Tesfa Nega Gesese

The rising demand for onion production results in significant waste, harming the environment. Onion waste is unsuitable for animal feed and difficult to dispose of due to its strong odor and potential for phytopathogen growth. Pyrolysis is a promising method for repurposing food waste, requiring minimal infrastructure and offering rapid processing and environmental benefits. The main goal of this study was to examine the potential of onion peel as a viable and sustainable pyrolysis feedstock by utilizing kinetic and thermodynamic studies. This study utilized a thermal analyzer to investigate the thermal decomposition of onion peel waste in a nitrogen atmosphere at heating rates of 15, 20, and 25°C/min, from room temperature to 800°C. The study applied four model‐free isoconversional kinetic techniques—Kissinger–Akahira–Sunose (KAS), Flynn–Wall–Ozawa (FWO), Starink (STK), and Friedman (FR)—to analyze the relationship between activation energy (Eα) and the degree of conversion ( α ). The average activation energies from KAS, FWO, STK, and FR were 81.22 kJ/mole, 89.06 kJ/mole, 83.64 kJ/mole, and 68.14 kJ/mole, respectively. The reaction mechanism of thermally degraded onion peel follows one‐dimensional diffusion, three‐dimensional diffusion, power law, exponent power first‐order, exponent power second‐order, first‐ and third‐order reactions, and Avrami–Erofeev reaction mechanism models. Thus, onion peel is a promising feedstock for bioenergy generation due to its low energy barrier and activation energy.

This study investigates the synthesis and characterization of biomass base ecofriendly biofilm composites reinforced with waste eggshells, utilizing biowaste materials as sources of starch and plasticizer, with eggshells serving as a filler to enhance overall material properties. Reusing biowaste is important in reducing environmental waste and promoting sustainable practices. Findings reveal that increasing eggshell content from 15 to 60% significantly reduces moisture absorption from 18.75 ± 0.02% to 5.31 ± 0.04%, while tensile strength declines from 8.18 ± 0.02 to 5.17 ± 0.02 MPa at constant glycerol levels. In contrast, glycerol enhances moisture retention, increasing absorbance from 18.75 ± 0.02% to 20.15 ± 0.02% as glycerol concentration rises from 5 to 20% in a 15% eggshell composite. The optimal biodegradability was achieved with a plasticizer concentration of 10% and a filler (clay) content of 30%, resulting in a degradation rate of 78.25 ± 0.01%. The eggshell at 30% and glycerol at 5% achieve a degradation rate of 87.31 ± 0.03%. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) reveal that the composites exhibit superior thermal stability, making them suitable for diverse applications. This research highlights the environmental benefits of biowaste materials, trade-offs in material performance, the need for moisture management in packaging, and enhancements from waste starch and plasticizer. These results underscore the potential for creating sustainable and functional composites through utilizing and reusing biowaste materials.

An estimated several billion tons of biological waste are produced each year as a result of the world’s population growth and population density. The conversion of garbage to biogas that is a prime example of waste-to-energy conversion is a great area of interest due to the increasing demand for renewable energy sources. This approach, which addresses two problems simultaneously (conversion of waste and production of biogas), is regarded as one of the best alternative energy sources. Biogas, produced through anaerobic digestion, is clean, affordable, sustainable, and environmentally friendly. This chapter assesses the current status of biogas production, its challenges, and future directions. In this work, all substrates for biogas production and treatment methods with its state-of-the-art and current applications were reviewed. The current status of anaerobic digestion technology and its challenges were also addressed. And finally, the overall challenges such as technological limitations, economic constraints, and environmental concerns, and future directions for biogas production, including advancements in technology, policy support, and integration with other renewable energy sources to enhance sustainability and economic viability were all addressed.

The increasing demand for energy, reliance on fossil fuels, heightened environmental concerns, and the political commitments established in the Paris Climate Agreement drive the pursuit of new energy sources that are more sustainable and compatible with environmental protection. Biomass has emerged as a primary renewable energy resource, offering significant advantages in terms of its diversity, availability, and sustainability for meeting energy needs in heating, electricity generation, and biofuel production for transportation, among other applications. Various strategies have been explored for effectively utilizing biomass, ranging from biological to thermochemical conversion methods. Gasification is a thermochemical process recognized as one of the most effective methods for energy recovery from biomass, producing syngas primarily composed of hydrogen (H₂), carbon monoxide (CO), and methane (CH₄). Currently, various parameters influencing the yield of product gas and the performance of the gasifier have garnered significant attention from researchers. This paper aims to review the theory and process of biomass gasification, including the different types of gasifiers. It compiles key operational and performance parameters of the gasification process, as well as their influence on gasification conditions and products. This approach seeks to provide a comprehensive overview of hydrogen-rich syngas production based on current technologies and industrial/commercialization pathways.

