Physiochemical Characterization Research Articles

Effect of N-Doped Carbon on the Morphology and Oxygen Reduction Reaction (ORR) Activity of a Xerogel-Derived Mn(II)O Electrocatalyst

This work synthesizes a xerogel from a sol–gel synthesis strategy and supports it on N-doped carbon support from spent coffee biomass (Mn(II)O/N-CC, hereafter MnO) as an efficient oxygen reduction reaction (ORR) catalyst in alkaline electrolytes. The effects of N-CC carbon content on MnO nanoparticle size, dispersion, distribution, morphology, and electrochemistry on ORR are discussed. The SEM and TEM measurements show that increasing the N-CC content during the MnO gelation reaction improved MnO dispersion and particle size during thermal treatment, increasing the ORR’s electrochemical active surface area. Several physiochemical and electrochemical characterizations show a clear relationship between N-CC catalysts and ORR activities. The best catalyst, MnO/N-CC-5, had an even distribution of 27 nm MnO nanoparticles on the N-CC support. The MnO/N-CC-5 catalyst had almost identical ORR kinetics and stability to those of the state-of-the-art Pt/C catalyst in 0.1 M KOH electrolytes, losing only 10 mV in half-wave potential after 5000 potential cycles and retaining 96% of current for over 10 h of continuous chronoamperometric stability. By measuring the electrochemical active surface areas of various catalysts by cyclic voltammetry at different scan rates and measuring the double layer capacitance (Cdl) and ECSA, MnO/N-CC-5 catalysts were shown to have enhanced ORR activity. The XPS analysis explains the ORR activity in terms of the Mn3+/Mn4+ ratio, and a mechanism was proposed. These findings suggest that the MnO/N-CC-5 catalyst could be a cathode catalyst in fuel cells, biofuel cells, metal–air batteries, and other energy conversion devices.

Structure-Driven Performance Enhancement in Palladium–Graphene Oxide Catalysts for Electrochemical Hydrogen Evolution

Graphene oxide (GO) has recently gained significant attention in electrocatalysis as a promising electrode material owing to its unique physiochemical properties such as enhanced electron transfers due to a conjugated π-electron system, high surface area, and stable support for loading electroactive species, including metal nanoparticles. However, only a few studies have been directed toward the structural characteristics of GO, elaborating on the roles of oxygen-containing functional groups, the presence of defects, interlayer spacing between the layered structure, and nonuniformity in the carbon skeleton along with their influence on electrochemical performance. In this work, we aim to understand these properties in various GO materials derived from different graphitic sources. Both physiochemical and electrochemical characterization were employed to correlate the above-mentioned features and explore the effect of the location of the palladium nanoparticles (Pd NPs) on various GO supports for the hydrogen evolution reaction (HER). The interaction of the functional groups has a crucial role in the Pd dispersion and its electrochemical performance. Among the different GO samples, Pd supported on GO derived from graphene nanoplate (GNP), Pd/GO-GNP, exhibits superior HER performance; this could be attributed to the optimal balance among particle size, defect density, less in-plane functionalities, and higher electrochemical surface area. This study, thus, helps to identify the optimal conditions that lead to the best performance of Pd-loaded GO, contributing to the design of more effective HER electrocatalysts.

Physicochemical and toxicological characteristics of leachates and water quality around dumpsites in Lagos Nigeria

Improper waste management leading to contamination of groundwater resources is a global environmental issue. This study examined the physicochemical and toxicological characteristics of leachates and their effect on water quality around the dumpsite in Alimosho Lagos, Nigeria. Samples of water and leachates were collected from boreholes around the dumpsite. Physiochemical and toxicological characterization of water around the dumpsite was based on American Public Health Association standards. Seventeen physiochemical and heavy metals of leachate and borehole water samples were analysed. The result of the study shows that the temperature, odour, appearance and turbidity of the water in the study area were within the limits set by WHO. However, the pH was below the WHO limits indicative of the acidity of the groundwater. The presence of Pb, Cr, and Cd confirmed leachate pollution. The contemporary effects confirmed the insignificant effect of the dumpsite operations at the groundwater source. Without a properly designed leachate series system, uncontrolled accumulation of leachates at the bottom of the dumpsite poses capacity infection dangers to groundwater resources. It is recommended that proper disposal of waste, in addition to implementing a higher sustainable environmental sanitation practice, is needed to ensure the safety of groundwater within the locality.

