Conversion of Polypropylene Waste into Value-Added Products: A Greener Approach.

Plastic has made our lives comfortable as a result of its widespread use in today's world due to its low cost, longevity, adaptability, light weight and hardness; however, at the same time, it has made our lives miserable due to its non-biodegradable nature, which has resulted in environmental pollution. Therefore, the focus of this research work was on an environmentally friendly process. This research work investigated the decomposition of polypropylene waste using florisil as the catalyst in a salt bath over a temperature range of 350-430 °C. A maximum oil yield of 57.41% was recovered at 410 °C and a 40 min reaction time. The oil collected from the decomposition of polypropylene waste was examined using gas chromatography-mass spectrometry (GC-MS). The kinetic parameters of the reaction process were calculated from thermogravimetric data at temperature program rates of 3, 12, 20 and 30 °C·min-1 using the Ozawa-Flynn-Wall (OFW) and Kissinger-Akahira-Sunnose (KAS) equations. The activation energy (Ea) and pre-exponential factor (A) for the thermo-catalytic degradation of polypropylene waste were observed in the range of 102.74-173.08 kJ·mol-1 and 7.1 × 108-9.3 × 1011 min-1 for the OFW method and 99.77-166.28 kJ·mol-1 and 1.1 × 108-5.3 × 1011 min-1 for the KAS method at a percent conversion (α) of 0.1 to 0.9, respectively. Moreover, the fuel properties of the oil were assessed and matched with the ASTM values of diesel, gasoline and kerosene oil. The oil was found to have a close resemblance to the commercial fuel. Therefore, it was concluded that utilizing florisil as the catalyst for the decomposition of waste polypropylene not only lowered the activation energy of the pyrolysis reaction but also upgraded the quantity and quality of the oil.

Remediation of pesticides using TiO2 based photocatalytic strategies: A review.

Nowadays, pesticides are regarded as the most dangerous of the various organic pollutants, posing substantial environmental and human threats worldwide. Pesticide contamination has become one of the most crucial environmental issues due to its bio-persistence and bioaccumulation. Different conventional methods are being utilized for pesticide removal, yet pesticides are thought to be significantly present in the environment. The development and application of sophisticated wastewater treatment methods are being pursued to remove contaminants effectively, particularly pesticides. In the past several decades, nanoscience and nanotechnology have emerged as essential tools for the identification, removal, and mineralization of persistent pesticides by employing advanced nanomaterials such as pristine titanium dioxide (TiO2), doped TiO2, nanocomposites (NCs) TiO2, and ternary nanocomposites (TNCs) TiO2 by advanced oxidation processes (AOPs). Advancement in the characteristics of TiO2 by doping, co-doping, construction of NCs and TNCs has contributed to the dramatic efficiency up-gradation by reducing band gap, solar active photocatalyst, enhancing PCA, high photostability, chemically inertness and multiple time reusability. Based on previous literature, utilizing La-TiO2 NCs photocatalyst, the mineralization of pesticide (imidacloprid) attained up to 98.17% that is almost 40-53% greater than pristine TiO2. The present review attempt to discuss the recent research performed on TiO2 based nanoparticles (NPs) and NCs for photocatalytic mineralization of various pesticides. The basic mechanism of TiO2 photocatalysis, types of reactors used for photocatalysis, and optimized experimental conditions of TiO2 for pesticides mineralization are discussed.

Polymer microgels for the stabilization of gold nanoparticles and their application in the catalytic reduction of nitroarenes in aqueous media.

