a Transmission Electron Microscope (TEM) and Scanning Electron Microscope (SEM). The crystallite size was found to be 10–50 nm using XRD data and the average particle size to be 221 nm using PSD analysis.

A Polymer Electrolyte Membrane (PEM) fuel cell is a device in which an electrochemical reaction occurs between fuel and oxidant producing electricity and water is the only by-product with zero emission. Usually, Pt nanoparticles prepared on carbon support used as oxidation and reduction reaction in PEM fuel cells. Because, carbon-supported platinum shows better oxidation and reduction activity among all the pure metals. Alloying of Pt with another non-noble metal is a strategy to develop Pt-based electrocatalysts, which reduces the Pt loading in electrodes and alters the intrinsic properties such as active sites available on surface and binding strength and electronic effect of species. Carbon support loss its catalytic activity due to electrooxidation under fuel cell operating conditions for long-term operations. In particular, the encapsulation of carbon with polyaniline (PANI) supported Pt enhances the electrode stability in fuel cells by Enhancing the Active Surface Area (EASA), chemical resistance and electron conductivity. Different supported catalysts have been proposed to improve electrochemical stability of nanoparticles in PEM fuel cells and supercapacitor.

Encapsulation is the process of stabilization of active compounds through the structuring of systems capable of preserving their chemical, physical, and biological properties, x their release or delivery under established or desired conditions In the process of encapsulation, either one or the mixture of bioactive material is coated with another single material or combination of materials. In encapsulation, two main terminologies are frequently used. One is the material that is being coated is termed active material or core material, and the other is the shell material that is also termed carrier material (shell). The shell material can be in solid, liquid droplets, and gas bubbles to encapsulate liquid or gas inside as a core. The core and shell structure can be in various shapes such as the sphere, microcapsules, microbeads, monocore, multicore, matrix, and multishell.

A simple hydrothermal method is adopted to prepare ternary Mn doped ZnO nanoparticles uniformly grafted on reduced graphene oxide (RGO) sheets. The effect of Mn doping on ZnO/RGO nanocomposite has been investigated using different characterization techniques. Field emission scanning electron microscope (FESEM) images clearly show the uniform distribution of nanoparticles on RGO sheets. The doping of Mn in ZnO/RGO composites have been confirmed by X-ray photoelectron spectroscopy (XPS). Photocatalytic activities of as-prepared samples were examined by the degradation of Rhodamine B (RhB) and Congo red (CR) under sun light. The prepared ternary heterojunction photocatalyst exhibit the excellent photocatalytic activity for degradation of RhB (degradation rate nearly 99% within 140 min) and CR (degradation rate nearly 100% within 160 min) under sunlight irradiation which is higher than that of binary ZnO/RGO heterojunction. The improved photocatalytic performance of the ternary nanocomposite can be ascribed to extend solar light absorption, enhanced adsorption of the composite catalyst surface and efficient charge separation of photo-induced electrons.

In the present study, aluminum pillared montmorillonite clay was modified with cationic corrosion inhibitors Ce3+/Zr4+. The modification of the montmorillonite clay was carried out by two methods; (a) by simple mixing of inhibitor solutions along with clay by stirring for 30 min and (b) by homogenization of inhibitor solutions and clay for a very short time of 15 min followed by evacuation. The modified and as-received clays were dispersed in hybrid organic-inorganic sol-gel matrix silica sol, which were coated on magnesium alloy AZ91D and cured in air at 130 °C for 1 h. Corrosion protection ability of coatings was evaluated by electrochemical impedance spectroscopy, potentiodynamic polarization and weight loss measurements after exposure to 3.5 wt% NaCl solution for different exposure durations between 24 h to 120 h. Coatings were evaluated for their self-healing ability using scanning vibrating electrode technique for varying time duration from 1 h to 24 h. Coatings generated with the sol using the pillared montmorillonite clay after modification as described in (b) were found to exhibit better anticorrosive properties even after prolonged exposure to the corrosive medium.

This study emphasizes on the evaluation and comparison of the anticorrosive properties of sol–gel coatings with and without inhibitor loaded nanocontainers. In this case, naturally available clay nanotubes (halloysite) were loaded with cationic corrosion inhibitors Ce3+/Zr4+. These nanocontainers were dispersed in hybrid organic–inorganic sol–gel matrix sol. Coating was applied on magnesium alloy AZ91D using the sols containing modified and unmodified nanocontainers employing the dip coating method and cured at 130 °C for 1 h in air. Corrosion resistance of coated/uncoated substrates were analyzed using electrochemical impedance spectroscopy, potentiodynamic polarization and weight loss measurements after exposure to 3.5 wt% NaCl solution for varying time durations between 24 h to 120 h. Self-healing ability of coatings was evaluated by micro-Raman spectroscopy after 120 h exposure to 3.5 wt% NaCl solution. Coatings generated after dispersion of corrosion inhibitor loaded clay in hybrid sol–gel matrix have shown more promising corrosion resistance when compared to just the sol–gel matrix coatings, after prolonged exposure to corrosive environment. Keywords: Self-healing coating, Halloysite nanoclay, Cationic corrosion inhibitors, Magnesium alloy AZ91D, Micro-Raman spectroscopy, Corrosion protection

