Biochar is a carbonaceous material with an adjustable surface structure and porosity. It can be produced by thermal decomposition from biomass under restricted oxygen conditions. Moreover, the functionalities of biochar can be enhanced through various modifications to meet the desired application, especially in agriculture. This chapter introduces the physicochemical properties of original biochar from different feedstocks and modification methods to improve biochar performances. Besides, recent studies on biochar application as a carrier for agrochemicals (fertilizers and pesticides) are discussed. Physical, chemical, and biological methods have been employed to improve the functionalities of biochar in terms of its particle sizes, surface area, pore size, adsorption, and desorption properties. Among all techniques, the chemical activation method has greater effectiveness and advantages. The recent developments of biochar as fertilizers and encapsulation material demonstrate that biochar can significantly improve crop productivity and soil properties. Moreover, the applications of biochar as a controlled release for different kinds of pesticides are mostly related to its ability in sorption and release properties.

The significant health risks presented by the rising levels of heavy metals and other contaminants in wastewater are driving an increase in research on water treatment for heavy metal removal. Extensive research has been carried out for effective and economical techniques for wastewater treatment. Current research on designed biochar explores fruitful and novel inventions in many different sectors. Due to its high carbon content, low cost, and low inorganic material concentration, biochar is frequently used in water treatment operations. It also has good adsorption capabilities. This book chapter focuses on the production of biochar from diverse agricultural wastes and the modification of biochar to increase its porosity, surface area, and functional groups, hence boosting the development of active sites for the removal of heavy metals. This chapter will also discuss several studies on biochar's effectiveness as adsorbents for removing various heavy metals, in which utilizing biochar from abundantly available wastes can help in resolving issues such as solid waste disposal to the environment.

Lignocellulosic biomass has garnered an amazing amount of interest due to its great availability and cheap cost as one of the sustainable and renewable resources for manufacturing valuable products, such as biochar. In this work, the latest findings on the production of biochar by pyrolysis and its uses in the adsorption of dyes and heavy metals are examined. Technologies based on pyrolysis, such as gasification and mild and rapid pyrolysis, are effective methods for turning lignocellulosic biomass into products with a high added value (biochar, bio-oil, biogas, etc.). Biochar is considered as an outstanding candidate for the remediation of heavy metals, dyes from wastewater, enhance soil fertility, etc. By carbon sequestration, biochar can regulate climatic changes. The capacity of this substance to enhance soil, boost agricultural productivity, and raise soil fertility makes it one of a kind; as a result, soil fertility is highest where biochar is found. According to the research conducted on biochar production processes, the highest percentage of biochar with a percentage above 35 is related to the torrefaction process and after that pyrolysis and gasification with approximate percentages of 12–34 and 10%, respectively.

Water is the basic necessity of all the creatures that are present on this globe. Despite the fact that there is abundant water available on earth, the one useful for consumption purposes is still very low as the rest is seawater. However, even a small percentage of consumable water is getting polluted at an alarming rate. Hence, there is a severe need to formulate necessary precautions to control water pollution and develop novel water treatment methods. Major pollutants present in water are organic pollutants such as dyes, drugs, and pesticides. Even in small amounts, these pollutants are very dangerous, and they can kill both plants and animals. Among various materials, the use of biochar-mediated water treatment is a method which is getting a great interest nowadays. This book chapter provides examples of how biochar can be used in a variety of redox-mediated processes to remove organic pollutants. The conditions under which biochar is treated, such as the temperature of the pyrolysis and the pH of the product, have a significant impact on its effectiveness. The kind of biomass used as the starting material affects both the chemical and physical properties of biochar. Biochar shows good performance in removing organic pollutants such as dyes, drugs, and pesticides.

Biochar is a value-added product of biomass which is thermochemically synthesized. Application of biochar covers different processes/activities including environmental remediation, water purification, catalysis, tissue engineering, additive in organic waste compost, electrode material and modifier, and so on. Biochar is modified with respect to the target application. Different types of physical and chemical modifications have been reported. For application as adsorbent, pristine biochar exhibits lower surface area in comparison with the commercial activated carbon and this shortcoming necessitates appropriate treatment to make the biochar an effective adsorbent with larger surface area and improved surface properties. Modification process can be physical, or chemical, or a combination of both the treatment. Physical treatment entails enhancing the porosity, surface area, pore volume, and other physical features of biochar by activating its surface morphologies and properties. Chemical modification involves the use of solvents, acids/bases, or other substances to change and improve the functionality, pore structure, and surface area of biochar and can entail both one-step and two-step modification procedures. The current chapter highlights recent advances in physical and chemical treatment of the biochar, outlining major effects on the surface properties of the biochar.

