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Carbon dots (CDs) are class of carbon based nanomaterials with excellent optical properties. However, in solid state the fluorescence of CDs is not observed due to aggregation-caused quenching effect. Herein, we present a facile thermal method for preparing solid state yellow emissive nitrogen doped carbon dots (N-CDs) using organic solvents, ethanolamine and acrylonitrile as the precursors without further surface passivation. In addition, N-CDs aqueous dispersion exhibits tunable blue to green emission, while acetone dispersion show yellow emission. Moreover, the aqueous dispersion of N-CDs is employed for detecting picric acid selectively by fluorescence quenching mode based on inner filter effect. A good linearity is observed in the range from 0 to 45 μM, with a detection limit of 1.17 μM. The method is successfully applied for determination of picric acid in environmental samples.

Raw materials from renewable natural resources for industrial applications are in high concern in recent industrial research. Researchers invest their time in the management of waste as well as the conversion of waste to wealth. In that line, the production of biofuels including biodiesel, and value-added products from non-edible oil sources as well as from the generated waste biomasses, are in the tilt of research in recent times. Preparation of different oleochemicals such as grease, resins, soap, lubricants, etc. from vegetable oils, and utilization of seed cake as fertilizer, animal feed, medicine, etc. are encouraged as a part of the generation of waste to wealth as per today’s environment is concerned. In recent days, various reports on the production of biodiesel and other oleochemicals from non-edible oil sources are published in various scientific journals. Yellow oleander (Thevetia peruviana) is a tropical shrub which produces a toxic non-edible fruit containing a high percentage of seed oil (up to 67%), protein (30-37%) as well as other medicinally important phytochemicals. It is attracting the researchers worldwide for the production of biodiesel, various oleochemicals, medicine, animal feed, etc. In this study, biodiesel and various value-added products synthesized from Thevetia peruviana oil and cake are reviewed to generate and popularize the potential use of yellow oleander seed for various industrial applications and accordingly, for substantial growth in cultivation for commercial-scale requirements.

Waste Sesamum indicum plant derived heterogeneous catalyst was utilized for the first time for biodiesel synthesis from sunflower oil. The derived catalyst was characterized by using Powder XRD, FT-IR, BET, TGA, XRF, AAS, XPS, SEM-EDX and TEM, and the characterization revealed the presence of Na, K, Ca, Mg, Fe, Mn, Zn, Si, Sr and Cl with high percentage of K (29.64 wt %) and Ca (33.80 wt %) as oxides and carbonates. The catalyst with a moderate surface area of 3.66 m2 g−1 exhibited excellent catalytic activity producing a yield of 98.9% biodiesel under the optimized conditions of 12:1 methanol to oil molar ratio and catalyst loading of 7 wt % at the reaction temperature of 65 °C in a short reaction time of only 40 min. The catalyst could be reused up to the 3rd cycle of reaction with the yield of 94.2% biodiesel. The characterization of biodiesel was done by using FT-IR, NMR, and GC-MS techniques. The fuel property of produced biodiesel meets the prescribed limits of international standard. The prepared catalyst is easy to handle, reusable, and found to be highly efficient green catalyst that could help in reduction of biodiesel cost. Thus, the catalyst can be recommended as a potential candidate for cost-effective biodiesel production at a large scale.

Background: Fishes are good sources of the fatty acids such as ω-3 and ω-6 polyunsaturated fatty acids, and fat-soluble vitamins for human consumption which play vital roles for various biological processes in the body and help in the proper growth and prevention of diseases. Objective: The objective of the present study was to determine the fatty acid composition, cholesterols, triglyceride and vitamin contents of some selected fishes from Hel river, Assam, India. Methods: Fatty acid composition of fish species was examined using gas chromatography-mass spectrometry, lipid components were determined following the reported methods and vitamins A and D contents were investigated by reversed-phase high-performance liquid chromatography. Results: Fatty acid compositions varied from 51.20-89.47% of saturated fatty acids, 0.27-19.68% of monounsaturated fatty acids and 1.75-30.76% of polyunsaturated fatty acids. Eicosapentaenoic acid and docosahexaenoic acid ranged from 0.54-22.30% and 1.26-18.85%, respectively. The fish species showed varying amounts of lipid components. The vitamins A and D were found in the range of 15.85-1287.0 μg/100 g and 45.0-677.24 μg/100 g, respectively. Conclusion: The fish species of this study are found rich in ω-3 polyunsaturated fatty acids such as eicosapentaenoic acid and docosahexaenoic acid along with noticeable amounts of vitamins A and D. Hence, these fish species have the potentials to serve as the natural dietary supplements for ω-3 fatty acids and other nutrients.

