Browsing by Author "Bediako, J.K."
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Item Adsorbents for water decontamination: A recycling alternative for fiber precursors and textile fiber wastes(Science of the Total Environment, 2024) 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.Item Bio-based and sustainable food packaging systems: relevance, challenges, and prospects(Applied Food Research, 2023) Donkor, L.; Kontoh, G.; Yaya, A.; Bediako, J.K.; Apalangya, V.Packaging materials are critical in ensuring the safety and quality of foods. Conventional packaging materials from non-renewable sources have revolutionized the food packaging industry, driven largely by convenience, low cost, good moisture barriers, and exhibition of excellent mechanical and handling properties. However, the growing ecological crisis and health burden emanating from heterogenous plastic waste demands sustainable and biodegradable alternatives, which promote circularity and lead to responsible material consumption. Beyond protection and containment, sustainable food packaging materials, unlike their traditional fossil cousins, leave minimal environmental impact and low carbon footprint from birth to dust. There is, therefore, a growing body of research on sustainable food packaging systems from different classes of natural polymers derived mainly from plants and animals. Bio-based packaging materials have been identified as possible renewable sources that can potentially replace conventional packaging materials. They can be extracted from biomass, chemically synthe sized, or produced by microorganisms. Besides, they can be processed using wet and dry processes, and other complementary processes. Bio-based materials are generally abundant in nature, and their sources can be broadly categorized into polysaccharides, proteins, and polyhydroxyalkanoates. Though noted as renewable sources, their application has some limitations, such as difficulty in processing and poor performance. However, they can be blended with other materials to overcome these limitations, improving their intrinsic and extrinsic properties, thereby increasing their applicability in the food industry. This review aims to provide an overview of bio-based packaging materials and their consideration for sustainable food packaging. Besides, it discusses the properties critical for their application in the food industry, their limitations, and prospects.Item Development of melamine-impregnated alginate capsule for selective recovery of Pd(II) from a binary metal solution(Journal of Cleaner Production, 2021) Wei, W.; Qiu, Y.; Zhao, Y.; Zhang, K.; Ji, Y.; Gao, H.; Bediako, J.K.; Yun, Yeoung-Sang.An “ionic barrier” concept is proposed to introduce selectivity function to adsorbents towards precious metals (PMs) in the present study. As a model system, melamine-impregnated alginate capsule (MIAC) was prepared and used as a Pd(II) selective adsorbent from a binary metal solution containing Pt (IV) and Pd(II). The MIAC exhibited excellent Pd(II) selectivity for a pH around 4.3, where the selectivity coefficient reached a high value of 2190.66. In comparison to the very low Pt (IV) uptake, a high maximum uptake of Pd(II) was estimated of 316.92 ± 9.50 mg/g by the Langmuir isotherm model. Sorptiondesorption studies showed that the MIAC had a good reutilization property. The selective process for Pd(II) recovery was proposed as follows: the electroneutral Pd(OH)2 but not anionic PtCl5 first penetrate the outer ionic barrier; then, the penetrated Pd(OH)2 was bound by the inner melamine through chelation. The ionic barrier-based sorbent thus can be considered as an alternative one for separation and recovery of Pd(II).Item Exploring the insights and benefits of biomass-derived sulfuric acid activated carbon for selective recovery of gold from simulated waste streams(Waste Management, 2024) 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.Item Polyethyleneimine impregnated alginate capsule as a high capacity sorbent for the recovery of monovalent and trivalent gold(Scientific Reports, 2021) Dangi, Y.R.; Bediako, J.K.; Lin, X.; Choi, J-W.; Lim, C-R.; Song, M.H.; Han, M.; Yun, Y-S.For the first time, a polyethyleneimine-impregnated alginate capsule (PEIIAC) with a high adsorption capacity is developed for the recovery of monovalent and trivalent gold from an acidic solution. The strategy results in a new type of adsorbent, polyethyleneimine impregnated alginate capsule (PEIIAC) with a core–shell structure having a large number of amine groups as cationic binding site, facilitating maximum uptake of anionic auric chloride. The maximum uptake of PEIIAC was 3078 and 929 mg/g for Au (III) and Au (I), respectively, are recordable compared to other reported adsorbents to date. The as-prepared material was executed to check the sorption efficacy for Au (III) and Au (I) in the pH range of 1–12. With an increment in pH, the uptake capacity for Au (III) increased, while the uptake capacity for Au (I) decreased. The FTIR, XRD, and XPS studies revealed that the gold adsorption mechanism includes ionic interactions and reduction, wherein the amine, hydroxyl, and carboxyl groups are involved. The capsule showed a higher adsorption efficiency than other reported sorbents, making the material applicable in acidic solutions for the recovery of Au (I) and Au (III).Item Preparation and Characterization of Rubber Blends for Industrial Tire Tread