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[Display omitted] • WTE assessment of biomass residue valorization pathway. • Optimization of WTE via multi-criteria decision method. • Pequi seed without extractives reported improved biochar properties. • Optimal gasification condition was obtained with O 2 /H 2 O/N 2 carrier gas. • WTE could be optimized by the seed fat extraction previously to pyrolysis. The waste-to-energy (WTE) valorization pathway of Caryocar brasiliense (pequi) seeds was investigated via pyrolysis, gasification, and transesterification to understand its potential as biochar, syngas, and biodiesel. First, the pyrolysis (300–700 °C) was conducted in N 2 atmosphere for pequi seeds (PS) and pequi seeds without its extractives (PSWE), characterizing its biochar properties. The PSWE was then gasified at 1000 °C under O 2 /N 2 , O 2 /CO 2 /N 2 and O 2 /H 2 O/N 2 atmospheres to evaluate the characteristics of the producer gas. The PS extractives were then transesterified and characterized for biodiesel production. Finally, a multiple-criteria decision analysis assessed the PS products' potential within the thermochemical routes. The results evidenced better biochar (up to 22.29% HHV enhancement, higher mass and energy yield, up to 75.9 and 85.5% reduction of O/C and H/C, respectively, and enriched N content) via PSWE pyrolysis than PS considering biofuel application and optimistic perceptions for soil amendment. This indicates that the preceding extraction of vegetal fat from PS strengthens the WTE by including further processing of extracted oil. The produced syngas under O 2 /H 2 O/N 2 gasification atmosphere showed better applicability as a biofuel (16.37 MJ·kg−1 lower heating value, 107.33% cold gas efficiency, and 113.55% carbon conversion efficiency) with up to 24% higher success rate. The transesterification of the extractives revealed its potential (98% conversion rate) for use as feedstock for in situ power generation, or blended for biodiesel production. The results provide insights into the circular economy in agro-extractivist communities that may support Brazil's small and medium agro-food industries with their energy demands. [ABSTRACT FROM AUTHOR]

Contamination by potentially toxic metals and metalloids (PTMs) has become a significant health and environmental issue worldwide. Sorption has emerged as one of the most prominent strategies for remediating both soil and water contamination. New sorbents are being developed to provide economically viable and environmentally sound alternatives, in alignment with the principles of the Sustainable Development Goals. This research aimed to assess the potential effects on human health and environmental toxicity following the sorption of cadmium (Cd), lead (Pb), and zinc (Zn) using peat, compost, and biochar as sorbents. The peat was collected in Brazil, a country with a tropical climate, while the compost and biochar were produced from the organic fraction of municipal solid waste (OFMSW). In terms of bioaccessibility, the results showed the following order: compost < biochar < peat for Pb, and compost < peat < biochar for Cd and Zn. There was a significant growth inhibition for Eruca sativa and Zea mays exposed to increasing concentrations of PTMs treated with peat and compost. The presence of contaminants played a decisive role on immobilization of neonates of Ceriodaphnia silvestrii after treatments with compost and, especially, peat. However, the biochar addition rate caused a significant influence on the outcomes of ecotoxicity across all tested species. Although the samples treated with biochar exhibited lower residual concentrations of PTMs than those treated with compost and peat, the inherent toxicity of biochar might be attributed to the material itself. The exposure to residual PTM concentrations post-desorption caused ecotoxic effects on tested species, emphasizing the need to assess PTM desorption potential. Peat, compost, and biochar are promising alternatives for the sorption of PTMs, but the addition rates must be properly adjusted to avoid the occurrence of undesirable ecotoxicological effects. This research offers valuable insights for sustainable environmental management and protection by thoroughly investigating the impacts of different sorbents and contaminants on aquatic and terrestrial ecosystems. [Display omitted] • Pb had lowest bioaccessibility among tested metals when pre-sorbed onto the compost. • The sensitivity order was established as: root length > shoot length > germination. • Eruca sativa displayed higher phytotoxicity compared to Zea mays. • Biochar revealed inherent aquatic ecotoxicity in Ceriodaphnia silvestrii. • The toxicity of peat and compost samples originated from the presence of PTMs. [ABSTRACT FROM AUTHOR]