Biochar is a multifaceted, inexpensive, and sustainable material with amazing physio-chemical properties for versatile research applications. Extensive research has been carried out to produce and utilize biochar as a catalyst with a wide range of surface conditions. Metallic and nonmetallic biochar-derived catalysts have multifunctional roles in advanced oxidation processes for effective degradation processes. Current research on biochar modification explores fruitful and novel inventions in different fields. Due to raw biochar bottlenecks such as poor adsorption capacity, low conductivity, low stability, and poor porosity, it is essentially required physical, chemical, and magnetic modification for biochar. This book chapter investigates the role of biochar as the catalyst for pollution control, specifically focusing on biochar textural properties, porosity, conductivity, surface area, surface functional groups, and effect on pollutant degradation or removal. This chapter will also cover the mechanistic degradation of toxic materials or pollutants and their role in biochar catalytic activities in marvelous applications such as tar cracking, bio-oil upgrading, biodiesel production, and NOx reduction. Additionally, its assessments have also been articulated in real-life applications and commercialization as biochar-based catalysts in developed technologies.

Biochar-based research has been widely studied due to its superb physio-chemical properties and versatile applications. Numerous carbonization techniques of biomass have been introduced to form unique properties of biochars through thermochemical decomposition from the conventional to the latest technology (i.e., muffle, microwave, and tube pyrolysis) with higher porosity. During pyrolysis, the biowaste materials steadily transformed themselves into porous structured spherical shape particles with smaller particle sizes and higher surface area distributions. Nanostructure biochar showed a distinctive and ideal material for transdisciplinary usage due to its outstanding chemical, physical, and biological elements. Biochar has adaptable applications as fertilizer for soil amendment and also as an adsorbent for the removal of organic pollutants, dyes, and heavy metals. This chapter also describes the advancement in technology for the bioconversion of agricultural wastes into value-added products, which provides an eco-friendly alternative for a sustainable waste management system and benefits mankind.

This chapter explores the application of microbial electrolysis cells (MECs) in anaerobic digestion (AD). The overview of AD and MECs is defined, and the integration of these two technologies is discussed in terms of their advantages in treating biogas and producing high-value products. The fundamentals of this integration are explained in detail, along with the effect of the parameters such as feedstock type, temperature, hydraulic retention time, pH, voltage applied and electrode. Next, the existing configuration for the system integration is also discussed comprehensively. Lastly, the challenges and future prospects emphasise the technical inadequacy, economic feasibility and environmental aspects.

The novel combination of electrochemical and microbiological principles found in microbial electrolysis cells (MECs) provides a sustainable means of transforming energy and wastewater disposal. Microbes function as biocatalysts in these cell types, assisting in the anaerobic oxidation of organic matter by producing electrons that transit through an exterior circuit to the cathode generating hydrogen gas. Microbial electron transfers processes, electrode reactions, and microbial metabolism are all deeply ingrained in the theoretical and electrochemical roots of MECs. The fundamental mechanism of MECs is the utilization of extracellular electron transfer-capable bacteria or other electroactive microorganisms for their metabolic processes. Organic substrates are broken down and electrons are released during microbial oxidation, which takes place at the anode. To reach the cathode, where reduction events take place and hydrogen gas is produced, these electrons travel via an external circuit. In order to forecast and maximize MEC performance, theoretical models are essential. These models take into account several aspects like mass transfer, electrochemical characteristics, and microbial kinetics. This chapter shows how MECs can use microbiology and electrochemistry to recover energy and remediate wastewater, with potential applications in renewable energy production and environmental remediation.