Polymer microgels containing a polystyrene core and poly(N-isopropylmethacrylamide) shell were synthesized in aqueous media following a free radical precipitation polymerization. Au nanoparticles were fabricated into the shell region of the core-shell microgels denoted as P(STY@NIPM) by the in situ reduction of chloroauric acid with sodium borohydride. Various characterization techniques such as transmission electron microscopy (TEM), ultraviolet-visible spectroscopy (UV-visible) and Fourier transform infrared spectroscopy (FTIR) were used for the characterization of Au-P(STY@NIPM). The catalytic potential of Au-P(STY@NIPM) toward the reductive reaction of 4-nitrophenol (4NP) under various reaction conditions was evaluated. The Arrhenius and Eyring parameters for the catalytic reduction of 4NP were determined to explore the process of catalysis. A variety of nitroarenes were converted successfully into their corresponding aminoarenes with good to excellent yields in the presence of the Au-P(STY@NIPM) system using NaBH4 as a reductant. The Au-P(STY@NIPM) system was found to be an efficient and recyclable catalyst with no significant loss in its catalytic efficiency.

Highly Efficient Visible Light Active Doped ZnO Photocatalysts for the Treatment of Wastewater Contaminated with Dyes and Pathogens of Emerging Concern.

Water is obligatory for sustaining life on Earth. About 71% of the Earth's surface is covered in water. However, only one percent of the total water is drinkable. The presence of contaminants in wastewater, surface water, groundwater, and drinking water is a serious threat to human and environmental health. Their toxic effects and resistance towards conventional water treatment methods have compelled the scientific community to search for an environmentally friendly method that could efficiently degrade toxic contaminants. In this regard, visible light active photocatalysts have proved to be efficient in eliminating a wide variety of water toxins. A plethora of research activities have been carried out and significant amounts of funds are spent on the monitoring and removal of water contaminants, but relatively little attention has been paid to the degradation of persistent water pollutants. In this regard, nanoparticles of doped ZnO are preferred options owing to their low recombination rate and excellent photocatalytic and antimicrobial activity under irradiation of solar light. The current article presents the roles of these nanomaterials for wastewater treatment from pollutants of emerging concern.

Synthesis and Characterizations of PdNi Carbon Supported Nanomaterials: Studies of Electrocatalytic Activity for Oxygen Reduction in Alkaline Medium.

Electrocatalytic materials offer numerous benefits due to their wide range of applications. In this study, a polyol technique was used to synthesize PdNi nanoparticles (NPs) with different percent atomic compositions (Pd = 50 to 90%) to explore their catalytic efficiency. The produced nanoparticles were characterized using X-ray diffraction (XRD) and electrochemical investigations. According to XRD measurements, the synthesized NPs were crystalline in nature, with crystallite sizes of about 2 nm. The electrochemical properties of the synthesized NPs were studied in alkaline solution through a rotating ring-disk electrode (RRDE) technique of cyclic voltammetry. The PdNi nanoparticles supported on carbon (PdNi/C) were used as electrocatalysts and their activity and stability were compared with the homemade Pd/C and Pt/C. In alkaline solution, PdNi/C electrocatalysts showed improved oxygen reduction catalytic activity over benchmark Pd/C and Pt/C electrocatalysts in all composition ratios. Furthermore, stability experiments revealed that PdNi 50:50 is more stable in alkaline solution than pure Pd and other PdNi compositions.

Highly selective, sensitive and simpler colorimetric sensor for Fe2+ detection based on biosynthesized gold nanoparticles.

Herein, we describe the fabrication of green bell pepper, Capsicum annuum L. extract capped gold nanoparticles (CA-AuNPs) in aqueous medium using tetrachloroaurate (HAuCl4·3H2O) as precursor salt and sodium hydroxide (NaOH) solution as accelerator as well as pH adjuster. Formation of CA-AuNPs was verified via colour change from yellowish to ruby red with further confirmation through surface plasmon resonance (SPR) band at 519 nm using ultraviolet violet-visible (UV-Vis) spectroscopy. Other characterizations techniques include, Fourier transform infra-red (FTIR) spectroscopy, atomic force microscopy (AFM), dynamic light scattering (DLS) with Zeta-potential analysis (ZPA) and X-ray diffraction (XRD) method. The resulting AuNPs were efficaciously implemented as highly sensitive colorimetric sensor for selective detection of Fe2+ in the presence of several interfering cations including Fe3+. Importantly, the fabricated CA-AuNPs based colorimetric sensor functioned linearly in the range of 0.3-7.0 ppb Fe2+, based on increasing absorption intensity with R2 value of 0.9938 using UV-Vis spectrometry. The limit of detection (LOD) and limit of quantification (LOQ) for Fe2+ were estimated as 0.036 and 0.12 ppb, respectively. Finally, the sensor was effectively tested for determination of Fe2+ in some locally collected real water samples.