The present study deals with the successful preparation of kaolin/chitosan/titanium dioxide (KL-CTS-TiO2) ternary hybrid nanocomposite adsorbent using conventional and ultrasound assisted method synthesis. The particle size (observed form TEM image) of TiO2 nanoparticles dispersed in the nanocomposite was found to be around 5 nm for U-KL-CTS-TiO2 nanocomposite (ultrasonically prepared), which is lesser compared to conventionally prepared nanocomposite. The average particle size of U-KL-CTS-TiO2 nanocomposite was observed to be 293 nm which is very less compared to C-KL-CTS-TiO2 nanocomposite (prepared by conventional method) that is 439 nm. The BET surface area of U-KL-CTS-TiO2 nanocomposite was found to be 116.5 m2/g which is significantly higher than the C-KL-CTS-TiO2 nanocomposite (4.95 m2/g). In batch adsorption experiments the effect of initial dye concentration, time, temperature, and adsorbent dose was studied and equilibrium data, adsorption kinetics and adsorption isotherms parameters are reported. The adsorption equilibrium data was best fitted by Freundlich isotherm compared to the Langmuir and Temkin model for U-KL-CTS-TiO2 and C-KL-CTS-TiO2 nanocomposite. The % removal of CV dye for 2 g/L loading of U-KL-CTS-TiO2 and C-KL-CTS-TiO2 nanocomposite was found to be 93.30% and 85.49%, respectively. The higher adsorption in the case of U-KL-CTS-TiO2 nanocomposite is attributed to the physical effects of ultrasound which are responsible for the preparation of finely dispersed KL-CTS-TiO2 nanocomposite compared to conventional method. Finely dispersed KL-CTS-TiO2 nanocomposite provides more sites for the adsorption which in turn enhances the adsorption capacity of CV dye on ultrasonically prepared KL-CTS-TiO2 nanocomposite.

In this work, intensification of removal of crystal violet (CV) dye in terms of total organic carbon (TOC) from aqueous media has been investigated by a novel hybrid treatment technique involving hydrodynamic cavitation (HC), and hydrogel adsorption. Hydrodynamic cavitation (HC) combined with poly-acrylamide (PAM) hydrogel nano-composite was studied for CV dye removal. TiO2 nano-particles embedded poly-acrylamide (PAM) nano-composite hydrogel was prepared by using the ultrasound polymerization technique. Characteristics of TiO2 nano-particles and hydrogel nano-composite were studied by using XRD and TEM analysis respectively. Degradation of CV dye was carried out by hydrodynamic cavitation and subsequent adsorption of dye molecules were carried out in hydrogel adsorption column. Effect of different operating parameters such as inlet pressure to the cavitation device (orifice), the effect of TiO2 loading in PAM hydrogel, effect of hydrogel loading in the adsorption column was studied. For hydrogel loading of 5 g/L and inlet pressure to orifice at 3 bar, the hybrid system intensifies the removal of dye in terms of operating time compared to its individual operation. Studies revealed that the PAM-TiO2 hydrogel obeys the pseudo-second order kinetic model for CV dye adsorption. Two adsorption isotherm models such as Langmuir and Freundlich were evaluated in order to identify the adsorption behavior.

Critical Heat Flux or CHF is a phenomenon in pool boiling, which limits the thermal flux during the nucleate heating phase. Presented research paper is an investigation of the CHF of Al2O3, Fe2O3 and CuO nanoparticles in water as base fluids. Critical Heat Flux of water and nanofluids were measured at 100 °C and 0.10325 MPa using 29 × 22 W DC power supply and NiCr 32AWG wire as the primary heater. Concentration of nanoparticles in the respective base fluids was varied from 0.01 vol% to 0.1 vol% in the step of 0.1%. Nanofluids were used as the working fluid and sent to circular bath. A significant enhancement in CHF was found of nanofluid over base fluid is found in the study. As the concentration of nanoparticles in water increases, the CHF also increases up to their optimum concentration and then starts to drop and almost becomes constant at 0.1%. The enhancement is due to enhanced surface wettability, increased heat transfer coefficient and nanoparticle deposition on heating element. The decrease in CHF over higher concentration is due to probable agglomeration due to prevalent surface charges of nanoparticles.

