Journal of Nepal Chemical Society

Solid-Liquid Equilibrium Study for Binary System Forming Intermolecular Compound: Phase Diagram, Thermal, Physicochemical and Powder XRD study

Krishna Sharma — 2022-08-30

The phase diagram study of the binary organic system has been investigated by the thaw melt method using 4-hydroxy- 3 methoxybenzaldehyde (HMB) and 4-nitroaniline (NA). The temperature-composition plot showed that the intermolecular compound (IMC) has formed at 1:1 molar ratio with two eutectics on either side of IMC. The melting points of eutectics and IMC along with parents are verified by the DSC method. The different phases of the systems which are in equilibrium and their physicochemical properties are estimated using the enthalpy of fusion values obtained from DSC. The higher melting temperature of IMC suggested the formation of Schiff base during homogenization process. The new and moderately sharp Bragg’s peaks at specific 2θ values found in the diffractogram of IMC revealed the novelty and crystalline nature of IMC while repeated peaks in the diffractogram of eutectics suggest the mechanical mixture of eutectics

Synthesis, Characterization, Biological Study of Synthesized Lauha Bhasma

Rajesh Paudel — 2022-08-30

Bhasmas are prepared from metallic and herbal ingredients and are also referred to as herbo-metallic preparations. Lauha bhasma (LB) is one of the iron-based herbo-metallic preparations used in Ayurvedic medicine for treating various ailments due to iron deficiency. The preparation of LB involves normal purification (samanya sodhana), special purification(vishesha sodhana) followed by drying under sunlight (bhanupaka), heating in a frying pan (sthalipaka), and calcination (putapaka) with Triphala kwatha as a medium under the temperature of 650 ^oC in an electric muffle furnace (EMF) and maintained for 1 hour. LB is subjected to different physicochemical analysis and modern analytical methods using Fourier Transform Infrared Spectroscopy (FTIR), X-ray Spectroscopy (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDX). Prepared LB is also undertaken to antibacterial study and is compared with market samples. The results suggest that organoleptic characters, preliminary test, and the physicochemical result of LB suggest that these steps were necessary to obtain a good quality of bhasma and also make it acceptable during the Bhasmikarna process. From physicochemical analysis data, it was observed the negligible moisture content (0.42 %; loss on drying), total ash value (17.3 %), acid insoluble ash value (7.6 %). It was observed that LB was prepared in 21 puta where the average crystalline size was found to be 57.23 nm from XRD spectra. SEM analysis shows the fine coarse structure with a uniform particle size of LB. EDX graph shows the presence of Fe (75.43 %) as a major element.FTIR spectra suggest the presence of different organic moieties which enhance the therapeutic action due to which bhasma shows significant antibacterial properties.

Characteristics of the ammonium ion adsorption from wastewater by the activated carbon obtained from waste tire

Ram Ghising — 2022-08-30

The activated carbons were prepared from waste tire using a pyrolysis technique in different environments, namely: activated carbon in the open air (AC-O), nitrogen gas (AC-N), nitrogen gas and water steam (AC-NW), and a composite of tire and aluminum hydroxide in nitrogen and steam atmosphere (AC-COM), in order to study the change in specific surface area and making the composite of activated carbon and alumina. The X-ray diffraction study revealed the presence of quartz, alumina, zinc sulfide, and activated carbon. Methylene blue adsorption isotherm showed that the highest specific surface area of 218m²/g was found in the case of activated carbon prepared in an oxygen atmosphere and subsequently used for ammonium ion adsorption. The adsorption isotherm and kinetic behavior were studied with optimum pH 9. The adsorption isotherm fitted well to the Freundlich Model than that of Langmuir and the equilibrium monolayer adsorption capacity calculated from Langmuir was 277.8mg/g at room temperature. The adsorption reached equilibrium in 120 minutes, and kinetic data fitted well to the pseudo-second-order model with a rate constant value 5.3×10^-3L g/(mg·min). Real water samples from different places within Kathmandu valley were subjected to ammonium ion adsorption onto the active carbon and were worked for the adsorption smoothly

