School of Engineering Scienceshttp://ugspace.ug.edu.gh:8080/handle/123456789/230312024-03-28T17:48:28Z2024-03-28T17:48:28ZThe Use of Recycled Polyethylene in Water-Oil Emulsion for Lightweight ConcreteNangor, E.Annan, E.Konadu, D.S.Damoah, L.N.W.et al.http://ugspace.ug.edu.gh:8080/handle/123456789/414342024-03-28T13:35:46Z2024-01-01T00:00:00ZThe Use of Recycled Polyethylene in Water-Oil Emulsion for Lightweight Concrete
Nangor, E.; Annan, E.; Konadu, D.S.; Damoah, L.N.W.; et al.
This study was to determine the suitability of recycled waste polyethylene (WPE) processed into water-oil emulsion for
lightweight concrete applications. The processed WPE in the form of polyethylene emulsion (PE-e) is to promote physical
interaction between the polymeric material and the cementitious matrix. The PE-e used was also to partially replace concrete
mix composition by PE-e_1, PE-e_2.5, PE-e_5, and PE-e_10 percents for reference concrete and to introduce plasticity into the
mechanical behaviour of the concrete. The PE was processed into PE-e to promote affinity for water, and this hydrophilicity
was prominent in PE-e_1 and PE-e_2.5 percent concretes. Concretes with PE-e_1 and PE-e_2.5 percent formed good
miscibility with the cementitious matrix. The density of the PE-e concrete decreased to 13.68% with 10% PE-e at 28 days. The
replacement of mix constituents of PE-e_1, PE-e_2.5, and PE-e_5 percent induced elastic to plastic behaviour in the concrete
coupled with low water absorption. The FTIR data showed characteristic peaks of 3378 cm-1, 1740 cm-1, and 1148 cm-1 in the
PE-e. Using optical microscopy, it was shown that the PE particles were homogenously dispersed in the concrete matrix. The
study shows the feasibility of using PE-e_1 percent to produce structural lightweight concrete and up to PE-e_10 percent for
nonstructural applications mainly for light, non-load-bearing partitions
Research Article
2024-01-01T00:00:00ZExploring the insights and benefits of biomass-derived sulfuric acid activated carbon for selective recovery of gold from simulated waste streamsBediako, J.K.Kudoaho, E.Affrifah, N.S.et al.http://ugspace.ug.edu.gh:8080/handle/123456789/414192024-03-08T18:56:26Z2024-01-01T00:00:00ZExploring the insights and benefits of biomass-derived sulfuric acid activated carbon for selective recovery of gold from simulated waste streams
Bediako, J.K.; Kudoaho, E.; Affrifah, N.S.; et al.
The surging affluent in society, concomitant with increasing global demand for electrical and electronic devices,
has led to a sharp rise in e-waste generation. E-wastes contain significant amounts of precious metals, such as
gold, which can be recovered and reused, thus reducing the environmental impact of mining new metals. Se lective recovery using sustainable and cost-effective materials and methods is therefore vital. This study un dertook a detailed evaluation of low-cost biomass-derived activated carbon (AC) for selective recovery of Au
from simulated e-waste streams. Utilizing high-performance synthesized H2SO4-AC, the adsorption mechanisms
were explicated through a combination of characterization techniques, i.e., FE-SEM, BET, TGA, XRD, FTIR, XPS,
and DFT simulations to conceptualize the atomic and molecular level interactions. Optimization of coordination
geometries between model H2SO4-AC and anionic complexes revealed the most stable coordination for AuCl4
-
(binding energy, Eb = -4064.15 eV). The Au selectivity was further enhanced by reduction of Au(III) to Au(0), as
determined by XRD and XPS. The adsorption reaction was relatively fast (~5h), and maximum Au uptake
reached 1679.74 ± 37.66 mg/g (among highest), achieved through adsorption isotherm experiments. Further more, a mixture of 0.5 M thiourea/1 M HCl could effectively elute the loaded Au and regenerate the spent AC.