Background:The two wild plants viz. Sphenoclea zeylanica and Sphaerantus peguensis are seasonally consumed as vegetables by the Bodo people in Assam of North East India. Wild vegetables are considered as one of the cheapest sources for human nutrition that contains rich sources of numerous minerals and bioactive compounds which on consumption can contribute several health benefits against various diseases.Objective:The aim of the present study is to investigate amino acid profiles, antimicrobial property and anti-nutritional contents of the two wild edible plants.Methods:Amino acid profiles were determined by using ultra-performance liquid chromatography, antimicrobial activities of aqueous and methanol extracts of the plants were tested following the disc diffusion method against Bacillus cereus, Staphylococcus aureus, Proteus vulgaris and Escherichia coli, and anti-nutritional contents were evaluated based on the reported methods.Results:The total amino acid content found in S. zeylanica was 42.87 mg/g dry weight and it was found to be 32.65 mg/g dry weight in S. peguensis. The methanol extracts of the plants are exhibiting antibacterial activities against all the studied microorganisms. However, aqueous extracts showed no antibacterial activity against P. vulgaris and B. cereus. In this study, S. zeylanica species showed higher levels of anti-nutritional contents compared to S. peguensis.Conclusion:In the study, higher levels of essential amino acids were detected in S. zeylanica compared to S. peguensis. The methanol extracts of the plants showed more effective antimicrobial activities in comparison to the aqueous extracts and this may be due to the presence of antimicrobial compounds which are more readily soluble in methanol.

Renewable sources, especially the wind power, are volatile in nature which introduce non-linear uncertainties in wind power forecasting (WPF). These non-linear uncertainties hinder the way ...

Background: Layered double hydroxides (LDH) are drawing much attention as solid catalysts in recent years and have applications in various organic transformations as they possess a variety of basic sites which could be obtained by exchange of metal ions or by intercalation of suitable anions into their interlayer space. Ru based complexes have widespread catalytic applications in many organic reactions. Herein, novel ruthenium containing ternary LDH has been synthesized and used as a multifunctional catalyst for Aldol condensation and transfer hydrogenation reactions. Methods: Ternary LDH multifunctional catalyst containing Mg, Ru and Al was prepared by coprecipitation and hydrothermal treatment. The catalyst was characterized by elemental analysis, Powder XRD, FT-IR, BET, TGA, DRS, SEM, EDX, XPS and TEM. The products of the reactions were characterized by 1H NMR and GC-MS. Results: The analysis of catalyst revealed incorporation of Ru in the brucite layers of the LDH and showed the mosaic single crystal with BET surface area of 84.25 m2 g-1. This catalyst yielded 85–98% products for Aldol condensation reactions within 4 h reaction time, and 82–98% products for transfer hydrogenation reactions within 16 h reaction time. Conclusion: The resultant MgRuAl-LDH with acid and base sites was found to be highly active and selective for one-step synthesis of nitrile compounds. The catalyst works more efficiently for Aldol condensation reactions in shorter reaction times compared to transfer hydrogenation reactions.

The aim of present study was to ascertain the nutritional properties, phytochemical contents and in vitro antioxidant capacities of two wild edible fruits viz. Aporosa dioica (Roxb.) Muell.-Arg. and Ottelia alismoides (L.) Pers. found in Assam of North-East India. Nutritional properties, phytochemical screening, total phenolic content (TPC) and total flavonoid content (TFC) were investigated employing standard methods. Antioxidant properties were assessed following DPPH (1, 1-diphenyl-2-picrylhydrazyl), ABTS (2, 2´-Azinobis (3-ethylbenothiazoline-6-sulfonic acid) diammonium salt), H 2 O 2 (Hydrogen peroxide) and FRAP (Ferric reducing antioxidant power) assays. The results obtained in this study were presented and discussed. A. dioica fruit extract exhibited lower IC 50 (DPPH, ABTS and H 2 O 2 ) values in contrast to O. alismoides fruit extract indicating stronger antioxidant capacity in A. dioica fruit. Higher FRAP value of 106.583 ± 5.204 μM trolox equivalent (TE)/g dry extract (DE) was found in the methanol extract of A. dioica fruit compared to that of O. alismoides fruit (44.083 ± 7.637 μM TE/g DE). The TPC found in the methanol extracts of A. dioica and O. alismoides fruits were 146.710 ± 2.807 mg gallic acid equivalents (GAE)/g DE and 93.860 ± 1.172 mg GAE/g DE, respectively, while the TFC was found to be 72.510 ± 8.833 mg quercetin equivalents (QE)/g DE in A. dioica fruit and 43.270 ± 5.361 mg QE/g DE in O. alismoides fruit. These fruits are good sources of nutrients and natural antioxidants and may find applications in formulation of various pharmaceutical drugs.

