Multifunctional applications of biochar beyond carbon storage

Abstract

Biochar is produced as a charred material with high surface area and abundant functional groups by pyrolysis, which refers to the process of thermochemical decomposition of organic material at elevated temperatures in the absence of oxygen. The carbon component in biochar is relatively stable, and, hence, biochar was originally proposed as a soil amendment to store carbon in the soil. Biochar has multifunctional values that include the use of it for the following purposes: soil amendment to improve soil health, nutrient and microbial carrier, immobilising agent for remediation of toxic metals and organic contaminants in soil and water, catalyst for industrial applications, porous material for mitigating greenhouse gas emissions and odorous compounds, and feed supplement to improve animal health and nutrient intake efficiency and, thus, productivity. This article provides for the first time an overview of the multifunctional values and unintended consequences of biochar applications.

Technologies and perspectives for achieving carbon neutrality

“… 221 A plethora of organic resources, such as crop residues, 222 forest residues, livestock manure, food wastes, industrial biowastes, municipal biowastes, and animal carcasses, are feedstocks that can be used to produce biochar for different purposes. 223 , 224 Some researchers have made great progress by investigating the pyrolysis of plastic waste for char production, 225 , 226 while others have studied the co-pyrolysis of organic materials and plastics. 227 Char production from fossil-fuel-derived materials neither constitutes a way to withdraw carbon dioxide from the atmosphere nor qualifies as a soil amendment (and is therefore not called biochar) but has application as construction material.…”

“…Bolan et al. 223 discussed the trends in biochar applications in different areas, including crop-livestock production, environmental remediation, direct climate change, air pollution mitigation, chemical and materials industry, and construction industry. Beyond elucidating multi-purpose benefits of biochar, Bolan et al.…”

“…Beyond elucidating multi-purpose benefits of biochar, Bolan et al. 223 also summarized the negative side of biochar applications, stressing the need for biochar life-cycle analysis from an environmental, energy, economic perspective before its intended use. Although the above reviews offered a wealth of information on waste valorization, they focused only on biochar generated from biomass wastes, leaving out char made from plastic wastes, which can be effective in environmental remediation.…”

Life cycle assessment of urban uses of biochar and case study in Uppsala, Sweden

“…The increasing interest in biochar production near urban areas is motivated, beyond CDR, by the multiple applications that biochar can have within urban areas and the availability of low-grade biomass for biochar production in these areas (Bolan et al 2021). The most well-established application of biochar in Sweden is in constructed soils in urban environments.…”

Co-Pyrolysis of Sewage Sludge and Wetland Biomass Waste for Biochar Production: Behaviors of Phosphorus and Heavy Metals

“…Landfill and land application have been restricted due to the poisonous leachate and limited soil area, while incineration is limited by high operational cost and emission of hazardous gases [ 8 ]. Pyrolysis (the process of thermochemical decomposition of organic matter under anoxic conditions) is a promising alternative as it can not only kill the pathogens and parasites contained in sewage sludge, but also produce value-added bioenergy (bio-oil and bio-gas) [ 7 , 9 ]. The remaining solid residue, biochar, has good potential to improve soil quality via increasing contents of soil nutrients (i.e., N, P, and K), soil microbial biomass, and soil pH [ 10 ].…”