This work deals with encapsulation of corrosion inhibitor in inorganic nanocontainer and the investigation of the corrosion inhibition rate from the nanocontainer. Halloysite nanotubes were used as inorganic nanocontainer for encapsulating the active corrosion inhibitor. These cylindrical shaped halloysite nanotubes are a natural aluminosilicate, which possesses similar chemical composition as that of pure kaolin clay. The structural morphology and functional organic attachments to the halloysite nanocontainers were determined by using TEM and FTIR analysis. It is found that, halloysite nanocontainers are having external and internal lumen is in nanosize (diameter) and length up to several micrometers. A maximum benzotriazole loading up to 10% (by weight) was achieved in inorganic nanotube of 50 nm external diameters and lumen of 15 nm. The release of corrosion inhibitor was carried out for 18 h at different pH ranging from 3 to 10. The weight percent of the benzotriazole encapsulated halloysite nanocontainer was varied from 2 to 10 and then dispersed in 2K clear coat epoxy-polyamide. The self-healing anticorrosion performance of these nanocomposites coating was tested with help of electrochemical impendence spectroscopy (EIS) and Tafel plot. From Tafel plots it is found that the Icorr value decreases to 1.018E–7A/cm2 from 0.018 A/cm2, when coating was applied with 2 wt % nanocontainer.

Mg doped ZnO nanoparticles decorated on graphene oxide (GO) sheets were synthesized by a wet impregnation method. The effect of Mg doping on ZnO and ZnO-GO composite has been evaluated by using x-ray diffraction (XRD), Williamson-Hall Plot (W H Plot), field emission scanning electron microscope (FESEM), transmission electron microscopy (TEM) and energy dispersive x-ray spectroscopy (EDX). The physical parameters of as-prepared samples were estimated by XRD data. FESEM and HR-TEM images showed the uniform distribution of nanoparticles on GO crumpled paper like sheet. Solar light photocatalytic activities of samples were evaluated spectrophotometrically by the degradation of p-nitrophenol (PNP) and indigo carmine (IC) solution. Mg ZnO decorated on GO sheets exhibit excellent catalytic efficiency compared to all other prepared samples under identical conditions, degrading PNP and IC nearly 99% within 60 min under sunlight. The effective degradation by Mg ZnO decorated on GO sheet would be due to extended solar light absorption, enhanced adsorptivity on the composite catalyst surface and efficient charge separation of photo-induced electrons. Finally, plausible mechanism was suggested with the help of scavengers study.

The present work deals with the preparation of graphene oxide (GO) using Hummers-Offeman method in the presence of ultrasonic irradiations. Further loading of TiO2 photocatalyst on prepared GO was accomplished which is basically oxidation reduction reaction between graphene oxide and titanium isopropoxide that leads to the formation of graphene-TiO2 nanocomposite. Graphene-Ce-TiO2 and Graphene-Fe-TiO2 nanocomposites were prepared using one step in-situ ultrasound assisted method using GO, titanium isopropoxide, cerium nitrate, ferric nitrate, and 2-propanol. The successfully prepared graphene-TiO2, Graphene-Ce-TiO2, Graphene-Fe-TiO2 nanocomposites were then characterized using XRD, SEM and TEM analysis. The obtained XRD patterns clearly indicates the formation of anatase TiO2 on graphene nanosheets and it also indicates the presence of Ce and Fe in the Graphene-Ce-TiO2 and Graphene-Fe-TiO2 nanocomposite respectively. Further the use of the prepared nanocomposites as a photocatalyst have been studied for the degradation of crystal violet dye. The effect of various parameters such as catalyst doping, catalyst loading and initial concentration of dye on its degradation were studied. The effectiveness of the prepared catalysts were compared for the degradation of crystal violet dye. It has been observed that Graphene-Fe-TiO2 exhibits maximum photocatalytic activity compared to Graphene-Ce-TiO2 and Graphene-TiO2 nanocomposite photocatalyst.

In the current work smart coating of corrosion inhibitive nanocontainer was developed based on the encapsulation of ultrasonically synthesized Zinc Molybdate (ZM) nanoparticles. The ZM nano...

In the present work, synthesis of iron oxide nanoparticles (NPs) using continuous flow microreactor (MR) and advanced flow™ reactor (AFR™) has been investigated with evaluation of the efficacy of the two types of MRs. Effect of the different operating parameters on the characteristics of the obtained NPs has also been investigated. The synthesis of iron oxide NPs was based on the co-precipitation and reduction reactions using iron (III) nitrate precursor and sodium hydroxide as reducing agents. The iron oxide NPs were characterized using transmission electron microscopy (TEM), Fourier transform infrared spectroscopy, and X-ray diffraction (XRD) analysis. The mean particle size of the obtained NPs was less than 10 nm at all flow rates (over the range of 20−60 ml/h) in the case of spiral MR, while, in the case of AFR™, the particle size of NPs was below 20 nm with no specific trend observed with the operating flow rates. The XRD and TEM analyses of iron oxide NPs confirmed the crystalline nature and nanometer size range, respectively. Further, magnetic properties of the synthesized iron oxide NPs were studied using electron spin resonance spectroscopy; the resonance absorption peak shows theg-factor values as 2.055 and 2.034 corresponding to the magnetic fields of 319.28 and 322.59 mT for MR and AFR™, respectively.