Bimetallic cobalt-iron diselenide nanorod modified glassy carbon electrode: an electrochemical sensing platform for the selective detection of isoniazid.

The increasing demand of a sensitive and portable electrochemical sensing platform in pharmaceutical analysis has developed widespread interest in preparing electrode materials possessing remarkable properties for the electrochemical determination of target drug analytes. Herein, we report the synthesis, characterization and application of bimetallic cobalt-iron diselenide (FeCoSe2) nanorods as electrode modifiers for the selective detection of a commonly used anti-tuberculosis drug Isoniazid (INZ). We prepared FeCoSe2 nanorods by a simple hydrothermal route and characterized these by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX) and temperature-programmed reduction (TPR) techniques. The electrochemical characterization of FeCoSe2 modified GCE was performed by cyclic voltammetry (CV) and square wave anodic stripping voltammetry (SWASV). Under optimized experimental conditions, a linear current-concentration response was obtained for INZ in the range of 0.03-1.0 µM, with very low limit of detection 1.24 × 10-10 M. The real applicability of the designed FeCoSe2/GCE sensing platform was adjudicated by the detection of INZ in biological samples.

Electrochemical sensing platform for the simultaneous femtomolar detection of amlodipine and atorvastatin drugs.

The development of a proficient and ultra-high sensitive functionalized electrode for accurate analysis of drugs is a long-standing challenge. Herein, we report an electrochemical nanocomposite scaffold, comprising of silver nanoparticles integrated with functionalized carbon nanotubes (COOH-CNTs/Ag/NH2-CNTs) for the simultaneous quantification of two widely used amlodipine (AM) and atorvastatin (AT) drugs. The sandwiched nanocomposite materials were thoroughly characterized morphologically and structurally. The nanocomposite COOH-CNTs/Ag/NH2-CNTs immobilized over glassy carbon electrode catalyzed electron transfer reactions at the electrode-electrolyte interface and facilitated detection of targeted drugs, as revealed by the significant decrease in oxidation potentials at 879 mV and 1040 mV and improved current signals. Electrochemical characterization and testing show that the functionalized porous architecture with a large effective surface area is a promising scaffold for the sensing of a binary mixture of AM and AT with limits of detection in the femtomolar range (77.6 fM, and 83.2 fM, respectively). Besides, the specificity, stability, and reliability of the electrochemical sensing platform in simple and complex biological and pharmaceutical samples with high percentage recoveries highlight its scope for practical applications. Computational studies supported the experimental outcomes and offered insights about the role of modifier in facilitating electron transfer between transducer and analytes.

Phenolic water toxins: redox mechanism and method of their detection in water and wastewater.

Phenolic pollutants are highly toxic and persistent in the environment. Their efficient detection is a pressing social demand. In this regard we introduce a novel ultrasensitive electroanalytical platform for the individual and synchronized detection of three phenolic isomers commonly known as hydroquinone (HQ), resorcinol (RC), and catechol (CC). The sensing device consists of a glassy carbon electrode (GCE) modified with functionalized carbon nanotubes (fCNTs) and gold-silver (Au-Ag NPs) bimetallic nanoparticles. The sandwiched scaffold represented as fCNTs/Au-Ag NPs/fCNTs/GCE efficiently senses HQ, RC, and CC with detection limits of 28.6 fM, 36.5 fM and 42.8 fM respectively. The designed sensor is more promising than reported sensors for phenolic toxins in the context of high sensitivity, selectivity, and rapid responsiveness. The designed sensor also shows the qualities of stability, reproducibility, reliability, and selective recognition capacity for target analytes in multiple real water samples. Moreover, computational calculations explain the function of the electrode modifier in facilitating charge transfer between the transducer and analytes.