Exploration of economically viable and environmentally benign solid base-catalyzed transesterification of oil is extremely important to significantly reduce the cost of biodiesel. In this study, heterogeneous base catalysts from the peel, trunk and rhizome of Musa paradisiaca (Malbhog) were prepared by burning the dry materials followed by calcination at 550 °C for 2 h. The catalysts were investigated for biodiesel production using jatropha oil as a feedstock. Catalysts were characterized using powder X-ray diffractometer (XRD), Fourier transform infrared spectrometer (FT-IR), Brunauer–Emmett–Teller (BET), Energy dispersive X-ray (EDX), Field emission scanning electron microscope (FESEM), X-ray photoelectron spectrometer (XPS) and HRTEM (High resolution transmission electron microscope). EDX and XPS studies exhibited that M. paradisiaca trunk catalyst possessed higher potassium content than the peel and rhizome catalysts. M. paradisiaca trunk catalyst displayed better efficacy which yielded 97.65% of biodiesel at 65 °C only in 9 min of reaction time using 5 wt % of catalyst and 9:1 MTOR (methanol to oil ratio). Basicity of catalyst was found in the increasing order of 1.39 mmol g−1 (rhizome)

This study explores the application and efficacy of the green catalyst derived from Heteropanax fragrans in the production of Jatropha curcas biodiesel. The catalyst was prepared by calcination of the ash at 550 and 850 °C for 2 h. Powder-XRD, BET, FT-IR, FESEM, EDX, XPS and HRTEM were employed for catalyst characterization. The characterization indicated that among the various metals present, potassium was found to be the highest being 14.69 wt% in UHC (uncalcined H. fragrans catalyst), 19.05 wt% in the CC-550 (catalyst calcined at 550 °C), and 19.27 wt% in the CC-850 (catalyst calcined at 850 °C). The BET analysis of UHC, CC-550 and CC-850 showed the appreciable surface areas of 96.57, 27.50, and 78.45 m2 g−1, respectively. The CC-550 with the highest basic character (pH value = 12.89 at 1:5 w/v) is exhibiting better performance producing a high biodiesel yield of 97.75% in 65 min with TOF (Turnover frequency) of 35.55 min−1 compared to the CC-850 (96.58%, 115 min) and UHC (96.61%, 110 min) with TOF of 27.71 and 29.47 min−1, respectively at the optimum experimental conditions of 12:1 MTOR (methanol to oil ratio), and 7 wt% of catalyst at 65 °C. Hammett method showed stronger basicity of CC-550 (0.423 mmol/g) representing the better efficacy for the catalysis in comparison to that of CC-850 (0.303 mmol/g) and UHC (0.298 mmol/g). The catalyst is reusable which could produce a high biodiesel yield (90.22%) even in the 3rd reaction cycle. The activation energy of H. fragrans catalyzed biodiesel synthesis is found to be 32.31 kJ mol−1. FT-IR, NMR, and GC–MS techniques were used to characterize J. curcas biodiesel. The properties of J. curcas biodiesel were found to be within the limits of international standards. The prepared catalyst is an environmental-friendly, renewable, inexpensive and highly efficient base catalyst. Thus, the utilization of this catalyst for biodiesel production will add an aspect in the biorefinery for exploring sustainable raw materials with the overall capacity of reduction in biodiesel-cost.