The generation of hydrogen gas through microbial electrolysis (MEC), which is one of the bioelectrochemical system (BES) approaches, has been extensively explored in recent years. The biohydrogen produced in this process is considered green hydrogen and thus is an alternative to other conventional methods that mostly produce blue or gray hydrogen which is unsustainable. MEC harnesses electrogenic microbes, which can metabolize organic matter and generate electricity to drive the recombination of protons to hydrogen gas, which can metabolize organic matter and generate electricity to drive the recombination of protons to hydrogen gas. Albeit its’ potential as a green technology for green fuel synthesis, the process is still far from realization, mainly due to the low productivity and the low rate of reaction which is still low. Plus, the feasibility of MEC on a large scale is challenging because expensive electrode catalysts usually consist of noble metals. However, recent revelations and breakthroughs have provided insight into the accelerating potential of MEC in terms of electrode materials, system configurations, microbiology aspects of the microbes used, modeling, and recent scale-up attempts at MEC that have shown promising results. This review will discuss recent achievements relating to the MEC system and highlight future recommendations.

Microbial electrolysis cells (MECs) are potential for wastewater management and renewable energy generation. This chapter discusses MEC materials and reactor architecture. While detoxifying effluent, MECs transform organic materials into hydrogen gas or energy using electrochemically active microorganisms. Performance, efficiency, and durability of microbial electrolytic cells depend on material selection. Proton exchange membranes, reactor designs, and anode and cathode materials are critical. Conductive anodes like carbon cloth or graphite help exo-electrogenic bacteria oxidize organic molecules. Cathode materials, usually platinum or other noble metals, allow proton reduction, generating hydrogen gas or other compounds. Proton exchange membranes separate anode and cathode compartments, allowing ion transfer while inhibiting vapor or substrate exchange. Microbial electrolysis cells vary in design dependent on goals. Single-chambered electrode assemblies are simple and inexpensive. Dual-chamber membrane electrode assemblies reduce gas crossing and increase efficiency by separating the anode and cathode compartments. This chapter emphasizes material selection and reactor design in microbial electrolysis cells for bio-hydrogen production and wastewater treatment. To optimize microbial electrolysis cells for sustainable energy generation and environmental cleanup, one must understand how materials and configurations affect performance. To improve efficiency and versatility of microbial electrolysis cell technology, future research should focus on innovative materials and reactor topologies.

Global concerns over the reliance on unsustainable fossil fuels have resulted in the demand for alternative resources. At the same time, the problem regarding wastewater management parallel to emerging industrialization is also becoming more serious. These two emerging scenarios led to the establishment of a multipurpose technique such as microbial electrolysis cell (MEC) with the ability to generate energy and applicable for wastewater treatment. The MEC is an environmentally friendly biochemical system based on waste-product conversion, designed to generate hydrogen or non-polluting by-products from biodegradable waste using electrochemically active bacteria. In this chapter, further basic introductory information of the MEC is presented. This chapter consists of two main sections including the first section which is dedicated to the definition, background, and importance or advantages of MEC. Meanwhile, the second section then outlines the brief concept in the MEC system particularly in terms of general components and basic electrochemical reactions that occurred during the process.

Annually, the budget allocated to developing new or improving existing green technologies continues to rise, reflecting the growing demand and their potential to address ongoing environmental challenges. Among these technologies, Microbial Electrolysis Cells (MECs) play a pivotal role in concurrently treating wastewater and producing (bio)hydrogen at the anode and cathode, respectively, with the assistance of electroactive microorganisms as biocatalysts. As the anode serves as the system’s driving force, selecting or adapting an appropriate electrode material with desirable characteristics like biocompatibility, chemical stability, non-corrosiveness, electrical conductivity, low resistance, affordability, and porosity is crucial. These attributes promote bacterial adhesion while facilitating electron transfer and flow. Conversely, the cathode must offer a flexible platform for hydrogen evolution reactions (HER) in MECs. Hence, researchers have explored various cathode materials as more cost-effective alternatives to metal-based catalysts, emphasizing sustainability and the reduction of HER overpotential. This chapter provides a review of diverse electrode material designs and types investigated to enhance both substrate oxidation and hydrogen production in MECs.

In the intricate realm of microbial electrolysis cells (MECs), the synergy between microbiology and electrochemistry unfolds a fascinating narrative. This chapter delves into the pivotal role of microbiology in the study of MECs, unraveling the essential interplay between microorganisms and electrochemical processes. In this chapter, we will explore the microbial communities thriving within MECs, their metabolic activities, and their profound impact on the efficiency and performance of this groundbreaking technique. Join us in unlocking the secrets of microbial intricacies that underpin the success of microbial electrolysis, as we bridge the gap between microbiology and electrochemistry in this vital exploration.

