Evaluation of Pb (II) Removal by Tea Pulp Modified with Magnetite Nanoparticle

Tea waste was used to successfully synthesize magnetic nanoparticles (TWMNPs). In this investigation, Pb (II) was eliminated by tea waste modified with magnetite nanoparticles (TWMNPs) was investigated. To prepare the TWMNPs, FeCl3.6H2O was dissolved in double distilled water (DDW) and 20 g of pulp tea was added slowly and stirred, after 30 min TWMNPs adsorbent were separated through an external magnetic field and washed three times with double distilled water (DDW) and ethanol then dried at 60°C. The FESEM test of TWMNPs shows the particle size in the range of 15-20 nm and spherical/cuboid-shaped crystal structure of Fe3O4 (magnetite). X-ray analysis showed that the main XRD diffraction peaks of TWMNPs are related to Fe3O4, HighScore plus X'Pert software was used to identify the phase in this sample. The specific surface area of the prepared magnetite nanoparticles was 25.2 m2.g-1. The pore volume, maximum pore radius, and VSM of TWMNPs were 14.4 cm3.g-1, 2.3 nm, and 3.37-2.41, respectively. The effects of various parameters, such as contact time, pH, concentration, and adsorbent dosage, were studied. The experimental isotherm data were analyzed using the Langmuir and Freundlich models, and it was found that the removal process followed the Langmuir isotherm and the maximum adsorption capacity calculated by Langmuir fitting was 10.67 mg.g-1. In addition, the adsorption kinetics followed the first-order kinetic model and the value of rate constant was found to be 14.04 × 10-2 min-1. The results showed that increasing the pH level led to a rise in the response level and Pb (II) removal. Also, the trend in Pb (II) removal and response level had an increase with increasing the initial concentration of Pb (II). Increasing contact time from 5 to 20 minutes has a slight effect on Pb (II) removal. Considering the results, TWMNPs could lead to suitable results for the removal of Pb (II) from wastewater containing this metal. And the maximum adsorption capacity was found to be 10.67 mg.g-

Microwave-Assisted Synthesis of 3,4-Dihydropyrimidin-2(1H)-Ones Using Acid-Functionalized Mesoporous Polymer

Synthesis and application of acid-functionalized mesoporous polymer catalyst for the synthesis of 3,4-Dihydropyrimidin-2(1H)-ones via Biginelli condensation reaction under microwave irradiation is investigated. Several analytical techniques such as FT-IR, BET, TEM, SEM and EDX were employed to characterize the synthesized polymeric catalyst. High acidity (1.15 mmol g-1 ), high surface area (90.44 m2 g -1 ) and mesoporous nature of the catalyst effectively promoted the synthesis of 3,4-Dihydropyrimidin-2(1H)-ones. Microwave irradiation shows higher yield (89-98 %) as compared to conventional heating (15-25 % yield) under our optimized reaction conditions such as 1:1:1.2 molar ratio of aldehyde/ethylacetoacetate/urea, catalyst loading of 6 wt.% (with respect to aldehyde), the temperature of 80 °C and microwave power of 50 W. The synthesized Biginelli products were fully characterized by 1H and 13C NMR. The reusability of the catalyst was investigated up to 5 successive cycles and it showed great stability towards the synthesis of 3,4-Dihydropyrimidin-2(1H)-ones without any significant depreciation in yields

Mikania Mikrantha Leaf Extract Mediated Biogenic Synthesis of Magnetic Iron Oxide Nanoparticles: Characterization and Its Antimicrobial Activity Study

With an aim to introduce a new highly potent antimicrobial nanoparticles using an environment-friendly route, he present work reports the green synthesis of iron oxide nanoparticles (Fe3O4NPs) utilizing Mikania mikrantha leaf extract and its application as efficient antimicrobial agent. The green Fe3O4NPs have been described by X-beam diffraction (XRD), Ultraviolet-Visible (UV-Vis) spectroscopy, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Fourier Transform-Infra Red (FT-IR) investigation. The TEM image shows the rhomboidal Fe3O4NPs with average mean sizes 20.27 nm. The FT-IR investigation proved Fe3O4NPs have been balanced out through the associations of steroids, terpenoids, flavonoids, phenyl propanoids, phenolic acids and proteins present in the leaf extract. The synthesized Fe3O4NPs shows a very high antibacterial and antifungal property against 5 bacterial strains such as Bacillus cereus, Acinetobacter johnsonii, Pseudomonas aeruginosa, Achromobacter spanius and Chromobacterium pseudoviolaceum strain, and 4 fungal strains (Aspergillus niger, Penicillium citirinum, Fusarium oxysporium, and Candida albicans). The green synthesized iron oxide nanoparticles can interfere metabolic activities of microorganisms which determine its antimicrobial properties and could bring a promising application in the fields of medicine. </p

Widely used catalysts in biodiesel production: a review.