Structural study and molecular docking insights into laccase-mediated dye degradation

Industrial wastewater often contains harmful dyes, posing significant environmental challenges. This study used computational tools to investigate the interactions between the low-degradability Azo dye, Reactive Blue 19, and laccase enzyme from two fungi species, Lentinus sp. WR2 and Trametes versicolor, as well as the protein Xyn5B (GH30) from Bacillus sp. BP7. Physiochemical characterization indicated acidic properties for Lentinus sp. WR2 and T. versicolor, while basic characteristics for Bacillus sp. BP7. Secondary structure (SOPMA analysis) revealed that most laccases had random coiling, enhancing protein flexibility. The negative GRAVY index revealed favorable water interaction for Lentinus sp. WR2 and Bacillus sp. BP7. The ERRAT plot validated the laccase 3D structure. The molecular docking results were compared using active site prediction and docking score. Lentinus sp. WR2 is linked with Reactive Blue 19 through a single residual amino acid THR 168; T. versicolor is linked through GLY 101, TRP 98, and TRP 512; and Bacillus sp. BP7 exhibited four linkages: VAL 262, TYR 263, TRP 117, and THR 260. The molecular docking results showed that Xyn5B demonstrated laccase activity and bound effectively with Reactive Blue 19, outperforming a commonly used fungal laccase in dye degradation. These findings enhance our understanding of enzyme-substrate interactions and highlight the potential of Xyn5B in eco-friendly dye degradation.

Ultrasound-Assisted Advanced Oxidation Process Using Perovskite-Type LaMnO3 Nanospheres.

Among the perovskite oxide community, La-based perovskites have garnered considerable interest due to their remarkable properties including catalytic, electrocatalytic, photocatalytic, sensing, electrical, magnetic, and optical characteristics. Herein, rhodamine-B (RB) dye has been reported to be sono-catalytically decomposed by an ultrasound-assisted advanced oxidation process (AOP) using perovskite-type LaMnO3 (LMO) nanospheres synthesized via ultrasonic approach. Several physiochemical characterizations such as XRD, FT-IR, XPS, SEM, TEM, and SEM-EDS investigations were used to investigate the LMO perovskite nanospheres. Then, LMO potential for adsorption and the sonocatalytic decolorization of RB dye in an aqueous solution are examined. With LMO perovskites, the adsorption and removal kinetics of RB correspond to the pseudo-first-order model. Furthermore, by utilizing the pseudo-first-order, the RB dye process is removed with improved efficacy in the following sequence: Agitation alone: 3.76×10-4 min-1<US only: 5.02×10-3 min-1<LMO only: 5.85×10-3 min-1<LO@MO + US: 1.38×10-2 min-1<LMO + US: 1.75×10-2 min-1, accordingly. Perovskite-type LMO, which has significant reusability and stability, is an ensuring sonocatalyst for dye decomposition in wastewater, enabling faster decolorization. A prospective mechanism has been suggested for the sonocatalytic decomposition of RB.

In-situ realtime study of zinc selenide nanoparticles sustained by polypyrrole in alkaline water oxidation

Interest in metal electrodeposition for synthesizing customized nanomaterials has resurged, particularly for applications such as sensors and fuel cells. The present study involved the synthesis of ZnSe nanoparticles (via hydrothermal method) while polypyrrole and novel composite Ppy@ZnSePpy@Ppy (via sequential electrodeposition technique) on a glassy carbon (GC) electrode and their physiochemical, electrochemical, and operando spectro-electrochemical characterizations towards oxygen evolution reaction (OER). Results indicated that ZnSe nanoparticles are well embedded within the Ppy layers and during OER the composite electrocatalyst approached 398 mV at 10 mA cm−2 and exhibited Tafel value (b ∼ 75 mV dec−1) with ECSA (0.03) which shows better results than other two. In addition, the operando spectro-electrochemical spectra of the composite revealed the significant generation of active intermediate oxygen species of selenium and Zn2+. The important feature of the current work is the disclosure of Se's questionable role and species involved in OER found to be Se4+.