This book chapter provides a comprehensive overview of the latest advancements in the development of biochar-based catalysts for hydrogen production. Researchers are exploring alternative energy sources to address the growing demand for energy driven by the rising price of crude oil and the depletion of fossil fuel supplies. Biochar, a carbon-based fuel is produced using thermochemical techniques and has a unique structure with carbon atoms arranged in a two-dimensional, parallel stack. Biochar has various applications, including as a catalyst, electrode, supercapacitor, and soil amendment. However, the initial physicochemical properties of biochar are often suboptimal due to the type of biomass, carbonization technique, and activation processes used in its synthesis. This chapter discusses various types of biochar-based catalysts in detail, including metal-supported biochar, biochar-supported metal oxide, nitrogen-doped biochar, acid-activated biochar, and base-activated biochar. Using metal-based catalysts over biochar is a promising approach to enhancing its catalytic activity. These strategies offer significant potential for developing cost-effective and sustainable catalysts for hydrogen production.

Biochar is a low-cost carbon-rich material derived from the thermochemical degradation of biomass, with a large surface area and tailored surface functional groups through activation and functionalization. This versatility makes biochar a valuable catalyst and catalyst support for various chemical methods. Furthermore, biochar can be enhanced through the addition of surface functional groups to optimize its performance for specific reactions. This chapter covers the necessity, applications, sources, functionalization, and benefits of biochar. It also explores different activation methods, both physical and chemical, such as steam, carbon dioxide, hydrogen peroxide, potassium hydroxide, and zinc chloride activation. Additionally, the chapter provides a comprehensive explanation of biochar functionalization through the introduction of metals, non-metals, and polymers. Subsequently, it explores the specific utilization of biochar-based catalysts in biomass hydrolysis, which involves using biochar-based solid acids to perform biomass isomerization and dehydration while also employing biochars as catalyst supports for rehydration.

The rapid increase in population leads to the swift development of industries, which releases substantial amounts of impurities, including metal ions and organic pollutants, into the environment, thereby posing risks to human beings and creating environmental problems. The primary demand is for advancements in wastewater treatment technology aimed at reducing the overall cost and duration of treatment processes. Biochar and the composites that are based on biochar have garnered great interest, particularly in the realm of environmental problems, due to porous structures, abundant functional groups, and photocatalytic capabilities. The structural and chemical attributes of biochar increase the effectiveness of the photocatalyst, thereby getting better stability and optical properties. This chapter summarizes the various waste sources from which biochar can be derived and explores the application of biochar and the composites that are based on biochar as photocatalysts for degrading various contaminants such as pesticides, dyes, and drugs. Biochar-based composites are eco-friendly materials and hold promise as candidates for environmental pollution remediation. The chapter concludes by providing insights into the challenges and prospects of biochar-based catalysts.

Biochar-based transition metal catalysts have been identified as excellent peroxymonosulfate (PMS) activators for producing radicals used to degrade organic pollutants. The severity of environmental pollution has increased. These pollutants can pose a critical threat to humans, animals, and ecosystems. The creation of efficient treatment methods for eliminating pollutants from the environment is required to promote socially sustainable development and safeguard human health. Biochar materials have proven to be more effective as a catalyst or catalyst support in a wide range of applications, including transesterification and esterification, catalytic reforming and cracking, gasification and pyrolysis, hydrolysis, electrochemical reactions, photocatalysis, and persulfate/peroxymonosulfate oxidation, among many others. Various processes for the synthesis of biochar and its modification were discussed in this study.

Non-renewable energies and renewable energies still remain to be imbalance up to today, with the over dependency on finite fossil fuels. The pros and cons of each energy technology have been discussed briefly, whereby among all those technologies, bioenergy shows great potential in the energy sector. To produce bioenergy, 2nd generation biofuels can be produced from waste materials of two main forms such as lignocellulosic and non-lignocellulosic origins, without competing with the food resources. To date, one of the most feasible thermochemical methods—pyrolysis can be  set with fast heating rate and enhanced with microwave technology which is also known as fast microwave-assisted pyrolysis in order to produce high yield and high energy-dense biofuels with rapid processing. The fundamentals of pyrolysis and microwave technologies have been critically described along with their combination in operation setup for biofuel production. In this book chapter, various lignocellulosic and non-lignocellulosic wastes such as municipal wastes, agricultural wastes, plastics, and others have been reviewed as feedstock for fast microwave-assisted pyrolysis. Overall, this technology is viable however comes with the challenges in the scaling up stage and production issues. Nonetheless, with the current development, fast microwave-assisted pyrolysis can be a great form of waste-to-energy (WtE) or Energy from Waste (EfW) technology to be applied in the energy industry.