An ever-increasing energy demand and environmental problems associated with exhaustible fossil fuels have led to the search for an alternative renewable source of energy. In this context, biodiesel has attracted attention worldwide as an eco-friendly alternative to fossil fuel for being renewable, non-toxic, biodegradable, and carbon-neutral. Although the homogeneous catalyst has its own merits, much attention is currently paid toward the chemical synthesis of heterogeneous catalysts for biodiesel production as it can be tuned as per specific requirement and easily recovered, thus enhancing reusability. Recently, biomass-derived heterogeneous catalysts have risen to the forefront of biodiesel productions because of their sustainable, economical and eco-friendly nature. Furthermore, nano and bifunctional catalysts have emerged as a powerful catalyst largely due to their high surface area, and potential to convert free fatty acids and triglycerides to biodiesel, respectively. This review highlights the latest synthesis routes of various types of catalysts (including acidic, basic, bifunctional and nanocatalysts) derived from different chemicals, as well as biomass. In addition, the impacts of different methods of preparation of catalysts on the yield of biodiesel are also discussed in details

Widely Used Catalysts in Biodiesel Production: A Review

An ever-increasing energy demand and environmental problems associated with exhaustible fossil fuels have led to the search for an alternative renewable source of energy. In this context, biodiesel has attracted attention worldwide as an alternative to fossil fuel for being renewable, non-toxic, biodegradable, carbon-neutral; hence eco-friendly. Despite homogeneous catalyst has its own merits, currently, much attention has been paid to chemically synthesize heterogeneous catalysts for biodiesel production as it can be tuned as per specific requirement, easily recovered, thus enhance reusability. Recently, biomass-derived heterogeneous catalysts have risen to the forefront of biodiesel productions because of their sustainable, economical and eco-friendly nature. Further, nano and bifunctional catalysts have emerged as a powerful catalyst largely due to their high surface area and potential to convert free fatty acids and triglycerides to biodiesel, respectively. This review highlighted the latest synthesis routes of various types of catalysts including acidic, basic, bifunctional and nanocatalysts derived from different chemicals as well as biomass. In addition, the impacts of different methods of preparation of catalysts on the yield of biodiesel are also discussed in details.</p

Green synthesis of silver nanoparticles using plant extracts and their antimicrobial activities: a review of recent literature.

Synthesis of metal nanoparticles using plant extracts is one of the most simple, convenient, economical, and environmentally friendly methods that mitigate the involvement of toxic chemicals. Hence, in recent years, several eco-friendly processes for the rapid synthesis of silver nanoparticles have been reported using aqueous extracts of plant parts such as the leaf, bark, roots, etc. This review summarizes and elaborates the new findings in this research domain of the green synthesis of silver nanoparticles (AgNPs) using different plant extracts and their potential applications as antimicrobial agents covering the literature since 2015. While highlighting the recently used different plants for the synthesis of highly efficient antimicrobial green AgNPs, we aim to provide a systematic in-depth discussion on the possible influence of the phytochemicals and their concentrations in the plants extracts, extraction solvent, and extraction temperature, as well as reaction temperature, pH, reaction time, and concentration of precursor on the size, shape and stability of the produced AgNPs. Exhaustive details of the plausible mechanism of the interaction of AgNPs with the cell wall of microbes, leading to cell death, and high antimicrobial activities have also been elaborated. The shape and size-dependent antimicrobial activities of the biogenic AgNPs and the enhanced antimicrobial activities by synergetic interaction of AgNPs with known commercial antibiotic drugs have also been comprehensively detailed

Biosynthesis of Triangular-Shape ZnO Nanoparticles Using Tecoma Stans and Its Antimicrobial Activity