Fabrication(International Journal of Polymer Science, 2018-09) Mensah, B.; Agyei-Tuffour, B.; Nyankson, E.; Bensah, Y.D.; Dodoo-Arhin, D.; Bediako, J.K.; Onwona-Agyeman, B.; Yaya, A.The physico-mechanical properties of variable rubber blends including epoxide natural rubber (ENR), polybutadiene rubber (BR), and solution polymerized styrene-butadiene rubber (SBR) filled with silanized silica and carbon black mixtures were explored. The tensile, hardness, resilience, abrasion, and fatigue behavior were investigated. An optimized composition involving 30 phr of ENR and 70 phr SBR filled with mixtures of carbon blacks and silanized silica was proposed to be a suitable composition for the future development of green passenger truck tires, with low rolling resistance (fuel saving ability), high wear resistance, and desired fatigue failure properties.Item Recovery of gold via adsorption-incineration techniques using banana peel and its derivatives: Selectivity and mechanisms(Waste Management, 2020-06-11) Bediako, J.K.; Choi, J-W.; Song, M-H.; Zhao, Y.; Lin, S.; Sarka, A.K.; Cho, C-W.; Yun, Y-S.In this study, banana peel (BP) and its derivatives after sequential extraction of biochemical components were evaluated for selective recovery of gold. In-depth instrumental characterizations including XPS, FTIR, XRD and HR-TEM were performed to understand the adsorption mechanisms. The biomass after lipid extraction, BP-L, demonstrated very good affinity and selectivity towards gold. In multi-metal systems containing 100 mg/L of Pt(IV), Au(III), Pd(II), Zn(II), Co(II), Ni(II) and Li(I), the selectivity coefficient increased from 978.45 in BP to 2034.70 in BP-L. Moreover, the equilibrium gold uptake was improved and reached 475.48 ± 3.08 mg/g owing to reduction-coupled adsorption mechanisms. The BP-L also showed improved gold nanoparticle formation properties that were pH-dependent. In a strategic adsorptioncombined incineration process, metallic gold reaching 99.96% in purity was obtained. The BP and its derivative, BP-L have thus shown potentials for multiple applications in the areas of precious metal recovery and nanoscience.Item Strategies for recovery of copper and gold as single constituents or an alloy: Selective separation and adsorption-coupled incineration of the bulk metal-loaded adsorbents(Resources, Conservation & Recycling, 2022) Bediako, J.K.; Choi, J-W.; Song, M-H.; Yun, Y-S.To recover useful metals from waste PCBs, environmentally friendly bioleaching has recently attracted attention. Accordingly, distinct protocols are required to adequately recover the bioleached metals. Herewith, we present strategies to separate and recover copper and gold from a bioleached solution of waste PCBs. Polyethylenimine-polyacrylic acid composite adsorbents (PPCAs) were screened from among different candidate adsorbents. By only adjusting the mixing ratio of PEI and PAA, it was possible to recover gold and copper as single constituents or an alloy. A two-step strategy was designed, leading to the successful separation of copper and gold, first through selective adsorption of copper and then by bulk adsorption of copper and gold. The experimental maximum equilibrium uptakes of copper by PPCA-2 and PPCA-7 were 667±0.06 and 587±0.16 mg g-1, respectively. The pseudo-first- and pseudo-second-order models fitted the kinetic data of copper better than gold. Following incineration, the adsorbents were characterized for examining the crystallinity and atomic energy states of the metals. Consequently, XRF analysis revealed that the copper-gold alloy ash contained 96.7±0.40% Cu and 1.73±0.26% Au. This study would be helpful for future studies that would aim at the separation and recovery of metallic minerals from bioleachates.Item Sustainable gliadin - Metal oxide composites for efficient inactivation of Escherichia coli and remediation of cobalt (II) from water(Elsevier Ltd, 2023) Massima Mouele, E.S.; Bediako, J.K.; Anugwom, I.; et al.Bio-based materials facilitate greener approach to engineering novel materials with multifunctional properties for various applications, including water treatment. In this study, we extracted gliadin from wheat gluten using alcoholic solvent. The aggregation limitations of gliadin protein were overcome by functionalization with metal oxides (MOs) TiO2, AgFe2O3, and AgFe-TiO2 prepared by chemical precipitations. The novel composites were characterised by scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), X-Ray diffraction (XRD), thermogravimetry analysis (TGA), Brunauer Emmet-Teller (BET), and zeta potential. The multifunctionality of MOs-gliadin composites was tested through toxic Escherichia coli (E. coli) inactivation and Co2+ adsorption from water. The antibacterial results showed excellent inhibition under both dark and light conditions. The maximum Co2+ uptake of 101 mg/g was reached with TiO2@gliadin after 24 h and best fitted the Langmuir isotherm model. The adsorption process followed pseudo-second-order model with an equilibrium adsorption capacity, qe2 = 89.86 mg/g, closer to the experimental data. Thermodynamic investigations indicated that ΔG◦ = − 9.677 kJ/mol, ΔH◦ = − 123 kJ/mol, and ΔS◦ = 0.490 J.K./mol, respectively, suggesting that adsorption was spontaneous and endothermic. The The regenerated TiO2@gliadin composite was still efficient after five consecutive cycles. This study demonstrates that MOs-gliadin-blend composites are sustainable for water purification.