Effect of Tween 80 and Pluronic 127 on the stabilization of zein nanocarriers for the delivery of piperine

In the current research work, zein-based polymeric nanocarriers were developed for the delivery of piperine, where the effect of non-ionic surfactants (Tween 80 and Pluronic F-127) on the stability and in vitro drug release characteristics were studied. Physiochemical characterization studies showed that the particle size of blank and drug-loaded surfactant stabilized zein nanoparticles were <200 nm and particles were spherical in shape. FTIR studies confirmed the successful incorporation of piperine within the zein nanoparticle without any alteration in primary structure of zein. The circular dichroism spectroscopy suggested that α-helix content of zein was reduced following the incorporation of drug within nanoparticles. The solubility of piperine was enhanced significantly in the gastrointestinal tract, and higher sustained release was observed for tween 80-stablized zein nanoparticles. The formulations were stable towards thermal treatment up to 90 °C, showed superior resistance towards aggregation even at ionic strength >50 mM NaCl, and did not show any aggregation even at the isoelectric pH. Tween 80-stablized zein nanoparticles showed good redispersibility index with the cryoprotectant mannose (5 % w/v) after lyophilization. The current research would contribute to the advancement of zein nanoparticles for the delivery of nutraceutical agents, which may be utilized in the food supplements or therapeutic agents to improve the human health.

Poly(lactic acid hydroxyacetic acid)-poly(ethylene glycol)-modified ginsenoside Rg3 nanomedicine enhances anti-tumor effect in hepatocellular carcinoma

Objective This research aims to improve the bioavailability and anti-hepatocellular carcinoma (HCC) efficacy of Ginsenoside Rg3 by modification with poly (lactic acid hydroxyacetic acid)-poly(ethylene glycol) (PLGA-PEG). Methods PLGA-PEG-Rg3 was obtained by emulsification and evaluated it physiochemical characterization by FTIR, SEM, laser particle-size analyzer and HPLC. The effect of the PLGA-PEG-Rg3 and Rg3 on HepG2 cells was compared in vitro studies, including cell proliferation, transwell and a series of apoptosis detection, and in-situ HCC model. Results The PLGA-PEG-Rg3 were 122 nm in size and 0.112 in polydispersity index with sustained release profile in vitro. Compared to Rg3, PLGA-PEG-Rg3 was more effective in suppressing HepG2 growth and inducing apoptosis by the mitochondrial apoptosis pathway in vitro. And PLGA-PEG modification enhanced the liver-targeting ability and drug circulation time of Rg3 in vivo, resulting in PLGA-PEG-Rg3 possessing superior performance in inhibiting tumor growth and prolonging the survival time of tumor-bearing mice than Rg3. Conclusions Overall, these results showed PLGA-PEG-Rg3 enhanced the anti-tumor effect of Rg3 in HCC.

Insight into the efficient electrochemical reduction of nitrate employing Pd/Ru bimetallic doped copper foam cathode: Selectivity and reliability

Nitrate pollution threatens ecological environment and human health. Electrochemical reduction of nitrate to ammonia using metal-doped modified cathode is a promising technique for nitrate removal. In this work, a bimetallic Ru/Pd-doped Cu foam (CF) electrode was developed for nitrate reduction using cation exchange method. Confirmed by various physio-chemical characterization, it was found that the Ru/Pd-Cu Spongy Copper Foam (SCF) was successfully prepared. In addition, nearly 100 % nitrate removal, 94.07 % NH3 selectivity, and 84.9 % Faradaic efficiency (FE) could be achieved, under the optimized conditions as 100 mg L−1 of initial NO3--N concentration, 0.3 mol L−1 of Na2SO4 as electrolyte and the applied current of 5.42 mA cm−2. Through electrochemical testing and DFT calculation, it was revealed that the bimetallic doping of Ru/Pd facilitate electrocatalytic nitrate reduction reaction (NO3RR) by reducing the energy barriers of the NO3--to-NH3 pathway from 0.81 to 0.56 eV. Besides, the electrode showed excellent stability and anti-toxicity even after 10 repeated NO3RR cycles, since the NH3 yield rate and NH3 selectivity ranged from 0.206 to 0.231 mg h−1 cm−2, 87–96.87 % respectively. After NO3RR, an extended electrochemical oxidation process was implemented to remove ammonia, and nearly 100 % of NH3 was oxidized to N2 without byproducts. Thereby, this study provides a new option for the electrochemical reduction of nitrate to ammonia via cathode modification, to achieve the substantial nitrate removal from nitrate-containing water.