In the present study, heat transfer enhancement with the use of water based PANI (polyaniline) nanofluid was investigated in vertical helically coiled tube heat exchanger. Initially, PANI nanofibers were prepared with the use of ultrasound assisted emulsion polymerization method. Then the prepared PANI nanofibers were dispersed in base fluid in varying concentration (0.1–0.5 vol%) in order to get uniformly dispersed PANI nanofluid in the presence of sonication. The effect of PANI nanofibers concentration in nanofluid and Reynolds number on heat transfer coefficient have been investigated in helical coiled heat exchanger. It was found that the average heat transfer coefficient increases with an increase in the volume% of PANI nanofibers in nanofluid and Reynolds number. The heat transfer coefficient of base fluid i.e. distilled water was found to be 304 W/m 2 °C (at x i / D = 692.3) whereas it was found to be increased to 515.8 W/m 2 °C (at x i / D = 692.3) for 0.5 vol% PANI concentration in nanofluid. The percentage enhancement in the heat transfer coefficient was found to be 10.52% at 0.1 vol% of PANI nanofibers in nanofluid and was found to be increased to 69.62% for 0.5 vol% of PANI nanofibers.

The present study deals with preparation of emulsion liquid membrane (ELM) in hydrodynamic cavitation system using organic phase containing Aliquat 336 carrier, diluents i.e., kerosene and Span 80 surfactant and stripping phase (0.1 M NaOH solution). Further experimental investigation on extraction/removal of Pb (II) from feed solution containing Pb (II) was conducted with the use of hydrodynamic cavitationally prepared ELM. Influence of the several process parameters like carrier concentration, surfactant concentration, strength of stripping solution, cavitation time and size of orifice during preparation of ELM phase and ELM to feed water ratio on extraction/removal of Pb (II) from feed solution was investigated during experimental runs. Almost 100% removal/extraction efficiency Pb (II) from feed solution was observed with the use hydrodynamically prepared ELM for the optimised condition of 2 mm orifice diameter, 1:05 ELM to feed water ratio, 0.1 M NaOH strength of stripping solution, 3% (v/v) Span 80 surfactant concentration, and 1% (v/v) carrier concentration. Further, artificial neural network (ANN) modeling was used for the prediction of % extraction efficiency of Pb (II) from feed solution. Hence, the use of hydrodynamic cavitation-based novel process for synthesizing ELM having outstanding stability is possible for removal/extraction of Pb (II) from aqueous feed phase.

In the present work, degradation of methylene blue (MB) dye in aqueous solution by using hydrodynamic cavitation combined with H2O2 and Bi-doped TiO2 photocatalyst was investigated. Bi-doped TiO2 photocatalyst was prepared by using a sol-gel synthesis method. The synthesized Bi-doped TiO2 material was characterized by X-ray diffraction spectra (XRD), FT-IR and TEM. The effect of various operating parameters such as inlet fluid pressure, solution pH, addition of H2O2 and photocatalyst on the degradation of MB dye were studied. The maximum extent of degradation of methylene blue was obtained at inlet pressure of 5 bar and pH 2. The molar ratio of MB: H2O2 i.e. 1:20 was shown 94.64% of MB decolorization over 60 min. Combination of hydrodynamic cavitation and H2O2 has shown high synergetic effect than the combination of hydrodynamic cavitation and Bi-doped TiO2 photocatalytic process.

This work first time reports the intensification of real wastewater treatment by combination of hydrodynamic cavitation (HC), Fenton reagent, and membrane separation. In this work, a micro-porous ceramic membrane was used for the preparation of nano-porous catalytic membrane reactor. Initially, the aluminium boehmite sol has been synthesized and coated onto the tube side of the ceramic membrane by wet impregnation technique. A layer by layer technique was adopted for the wet impregnation of boehmite sol onto the ceramic membrane. After achieving a desired number of layers coating onto the ceramic membrane, a prepared catalyst sol was further used for coating. The dried boehmite powder was characterized using X-ray diffractometer and particle size distribution analysis. Mercury intrusion porosimetry (MIP) technique was used to identify the pore size distribution of modified ceramic membrane. The modified ceramic membrane was used in conjunction with HC for industrial dye wastewater treatment. The impact of process parameter such as cavitation unit (orifice) inlet pressure, intensifying chemical additive like Fenton reagent, and H2O2 dosage was investigated. HC along with intensifying chemical additives H2O2 and Fenton reagent improved the organic pollutants removal from textile industry wastewater