In the present work, a solid catalyst has been derived by calcination (550 ​°C, 2 ​h) of waste sugarcane bagasse ash and applied for the production of jatropha seed oil methyl esters (JSOME). The prepared catalyst was well-characterized by using Brunauer–Emmett–Teller (BET) method, Fourier transform infrared spectrometer (FT-IR), X-ray diffractometer (XRD), Field emission scanning electron microscope (FESEM), Energy dispersive X-ray (EDX), High resolution transmission electron microscope (HRTEM) and X-ray photoelectron spectrometer (XPS). The analysis revealed that the catalyst is composed of various metal oxides and carbonates. The catalyst could produce 92.84 ​wt. % yield of JSOME (biodiesel) at 9:1 methanol to oil ratio (MTOR), 10% catalyst and at 65 ​°C in 285 ​min, and found to be reusable. The polycrystalline catalyst with a surface area of 7.66 m2 g-1 and basic strength within 10.1 < H_ < 18.4 possesses good efficacy for the reaction with turnover frequency (TOF) of 6.59 h−1. The kinetic and thermodynamic parameters of the reaction were studied. JSOME was characterized by 1H NMR and GC-MS techniques, and fuel properties were also assessed. Biodiesel synthesis with such a renewable catalyst will add value to waste sugarcane bagasse and is considered sustainable for material development.

In the present study, the heterogeneous base catalyst was derived from the waste Brassica nigra plant and utilized as an efficient catalyst in the transesterification of soybean oil for biodiesel production. The catalyst was prepared by calcination of ash obtained after burning the dried waste Brassica nigra plant and well characterized using instrumental techniques like powder XRD, FT-IR, BET, XRF, AAS, XPS, SEM-EDX, and TEM. The analysis of the catalyst indicated potassium (56.13 wt%) as the major component followed by calcium (26.04 wt%) in the form of oxide, carbonate, and chloride. The catalyst showed excellent catalytic activity in converting soybean oil to biodiesel with 98.79% yield in a short time period of 25 min at 65 °C under the optimum conditions of 12:1 ratio of methanol to oil and 7 wt% of catalyst. The reaction yielded 98.87% biodiesel at room temperature of 32 °C within 75 min of reaction time under optimized conditions. The activation energy (27.87 kJ mol−1) indicates the reaction is a chemically controlled reaction. The catalyst was reused up to the third cycle of reaction which yielded 96% biodiesel without significant loss in catalytic activity. The biodiesel was characterized by FT-IR, 1H NMR, 13C NMR, and GC-MS. The fuel properties studied are well comparable with the international standards as well as with reported literatures. The synthesized heterogeneous catalyst is non-toxic, biodegradable, environmentally benign, green in nature, easy to handle, reusable and can be prepared with minimum cost as the raw materials are naturally plenty enough as wastes with free of cost which is a value addition to the generated wastes along with a viable capability in reduction of the overall biodiesel production cost.

Yellow oleander (Thevetia peruviana Schum.) seed oil has been investigated to produce biodiesel. Transesterification of the oil to biodiesel was carried out in methanol by batch reaction using a heterogeneous catalyst derived from the trunk of Musa balbisiana Colla (one variety of banana plant). 96 wt.% of the oil is converted to biodiesel at 32 °C in 3 h. The wt.% composition of the biodiesel is methyl oleate 43.72, methyl palmitate 23.28, methyl linoleate 19.85, methyl stearate 10.71 and methyl arachidate 2.41. Fuel properties conform to standards set for ASTM D6751, EN 14214, BS II and BS III, and in certain aspects better. The biodiesel is free from sulfur and has exhibited a high cetane number of 61.5.

Agro-wastes are the post-harvest products or agricultural residues generated through various agricultural activities which have diverse scopes for various applications. Reutilization of agro-waste is an environmentally safe and cost-effective process of waste management. Proper and optimal utilization of these waste by-products is one of the major challenges for the human society nowadays. The recent trend around the globe is to transform waste into different products useful for various applications. Agro-waste derived ashes have recently been extensively studied as the heterogeneous base catalysts in biodiesel synthesis which is attracting increasing attention worldwide. Agro-waste derived catalysts are easily available, simple to prepare, easy to handle, biodegradable, non-toxic, more environmentally benign, and more cost-effective. In this study, an attempt has been made to review the utilization of agro-waste derived ashes as heterogeneous catalysts and metal loaded ash catalysts in synthesis of biodiesel through transesterification reaction of various oil feedstocks. Several parameters like the calcination temperature, catalyst amount, ratio of methanol to oil, reaction times, and temperatures which affect the transesterification reaction were also briefly discussed herein. The agro-waste derived heterogeneous base catalysts are highly active for catalysing transesterification of oil to biodiesel with a shorter reaction time and higher conversion up to 100% as compared to commercial catalysts and other catalysts derived from other renewable biomasses such as egg shells, fish scales, and bones. Further, the performance of agro-waste derived heterogeneous base catalysts is better and more efficient than that of the metal source loaded ash catalysts. The high activities of these catalysts are due to the higher potassium content which is accrediting their high basicity. Moreover, efficient utilization of waste materials will help to reduce global warming and enhance the clean and clear environment in the society.