Geopolymerization Behaviour of Red and White Clays

Arvind Pathak — 2022-08-30

Construction is one of the most important activities increasing the demand for Portland cement resulting significant amount of CO₂ emission, natural resources degradation, and a high amount of energy consumption. The use of geopolymer has been studied as a potential substitute for Portland cement. Geopolymers are environmentally-friendly binding materials that are produced by the polymerization of alumino-silicates in presence of alkali polysilicates forming Si-O-Al bonds, which are used for several building applications. In this study, red and white clays which contain solid alumino-silicate have shown reactive in presence of an alkaline activator. The addition of lime has shown improvement in the mechanical and physical properties of the geopolymer products. The FTIR analysis and SEM images of the product have shown the formation of aluminosilicate gel in the geopolymeric product. The maximum compressive strength of the geopolymer products RCW and RWL were achieved to be 15.91 and 20.30 MPa, respectively. Such geopolymer products are in good agreement with cementitious products and can be used in building applications.

Biological and Chemical Studies of Essential Oil and Extracts of Rhizome of Acorus calamus Linn

Rajesh Timilsina — 2022-08-30

The essential oil (EO) of the rhizome of Acorus calamus Linn. was isolated by using a Clevenger apparatus and extracts were prepared by cold percolation technique using the solvents hexane and methane. The chemical constituents of EO were analyzed by Gas Chromatography-Mass Spectroscopy (GC-MS) analysis. A total number of nine chemical compounds were identified and quantified occupying 100% of the total oil composition. The major chemical constituent was reported to be β-asarone (84.87%). Acid value, saponification value, and iodine number of the oil were measured and found to be 0.24 mg KOH/g, 0.42 mg KOH/g, and 31.75 g I₂/100gm, respectively. The antibacterial activity of the hexane and methanol extract was examined against two bacteria by the agar well diffusion method. The hexane extract showed antibacterial activity against E. coli with a zone of inhibition(ZOI)of 10 mm, and. subtilis with ZOI of 7 mm. The methanol extract showed antibacterial activity against B. subtilis only, with a ZOI of 4 mm. Hexane and methanol extract also showed significant antifungal activity against fungi C. albicans with a ZOI of 6 mm and 5 mm, respectively.DPPH assay showed that the percentage of free radical scavenging activity increased with an increase in the concentration of the extract. The total phenolic content of the methanol extract of A. calamus was found to be 48.36 mg/g GAE.

Phytochemical and biological screening of Lantana camara linn. leaves extract

Shiva Pandeya — 2022-08-30

The current study evaluated the phytochemical and biological screening of Lantana camara (Verbenaceae). It is a highly invasive ornamental garden plant species, native to tropical and sub-tropical America. Leaves of L. camara were extracted successively by petroleum ether and methanol by continuous hot percolation. The phytochemical screening was carried out by color reaction with different reagents. The Well diffusion method on Mueller Hinton agar was used for evaluating antimicrobial activity. The LD₅₀ value was determined by acute toxicity studies. The analgesic activity was carried out by tail immersion method, antimotility activity was carried out by charcoal movement test and the antidiabetic activity was carried out by oral glucose tolerance test. The extractive value of methanolic and petroleum ether was found to be 10.11% and 3.11% respectively. The preliminary phytochemical screening showed a positive reaction test for glycoside, tannin, saponin, steroid, flavonoid, carbohydrates, diterpene, and triterpene. The extract showed significant antimicrobial activity against S. aureus (p<0.05) and didn't show any activity against E. coli. The LD₅₀value was found above 2000mg/kg. The analgesic, antimotility and antidiabetic activity of plant extract showed significant results in a dose-dependent manner (p<0.05). The study revealed that the plant possessed antibacterial, analgesic, antimotility and antidiabetic activity. Further studies are needed to standardize the extract and evaluation of the safety profile in long-term toxicity studies is recommended

Biogenic Synthesis of Silver Nanoparticles Using Terminalia chebula Retz. Leaf Extract and Evaluation of Biological Activities