Strategically engineered multifunctional graphene oxide hybrid nanomaterials for efficient catalytic degradation and emerging contaminants treatment

The use of functional textiles is growing in all fields of science and technology. Surface functionalization is mainly used to impart conventional textiles with new functionalities and improved performances. In the present study, a cobalt ferrite nanoparticle/graphene oxide (CoFe2O4/GO) coated polyethylene terephthalate (PET) fabric with excellent catalytic and antibacterial properties, has been successfully developed. The PET-coated CoFe2O4/GO samples, ranging from 1 % to 5 % wt. were obtained using a simple dip-coating method in CoFeO/GO solution (1 mg/mL), and were investigated through several physiochemical characterization techniques. CoFe2O4/GO and PET fabric have been shown to establish an interfacial connection by Fourier transform infrared spectroscopy (FTIR). X-ray diffraction (XRD) results showed that CoFe2O4/GO coating did not affect the PET crystallinity and that CoFe2O4/GO hybrid was incorporated in the PET samples, which was proved as well by the morphological study through Scanning electron microscopy (SEM). Furthermore, thermogravimetric characterisation (TGA) verified that the coating does not change or impair the quality of the fibre and that the PET@CoFe2O4/GO as made is thermally stable. Tensile strength tests demonstrated that coated fabrics exhibited outstanding mechanical properties in comparison with pristine PET. Moreover, the coated PET@CoFe2O4/GO fabric was used as a model catalytic system for peroxymonosulfate (PMS) activation in the rhodamine B (RhB) degradation reaction. Total Organic Carbon (TOC) measurements showed that TOC removal reached 89.82 % in only 12 min reaction. The results confirmed that the coated fabrics exhibited high catalytic performances, good stability and reusability in consecutive degradation experiments with a degradation rate over 60 % even after 7 degradation cycles; Moreover, it is easily and simply separated from the mixture, by removing the textile sample from the aqueous solution. It is worth mentioning that the PET@CoFe2O4/GO fabrics showed outstanding antibacterial activity against both Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) bacteria with an inhibition diameter zone of up to 13 mm for PET@CoFe2O4/GO (5 %). Overall, these findings are of great importance as they permit the development of a novel multifunctional textile fabric, combining anti-bacterial activity, catalytic performance and mechanical properties. The study provides a textile-based catalyst with improved catalytic performance, re-usability in consecutive degradation reactions and easy catalyst separation compared to traditional supports. Thus, a huge potential application in several fields such as medicine, heterogeneous catalysis, and wastewater treatment.

A self-integration via dual-active mode structural-SC-TENG energy device for electrochemical energy storage and triboelectric energy harvesting

The structural supercapacitor with triboelectric nanogenerator (structural-SC-TENG) is a remarkable integrated energy device utilized for clean energy storage and harvesting. Here, we demonstrated the structural-SC-TENG device based on a multifunctional storage and harvester using dual-functional MoO3 grown on a carbon cloth electrode (CC) via hydrothermal technique and physiochemical characterization revealed the formation of an orthorhombic phase of MoO3. The FE-SEM morphological analysis confirms that the cubes-like peals were uniformly decorated on the CC surface in an upward and downward direction. The dual-functional MoO3 grown on the CC electrode was used for the construction of the supercapacitor and TENG device which will act as a charge-storing electrode in the supercapacitor and charge-sharing electrode in TENG. The constructed MoO3 SSC provides an excellent device capacitance of 97.86 F g−1, energy density of 40.50 Wh kg−1, and a high-power density of 28,125 W kg−1 with remarkable cyclic life modeled/predicted via time series analysis (TSA) technique. On the other side, the TENG device constructed using MoO3 on CC as the positive electrode (confirmed through KPFM analysis) and PDMS as the negative electrode exhibited a better electrical response with a high voltage and current of 55 V and 0.19 μA and delivered a peak power of 4.17 μW. This type of integrated device is splendid and possibly be used for self-powered sensors, smart IoTs, self-charging power systems, low-power electronics, and various indoor/outdoor environments.

