Department of Biological and Environmental Sciences

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Browsing Department of Biological and Environmental Sciences by Author "Abdulhameed, Adamu"

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    Microwave synthesis of Carboxymethylcellulose (CMC) from Rice Husk
    (IOSR Journal of Applied Chemistry, 2019-12-07) Abdulhameed, Adamu; Mbuvi, Harun M.; Changamu, Evans O.; Maingi, Francis M.
    Carboxymethylcellulose is an important non-toxic cellulose derivative which plays vital roles in paper coating, pharmaceuticals, food, detergents, and others. Research work involving the extraction of cellulose from agricultural biomass and its modification cellulose using a microwave has been reported, but not much work has been done on the rice husk, thus helping in managing associated waste. In this study, cellulose extracted from rice husks was used as the raw material for the synthesis of food-grade carboxymethylcellulose (CMC). In the process of the synthesis of carboxymethylcellulose from rice husk, cellulose was carried out by alkalization, an etherification process, using sodium hydroxide (NaOH) and monochloroacetic acid (MCA). Characterizations of CMC products was carried out by Fourier Transform Infrared (FTIR) spectroscopy and Xray Diffraction (XRD). The reaction conditions optimized include power (microwave), sodium hydroxide concentration, amount of monochloroacetic acid and reaction time. The degree of substitution (DS) was determined using a potentiometric titration method and the maximum DS of 0.79 was obtained when 30% NaOH was used.
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    Pyro-processed Coconut Fibre for Removal of Lead Ions from Aqueous Solution
    (American Journal of Chemistry and Pharmacy, 2026-05-25) Kasimu, Titus M.; Maingi, Francis M.; Mbuvi, Harun M.; Ng’ang’a, Margaret M.; Abdulhameed, Adamu
    Approximately 80% of the population in developing countries lacks access to clean, safe water. A major source of water contamination is heavy metal ions, which pose great risks to human health. This is expected to increase with the projected population and industrial growth if immediate remediation is not taken. Current operational methods for removing the heavy metal ions in wastewater include: chemical coagulation, ion exchange, electrochemical methods, adsorption using activated carbon, natural zeolite, membrane process, ultra-filtration, among others, which are uneconomical due to high costs and unaffordable to low-income earners. Coconut fibres are locally available agricultural waste that can be converted by activation into adsorbents for water remediation due to their fineness and large surface area. This study reports the synthesis and characterization of coconut fibre charcoal (CFC) and activated coconut fibre charcoal (ACFC) to remediate water contaminated with Pb2+ ions. This involved burning dry coconut fibre in a limited amount of air to obtain coconut fibre charcoal followed by dissolving fine powder of charcoal in 2 M phosphoric acid for 24 hours at a temperature of 25 ºC to obtain activated coconut fibre charcoal. The adsorbents were characterized using FT-IR and SEM. Batch sorption studies were carried out while varying parameters of contact time, shaking speed, temperature, adsorbent dose, pH, and initial concentration of metal ions in solution. Residue Pb2+ ion concentrations were determined using atomic absorption spectroscopy (AAS). The FT-IR results showed absorption peaks at 1423 cm-1 and 840 cm-1 attributed to symmetric –COO- stretch and -OH deformation in ACFC adsorbent, these peaks shifted to 1384 cm-1 and 813 cm-1 while PO4- aromatic strain vibration in ACFC disappeared upon saturation of ACFC with Pb2+ ions respectively. SEM analysis showed pores of different sizes and shapes in ACFC compared to a rigid, concrete, and smooth surface upon saturation with Pb2+ ions. Adsorption data for Pb2+ ions best fitted into the Freundlich model with maximum adsorption capacities of 32.09 mg lead/g activated coconut fibre charcoal. The results from this study suggest that coconut fibre charcoal and activated coconut fibre charcoal are potential adsorbents of Pb2+ions.
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    Synthesis of Silicon Nitride from Rice Husk and Sugarcane Bagasse Ashes
    (Journal of Water technology and Treatment methods, 2018-01-22) Abdulhameed, Adamu; Mbuvi, Harun M.; Changamu, Evans O; Maingi, Francis M.
    Silicon nitride (Si3N4) SNA, SNB, SNC and SND were synthesized by hydrothermal process at temperature of 100oC, 150oC, 200oC and 300oC using Rice Husk Ash (RHA) and Sugarcane Bagasse Ash (SBA) respectively. The percentage of silica ranges from 90.10 to 94.19 with minute impurities.Based on their infrared spectra, for SNA absorption band at 470.6 cm-1 is attributed to Si-N (stretching), which were also observed with SNB, SNC and SND, a weak band at 671.2 cm-1 which is characteristic of a silicon nitride Si-N-Si stretching vibration was observed, for SNC, peak at 574 cm-1 attribute to α-silicon nitride, as temperature increases the spectrum becomes sharper. X-ray diffraction pattern indicates that SNA material contained 64.6% α-phase and 27.8% β-phase silicon nitride. Therefore, rice husks and sugarcane bagasse have great potential as a raw material for producing Si3N4, by the hydrothermal method