Of recent, immense attention has been given to chitosan in the biomedical field due to its valuable biochemical and physiological properties. Traditionally, the chief source of chitosan is chitin ...from crab and shrimp shells. Chitin is also an important component of fish scales, insects and fungal cell walls. Thus, the aim of this study was to isolate and characterize chitosan from locally available material for potential use in the biomedical field. Chitosan ash and nitrogen contents ranged from 1.55 to 3.5% and 6.6 to 7.0% respectively. Molecular weight varied from 291 to 348KDa. FTIR spectra revealed high degree of similarity between locally isolated chitosan and commercial chitosan with DD ranging from 77.8 to 79.1%. XRD patterns exhibited peaks at 2θ values of 19.5° for both mushroom and banana weevil chitosan while Nile perch scales chitosan registered 3 peaks at 2θ angles of 12.3°, 20.1° and 21.3° comparable to the established commercial chitosan XRD pattern. Locally isolated chitosan exhibited antimicrobial activity at a very high concentration. Ash content, moisture content, DD, FTIR spectra and XRD patterns revealed that chitosan isolated from locally available materials has physiochemical properties comparable to conventional chitosan and therefore it can be used in the biomedical field.
Green synthesized iron(III) oxide (Fe
O
) nanoparticles are gaining appeal in targeted drug delivery systems because of their low cost, fast processing and nontoxicity. However, there is no known ...research work undertaken in the production of green synthesized nano-particles from the Ugandan grown Moringa Oleifera (MO). This study aims at exploring and developing an optimized protocol aimed at producing such nanoparticles from the Ugandan grown Moringa.
While reducing ferric chloride solution with Moringa oleifera leaves, Iron oxide nanoparticles (Fe
O
-NPs) were synthesized through an economical and completely green biosynthetic method. The structural properties of these Fe
O
-NPs were investigated by Ultra Violet-visible (UV-Vis) spectrophotometry, X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX) and scanning electron microscopy (SEM). These nanoparticles exhibited UV-visible absorption peaks at 225 nm (nm) for the sixth dilution and 228 nm for the fifth dilution which indicated that the nanoparticles were photosensitive and the SEM study confirmed the spherical nature of these nanoparticles. The total synthesis time was approximately 5 h after drying the moringa leaves, and the average particle size was approximately 16 nm. Such synthesized nanoparticles can potentially be useful for drug delivery, especially in Low and Middle Income Countries (LMICs).
One of the most worrying environmental issues affecting all forms of life, the economy, and natural ecosystems globally is the accumulation of polyethylene (PE) plastic garbage. Creating peaceful and ...environmentally friendly alternatives to conventional disposal techniques, like transforming plastic waste into cherished carbonaceous nanomaterials, is of utmost importance considering this threat. The current study carefully employed a cleaner upcycling technique to create carbon-based nanomaterials (CNMs) for supercapacitors. Using solvothermal/hydrothermal synthetic techniques, the PE waste was transformed into CNMs used in energy storage supercapacitors application. With an energy density of 21.6 W h kg
−1
and a current density of 0.25 A g
−1
, the electrochemical test showed a specific capacitance of 155.5 F g
−1
. Additionally, the materials demonstrated 98.5% capacitance retention after 9000 cycles at a constant current density of 1.0 A g
−1
.
Abbreviations: AC: activated carbon; CNM: carbon nanomaterials; CV: cyclic voltammetry; EC: electrochemical system; EDLC: electrical double layer capacitor; EIS: electrochemical impedance spectroscopy; FESEM: field emission scanning electron microscopy; FTIR: Fourier transform infrared; GCD: galvanostatic charge-discharge; HDPE: high-density polyethene; KOH: potassium hydroxide; LLDPE: linear low-density polyethene; Mn: manganese; PE: polyethene; Rct: charge transfer resistance; SSA: specific surface area; TEM: transmission electron microscopy; TGA: thermogravimetric analysis; UV-VIS: ultraviolet-visible spectroscopy; XRD: X-ray diffraction
Highlights
The article explored a low-temperature and non-emission upcycling method of polyethylene plastic waste into carbon-based nanomaterials (CNMs).
CNMs were characterised for physical-chemical properties using different characterisation techniques.