Geological, physiochemical, mineralogical, and rheological characterizations of clay deposits in Northeast Libya

ABSTRACT This study was conducted on bentonite deposits in Um Al Rozm and Ain Al Ghazala areas that lie between Latitudes º32 “00 ‘30 and º32 “33 ‘30 N and Longitudes º23 “00 ‘30 and º23 “20 ‘30 E in Northeast Libya. The objective of this study is the assessment of geological, physiochemical, mineralogical, and rheological properties and the potentiality of utilizing these rocks as drilling fluids for oil and gas wells. Chemical and mineralogical analyses were performed by XRF and XRD, respectively. Rheological properties are investigated before and after the treatment process by adding additive materials such as Na2CO3 and CMC. The chemical analysis results of bentonite showed a discrepancy in the proportions of the major components. The results after the treatment process for bentonite in Um Al Rozm exhibit rheological properties consistent with those stipulated by API and other standard bentonites, but for Ain Al Ghazala, the results are unsatisfactory. Mineral analysis of bentonite from the two areas revealed a difference in the mineral composition. The bentonite of the Um Al Rozm area is Na-bentonite, while the bentonite of the Ain Al Ghazala area is Ca-bentonite, whose rheological properties aren’t acceptable as drilling fluid properties stipulated by API.

Fabrication of Hybrid Coated Microneedles with Donepezil Utilizing Digital Light Processing and Semisolid Extrusion Printing for the Management of Alzheimer's Disease.

Microneedle (MN) patches are gaining increasing attention as a cost-effective technology for delivering drugs directly into the skin. In the present study, two different 3D printing processes were utilized to produce coated MNs, namely, digital light processing (DLP) and semisolid extrusion (SSE). Donepezil (DN), a cholinesterase inhibitor administered for the treatment of Alzheimer's disease, was incorporated into the coating material. Physiochemical characterization of the coated MNs confirmed the successful incorporation of donepezil as well as the stability and suitability of the materials for transdermal delivery. Optical microscopy and SEM studies validated the uniform weight distribution and precise dimensions of the MN arrays, while mechanical testing ensured the MNs' robustness, ensuring efficient skin penetration. In vitro studies were conducted to evaluate the produced transdermal patches, indicating their potential use in clinical treatment. Permeation studies revealed a significant increase in DN permeation compared to plain coating material, affirming the effectiveness of the MNs in enhancing transdermal drug delivery. Confocal laser scanning microscopy (CLSM) elucidated the distribution of the API, within skin layers, demonstrating sustained drug release and transcellular transport pathways. Finally, cell studies were also conducted on NIH3T3 fibroblasts to evaluate the biocompatibility and safety of the printed objects for transdermal applications.

A novel binary composite of CuCoNi-MOF/MoO3 with exceptional capacitance as electrode material for supercapacitors

Metal-organic framework (MOF), a new type of electrode material with a porous structure, has shown promise as a good choice for supercapacitors in the next generation of energy storage devices. These research endeavors initiated the development of a doping technique and the creation of a composite material using solvothermal synthesis. This study involves the successful synthesis of CuCo-MOF and CuCoNi-MOF by introducing Co and Ni metals into the Cu-MOF. The CuCoNi-MOF is then combined with MoO3 to form a novel binary composite known as CuCoNi-MOF/MoO3. These prepared materials are then subjected to several physiochemical and electrochemical characterization techniques. The electrochemical characteristics of the prepared samples are estimated using a three-electrode cell setup. The analysis included cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge/discharge (GCD). The examination of the CV reveals that the binary composite CuCoNi-MOF/MoO3 exhibits exceptional capacitance (937.5 Fg−1 at 5 mVs−1) in comparison to the other materials that were synthesized. Moreover, the GCD study reveals that it has a capacity of 1364.69 Fg−1 at 0.5 Ag−1. Furthermore, it retained 91.5 % of its capacity after 5000 cycles demonstrating its exceptional stability. Owing to the exceptional electrochemical properties of CuCoNi-MOF/MoO3, it is employed as the positive electrode and activated carbon (ActC) as a negative electrode for device fabrication. The supercapattery (CuCoNi-MOF/MoO3||Act-C) showed an excellent specific capacitance of 218.83 Fg−1 at 1 Ag−1 along with an outstanding energy density of 59.57 Wh.kg−1 and power density of 704.9 W.kg−1. Moreover, the assembled supercapattery device shows remarkable stability of 95.2 % at 10 Ag−1 after 15,000 cycles.