The present work reports the first green synthesis of zinc oxide nanoparticles (ZnO-NPs) using Tecoma stans leaf extract. The ZnO-NPs have been investigated by X-Ray Diffraction (XRD), Ultra Violet-Visible (UV-Vis), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Fourier Transform-Infra Red (FT-IR) analysis. XRD investigation confirms the crystalline structure of ZnO. The TEM images show triangular shape ZnO-NPs with sizes running from 15-20 nm. The XPS spectrum revealed the presence of Zn and O in the sample. Photoluminescence studies of ZnO-NPs displayed a sharp emission of blue band at 447 nm which is attributed to the defect structures in ZnO crystal. The presence of alcoholic, phenolic amide groups in the plant extracts is responsible for the formation of ZnO-NPs. The synthesized ZnO-NPs showed a very high antibacterial property against five bacterial strains such as Bacillus cereus,Acinetobacter johnsonii, Achromobacter xylosoxidans, Achromobacter spanius and Chromobacterium pseudoviolaceum, with the highest zone of inhibition (ZOI) of 24 mm being shown against Achromobacter spanius strain. Further, the synthesized nanoparticles displayed excellent activities against four fungal strains, where a highest ZOI of 30 mm was observed against Penicillium citirinum, hence proving its high efficacy as antimicrobial agents.</div

Recent Advances in Conversion of Glycerol: A Byproduct of Biodiesel Production to Glycerol Carbonate

Owing to erupted ecological concerns and escalated energy consumption, biodiesel produced by transesterifying nonedible and used cooking oils has been acknowledged as a viable source of clean and sustainable energy, alternative to fossil fuels. This transesterification process led to an excessive supply of glycerol as the primary byproduct which can then be transformed into value-added derivatives, primarily glycerol carbonate (GC), thereby drawing attention to its potential use in industrial applications. Although several methods for synthesis of GC utilize glycerol as building block, the transesterification approach using dimethyl carbonate (DMC) is the most effective route implementing safer and greener reaction conditions. This review is focused on different types of heterogeneous catalysts and characterization techniques used for identifying and deactivating those catalysts, covering the literature from the last decade to till date on this topic. Potent applications of GC as a versatile compound are elucidated in brief. Finally, a conclusion, outlook, and author’s perspective have been provided in brief

Stimulation in fullerene for adsorbing pollutant gases: A review

The catalytic activities of fullerene are affected largely by different shapes and surface arrangements influencing catalyst activity and stability a lot. Surface structures of metal oxides (MOs) adsorbed on surfaces of C60-fullerene can show gas sensing properties. Greenhouse gases can be captured and stored on those surfaces. Adsorption of gases on the MOC60 complex is more effective than the direct adsorption of gases on fullerene only. The possibility of morphological structures has been considered in the paper for adsorption of gases like NO2, CO, CO2, N2O on the surface of MO-[60] fullerene. Cu2O, ZnO and NiO metal oxides (MOs) when exposed to [60] fullerene at different sites between rings, MOs occupy different positions. The formation of quasi- rings provides extra stability to the adsorbed molecules thereby helping towards the greener and cleaner environment. In this review we have summarized the more effective adsorption of gases on MO- C60 surface as compared to that of direct adsorption. The morphological changes in the structures are predicted furthermore

Biomass waste-derived catalysts for biodiesel production: Recent advances and key challenges

Biomass-derived catalysts are being intensively studied as potential replacements for traditional chemical catalysts in the sustainable generation of biodiesel because of their unique combination of characteristics; catalytic activity, low-cost, plentiful supply and ecologically friendly and efficient manufacturing procedures. This critical review discusses the recently reported approaches that have been used (mostly since 2016) towards cost-effective and environmentally benign solid base/acid/acid-base catalysts from a range of biomass. Sources include shells, animal bones, and plants. Outlined alongside the push for optimized conversion and yield is the increasing trend for enhanced catalyst reusability and recyclability. Outstanding technical problems associated with catalyst preparation or stability, or waste generation are considered individually. The outlook for solving each of these is discussed, as is the potential of biomass-derived catalysts and the biodiesel they produce to develop the fields of fuel synthesis and energy use. Overall, this review aims to assess the viability of biomass-derived catalysts in the commercial sector and the most promising routes for transferring new technologies from the academic environment to industry