Chemistry

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https://hdl.handle.net/20.500.14540/125

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Browsing Chemistry by TU Institute "Amrit Campus, Lainchaur"

Now showing 1 - 20 of 37
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    ADSORPTIVE REMOVAL OF LEAD(II) USING ACTIVATED CARBONACEOUS ADSORBENT OBTAINED FROM WALLNUT SHELL(Juglans regia)
    (Amrit Campus, 2023-08-17) TIMALSINA, SURESH
    Presence of heavy metal ions in excess than permissible limit in aquatic environment can cause serious problems to human being and aquatic life. Adsorption is by far the most effective method for the removal of trace amounts of toxic heavy metals from wastewater. The main aim of this thesis work is to prepare a low-cost, effective, and highly efficient adsorbent from the walnut shell by chemical modification for the removal of Pb(II) ions from an aqueous solution. Charred walnut shell (CWS) and xanthated walnut shell (XWS) as adsorbents have been prepared. FTIR, XRD, and SEM characterization are used for the characterization of adsorbents. Batch experiments are performed for analysis. The effect of pH, Pb(II) concentration, and contact time have been investigated using both CWS and XWS adsorbents. The optimum working pH of 4 and optimum time of 150 min are determined for both the adsorbents. Equilibrium sorption data are best fitted for the Langmuir isotherm model and the maximum adsorption capacity of CWS and XWS are found to be 61 mg/g and 109.9 mg/g, respectively. Kinetic modeling studies revealed that the experimental data best fit to pseudo-second-order kinetic model. These results demonstrate that XWS may be an attractive alternative bio-adsorbent for the removal of Pb(II) from an aqueous solution
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    Alkaloid extract of Acacia Catechu Bark as Green inhibitor for Mild Steel Corrosion in 1 M H2so4 Solution
    (Amrit Campus, 2023-08-17) Karki, Rajaram
    In situ corrosion inhibition in acid cleaning processes by using green inhibitors is at the forefront in corrosion chemistry. Plant extracts, especially alkaloids, are known to be good corrosion inhibitors against mild steel corrosion. In this research, alkaloids extracted from Acacia catechu has been used as green corrosion inhibitor for mild steel corrosion in 1 M H2SO4 solution. Qualitative chemical tests and FTIR measurements have been performed to confirm alkaloids in the extract. The weight loss measurement has been adopted for the study of inhibitor concentration effect as well as variation of inhibition efficiency for time and temperature. Weight loss measurement reveals the maximum efficiency of 93.96 % at 3 hrs at 28 C. The 1000 ppm inhibitor can work up to a temperature of 48 C with 84.39 % efficiency. The inhibition efficiency of extract has been studied by using weight loss and potentiodynamic polarization methods. Electrochemical measurement results revealed that the alkaloids act as a mixed type of inhibitor. The inhibition efficiency of 98.91 % and 98.54 % in the 1000 ppm of inhibitor concentration for as-immersed and immersed conditions, respectively has been achieved. The adsorption isotherm indicated the physical adsorption of alkaloids. Also, the spontaneous and endothermic adsorption processes have been indicated by thermodynamic parameters.
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    ALKALOID EXTRACT OF ALNUS NEPALENSIS BARK AS GREEN INHIBITOR FOR MILD STEEL CORROSION IN 1 M H2SO4 SOLUTION
    (Amrit Campus, 2022-08-29) Dhakal, Kamala
    Extraction of alkaloids from Alnus nepalensis bark has been successfully carried out, and used as green inhibitor for mild steel corrosion exposed to 1 M H2SO4 solutoin. Corrosion inhibition has been monitored by weight loss measurement and electrochemical methods (open circuit potential method and potentiodynamic polarization method). Alkaloids have been tested by two qualitative chemical analysis: Mayers test and FTIR spectroscpic test. Weight loss measurement was employed to study the inhibitor concentration and immersion time effect. Similarly, temperature effect on inhibition efficiency was also carried out by this method. The corrosion inhibition efficiency with concentration at the various time showed that the maximum efficiency occurs at 3 h for 1000 ppm solution is 71.94 % at 25 C. These results concluded that the inhibition efficiency was incresed with inhibitor concentration. Potentiodynamic polarization for 3 h immersed samples in the presence and absence of inhibitors has been carried out. The maximum efficiency of immersed sample is 90.00 % for 1000 ppm solution. The corrosion potential density was decreased with increase in concentration. The OCP measurement revealed that alkaloids acted as a mixed type of inhibitor. The adsorption isotherm and theromdynamic parameters are calculated and energy of activation (Ea) is found to be 74.48 kJ/mol. The positive value of enthalpy indicated that the reaction involves is endothermic in nature.
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    Characterisization and
    (2025-04-24) Samdhya Parajuli; Dr. Puspa Lal Homagai
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    Chemical Analysis and Biological Studies
    (Amrit Campus, 2025-04-23) Ashika Tamang; Dr. Ram Lal Shrestha