Hydrothermal synthesis of cadmium sulfide decorated reduced graphene oxide photocatalyst for the degradation of photostable naphthol blue black dye

Photocatalysis is being used for the mineralization of recalcitrant organic pollutants in water that cannot be treated with conventional methods. Cadmium sulfide decorated reduced graphene oxide (rGO-CdS) nanocomposite photocatalyst was synthesized by hydrothermal method and evaluated for the removal of a photostable textile azo dye, naphthol blue black (NBB) under ultraviolet light (UV-A, 365 nm). The rGO-CdS combination was opted for due to utilizing the narrow band gap (Eg = ~2.4 eV) of CdS and robust rGO support, capable of attracting organic pollutants to surface, bear, and protect CdS from photocorrosion. The formation of rGO-CdS was proved from the findings of physiochemical characterization UV–visible-, X-ray diffraction photoelectron, Raman, energy dispersive X-ray-spectroscopic, and scanning, transmission electron, and atomic force microscopic studies. The spherical CdS was decorated on the random shaped rGO sheets. Eg of CdS and rGO-CdS were 2.42 and 2.39 eV, respectively. After 2 h of light exposure, 2 g/L of rGO-CdS mineralized 95 % of NBB (2 × 10−4 mol/L). After 5 cycles, 80 % of photocatalytic efficiency was retained. In gas chromatography-mass spectrometry studies, 8 fragments of NBB were found after 1 h and confirmed that the degradation was mediated by photocatalytic dilapidation. The optimum pH for NBB degradation was 9. The rGO-CdS was found to be a potentially stable and reusable photocatalyst for environmental applications.

Carbon Decorated MOF for Low-Cost Aqueous Al-Ion Supercapacitors: Effect of Redox Additives

The performance enhancement of ZIF-67 based Al-ion supercapacitors using conductive additives is presented. By using the simple co-precipitation technique, the porous ZIF-67 and composites of ZIF-67 with two distinct forms of carbon rGO and CNS were synthesized. Physiochemical characterizations like XRD, BET, FTIR, etc., were performed to confirm the successful synthesis of ZIF-67 and its composites. The electrochemical measurements were performed in the three-electrode configuration using 0.5 M AlCl3 electrolyte. Out of all, the composite of ZIF-67 with rGO (ZIF-67_rGO) outperformed all other materials because of its larger specific surface area and enhanced electrical conductivity. Further, the electrolyte modification was performed in 6 mM KFCN as a redox additive for ZIF-67_rGO composite. Here, the specific capacitance of ZIF-67_rGO composite enhanced from 245 F g-1 to 346 Fg-1 at 1 A g−1 current density. Using the redox additive, we observe an increment of almost 41% in ZIF-67_rGO composite than its pristine counterpart. The composite also delivered good cycling stability with excellent coulombic efficiency of 89% and 95% after 1000 cycles, at 5 A g-1 current density, respectively.

Implications of White Light-Emitting Diode-Based Photoirradiation on Green Synthesis of Silver Nanoparticles by Methanol- and Aqueous-Based Extracts of Bergenia ciliata Leaves.

Bergenia ciliata (BC) is a perennial herb that is frequently used as a traditional medicine. Its leaves and rhizomes are reported to have significant antioxidant, metal-reducing, and chelating properties. Although the rhizomes have the potential to synthesize silver nanoparticles (AgNPs), the leaves are yet to be studied for the green synthesis of metal nanoparticles. Likewise, photoirradiation also plays a significant role in the green synthesis of metal nanoparticles. In the current study, we intended to demonstrate the implications of photoirradiation by white light-emitting diode (LED) on the aqueous and methanol extracts (AE and ME, respectively) of BC leaf-mediated green synthesis of AgNPs. In this regard, the AgNP synthesis of the two extracts was performed in the dark and under 250-lumen (lm) and 825 lm LED bulbs. The physicochemical characterization of the synthesized nanoparticles was also performed, wherein percent nanoparticles yield, morphology of the nanoparticles, shape, size, percent elemental composition, crystallinity, and nanoparticle stability were studied. The nanoparticle-synthesizing potential of the two extracts contradicted significantly in the presence and absence of light, while the AE produced a significantly high number of nanoparticles in the dark (17.26%), and increasing light intensities only attenuated the nanoparticle synthesis, whereas ME synthesized comparatively negligible silver nanoparticles in the dark (1.23%). However, increasing light intensities significantly enhanced the number of nanoparticles synthesized in 825 lms (7.41%). The GCMS analysis further gave a comparative insight into the phytochemical composition of both extracts, wherein catechol and pyrogallol were identified as major reducing agents for nanoparticle synthesis. The influence of light intensities on the physiochemical characterization of AgNPs was predominant. While the size of both the AE- and ME-mediated AgNPs increased considerably (20-50 nm diameter) with increasing light intensities, the percent of silver atoms decreased significantly with increasing light intensities in both the AE- and ME-mediated AgNPs with ranges of 13-18% and 14-24%, respectively. The nanoparticle stability studies suggested that both the AE- and ME-mediated AgNPs were stable for up to 15 days when stored at 4 °C. The stability of both nanoparticles was attributed to the presence of a wide range of phytochemicals. In conclusion, the AE of BC leaves was reported to have significantly higher AgNP-synthesizing potential as compared to the ME. However, AE-mediated AgNP synthesis is attenuated by photoirradiation, whereas ME-mediated AgNP synthesis is enhanced by photoirradiation. The photoirradiation by white LED light increases the size of the AgNPs, while the percent silver composition declines, irrespective of the extract type. Both extracts, however, have nanoparticle stabilizing potential, thereby producing stable nanoparticles.