In this study, a novel nanocomposite of bimetallic Ag–Co nanoparticles supported on cellulose nanofibers (CNFs) was synthesised using the ultrasound-assisted wet-impregnation method for catalytic applications. CNFs were prepared from cellulose acetate using the electrospinning technique. Fourier transform infrared spectroscopy (FTIR) analysis confirmed the successful synthesis of CNFs. Further, scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDX) revealed a uniform dispersion of Ag and Co metals on the CNFs. At the same time, X-Ray diffraction (XRD) spectra indicated the highly crystalline nature of the as-produced composite. The hydrogenation of 4-nitrophenol (4-NP) was used to study the efficiency of the synthesised nanocomposite. The progress of the reaction was examined via UV–visible spectroscopy. It was noted that Ag-Co nanoparticles supported on CNFs catalysed the hydrogenation of 4-NP (0.1 mM) to 4-aminophenol within just 110 s with an apparent rate constant of 0.0172 s−1. This study proved that the obtained catalysts have superior stability and reusability with about 100% conversion up to 5 cycles. The excellent activity of the as-synthesised Ag-Co/CNFs nanocomposites makes it a promising nanocatalyst for catalytic applications.

Magnesium alloys are preferred extensively in automobile and aerospace industries, because of their very low density and high-specific strength. However, magnesium alloys are unstable in highly corrosive environments because of their extremely low standard electrode potential (−2.37 V). One of the most promising approaches to overcome this limitation is the use of eco-friendly and versatile sol-gel coatings. In the present work, corrosion-inhibition ability of various corrosion inhibitors, such as Ce3+-Zr4+, 8-hydroxyquinoline and 2-mercaptobenzothaizole, was evaluated on magnesium alloy AZ91D. For this purpose, inhibitors were loaded in as-received halloysite nanotubes (HNTs), which were then end-stoppered using polymeric microcapsules and dispersed in a hybrid silane matrix. The surface morphology of raw and inhibitor-loaded HNTs was examined with transmission electron microscopy analysis, whereas Brunauer-Emmett-Teller and scanning electron microscopy/energy-dispersive X-ray spectroscopy analyses were carried out to verify the encapsulation of inhibitors. The coatings were developed on coupons of AZ91D by the dip-coating technique, which were then thermally cured for 1 h at 130°C. The anticorrosion ability of inhibitor-encapsulated, HNT-based sol-gel coatings on AZ91D was evaluated using electrochemical impedance spectroscopy and potentiodynamic polarization for different durations of exposure to sodium chloride solution of 0.6 M concentration. Salt spray analysis was also carried out according to ASTM B117, Standard Practice for Operating Salt Spray (Fog) Apparatus, to examine the anticorrosion ability of coatings for a prolonged duration of exposure, 168 h. Electrochemical measurements and salt spray analyses have revealed that Ce3+-Zr4+-loaded HNT-based coatings were found to give better anticorrosion properties during prolonged durations of exposure to extremely corrosive environments, such as a 0.6 M sodium chloride solution.

The industrial waste water is always a bottleneck problem in the modern civilization of the present era. In a quest to develop effective methods for the elimination of lethal pollutants from the waste water and water remediation, this work is focused on the development of a rapid and proficient approach for preparing supported binary metal oxide catalyst for photocatalytic advance oxidation process used in waste water treatment applications. The sonochemical synthesis of novel S-scheme Bi2O3-ZnO supported on bentonite clay nanocomposite is demonstrated for the photocatalytic oxidation of Congo red (CR). The effectiveness of catalyst to degrade CR dye was determined using UV–visible spectroscopy under different experimental conditions such as catalyst loading, time of UV exposure and concentration of H2O2. The synthesized catalyst demonstrated excellent photocatalytic oxidation under UV light. The pseudo-first-order rate constant obtained for this reaction was 0.029 min−1. Nearly total degradation of CR dye was achieved in 1 h under UV light irradiation using the catalyst. This remarkable increase in the catalytic performance of Bi2O3-ZnO/bentonite clay is due to the S-scheme mechanism of charge transfer between ZnO and Bi2O3, through enhanced redox potential. Also, its efficient recoverability and reusability (5 times) establish its promising potential for catalytic applications.

The present work deals with two parts, the first one deals with the synthesis of Fe2O3 nanoparticles using acoustic and hydrodynamic cavitation techniques and the second one deals with layer by layer (LBL) assembly of Fe2O3 nanocontainers by loading a corrosion inhibitor, benzotriazole, in polyelectrolyte layers. The nanoparticles obtained from both these techniques are used as a core in the preparation of nanocontainers. The morphology of the nanoparticles and nanocontainers was analyzed by TEM. The release rate and corrosion inhibition properties of nanocontainers were evaluated for various prepared samples. Electrochemical impedance test and corrosion inhibition performance of Fe2O3 nanocontainers dispersed in epoxy coating were also evaluated. The presence of nanocontainers in the epoxy resin decreases the corrosion rate from 7.6 to 0.05 mm/year.