This study presents radical attempts to examine in detail, the synergistic effects of H2SO4 activation on biomass derived ACs for selective recovery of Au from complex mixtures. The paper therefore describes a novel approach
for the selective recovery of Au from e-wastes using multifunctional biomass-derived H2SO4-AC.
Research Article
2024-01-01T00:00:00ZAdsorbents for water decontamination: A recycling alternative for fiber precursors and textile fiber wastesBediako, J.K.Apalangya, V.Hodgson, I.O.A.Anugwom, I.Repo, E.http://ugspace.ug.edu.gh:8080/handle/123456789/414162024-03-08T10:52:33Z2024-01-01T00:00:00ZAdsorbents for water decontamination: A recycling alternative for fiber precursors and textile fiber wastes
Bediako, J.K.; Apalangya, V.; Hodgson, I.O.A.; Anugwom, I.; Repo, E.
The exponential growth in textile fiber production and commensurate release of textile waste-based effluents into
the environment has significant impacts on human wellbeing and the long-term planetary health. To abate these
negative impacts and promote resource circularity, efforts are being made to recycle these waste materials via
conversion into adsorbents for water decontamination. This review critically examines plant- and regenerated
cellulose-based fibers for removing water pollutants such as heavy metals, dyes, pharmaceutical and petro chemical wastes. The review reveals that chemical modification reactions such as grafting, sulfonation, car boxymethylation, amination, amidoximation, xanthation, carbon activation, and surface coating are normally
employed, and the adsorption mechanisms often involve Van der Waals attraction, electrostatic interaction,
complexation, chelation, ion exchange, and precipitation. Furthermore, the adsorption processes and thus the
adsorption mechanisms are influenced by factors such as surface properties of adsorbents, pollutant characteristics including composition, porosity/pore size distribution, specific surface area, hydrophobicity/
hydrophobicity, and molecular interactions. Besides, feasibility of the approaches in terms of handling and reuse,
environmental fate, and economic impact was evaluated, in addition to the performances of the adsorbents, the
prospects, and challenges. As current cost analysis is non-exhaustive, it is recommended that researchers focus on
extensive cost analysis to fully appreciate the true cost effectiveness of employing these waste materials. In
addition, more attention must be paid to potential chemical leaching, post-adsorption handling, and disposal.
Based on the review, fiber precursors and textile fiber wastes are viable alternative adsorbents for sustainable
water treatment and environmental management, and government entities must leverage on these locally
accessible materials to promote recyclability and circularity.
Research Article
2024-01-01T00:00:00ZFracture and Toughening of Mycelium-based BiocompositesEtinosa, P.O.Salifu, A.A.Osafo, S.et al.http://ugspace.ug.edu.gh:8080/handle/123456789/414132024-03-08T10:49:17Z2024-01-01T00:00:00ZFracture and Toughening of Mycelium-based Biocomposites
Etinosa, P.O.; Salifu, A.A.; Osafo, S.; et al.
This study presents a combined experimental and analytical study of the fracture behavior and toughening
mechanisms of bioprocessed mycelium-based biocomposites. The composites comprise hemicellulose hemp ducts
(as nutritional and reinforcing components) intertwined with increasing weight percentages of laterite particles.
Single-edge notched fracture experiments and in-situ observations of crack growth were used to explore the ef fects of varying proportions of laterite on the composite resistance-curve behavior. The toughening mechanisms,
fracture modes, and crack-microstructure interactions were also elucidated. Since crack-bridging and crack deflection were observed to be the dominant toughening mechanisms, they were modeled using fracture me chanics approaches. Crack-bridging was shown to dominate the toughening at lower weight fractions of laterite
(0–20 wt%). However, as the laterite content increases (20–40 wt%), a combination of crack-bridging and crack deflection was observed. Finally, at higher laterite weight fractions (>40 wt%), crack-tip shielding occurred
primarily via crack deflection. The fracture mechanics predictions of resistance-curve behavior are shown to be
consistent with the experimental measurements. The results suggest that mycelium-based and mycelium-laterite
composites can be engineered with tunable fracture toughness. The implications of the results are also discussed
for the development of sustainable building materials.
Research Article
2024-01-01T00:00:00Z