Ramesh Giri — 2022-08-30

Nanoparticles have been used in various fields of science and technology ranging from material science to biotechnology. The formation of nanoparticles has been confirmed through UV-visible spectroscopy (at 420 nm) by the change of color representing surface plasmon resonance. The synthesis of silver nanoparticles by a biogenic method is a novel approach due to its cost-effective, eco-friendly, and large-scale production possibilities. In the present study, silver nanoparticles (TC-AgNPs) were successfully synthesized using Terminalia chebula Retz. (T. chebula) leaf extract. Characterization of green synthesized silver nanoparticles was performed using UV-visible spectroscopy, Fourier transforms infrared (FTIR) spectroscopy, and X-ray diffraction (XRD). The formation of nanoparticles has been confirmed through UV-visible spectroscopy (at 420 nm) by the change of color representing surface plasmon resonance. The crystalline face-centred cubic property of the biosynthesized silver nanoparticles was established using XRD analysis. The XRD data gave the average particle size of 6.1 nm. The functional groups such as -OH, C=O, =NH were found responsible for reducing silver ions and helping to stabilize nanoparticles which were analyzed using FTIR spectroscopy. As the silver nanoparticles possess diverse applications, TC-AgNPs were investigated for antioxidant, antibacterial, and cytotoxic activity. The results showed TC-AgNPs showed potential antioxidant (IC₅₀=312.8 ± 2.28 µg/mL) and antibacterial activities against four pathogenic bacteria like Staphylococcus aureus, Acinetobacter baumannii, Salmonella typhi, and Escherichia coli. Also, the silver nanoparticles exhibited moderate cytotoxicity (LC₅₀= 477.53 ± 0.684 µg/mL) against brine shrimps nauplii in a dose-dependent manner.

Phytochemical Screening, GC Analysis and Antibacterial Activity of Citrus limon Peel Extract and Essential Oil

Surendra Thapa — 2022-08-30

Lemon (Citrus limon) is the most commonly grown tree fruit in the world. The fresh lemons were collected from the local market of Kathmandu, Nepal. Hexane and methanol extracts of plant material i.e. lemon peel were screened for the analysis of the presence of phytochemicals as well as their antibacterial activity. Methanol extract of lemon peel showed the maximum positive phytochemical test with the presence of alkaloids, flavonoids, polyphenols, terpenoids, glycosides, saponin, tannins etc. The essential oil was obtained by steam distillation from fresh peels of lemon using the Clevenger apparatus and analyzed by gas chromatography (GC). Twenty six (26) chemical components were identified in the essential oil of lemon peel. Lemon peel essential oil indicated the presence of Pinene (β) (15.46 %), Limonene (28.94 %), and Terpinene (γ) (8.64), Terpinen-4-ol (3.29 %), Neral (4.20 %), Geranial (5.28 %) as major components. The lemon peel essential oil was found to be a potent antibacterial agent against the Bacillus subtilis (21 mm).

Alkaloids extract of Alnus nepalensis bark as a green inhibitor for mild steel corrosion in 1 M H2SO4 solution

Kamala Dhakal — 2022-08-30

Extraction of alkaloids from Alnus nepalensis bark has been successfully carried out and used as a green inhibitor for mild steel corrosion exposed to 1 M H₂SO₄ solution. Alkaloids have been tested by chemical, UV and FTIR spectroscopic methods.Corrosion inhibition was monitored by weight loss measurement and electrochemical methods(open circuit potential method and potentiodynamic polarization method). Weight loss measurement was employed to study the inhibitor concentration and immersion time effect. Similarly, the temperature effect on inhibition efficiency was also carried out by this method. The maximum corrosion inhibition efficiency observed for 1000 ppm solution for 3 h was 71.94 % at 25 °C. The OCP measurement revealed that alkaloids acted as a mixed type of inhibitor. Potentiodynamic polarization for 3 h immersed samples in the presence and absence of inhibitors was carried out. The corrosion current density was decreased with the increasing concentration. The maximum efficiency of immersed sample in 1000 ppm inhibitor solution was 78.48 %. The adsorption isotherm and thermodynamic parameters were calculated and the energy of activation (Ea) was found to be 71.41 kJ/mol. The positive value of enthalpy indicated that the reaction involves is endothermic.

Extraction and Characterization of Cellulose from Agricultural Residues: Wheat Straw and Sugarcane Bagasse