In the present investigation, hybrid treatment process has been developed for the treatment of synthetic dye wastewater. Photocatalysis and ceramic nanoporous membrane are mainly used for process integration to minimize the fouling and increase the flux. Commercial ZnO powder has been used as a nano-photocatalyst for the degradation of rhodamine-B dye in the hybrid system. Commercial ceramic nanoporous tubular membranes have been used for the rejection of dye and suspended catalysts. Photocatalysis process alone has shown the 33% of decolorization, whereas ceramic nanofiltration has shown the 50% of decolorization. Integration of photocatalysis and ceramic nanofiltration were shown 96% of dye decolorization over 90 min of operation.

In this article, a first report on novel hybrid technique (hydrodynamic cavitation + hydro gels packed bed adsorption) has been reported for dye degradation and subsequent adsorption of dye molecules. Initially, hydrodynamic cavitation (HC) was employed for the degradation of crystal violet dye molecules and subsequent adsorption of dye molecules have been carried out by adopting synthesized polymer hydro gels. Poly-acrylic acid (PAA)/nano composite hydro gels have been synthesized via ultrasound assisted emulsion polymerization technique. Modified bentonite clay was used as a cross-linker during the synthesis of PAA in the presence of ultrasound for the uniform dispersion of bentonite clay in the hydro gel matrix and to improve the adsorption capacity of the hydro gels. The morphology of synthesized hydro gels has been studied by XRD and TEM analysis. Operational parameters such as effect of inlet pressure on CV dye removal, effect of bentonite clay content in PAA hydro gel, effect of quantity of hydro gel loading in packed bed, effect of pH, and effect of inlet flow rate to the packed bed on integral removal of crystal violet dye in the hybrid system have been investigated. The combined process of hydrodynamic cavitation and packed bed hydro gel demonstrated the higher percentage removal of the crystal violet dye as compared to packed bed hydro gel alone. Synergistic effect of combined technique was evaluated based on the total organic carbon removal from the dye solution.

Currently, process intensification research is focused on use of the continuous micro reactor over the batch reactors. The micro reactor process gives continuous product output, effective micro mixing and better yield in small residence time over batch reactors. A continuous flow process has been successfully developed for the tritylation of 5-(4′-methyl-[1,1′-biphenyl]-2-yl)-1H-tetrazole [MBPT] using different microreactors. The reaction was carried out in three different configurations of microreactors. The SSCR–1 mm and 2 mm (Stainless steel capillary coil micro reactors) gives yield of 93.72 and 92.87% for the residence time of 71 s and 324 s respectively. Among the three microreactors, Corning® AFR afforded effectively higher yield (95.18%) for the residence time of 27 s. Thus, 5-(4′-methyl-[1,1′-biphenyl]-2-yl)-1-trityl-1H-tetrazole, a useful intermediate material for some of the pharmaceutical products that can be produced industrially using microreactor.

The main objective of the study was to investigate the effect of loading cationic corrosion inhibitors into halloysite nanotubes on the corrosion resistance of self-healing coatings derived from these materials. For this purpose, corrosion inhibitors Ce3 +/Zr4 + were encapsulated into halloysite clay nanotubes. The encapsulated nanotubes were dispersed into a hybrid silica sol-gel matrix and deposited on magnesium alloy AZ91D substrates by dip coating method. The coatings were cured at 130 °C for 1 h in air. The bare, matrix sol coated and self-healing sol coated substrates were evaluated for their self-healing and corrosion protection abilities using weight loss experiments, potentiodynamic polarization and electrochemical impedance spectroscopy measurements after immersion in 3.5% NaCl solution for varying time durations between 1 h to 24 h. These results were further corroborated with those obtained from scanning vibrating electrode technique. The self-healing property and the promising nature of cationic corrosion inhibitor loaded halloysite nanotube based corrosion protection coatings on AZ91D substrates could be confirmed from the present investigations.

TiO2 is a more effective photocatalyst for the photocatalytic degradation of organic pollutants. However it shows more reactivity under UV light and around 5% of solar spectrum contains UV radiations. A new approach for the degradation of pollutants present in wastewater is suggested by making use of nanocomposite photocatalysts. The technique has potential for the treatment of wastewater because of the use of doped graphene-based nanocomposite photocatalysts. Graphene is a one-atom-thick planar sheet of sp2-bonded carbon atoms that are densely packed in a honeycomb crystal lattice. Furthermore, graphene has high electron mobility and therefore it will supress the recombination of the electron-hole pair formed which in turn improves the effectiveness of the graphene-TiO2 photocatalyst. In addition, development of doped graphene-TiO2 photocatalyst will be useful as it can be effective for the degradation of pollutants in the visible sunlight. Recently, there has been an increase in interest in the ...