Isolation and physiochemical characterization of Red kidney bean (Phaseolus vulgaris L.) starch

The current study focuses on the isolation and physiochemical characterisation of starch from Phaseolus vulgaris L. The yield of the starch was about 25.8 %. The size of the starch granules ranged between 10 and 25μm. The starch had a higher water binding capacity, swelling power and solubility but had low paste clarity. P. vulgaris starch exhibited high freeze thaw stability. The bulk, tapped and particle densities of the starch were 1.64 g/cm3, 2.06 g/cm3 and 0.66 g/cm3 respectively. The porosity of the starch was about 64.1%. The estimated Carr index and Hausner’s ratio indicated good flowability of the starch powder. X-ray diffraction analysis indicated that the starch was C-type starch. Fourier-transform infrared spectroscopy revealed the functional group corresponding to that of starch. Thermo gravimetric analysis indicated good thermostability.

Physio-chemical Characterisation of Dumped Solid Waste

Landfilling is the most common practice used for the disposal of solid waste since it is the cheapest method of municipal solid waste management. The present study aims to determine the physical and chemical characteristics of dumped solid waste collected directly from Okhla landfill site (New Delhi, India) which has been declared as exhausted in 2018. These waste samples have been collected having ages beyond 20 years. Further, several laboratory tests were performed on the samples to investigate parameters namely physical composition, moisture content, density, optimum moisture content, pH, electrical conductivity, percentages of carbon (C), nitrogen (N), hydrogen (H), sulphur (S) and C/N ratio. The physical composition of samples was found to be substantially heterogenous. The mean values for moisture content and optimum moisture content were observed as 10.03% and 22.27% respectively. Moreover, the mean of density, pH and electrical conductivity were obtained as 1323.88 kg/m3, 6.44 and 3.06 mho/cm respectively. On the other hand, the elemental parameters C, H, N, S mean percentages were evaluated as 5.98%, 0.73%, 0.27% and 0.71%. Consequently, C/N ratio was evaluated as 23.46 for the samples. These results have also been compared with the MSW characteristics of Asian countries.

Isolation, purification, and physio-chemical characterization of melanin pigment from nigerseed hulls (Guizotia abyssinica)

Plant melanin, a natural pigment, has gained significant attention recently due to its potential therapeutic and industrial applications. In this study, melanin pigments were extracted from Nigerseed hulls (NH) via alkali and acid extraction methods, followed by acid hydrolysis, organic solvent treatment, and repeated precipitation. The solubility of NH melanin was assessed, revealing solubility in alkali and dimethyl sulfoxide (DMSO) but insolubility in other common organic solvents. High-performance liquid chromatography (HPLC) was employed to measure the purity of NH melanin in comparison to standard melanin, while elemental analysis indicated a similarity between melanin extracted from nigerseed hulls and the standard counterpart. LC-MS data revealed a molecular weight of NH melanin. Furthermore, the stability of melanin was evaluated under varying conditions including temperature, oxidants, reducing agents, light exposure, and metal ion presence. Results demonstrated significant effects of Mg2+, Cu2+, and Fe2+ metal ions on melanin stability, with a minor effect observed for Ca2+, while sodium hyposulfite was found to destabilize the pigments. Our findings suggest that nigerseed hulls hold promise as a novel source for efficient melanin production, with potential applications in the food sector, food packaging, and biomedical fields.