The carbon material was used with other materials like activated carbon and manganese to produce nanocomposites tested for electrical double layer capacitor energy storage and exhibited higher energy density.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
This paper assessed the technical and economic viability of biodiesel production from Second-generation feedstocks native to East Africa, which included Castor, Croton, and Jatropha. Their oils were ...converted to biodiesel by transesterification and characterizations of B100 and B10 done following ASTM D6751. ASPEN Plus V11 was used in process simulation and profitability analysis. Oil yields obtained ranged from 29.5% to 35.6%. B100 and B10 properties conformed to ASTM D6751. The negative Net Present Values obtained render B100 and B10 production uneconomical unless incentivized. Sensitivity analyses showed that NPV varied with feedstock cost and biodiesel selling prices. This assessment established that though a B10 policy based on second-generation feedstocks is technically viable, interventions are needed to make it profitable in Uganda.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The application of biogas as a renewable energy source continues to face competition from conventional energy sources, which are readily available and seemingly cheap. In addition, productive biogas ...system deployments in Uganda are currently facing challenges related to sustainability of biogas production, which has led to massive dis-adoption in recent years. These systems have failed to utilize alternatives during scarcity of primary feedstock due to lack technical data for energy recovery, which could be linked to insufficient R&D in the biogas sector. Relatedly, global scientific research has placed focus mostly on methane yield improvements through optimization of anaerobic digestion kinetics on lab-scale, with little focus on the enabling environment for these kinetics to thrive in continuously operated systems.
This study therefore aimed to develop an integrated energy recovery system that enables alteration of feedstock and control of digester operating parameters for sustainable biogas production in continuously fed digesters. An array of system components was developed and integrated into a state-of-art energy recovery system, which was prototyped and deployed in real working environment for pilot studies. The system was configured to measure the moisture content of the feedstock and then determine and display to the operator the amount of water to be added to optimize the quality of the substrate. The system also monitors the digester operating parameters and prompts corrective action to prevent possible inhibition of biogas production process. Results show that the system is about 33% more efficient than the conventional one, allows alteration of feedstocks, and can be deployed to replace conventional energy usage for productive applications. For instance, a poultry farm with 10,000 commercial layers may have its energy needs be met 100% by the proposed system with a pay-back period of 4.5 years for deep liter system and 3.7 years for battery cage system.
Globally, a high prevalence of multi-drug-resistant (MDR) bacteria, mostly methicillin-resistant
Staphylococcus aureus
and carbapenem-resistant
Enterobacteriaceae
, has been reported. Infections ...caused by such bacteria are expensive and hard to treat due to reduced efficient treatment alternatives. Centered on the current rate of antibiotics production and approvals, it is anticipated that by 2050 up to 10 million people could die annually due to MDR pathogens. To this effect, alternative strategies such as the use of nanotechnology to formulate nanobactericidal agents are being explored. This systematic review addresses the recent approaches, future prospects, and challenges of nanotechnological solutions for controlling transmission and emergence of antibiotic resistance. A comprehensive literature search of PubMed and BioMed Central databases from June 2018 to January 2019 was performed. The search keywords used were “use of nanotechnology to control antibiotic resistance” to extract articles published only in English encompassing all research papers regardless of the year of publication. PubMed and BioMed Central databases literature exploration generated 166 articles of which 49 full-text research articles met the inclusion guidelines. Of the included articles, 44.9%, 30.6%, and 24.5% reported the use of inorganic, hybrid, and organic nanoparticles, respectively, as bactericidal agents or carriers/enhancers of bactericidal agents. Owing to the ever-increasing prevalence of antimicrobial resistance to old and newly synthesized drugs, alternative approaches such as nanotechnology are highly commendable. This is supported by in vitro, ex vivo, and in vivo studies assessed in this review as they reported high bactericide efficacies of organic, inorganic, and hybrid nanoparticles.