Enormous increase in the application of various heavy metals including lead for commercial and non-commercial purposes has also led to their enhanced occurrence in the effluents from industries and domestic discharge creating substantial environmental concerns. The existing techniques for removal of these contaminants such as reverse osmosis and ion exchange suffer a few disadvantages and hence, thrust to develop efficient techniques for the removal have been ever increasing. Adsorption based on the use of nanoadsorbents is promising being cost effective and based on the ease of operation. The present work furnishes a detailed overview on nanoadsorbents for removal of lead from water. The various nanoadsorbents covered in the analysis include alumina, anatase, carbon nanotubes, chitosan, copper, iron and zinc oxide, magnetite, nanoclay and zirconium nanoparticles. The review also gives an insight into the synthesis and characterization of nanoadsorbents followed by guidelines on optimum operating parameters to be used in the removal process for maximizing the extent of removal. The typical optimum conditions established based on the critical analysis of literature are pH ≤ 6, contact time ≥60 min and optimum adsorbent dose dependent on the nanomaterials. Comparison of different nanoparticles revealed that titanium oxide and hematite nanoparticles are the best, giving 100% removal efficiency for lead ions. The sequestration was mainly dependent on adsorbent dose that has to be kept optimum to yield adequate surface area and number of adsorption sites. Overall, nanoadsorbents have been established to yield efficient removal of lead from water.

In the present study, ultrasound assisted encapsulation of peppermint flavor (core material) in gum Arabic (GA; wall material) was carried out in the presence of Tween 80 surfactant. It is well known that the intense environment generated due to cavity collapse in the presence of ultrasonic irradiations help in the preparation of fine emulsion which enhances the encapsulation efficiency of flavor. In this work, the use of ultrasound during encapsulation of peppermint flavor in GA, enhances the encapsulation efficiency to 87%. The effect of various parameters such as flavor concentration, GA concentration, and inlet temperature and feed rate during spray drying on encapsulation efficiency, product yield and particle size was studied. Also, the encapsulation of peppermint flavor in GA was confirmed using Fourier‐transform infrared spectroscopy (FTIR) analysis. The particles size of obtained nanoparticles after spray drying is in the range of 45.2–255.7 nm. This encapsulation process is believed to enhance the shelf life and stability of flavors that may be protected from outside environment by reducing its reactivity. PRACTICAL APPLICATIONS: Components of the peppermint flavor are first of all mono and sesquiterpene hydrocarbons and their oxygenated derivatives, and also phenylpropanoids. These are volatile substances sensitive to oxygen, light, moisture, and heat. Stability and shelf life of peppermint flavor will be lower when it is in liquid state because it is very sensitive to outside environment. This ultrasound assisted encapsulation process improves the processing time and encapsulation efficiency in lesser time which improves its stability and shelf life. Upon investigation of effect of direct exposure of peppermint oil to acoustic cavitation with bath and probe type and obtained FTIR patterns, its properties were found to be unaffected with acoustic cavitation. Further, in the present work, the effect of ultrasonication is little after encapsulation of peppermint flavor in gum Arabic wall material. Further the produced encapsulated materials are having uniform particle size distribution which can be prepared at industrial scale.

Reduced graphene oxide (RGO) sheets decorated by ZnO nanoparticles were synthesized using wet impregnation method. The composite material was characterized by means of X-ray diffraction (XRD), Williamson-Hall Plot (W-H Plot) and Scanning Electron Microscope (SEM) analysis. The XRD pattern revealed orderly hexagonal (wurtzite) structure of the ZnO nanoparticles. Surface morphology of ZnO, RGO and RGO-ZnO was investigated using SEM analysis. SEM images indicated the uniform distribution of ZnO onto the RGO surface. The photocatalytic activity of nanocomposite was demonstrated by determining the degradation of methylene blue dye. The degradation of dye took place due to efficient electron-hole recombination of photo-induced electrons. Finally, plausible mechanism was explained with the help of scavengers. Overall, wet impregnation method was found efficient to produce RGO with uniform ZnO loading. The prepared RGO-ZnO composite can efficiently degrade the dye under UV radiation.

In this work, we synthesized ultra-small platinum (Pt) nanoparticles, capped with poly(vinylpyrrolidone) (PVP), in a continuous flow microreactor. This method facilitated the synthesis Pt nanoparticles less than 5 nm at room temperature, as opposed to the conventional high-temperature synthesis. Further, we have demonstrated the effect of capping agent and flow rate on particle size and aggregation state of Pt nanoparticles. We found that the flow rate of reactants also has a significant effect on determining crystallinity of Pt nanoparticles. As-synthesized Pt NPs were analyzed by high-resolution transmission electron microscopy and X-ray diffraction, revealing a monodisperse distribution of Pt nanoparticles, marked by crystalline and stable Pt nanoparticles.