In the present study, the methanol and aqueous extracts of six wild vegetables viz. Cardamine hirsuta, Tetrastigma angustifolium, Oenanthe javanica, Melothria perpusilla, Stellaria media, and Cryptolepis sinensis consumed by the Bodo tribes of Assam, India were tested for antimicrobial activities against four bacterial strains such as Staphylococcus aureus, Bacillus cereus, Escherichia coli and Proteus vulgaris by disc diffusion method. This study reveals that all the six plant species showed different antimicrobial activities with the highest zone of inhibition (16 mm) in the methanol extracts of S. media and O. javanica against E. coli and P. vulgaris, respectively. The methanol extracts of C. sinensis and M. perpusilla showed the highest zone (15 mm) against S. aureus and B. cereus respectively. However in aqueous extract, the highest zone of inhibition (13 mm) was observed in C. hirsuta, and S. media at 30 mg/mL concentration against E. coli. In this study, the MIC values of aqueous extracts of selected plants ranged from 15 to

Nanoparticle is termed as particle with a dimension in between 1–100 nm. Nanotechnology has potential prospects for research and development in modern science. Nanoparticles have wide applications in the field of electronics, biology, medicine, agriculture, cosmetics and many more. A bulk material has constant physical property but shows diverse physical, chemical and biological properties at the nano range. Silver nanoparticles (AgNPs) have gained a lot of interest in recent times due to their unique properties like electrical, optical, catalytic, antimicrobial and other biological properties. AgNPs can be produced by physical, chemical and biological processes. Although chemical synthesis produces large amount of AgNPs in a short period of time, the chemicals used are found to have many adverse effects on human health and the environment. Due to these adverse effects, the need for environment friendly and less harmful synthesis has become very essential. Hence, many researchers have developed several biological processes for the production of AgNPs. Biosynthesis of AgNPs includes synthesis using plants, fungi, algae, bacteria, yeast and other biological materials like fish scales, egg shells and crabs. Plant-based AgNPs synthesis is getting more and more attention among the researchers because this is nontoxic, cost-effective, relatively simple, and environmentally benign process. In this paper, an attempt has been made to review AgNPs synthesis using extracts of various biological materials along with their size, shape and applications such as antimicrobial, antifungal, antiviral, catalytic and anticancer activities.

A total of nine oilseeds with more than 15 wt% oil have been investigated for evaluating them as feedstock for biodiesel industries. Fatty acid profiles of all the nine oil samples have been determined by GC–MS analysis. The saponification numbers, gross heats of combustion of the oils and those of corresponding fatty acid methyl esters (FAMEs) as well as cetane indices of the FAMEs have been calculated empirically. Iodine values have been determined experimentally. These values have been used for predicting the quality of the corresponding biodiesels. If prepared from these oils, biodiesels are likely to meet the major specification of biodiesel standards of the USA, Germany and European Standard Organisation. Seed oil from Cucumis sativus is found rich in linoleic acid which is considered an essential fatty acid of biological significance.

Aim: The aim of present study was to investigate the nutritional composition, phytochemical constituents and in vitro antioxidant activities of a wild edible fruit in order to document data for further basic research needs or to widen its use among common people. Methods: The fresh fruits of Grewia sapida Roxb. ex DC. were collected from the Chirang district of Bodoland Territorial Area Districts of Assam, identified and freeze dried. Proximate composition, minerals content and phytochemical constituents were analyzed following standard and reported methods. The antioxidant activities of methanol extract were evaluated by 1, 1-diphenyl-2-picrylhydrazyl (DPPH) and 2, 2'-Azinobis (3-ethylbenothiazoline-6-sulfonic acid) diammonium salt (ABTS) assays. Results: The results obtained were reported and discussed. The phytochemical screening of different solvent extracts revealed that fruits contained a number of medicinally active secondary metabolites. The study showed antioxidant properties having IC50 value of 257.666 ± 2.516 μg/mL (DPPH) and 134.33 ± 4.041 μg/mL (ABTS). The total phenolic and flavonoid contents in G. sapida fruit were found to be 294.353 ± 4.696 mg GAE/g dried extract and 116.95 ± 10.71 mg QE/g dried extract respectively. Conclusion: The study suggests that G. sapida fruit could be a good source of minerals and natural antioxidants, and studied further for its beneficial effect in human health.