Tripeptide Derivative-Modified Glassy Carbon Electrode: A Novel Electrochemical Sensor for Sensitive and Selective Detection of Cd2+ Ions.

A N-[(Benzyloxy)carbonyl]-l-alanyl-l-prolyl-l-leucine-N-cyclohexylcyclohexanamine (Cbz-APL) tripeptide-coated glassy carbon electrode (GCE)-based sensor was used for sensitive and selective recognition of cadmium ions in environmental water. Detailed cyclic voltammetric and electrochemical impedance spectroscopic studies were performed to investigate the charge transfer and sensing activity of the developed electrochemical sensor. Square wave anodic stripping voltammetry (SWASV) was employed to further investigate the sensitivity, selectivity, validity, and applicability of the developed sensor. A sharp electrochemical signal of oxidized Cd at -0.84 V versus Ag/AgCl provides evidence for the higher sensing ability of Cbz-APL/GCE than bare GCE at -0.79 V. Moreover, on Cbz-APL/GCE, extraordinary low detection limits of 4.34 fM and linearity range of 15 nM to 0.1 pM with coefficients of correlation higher than 0.99 for Cd2+ were achieved. Besides, the influence of inorganic and organic interferents on the targeted analyte signals was examined, and high selectivity of Cbz-APL/GCE for Cd2+ ions was observed. Lastly, the validity and applicability of the developed electrochemical sensor for the detection of Cd2+ ions were checked in real water samples, and 100% recovery was obtained.

FeCoSe2 Nanoparticles Embedded in g-C3N4: A Highly Active and Stable bifunctional electrocatalyst for overall water splitting.

To investigate cost affordable and robust HER and OER catalysts with significant low overpotentials, we have successfully embedded FeCoSe2 spheres on smooth surfaces of graphitic carbon nitride that demonstrated high stability and electrocatalytic activity for H2 production. We systematically analyzed the composition and morphology of FexCo1-xSe2/g-C3N4 and attributed the remarkable electrochemical performance of the catalyst to its unique structure. Fe0.2Co0.8Se2/g-C3N4 showed a superior HER activity, with quite low overpotential value (83 mV at -20 mA cm-2 in 0.5 M H2SO4) and a current density of -3.24, -7.84, -14.80, -30.12 mA cm-2 at 0 V (vs RHE) in Dulbecco's Phosphate-Buffered Saline (DPBS), artificial sea water (ASW), 0.5 M H2SO4 and 1 M KOH, respectively. To the best of our knowledge, these are the highest reported current densities at this low potential value, showing intrinsic catalytic activity of the synthesized material. Also, the catalyst was found to deliver a high and stable current density of -1000 mA cm-2 at an overpotential of just 317 mV. Moreover, the synthesized catalyst delivered a constant current density of -30 mA cm-2 for 24 h without any noticeable change in potential at -0.2 V. These attributes confer our synthesized catalyst to be used for renewable fuel production and applications.

Synthesis of biocompatible triazole based non-ionic surfactant and its vesicular drug delivery investigation.