The increasing demand for sustainable materials has propelled research into biomass-derived adhesives as eco-friendly alternatives to traditional synthetic options. This chapter investigates the enhancement of physicochemical and thermomechanical properties of bio-based adhesives, highlighting their applications across diverse industries, including medical devices, construction, automotive, wood and wood-based panels, and packaging. Bio-adhesives, sourced from renewable materials such as lignin, tannins, and proteins, offer advantages like biodegradability and non-toxicity. However, challenges such as low water resistance, bonding strength, and thermal stability persist. Recent advancements, including the incorporation of nanofillers and cross-linking agents, have shown promise in overcoming these limitations, significantly improving adhesive performance. In medical applications, bio-adhesives must be biocompatible and biodegradable to facilitate wound healing without harmful effects. In construction and automotive sectors, they provide sustainable bonding solutions for lightweight materials, enhancing structural integrity under various environmental conditions. The packaging industry is also benefiting from bio-adhesives derived from proteins like whey and casein, which improve barrier properties while remaining renewable. Despite their potential, the commercialization of biomass-derived adhesives faces challenges such as higher production costs and variable performance. Ongoing research aims to address these issues through physicochemical modifications and the development of standardized testing methods. This chapter underscores the transformative potential of bio-based adhesives, emphasizing their role in promoting sustainability while meeting the rigorous demands of various applications. Ultimately, enhancing the properties of these adhesives can contribute significantly to a more sustainable future in material science.

The kinetics and thermodynamics of biomass pyrolysis are crucial for its design, optimization, and industrial application. In this study, proximate analysis, together with higher heating value (HHV) and kinetic and thermodynamic studies of water hyacinth (WH) and wheat straw (WS) pyrolysis were performed. Nonisothermal thermogravimetric analysis (TGA) at heating rates of 15, 20, and 25 °C min ⁻¹ were employed to investigate their pyrolysis kinetics experimentally. Detailed results from the proximate analysis and HHV measurements for both biomasses were documented and analyzed. Iso‐conversional kinetic analysis revealed that the effective activation energy varied significantly with the reacted fraction. For WS, the average activation energy values were 63.67 kJ mol ⁻¹ and 45.74 kJ mol ⁻¹ based on the Flynn–Wall–Ozawa (FWO) and Kissinger–Akahira–Sunose (KAS) methods, respectively. For WH, the corresponding values were 118.58 kJ mol ⁻¹ and 114.09 kJ mol ⁻¹ . The Coats–Redfern model demonstrated that the TGA data obtained in an inert environment were best described by a second‐order reaction mechanism and the ‘D3c’ three‐way diffusion model. Thermodynamic analysis indicated that the pyrolysis of WH and WS is not spontaneous and requires external energy input for thermal decomposition. Both processes were identified as endothermic, with reactivity increasing as pyrolysis advanced. The comprehensive pyrolysis index (CPI) increased with higher heating rates, suggesting that elevated heating rates were more favorable for the pyrolysis of these biomasses. These findings contribute to a better understanding of the reaction mechanisms and highlight the potential of WH and WS for bioenergy production.

In construction engineering, there is currently a strong emphasis on finding construction materials, mainly the binder which plays a crucial role, that meet multiple criteria, including sustainability, cost-effectiveness, durability, and reduced environmental impact. However, there is a growing interest in exploring alternatives to traditional binders to address the limitations associated with their production and use. One such alternative is the use of naturally occurring materials like clay. Clay deposits are abundant and widely available, making them a sustainable resource for construction applications. Moreover, clay contains significant amounts of silica and alumina, which are key components for inducing pozzolanic reactions that contribute to the strength and durability of concrete. In recent studies, nanoclays (NCs) have emerged as a promising addition to construction materials as supplementary cementitious materials. These nanoparticles possess unique properties that can enhance the performance of concrete. Nanoclays significantly improve the compressive strength, sustainability, and durability of concrete structures. The high surface area and reactivity of nanoclays facilitate better bonding between cement particles, resulting in enhanced mechanical properties. This chapter aims to discuss the state of the art on performance enhancements of building materials that employ different types of nanoclays in place of conventional binders and the future trends.