Journal Articles
Permanent URI for this collection
Browse
Recent Submissions
1 - 5 of 199
-
PublicationTensile, thermal properties, and biodegradability test of paddy straw powder-filled Polyhydroxybutyrate-3-Valerate (PHBV) biocomposites: acrylation pretreatment(Springer International Publishing, 2023)The mechanical, thermal, and biodegradability properties of paddy straw powder (PSP)-filled polyhydroxybutyrate-3-valerate (PHBV) biocomposites were investigated. The impacts of chemical alteration of PSP via acrylic acid treatment were examined as well. The outcomes of the study portrayed a decrease in the elongation at break and tensile strength when the filler loading increased; however, the modulus elasticity of composites could be seen to increase. Chemical alteration of PSP via acrylic acid enhanced modulus elasticity of the biocomposites and tensile strength; nevertheless, the elongation at break was decreased. Thermogravimetric analysis demonstrated the enhancement of thermal stability of the biocomposites via PSP compared to neat PHBV. The thermal stability of the biocomposites was positively affected by chemical alteration of PSP. Meanwhile, DSC analysis proved that the melting temperature (T m) of the biocomposites was not altered when the filler was added. Treated biocomposites demonstrated higher crystallinity (30.18%) compared to the untreated composites (26.24%). Biodegradability test showed the strains from both Aspergillus species have the potential to degrade PHBV/PSP biocomposites. The weight loss of biocomposites after undergoing fermentation with Aspergillus fumigatus strain SGE57 and Aspergillus niveus isolate A17 was 2.42% and 3.65%, respectively.
-
PublicationIsolation of cellulolytic microorganism from food waste-fertilized soil(AIP Publishing Ltd., 2023)Uncontrolled disposal of waste from cellulosic materials can add burden to the existing environmental crises. The aim of the study is to isolate microorganisms from food waste-fertilized soil and identification of the microorganism species by genotyping. Soil samples enriched with fruits, rice and vegetables wastes were collected, diluted and spread on agar supplemented with carboxymethylcellulose (CMC) for induction of growth and cellulase production. Following screening of cellulolytic activity, isolates with significant cellulolytic index (CI) were chosen for molecular identification by PCR, using the 16S rRNA as target sequence in combination with in silico analysis. Four out of eleven microorganisms isolated from fruits and vegetable-rich soils produced a CI ranging from 0.43 to 2.00. Of these, only two isolates produced clear bands on PCR with approximately 1500 bp in size. In silico analysis of the isolates suggested species of Ochrobactrum sp. and Bacillus sp. These microorganisms have the potential to be used for decomposition of the cellulosic wastes.
-
PublicationOptimization of microwave sol–gel synthesis of N-Ce-AC/TiO₂ for adsorption/photodegradation of tetracycline(Elsevier, 2023)Nitrogen (N) and cerium (Ce) co-doped titanium dioxide (TiO₂) supported activated carbon (AC) (N-Ce-AC/TiO₂) were synthesized to remove antibiotic tetracycline from aqueous solution via adsorption and photodegradation. The sol–gel technique, aided by microwave radiation, was used to synthesize N-Ce-AC/TiO₂. Central composite design under response surface methodology was used to optimize the variables comprising urea (N source) (A: 0.02–0.20 g), cerium(III) nitrate hexahydrate (Ce source) (B: 0.02–0.20 g), activated carbon (C: 0.10–0.50 g), and microwave power (D: 600–800 W), where the degradation of tetracycline was the response. Characterization of the produced catalyst was carried out by means of X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and the Brunauer–Emmett–Teller method for determining surface-texture parameters. N-Ce-AC/TiO₂ prepared with 0.50 g activated carbon, doped with 0.02 g urea and 0.20 g cerium, and activated at microwave power 600 W for 15 min exhibited 91.08% tetracycline removal when subjected to 7 W of UV irradiation, according to the results of optimal variable preparation.
-
PublicationAqueous Potassium salt of L-Cysteine as potential CO₂ removal solvent: an investigation on physicochemical properties and CO₂ loading capacity(MDPI, 2023)The operational and economic constraints suffered by amine solvents for CO₂ removal have motivated the research on an alternative solvent with better performance and cost-effectiveness. Amino acid salt (AAS) has been identified as an interesting green solvent, an alternative to commercial amine solvents. The present work evaluated the physicochemical and CO₂-solubility properties of potassium L-cysteine (K-CYS), a naturally occurring amino-acid-based solvent for CO₂ removal from natural gas. Its physicochemical properties, including density, viscosity, and refractive index, were measured at different temperatures ranging between 298.15 and 333.15 K and a concentration range of 5 to 30 wt.%. Based on the experiment, all properties were found to decrease with increasing temperature and increase with increasing concentration. The experiments also demonstrated a significant reduction of CO₂ loading from 2.4190 to 1.1802 mol of CO2/mol of K-CYS with increasing solvent concentration from 10 to 30 wt% at 313.15 K and 20 bar (g).
-
PublicationComparison between natural rubber, liquid natural rubber, and recycled natural rubber as secondary matrix in epoxy/natural rubber/graphene nano-platelet system(Springer International Publishing, 2023)A comparison is made between the effects of natural rubber (NR), liquid natural rubber (LNR), and recycled natural rubber (rNR) in the filled epoxy systems on the physical, mechanical, thermal, and electrical performances of filled epoxy systems. The results show that flexural strength and modulus values were improved. The toughness properties of the filled epoxy system were enhanced with NR phases (72 MPa, 2317 MPa, 4.2 MPa. m1/2), as compared to those with LNR (55 MPa, 2100 MPa, 3.2 MPa. m1/2) and rNR (52 MPa, 2000 MPa, 2.3 MPa. m1/2) at 5 vol.%. Scanning electron micrograph (SEM) analysis revealed that the particle sizes of NR phases dispersed within the epoxy matrix were smaller and more uniform (0.29-1.65 μm) as compared to those with LNR (0.64-3.57 μm) and rNR (≥250 μm) phases. The incorporation of NR, LNR, and rNR phases improved the thermal stability of the filled system. This is attributed to more heat energy being needed to overcome good interfacial bonding between epoxy matrices and the small NR phases. X-ray diffraction analysis results showed that the filled epoxy/NR/GNP system has higher 2θ values, indicating that d-spacing in GNP nano-fillers has the closer distance. Electrical bulk conductivity values of filled epoxy/NR/GNP systems were the highest, 4.50 x 10-3 1/Ω. cm at 20 vol.%. Small NR phases acted as elastomer spacers, which provided better GNP packing efficiency and realigned the GNP nano-fillers to form more effective conductive pathways for electron transport.