Numerous nanotechnological approaches have been widely practiced to improve the bioavailability of less aqueous soluble drugs; phospholipid based vesicles (liposomes) being the most widely applied drug delivery system. However; due to stability issues, large scale production limitations, sterilization and long term storage problems; non-ionic surfactant based vesicles (niosomes) are considered their excellent counterparts. Niosomes are vesicles of non-ionic surfactants having the ability to carrying both hydrophilic and hydrophobic drugs in their inner aqueous or lipid bilayer compartments. In this research work, triazole based non-ionic surfactant (TBNIS) was synthesized and characterized by different spectroscopic techniques and then screened for biocompatibility using NIH 3T3 cell line, blood hemolysis assay and acute toxicity in mice. The synthesized surfactant was then checked for niosomes' formation, Amphotericin B loading and entrapment efficiency, drug release, stability and bioavailability of the drug was assessed and compared with free drug solution. The synthesized surfactant was found biocompatible and caused less blood hemolysis, greater cell vial ability and negligible toxicity in animals. The size of drug loaded niosomal vesicles of TBNIS based surfactant was 179.9 ± 3.23 nm with smaller size distribution i.e. 0.29 ± 0.02. The triazole based surfactant vesicles showed 88.76 ± 3.45 % drug entrapment efficiency, sustained drug release profile and stability. The drug in TBNIS based vesicles has greater oral bioavailability 0.099 ± 0.03 as compared to plan drug solution 0.012 ± 0.023 µg/mL. Results of this study suggests that the newly synthesized triazole based surfactant can be used in drug delivery for improving bioavailability of less water soluble drugs like Amphotericin B.

Fabrication of a novel hybrid biocomposite based on amino-thiocarbamate derivative of alginate/carboxymethyl chitosan/TiO2 for Ni(II) recovery.

A novel hybrid biocomposite based on amino-thiocarbamate derivative of alginate, carboxymethyl chitosan and TiO2 (TiO2/TSC-CMC) was fabricated and characterized using Fourier transform Infrared spectroscopy (FTIR), Scanning electron microscopy (SEM) and Energy dispersive X-ray spectroscopy (EDX). The TiO2/TSC-CMC mass ratio (5.0-30.0%) was optimized and 3TiO2/TSC-CMC (hydrogel beads with TiO2/TSC-CMC mass ratio of 20.0%) was selected as the best sorbent for effective biosorption of Ni(II). Batch sorption experiments were conducted, instantaneous and equilibrium sorption capacities were investigated as function of pH, sorbent dose, initial metal concentration, contact time and temperature. Kinetic data could be well explained through pseudo second order rate equation (PSORE) depicting that the rate determining step involves the transfer of electron density from sorbent functional sites to central metal ion. Langmuir model fitted well with isothermal sorption data and maximum monolayer sorption capacity (qm) was computed as 172 mg/g at pH 6.0 and temperature 298 K. The values of thermodynamic parameters such as standard enthalpy change (16.94 kJ/mol) and standard Gibbs energy change (-18.67, -19.48, -20.57, and -21.38 kJ/mol) and standard entropy change (0.12 kJ/mol·K) concluded that sorption process is endothermic, spontaneous and resulted with increase in randomness. Hence, 3TiO2/TSC-CMC was found efficient and reusable sorbent.

Pyrolysis of polystyrene waste for recovery of combustible hydrocarbons using copper oxide as catalyst.

The present work is focused on pyrolysis of polystyrene waste for production of combustible hydrocarbons. The experiments were performed in an indigenously made furnace in the presence of a laboratory synthesised copper oxide. The pyrolysis products were collected and characterised. The Fourier transform infrared spectra showed that the liquid fraction contains C-H, C-O, C-C, C=C and O-H bonds, which correspond to various aliphatic and aromatic compounds. Gas chromatography-mass spectrometry traced compounds ranging from C1 to C4 in the gaseous fraction, whereas in the liquid fraction 15 components ranging from C3 to C24 were detected. From the results it has been concluded that CuO as a catalyst not only increased the liquid yield but also reduced the degradation temperature to great extent. Fuel properties of the pyrolysis oil were determined and compared with standard values of commercial fuel oil. The comparison suggested potential application of pyrolysis oil for domestic and commercial use.

Ranolazine-functionalized CuO NPs: efficient homogeneous and heterogeneous catalysts for reduction of 4-nitrophenol.