Wood waste can be decreased without significantly impacting the world's forests by enhancing the effectiveness of primary wood consumption and utilising raw wood supplies produced by sustainable forest administration. Wood waste can be utilised to create a wide range of goods, including engineered wood products, energy production (heat and electricity), mulch, and animal bedding. These low-cost, underutilised feedstocks have the potential to boost the added value of wood waste. Life cycle assessment (LCA) is a method for examining the environmental impact of materials, products, and services, and it is intended to aid in the development of sustainable decisions. This chapter discusses important difficulties concerning the life cycle assessment (LCA) of wood waste products. We looked at the process by which LCA evaluates the whole environmental effects of wood output, whether as input or output, over the course of a product’s life, from raw material to end-of-life disposal or rebirth as a new product.

The production of Ordinary Portland Cement (OPC) and concrete, as well as the production of aggregates, significantly increases carbon dioxide (CO2) emissions. However, bio-concretes can act as eco-friendly substitutes for conventional concretes making the demand for them on the rise for the many uses they are put to. Construction materials are usually recycled or turned into waste following demolition. As a result, a minor fraction of the economic value and sustainability inherent in them gets exploited by the construction industry. Consequently, the necessity for improving material effectiveness within the resource base will likely rise with the increase in human demand, as it would also be necessary to secure resources for the future. Circular economy (CE) principles may help mitigate the aforementioned problems within the construction industry if they are applied to recirculating construction materials. This chapter presents an approach toward using advanced technologies of implementing CE in the management and Life Cycle Assessment (LCA) of bio-concretes, which are produced by combining wood waste ash (WWA) in place of cement, wood waste (WW) as fine aggregates and wood aggregates (WA) as coarse waste. Thereafter, the chemical and physical properties, the microstructural characteristics, and the strength of wood waste–based bio-concrete (WWBC) are examined. Additionally, the ecological consequences and perspectives of WWBC production as well as its practical applications as a construction material have been examined to evaluate the effects of the emission of greenhouse gases (GHG) and carbon footprints. The circularity of WWBC has been discussed to achieve reduction in material waste and carbon footprint as well as encourage further research to improve the sustainability of construction materials in general.

The wood peeler core is a waste generated during the peeling process of the veneer. The peeler core size varies by species, spindle type, processing, and lathe machine. For several decades, the wood peeler core waste has been burned in a boiler to generate heat for kiln dryers, and some are selling for agriculture poles. Since wood has become more expensive, converting this waste to a more valuable material is paramount. One of the potentials of the wood peeler core is to use dye-sensitized solar cells (DSSC) to generate renewable energy, particularly electricity. Although the power conversion efficiency of DSSC from wood waste ranges only from 0.29 to 0.58% and is far below the commercial silicon solar cells (about 19%), it is potential as a low-cost material for renewable energy cannot be underestimated.

This chapter presents an extensive review of the scientific literature associated with various microwave treatments on wood waste products. First, the basic concepts of microwave radiation and its applications in wood waste product fabrication are reviewed. Then, an extensive literature review of the most significant experimental research papers is provided, divided into two microwave heating treatment uses: wood drying and wood waste products performance improvement. Next, the post-treatment of wood-plastic composites (WPCs) by microwave irradiation as a case study was reviewed and a real example of WPCs samples was discussed. Finally, the chapter concludes with a proposal of doing future research studies concerning the impact of microwave technology on some important properties of wood waste products, i.e., resistance to biological agents, fire, environmental conditions, and so on.

The valorization of wood waste as biosorbent has sparked intense interest from researchers, exclusively for removing organic and inorganic contaminants in aqueous solutions. Highlights on several desirable features including higher porosity, outstanding physicochemical properties, and selectivity offer a new vision towards sustainable chemistry for environmental protection. A decline in water quality poses significant domestic and industrial challenges. However, their performance and effectiveness for removing such contaminants from water depends on how they are fabricated, how they work together, and what mechanisms are at play. The use of this material and approach in the water recovery process suggests that developing an enhanced protocol is necessary for successfully and realistically removing the contaminants from the environment.