The present work deals with the preparation of CuO, polyaniline (PANI) and PANI-CuO nanocomposite by in-situ emulsion polymerization which is subsequently dispersed in water to get PANI and PANI-CuO nanocomposite based nanofluid to study its convective heat transfer performance. The enhancement in the convective heat transfer of PANI and PANI-CuO nanocomposite based nanofluids was investigated by adding 0.1–0.5 volume% PANI and PANI-CuO nanocomposite particles individually (having particle size less than 100 nm) in deionized water (basefluid), respectively. Further, the effect of percentage of PANI and PANI-CuO nanocomposite particles and inlet temperature, on convective heat transfer performance was investigated. The experimental results show an enhancement by more than 12% and around 38% in heat transfer coefficient, when 0.5 vol% of PANI and PANI-CuO nanocomposite particles were added to the base fluid, respectively. This is attributed to use of PANI encapsulated CuO nanocomposite particles in nanofluids, which enhances the heat transfer coefficient significantly compared to PANI nanoparticles alone in nanofluid.

The ultrasonic, photocatalytic and sonophotocatalytic degradation of Basic Red-2 accompanied by Nb2O5 nano catalysts were studied. The structure and morphology of synthesized Nb2O5 nano catalyst was investigated using scanning election microscopy (SEM), Electron dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD).The effects of various experimental parameters such as the Basic Red-2 concentration, catalyst dose, pH and addition of H2O2 on the ultrasonic, photocatalytic and sonophotocatalytic degradation were investigated. Photocatalytic and sonophotocatalytic degradation of Basic Red-2 was strongly affected by initial dye concentration, catalyst dose, H2O2 addition and pH. Basic pH (pH-10) was favored for the ultrasonic (US), photocatalytic (UV + Nb2O5) and sonophotocatalytic (US + UV + Nb2O5) degradation of Basic Red-2 by using Nb2O5 nano catalyst. The ultrasonic degradation of Basic Red-2 was enhanced by the addition of photocatalyst. Then, the effect of Nb2O5 dose on photocatalytic and sonophotocatalytic degradation were studied, and it was found that increase in catalyst dose increase in the percentage degradation of Basic Red-2. In addition, the effects of H2O2 on ultrasonic, photolytic, photocatalytic and sonophotocatalytic degradation was also investigated, and it was found that H2O2 enhances the % degradation of Basic Red-2. The possible mechanism of ultrasonic, photocatalytic and sonophotocatalytic degradation of Basic Red-2 reported by LC-MS shows generation of different degradation products

In this article, an acoustic cavitation engineered novel approach for the synthesis of TiO2, cerium and Fe doped TiO2 nanophotocatalysts is reported. The prepared TiO2, cerium and Fe doped TiO2 nanophotocatalysts were characterized by XRD and TEM analysis to evaluate its structure and morphology. Photo catalytic performance of undoped TiO2 catalyst was investigated for the decolorization of crystal violet dye in aqueous solution at pH of 6.5 in the presence of hydro dynamic cavitation. Effect of catalyst doping with Fe and Ce was also studied for the decolorization of crystal violet dye. The results shows that, 0.8% of Fe-doped TiO2 exhibits maximum photocatalytic activity in the decolorization study of crystal violet dye due to the presence of Fe in the TiO2 and it may acts as a fenton reagent. Kinetic studies have also been reported for the hybrid AOP (HAOP) that followed the pseudo first-order reaction kinetics.

In the present work, the preparation of liquid emulsion membrane (LEM) considering Aliquat 336 as a carrier was accomplished first time with the use of hydrodynamic cavitation (orifice based) process. The other components/ingredients used for the preparation of LEM were kerosene (diluent), span 80 (emulsifier) and NaOH which was used as a stripping agent in the internal phase. The extraction process of cobalt (II) from wastewater was investigated using the LEM prepared with the orifice plates having diameter equal to 1 mm and 5 mm. Further, the influence of various elected parameters like processing time, orifice diameter, carrier concentration and external feed phase to emulsion membrane phase ratio (i.e. treat ratio) on extraction efficiency of cobalt (II) from the feed phase have been examined and reported. The obtained results confirmed the possibility of 100% extraction of cobalt (II) using hydrodynamically prepared LEM from the aqueous feed phase which contains 100 ppm cobalt (II). The % extraction efficiency of cobalt increases with the carrier concentration and also with LEM prepared in hydrodynamic cavitation for various cavitation time up to certain limit. Further, the concentration of span 80 has been established to be adequate for the stability of the LEM throughout the cobalt (II) extraction process. In the present work, the effectiveness of hydrodynamic cavitation based process for the preparation of stable LEM with an application in the separation of cobalt (II) from the aqueous feed phase has been established.