In the present study copper oxide nanoparticles (CuO NPs) were synthesized using a hydrothermal method with ranolazine as a shape-directing agent. Ranolazine-functionalized CuO NPs were characterized by various analytical techniques such as scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). The SEM pattern confirmed the morphology of ranolazine-functionalized CuO NPs with well-defined rice-like structures. FTIR spectroscopy confirmed the interaction between CuO NPs and ranolazine. The XRD analysis indicated that the structure of ranolazine-functionalized CuO NPs was monoclinic crystalline and the size ranged between 9 and 18 nm with an average particle size of 12 nm. The smaller size range of CuO NPs gave a large surface area that enhanced the efficiency of these catalysts employed for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in the H 2 O system. In homogeneous catalysis, results showed that 50 µL of CuO NPs was required in the presence of NaBH4 for 99% reduction of 4-NP in 240 s. On the other hand, for heterogeneous catalysis, 0.5 mg of CuO NPs was used in the presence of NaBH4 for 99% catalytic reduction of 4-NP to 4-AP in 320 s. The rate of reaction for homogeneous catalysis and heterogeneous catalysis was determined from the plots of In(Ct /C0) of 4-NP versus time (s), which showed good linearity with values of 1.3 × 10 -2 and 8.8 × 10 -3 s -1 . respectively. The high-quality catalytic efficiency, good reusability, nontoxic nature, and low cost are favorable properties of the synthesized CuO NPs for use as efficient catalysts for reduction of 4-AP to 4-NP in both homogeneous and heterogeneous media.

Thermo-catalytic decomposition of polystyrene waste: Comparative analysis using different kinetic models.

Due to a huge increase in polymer production, a tremendous increase in municipal solid waste is observed. Every year the existing landfills for disposal of waste polymers decrease and the effective recycling techniques for waste polymers are getting more and more important. In this work pyrolysis of waste polystyrene was performed in the presence of a laboratory synthesized copper oxide. The samples were pyrolyzed at different heating rates that is, 5°Cmin-1, 10°Cmin-1, 15°Cmin-1 and 20°Cmin-1 in a thermogravimetric analyzer in inert atmosphere using nitrogen. Thermogravimetric data were interpreted using various model fitting (Coats-Redfern) and model free methods (Ozawa-Flynn-Wall, Kissinger-Akahira-Sunose and Friedman). Thermodynamic parameters for the reaction were also determined. The activation energy calculated applying Coats-Redfern, Ozawa-Flynn-Wall, Kissinger-Akahira-Sunose and Friedman models were found in the ranges 105-148.48 kJmol-1, 99.41-140.52 kJmol-1, 103.67-149.15 kJmol-1 and 99.93-141.25 kJmol-1, respectively. The lowest activation energy for polystyrene degradation in the presence of copper oxide indicates the suitability of catalyst for the decomposition reaction to take place at lower temperature. Moreover, the obtained kinetics and thermodynamic parameters would be very helpful in determining the reaction mechanism of the solid waste in a real system.

Biogenic Silver Nanoparticles for Trace Colorimetric Sensing of Enzyme Disrupter Fungicide Vinclozolin.

We report a novel, simple, efficient, and green protocol for biogenic synthesis of silver nanoparticles (AgNPs) in aqueous solution using clove (Syzygium aromaticum) extract as a reducing and protecting agent. Ultraviolet-visible (UV-Vis) spectroscopy was employed to monitor the localized surface plasmon resonance (LSPR) band of clove extract-derived AgNPs prepared under various conditions. Fourier-transform infrared (FTIR) spectroscopy analysis provided information about the surface interaction of the clove extract with the AgNPs. Ultrahigh-resolution transmission electron microscopy (UHRTEM) results confirmed the formation of spherical, uniformly distributed clove extract-capped AgNPs with sizes in the range of 2-20 nm (average size: 14.4 ± 2 nm). Powder X-ray diffractometry analysis (PXRD) illustrated the formation of pure crystalline AgNPs. These AgNPs were tested as a colorimetric sensor to detect trace amounts of vinclozolin (VIN) by UV-Vis spectroscopy for the first time. The AgNP-based sensor demonstrated very sensitive and selective colorimetric detection of VIN, in the range of 2-16 µM (R2 = 0.997). The developed sensor was green, simple, sensitive, selective, economical, and novel, and could detect trace amounts of VIN with limit of detection (LOD) = 21 nM. Importantly, the sensor was successfully employed for the determination of VIN in real water samples collected from various areas in Turkey.