Anup Karn — 2022-08-30

Wheat straw and Sugarcane bagasse are agricultural as well as industrial wastes rich in lignocellulosic components that can be extracted easily and used as a renewable source of energy. The main aim of this present work was to explore the alternative source of cellulose extraction using simple, fast, and eco-friendly conditions. The process involves NaOH degradation, acid hydrolysis, and bleaching using hydrogen peroxide as a bleaching agent. The extracted compound was analyzed by XRD and FTIR techniques. The XRD peaks obtained were specific to cellulose Iβ which is a crystalline allomorph with a monoclinic structure. The crystallite size of cellulose obtained from sugarcane bagasse was 10.51 nm which is larger than the size of cellulose obtained from wheat straw i.e 4.04 nm. Cellulose from sugarcane bagasse showed a crystallinity index of 51.84 % whereas wheat straw showed only 17.94 %. The yield was slightly higher in wheat straw than in sugarcane bagasse. FTIR analysis in sugarcane bagasse showed a characteristic peak at 3255.84 cm-1 which is shifted to 3340 cm-1 in the case of wheat straw. This peak is due to the vibration of the –OH group in both of the materials. However, both of the materials showed the vibration of the C-O-C bond at 1033 cm-1.

Influence of Magnesium Oxide Nanoparticles on the Compressive Strength of Urea Formaldehyde Resin

Susma KC — 2022-08-30

Urea Formaldehyde (UF) resins have good chemical resistivity and high thermal stability, making them an excellent choice in the construction industry. They, however, pulverize quickly and have low strength and toughness. In this work, magnesium oxide (MgO) nanoparticles were added to UF as nanofillers to influence its compressive strength. MgO nanoparticles were synthesized by reducing magnesium nitrate at different concentrations, using orange peel extract. X-ray Diffraction (XRD) and Fourier Transform Infrared (FTIR) techniques were used to confirm the formation of MgO nanoparticles. XRD results showed the formation of 43 nm, 35.28 nm, and 32.5 nm sized nanoparticles for 0.1 M, 0.2 M, and 0.4 M concentrations respectively. The varying-sized MgO nanoparticles were used for the preparation of UF/MgOnanocomposite at different weight-percentage (wt-%) ratios. A comparative study on the compressive strength of Urea Formaldehyde resins and UF/MgO was performed. From the results, it was found that the addition of MgO nanoparticles to UF resin enhances the compressive strength at certain wt-% ratios.

Effects of intumescent flame retardant based on THEIC-based oligomeric ester as char forming agent on thermal，mechanical and flame retardant properties of HDPE composites

Santosh Khanal — 2022-08-30

In this study, a new phosphor-ester (TPE) was prepared by one-spot polycondensation of tris (2-hydroxyethyl) isocyanurate (THEIC) and phenyl phosphonic dichloride (PPDC) and used as a charring agent in combination with ammonium polyphosphate (APP) to develop new intumescent flame retardant (IFR) for high-density polyethylene (HDPE). The thermal and flame retardant properties of composites were investigated by thermogravimetric analysis (TGA), limiting oxygen index measurement (LOI), and cone calorimetry (CCT). At the same time, the morphology and chemical structure of the char residue were analyzed by scanning electron microscopy, Fourier transfer infrared spectroscopy, and laser Raman spectroscopy. The results showed the LOI value of the composite HD/APP/TPE containing 25 wt. % of APP/THE reaches 28.2 %. The CCT test suggested that the peak heat released rate (PHRR) of the flame retardant composite is decreased by 37 % compared to that of pure HDPE. The use of IFR based on APP and TPE produces a compact char residue that acts as a barrier for heat, oxygen, and volatile combustibles and protects the underlying polymer. Besides TPE can produce the PO-type radicals that show some gas phase flame retardant action. However, the tensile strength of the composites is still lower than that of pure polymer.

Ligational aspects of some 4f metal complexes of a mesogenic Schiffbase, N,N’- di-(4-dodecyloxysalicylidene)-1’,3’-diaminopropane: Synthesis and spectral studies

Prem Shrestha — 2022-08-30

A liquid crystalline (smectic-F and smectic-A phases)Schiff base, N,N′-di-(4-dodecyloxysalicylidene)-1′,3′-diaminopropane(abbreviated as H₂L) and a series of lanthanide (III) complexes of the type [Ln₂(LH₂)₃(NO₃)₄](NO₃)₂, (Ln = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy and Ho) have been synthesized and characterized by elemental analysis, mass spectrometry, FTIR, and UV-Vis spectral techniques. The IR spectral data imply bidentate chelation of the Schiff base in its zwitterionic form (as LH₂) to the Ln^III ions through two phenolate oxygens, rendering the overall geometry of the complexes possibly to distorted mono-capped octahedra. The optical and thermal behavior studies (POM & DSC techniques) reveal that despite H₂L being mesogenic, none of the Ln^III complexes synthesized under this study exhibits mesomorphism. Fluorescence studies show emissions of H₂L and Sm^IIIcomplexx.