Global energy demand continues to increase owing to advancements in key growth sectors of Economies. Transportation-related emissions resulting from petroleum use account for 23% of total ...energy-related CO
2
emissions. Biofuels including biodiesel are renewable substitutes for transportation fuels that have attracted global interest. This paper reviewed existing literature on technological, economic, and life cycle environmental aspects vital for assessment of the viability of production of second-generation biodiesel including the B10 blend advocated for Uganda. The quantity of biodiesel required to fulfil a B10 blend for Uganda's downstream petroleum sector is one hundred million litres per annum. To meet this demand, 50,000 ha of land is required for cultivation of biodiesel feedstocks against the available 6,900,000 ha. Jatropha, castor, and croton, offer agronomical advantages. Biodiesel produced from these feedstocks through transesterification, should conform to ASTM D6751/EN14214 standards. Physicochemical, economic, and environmental assessments are vital to confirm its techno-economic viability.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
With a vibrant economic development, Greater Kampala Metropolitan Area (GKMA) would need to boast low-carbon electricity generation, reduce carbon emissions, and re-structure transportation, yet ...having no energy management plan. The main objective of this study is to develop a comprehensive framework for analyzing energy impacts and macroeconomic effects of low-carbon scenarios and to identify a sustainable pathway towards 2050 for GKMA. The study uses TIMES/CGE hybrid framework to address the knowledge gap in 4 scenarios. Business as usual is the reference case with Kabejja (20% CO2 abatement), Carbon-Tax (100$/ton), and Lutta (95% CO2 abatement) as alternative scenarios. The analysis shows an increase in consumption from 139.6PJ to 469.35PJ and carbon emissions from 4.6mtns to 7mtns in the reference case. However, consumption and carbon emissions decrease in all the alternative scenarios compared to the reference case. The GDP and equivalent variation (EV) in household welfare increase in all alternative scenarios compared to the reference case. Lutta promises a 60.6% reduction in the carbon emissions intensity of GDP to be realistic. Sustainability is achievable when low-carbon electricity becomes the major contributor to the demand by fuel type, optimization of the total primary energy supply, and construction of an electrified Kampala metro. Transportation, Industrial and Residential sectors are the greatest emitters of CO2 by sector in all scenarios and thus need policy interventions to realize deep CO2 emissions reductions. The study recommends that Lutta guarantee a sustainable low-carbon footprint for GKMA.
The increasing occurrence of active pharmaceutical ingredients (APIs) in water systems coupled with their recalcitrance to conventional water treatment methods calls for research into more ...eco-friendly and cost-effective curbing media. Mesoporous cassava peel activated carbon (CPAC) was prepared under conditions derived from optimizing the surface area and yield with the temperature and holding time as the model inputs using the response surface methodology. The sequestration potential and mechanisms of the resultant activated carbon (AC) for active pharmaceutical ingredients from wastewater were studied using batch experiments. The CPAC adsorption kinetics and isothermal mechanisms for the three pharmaceuticals (carbamazepine (CBZ), clarithromycin (CLN), and trimethoprim (TRM)) were studied in both wastewater and Milli-Q water. The API concentrations were measured using liquid chromatography coupled to a mass spectrometer (LC-MS) system. The maximum removal efficiencies were 86.00, 58.00, and 68.50% for CBZ, CLN, and TRM for wastewater, which were less than those from the Milli-Q water at 94.25, 73.50, and 84.5%, respectively. The sorption process for the CLN was better explained by the Freundlich model, whereas the CBZ and TRM adsorption processes could suitably be explained by both the Langmuir and Freundlich models. At an initial concentration of 20 mgL−1 for all APIs and a CPAC dosage of 2.0 gL−1, the maximum adsorption capacities were 25.907, 84.034, and 1.487 mgg−1 for CBZ, TRM, and CLN, respectively. These results demonstrated the potential of CPAC to remove APIs from water, with its sequestration potential being more exhibited after the removal of the organic matter owing to the lower competition for active sites by the APIs. Additionally, positive adsorbates were better removed than negatively charged adsorbates due to the dominance of anions in the cassava peel lattice.
Previous studies in Uganda have primarily explored kaolin's applications in composites, pottery, bricks, and insulation, neglecting its potential for coatings and paints, which is crucial for ...industrialization and saving foreign exchange. This study investigates the transformation of kaolin through various treatments and analyzes their impacts on its physical and chemical properties for potential use in coating applications. Thermal analysis, X-ray Fluorescence Spectroscopy (XRF), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), and transmission electron microscopy (TEM) techniques were employed to assess these alterations. The results show that thermal treatment of kaolin at 45.9 °C had minimal impact on mass loss, while the crystallinity of kaolinite was found to be lost around 600 °C, resulting in structural changes. XRF result demonstrates variations in SiO2 and Al2O3 composition, with low TiO2 content desirable for paint and coating applications. XRD results showed well-defined diffractions associated with kaolinite in all treated and untreated kaolin samples. The presence of K-feldspar and quartz are also identified. However, the thermal treatment at 800 °C transforms kaolinite into metakaolin, essential for enhancing coating properties. SEM-EDS results indicate increased porosity and reduced impurities in the thermal-treated sample, which might enhance the whiteness and suitability of pigment and binder dispersion in coatings. TEM images confirmed the hexagonal nature of kaolinite platelets and demonstrated the amorphous nature of kaolin nanoparticles with ammonium molybdate treatment, which led to the delamination and exfoliation of kaolinite layers, improving dispersibility. Kaolin thermally treated exhibited good crystallinity, solid growth, cubic morphology, and uniform size distribution. These findings suggest that tailored treatments can optimize kaolin's properties, making it a promising additive for high-performance coatings.
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