Calix[4]arene Derivative-Modified Glassy Carbon Electrode: A New Sensing Platform for Rapid, Simultaneous, and Picomolar Detection of Zn(II), Pb(II), As(III), and Hg(II).

The glassy carbon electrode was fabricated with multifunctional bis-triazole-appended calix[4]arene and then used for the simultaneous detection of Zn(II), Pb(II), As(III), and Hg(II). Before applying the square-wave anodic stripping voltammetry, the sensitivity and precision of the modified electrode was assured by optimizing various conditions such as the modifier concentration, pH of the solution, deposition potential, accumulation time, and supporting electrolytes. The modified glassy carbon electrode was found to be responsive up to picomolar limits for the aforementioned heavy metal ions, which is a concentration limit much lower than the threshold level permitted by the World Health Organization. Importantly, the designed sensing platform showed anti-interference ability, good stability, repeatability, reproducibility, and applicability for the detection of multiple metal ions. The detection limits obtained for Zn(II), Pb(II), As(III), and Hg(II) are 66.3, 14.6, 71.9, and 28.9 pM, respectively.

Wound healing potential of curcumin cross-linked chitosan/polyvinyl alcohol.

This study focusses on antibacterial properties and wound healing potential of curcumin cross-linked with chitosan-PVA membranes. The crude curcumin was extracted from the rhizome of (Curcumin longa) and chitosan-PVA 80 was also prepared separately. The synergistic potential 10, 20 and 30 mg of curcumin alone and in combination with chitosan-PVA was determined. The antibacterial, scavenging potential of free radical, total phenolic and total flavonoids contents were documented through spectrophotometric methods. Finally, the wound healing potential was tested on experimental animal (rabbits). Rabbits were divided into different groups; untreated (control), treated with 10, 20 and 30 mg of curcumin and its combination with chitosan-PVA80. Chitosan-PVA exhibited significant antibacterial property against bacterial pathogens. Wound healing trials on 2nd degree burns showed chitosan as substantial wound healing agent for wound bandages. Results have shown that chitosan wound gauzes augmented the granule and fibrous connective tissues formation.

Single-Pot Synthesis of Biodiesel using Efficient Sulfonated-Derived Tea Waste-Heterogeneous Catalyst.

The main purpose of this manuscript is to report the new usage of tea waste (TW) as a catalyst for efficient conversion of palm fatty acid distillate (PFAD) to biodiesel. In this work, we investigate the potential of tea waste char as a catalyst for biodiesel production before and after sulfonation. The activated sulfonated tea waste char catalyst was characterized using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray diffractometry (XRD), elemental composition (CHNS), nitrogen adsorption-desorption using Brunauer-Emmett-Teller (BET) and ammonia-temperature-programmed desorption (NH3-TPD). The activated tea waste char catalyst shows higher acid density of 31 µmol g-1 as compared to tea waste char of 16 µmol g-1 and higher surface area of 122 m2/g. The optimum fatty acid conversion conditions were found that 4 wt % of catalyst loading with 9:1 of methanol:PFAD for 90 min of reaction time at 65 °C gives 97% free fatty acid (FFA) conversion. In conclusion, the sulfonated tea waste (STW) catalyst showed an impressive catalytic activity towards the esterification of PFAD at optimum reaction conditions with significant recyclability in five successive cycles without any reactivation step.