Assessment of Neurotoxic Pesticides Residues in Fruits and Vegetables by Bioassay Technique

Khagendra Bohara — 2022-08-30

A study was performed to investigate the status of organophosphate and carbamate pesticide residues present in fruits and vegetables. For this purpose, samples were collected from the local markets of Godawari municipality and Dhangadhisub-metropolitan city of Sudurpaschim province in the Kailali district of Nepal. Samples were analyzed for pesticide residues by the rapid bioassay for pesticide residues (RBPR) technology. The obtained results showed that in fruits the highest inhibition (%) of carbamates(CMs) was present in the banana 29.488%and the highest inhibition (%) of organophosphates(OPs) was present in orange 17.433%. The highest acetylcholinesterase (AChE) inhibition (%) of CMs and OPs pesticides was found to be associated with Sting gourd i.e. 20.574% and 25.357% respectively. The findings point out the urgent need to address the potential risk of exposure to multiple pesticide residues via stringent monitoring programs on daily basis from pesticides present in the diet.

Microplastic Leaching in Local Candy, Pickles and Yogurt Packed in Plastic Containers

Jagjit Kour — 2022-08-30

Plastics degrade into nano plastic or microplastic. Microplastics (MPs) leaches from plastic packaging to food affect human health. In this study overall migration of different plastics packaging was determined by using IS 9845: 1998 method. Food simulant distilled water (Simulant A) for aqueous/non acidic foods (pH ≥ 5) without fat, 3% acetic acid (simulant B) for aqueous, acidic food (pH≤ 5) without fat at 40°C/10 days
and n-heptane (simulant D) for edible fatty foods at 38°C/0.5 were used as per Bureau of Indian Standards IS - 9845-1998. Overall migration in local candy (Titaura) ranges from 4.51580 to 20.43310 mg/kg in food simulant 3% acetic acid (simulant B) and by using n-heptane (simulant D) it ranges from 12.2400 to 41.1066
mg/kg. Similarly in pickles migration of microplastics range from 51.16 to 58.56 mg/kg by using simulant B and in the case of simulant D, it ranges from 7.2266 to 58.6266 mg/kg. The overall migration of microplastics in Yogurt samples were found to be 3.0186 to 19.2093 mg/L using simulant B and in the case of simulant D, it ranges from 7.2266 to 58.6266 mg/L.

α-Glucosidase and α-Amylase Inhibition Activities of Sarcococca coriacea Hook. And Sarcococca wallichii Staph. of Nepalese Origin

Janaki Baral — 2022-08-30

Diabetes mellitus is being severe health problem globally with an increasing number of patients every day. Due to the lack of effective and non-toxic medicine to cure diabetes, plants that are used in ethnomedicine may be a good source for antidiabetic drug discovery. Plants of the Sarcococca genus are medicinally important and are used by local people for managing many diseases including diabetes. In the course of our continuous search of antidiabetic plants and pure compounds, in vitro α-glucosidase, and α-amylase inhibition activity along with the antioxidant activity of methanolic extract of S. coriacea leaf ( Sc-A), S. coriacea stem (Sc-B), and dichloromethane fraction of methanolic extract of Sarcococca wallichi (Sw-D) were carried out. The research revealed dicholoromethane fraction of S. wallichii (Sw-D) with good inhibition of α- amylase enzyme (IC₅₀= 53.79 ± 2.50), whereas Sc-B inhibits α-glucosidase (20.97±2.37) effectively. Similarly, Sc-A showed significant antioxidant activity with IC₅₀=24.56±3.3. The total phenolic content on Sc-A and Sc-B was calculated as 151.35±4.42 mg GAE/g and 86.22±1.59 mg GAE/g whereas the total flavonoid content on Sc-A and Sc-B was found to be 21.61±4.88 mg QE/g and 24.09±4.02 mg QE/g respectively. Similarly, total phenolic and total flavonoid content on Sw-D were found to be 85.26±3.16 mg GAE/g and 21.57±1.26 mg QE/g. To the best of our knowledge, this is the first report of α-glucosidase and α-amylase inhibition activity in these plants. This research work has scientifically supported the use of these plants to manage diabetes by local people and has explored new plants for antidiabetic drug discovery research.