    Full text available
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    CHEMICAL AND BIOLOGICAL STUDIES OF Achyranthes aspera L. FROM MAHOTTARI DISTRICT OF NEPAL
    (Amrit Campus, 2025-04-23) MADHU KUMARI CHAUDHARY; Dr. Ram Lal Shrestha
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    CORROSION INHIBITION BY ALKALOIDS OF SOLANUM XANTHOCARPUM STEM FOR MILD STEEL IN 1 M H2SO4 SOLUTION
    (Amrit Campus, 2023-08-17) THAPA, ONISHA
    Alkaloids from Solanum xanthocarpum stem were successfully extracted. Extracted alkaloids were characterized by qualitative chemical tests and spectroscopic measurements. The effectiveness of the inhibitor was determined by weight loss and electrochemical measurement methods. From the weight loss measurement, maximum inhibition efficiency of 93.14% was achieved. The temperature effect study reveals that the inhibitor can work up to a temperature of 58 C. Electrochemical measurement reveals that alkaloids could inhibit effectively up to 98.14% and serve as a mixed type of inhibitor. A study on kinetic parameters reflects that the inhibitor forms a potential barrier to protecting the MS. The values obtained from the thermodynamic parameters study reflect that the process is a spontaneous endothermic process.
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    CORROSION INHIBITION BY SHOREA ROBUSTA (SAAL) BARK EXTRACT FOR MILD STEEL CORROSION IN 1 M H2SO4 SOLUTION
    (Amrit Campus, 2023-08-17) BAJGAI, AJAY KUMAR
    A novel corrosion inhibitor for mild steel (MS) corrosion has been extracted in methanol solvent from Shorea robusta bark. Qualitative chemical tests, VU, and FTIR measurements were carried out to confirm phytochemicals in the extract. The inhibition efficiency of extract has been studied by using weight loss and potentiodynamic polarization methods. The weight loss measurement has been adopted for the study of inhibitor concentration effect as well as variation of inhibition efficiency for time and temperature. Weight loss measurement reveals the maximum efficiency of 71.47% at ½ hours immersion time in 1000 ppm inhibitor concentration at 18 oC. The 1000 ppm inhibitor can work up to a temperature of 55 oC with 50% efficiency. The open-circuit potential (OCP) measurement reveals the extract as a mixed type of inhibitor. From the potentiodynamic polarization measurement results, the inhibition efficiency of the extract for MS was 93.73% and 75% in the 1000 ppm of inhibitor concentration for as-immersed and immersed conditions respectively. The adsorption isotherm and thermodynamic parameters support that the process is spontaneous and endothermic.
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    EVALUATION OF CHEMICAL CONSTITUENTS AND BIOLOGICAL PROPERTIES OF EXTRACTS OF LEAVES OF Kalanchoe pinnata (LAM.) PERS FROM RUPANDEHI DISTRICT OF NEPAL
    (Amrit Campus, 2023-08-17) BHUSAL, DAKSHINA
    The Crassulaceae family includes Kalanchoe pinnata (synonym: Bryophyllum pinnatum), also known as "Pattharchatta" in Nepali. The plant's therapeutic and medical properties contain wound-healing, antioxidant, antiproliferative, antimicrobial, anti allergic, analgesic, nephroprotective, gastroprotective, antidiabetic, antidepressant, sedative, antilithiatic, chemoprotective, antihypertensive and immunosuppressant activities. The current study examined phytochemical screening, GC-MS, UV, FT-IR, total phenolic and flavonoid content. Extracts of K. pinnata were also analyzed for antimicrobial, antioxidant, antidiabetic, cytotoxicity, thin-layer, and column chromatography. The air dried powder of K. pinnata were extracted using seven different solvents: hexane, DCM, chloroform, ethyl acetate, acetone, methanol, and water. The aqueous extract outperformed the other six, yielding 14.50 g, whereas ethyl acetate produced only 0.21 g. Phytochemical screening discovered the presence of flavonoids, phenolic chemicals, terpenoids, tannins, steroids, and carbohydrates. The antioxidant activity was assessed by DPPH free radical scavenging method. The 3,5- dinitrosalicylic acid (DNSA) technique revealed a range of α-amylase inhibition properties. Antimicrobial susceptibility tests were tested against Bacillus subtilis, Escherichia coli, and Candida albicans. All the extracts showed better antimicrobial properties. The quantitative analysis of phytochemicals revealed that the TPC and TFC of the ethyl acetate is higher as comparison to the methanol extract The IC50 values of chloroform, ethyl acetate and methanol extracts were 2219.41 µg/mL, 365.22 µg/mL, and 293.53 µg/mL, respectively, in the antioxidant assay. The IC50 values of acetone, ethyl acetate and methanol extracts were 285.71 µg/mL, 504.21 µg/mL, and 195.39 µg/mL, respectively, in the α-amylase inhibition assay. The LC50 values of chloroform, acetone and methanol extracts were 0.181 mg/mL, 0.175 mg/mL, and 0.29 mg/mL respectively. The best TLC was shown by methanol extract in the Acetone: Hexane solvent system. From the column chromatography, single spot is obtained at 1% Ac: Hex and 5% Ac: Hex. The existence of multiple bonds, aromaticity, conjugation, and unsaturated organic molecules were confirmed through UV-visible spectrophotometer's results. The presence of O-H, C-H, C=O, -CH2, -NO2 and C-O were verified by FT-IR findings.
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