Biodiesel production faces environmental and economic challenges due to the use of homogeneous catalysts, such as NaOH, KOH, NaOCH 3 , and KOCH 3. Despite their good activity, these catalysts are toxic and almost impossible to recycle/reuse. Heterogeneous catalysts, otherwise, can be reused and easily separated from the final product, resulting in more sustainable and cost-effective production. However, these catalysts leach, losing activity through reaction cycles and contaminating the biodiesel This review has therefore addressed the use of CaO – a promising catalyst for biodiesel synthesis – and various biochar-derived catalysts. Particular attention was paid to studies involving the use of CaO in a biochar matrix (CaO/Biochar), given the support essential role in making the CaO use feasible. The use of catalysts derived from sugarcane bagasse biochar was also highlighted, given this biomass importance, especially in Brazil. Studies have shown that biochar-derived catalysts have good activity, excellent stability, and can be reused for up to 10 cycles. Concerning CaO/Biochar, it was found that biochar significantly reduced Ca2+ leaching, but there is still a need to further reduce the Ca2+ release into biodiesel. There is also a need to give more focus on CaO leaching. Finally, a lack of studies on the use of catalysts derived from sugarcane bagasse biochar is notiable, showing no study involving the CaO-embedded sugarcane bagasse biochar. • There are no studies about biodiesel synthesis with CaO/Sugarcane biochar. • Biochars from different sources significantly reduced the Ca2+ leaching. • Biochar-based catalysts provided nearly 100 % biodiesel yield under relatively mild conditions. • Biochar support significantly increases catalysts' reusability. • Ca– O –Si bonds may be associated with the CaO anchoring. [ABSTRACT FROM AUTHOR]

N 2 O emissions resulting from the application of nitrogen (N) fertilizers and vinasse represent the main sources of greenhouse gases (GHG) emissions in sugar-energy sector. Conversely, the application of biochar in soils has been worldwide recognized as an strategy to mitigate N 2 O emissions, although little is known about their effects on soils under energy cane production. The study aimed to evaluate the effects of biochar addition as a strategy to mitigate soil N 2 O emissions in soil under energy cane cultivation, as well as to quantify the abundance of N 2 O-producing and N 2 O-reducing microbial guilds. A greenhouse experiment was conducted in a completely randomized design, with five treatments and four replications. The treatments were: i) no N fertilization (control); ii) N fertilization; iii) N fertilization plus vinasse; iv) N fertilization plus biochar; v) N fertilization plus vinasse plus biochar. All treatments (except control) were balanced to receive the same amount of nutrients. Biochar was added at a rate of 5 g kg−1 of soil. Soil N 2 O emissions were quantified by static chambers for 78 days, and soil sampling were performed to determine chemical and microbiological attributes, including functional genes of the nitrogen cycle (AOA, AOB, nir K, nir S, nos ZI and nos ZII) by real-time PCR. Results indicated that vinasse addition increased N 2 O emissions. Conversely, the application of biochar reduced N 2 O emissions associated with the application of N fertilizer (56 %) and N fertilizer + vinasse (41 %). The high N 2 O emissions observed in vinasse treatment were directly correlated with nitrifier microorganisms (AOB and AOA), indicating that nitrification should be the main pathway of N 2 O emissions in this treatment. The production of energy cane biomass was similar between N fertilizer treatments. High N 2 O emission intensities (mg N 2 O g biomass−1) were obtained in treatments with vinasse application. This study concluded that biochar is an effficient strategy to mitigate N 2 O emissions, providing the first insights into how biochar affects the microbial community associated with N 2 O emissions from soil under energy cane cultivation. [Display omitted] • Organic residues are important drivers of N 2 O emissions in agricultural soils. • The application of vinasse increased N 2 O emissions by 86 %. • Highest N 2 O emissions correlated with nitrifier microorganisms (AOB, and AOA). • The addition of biochar reduced N 2 O emissions by rates ranging from 41 % to 54 %. • Energy cane biomass was not affected by N fertilization methods. [ABSTRACT FROM AUTHOR]

Pasturelands, often degraded, represent most of the converted lands globally. It is important to understand how different pasture management approaches can improve soil quality, increase feed production and farmer income. Here, the impact of different soil enhancers on soil quality and productivity of three cultivars of Brachiaria (Syn. Urochloa) forage grass is presented. Soil enhancers included: biochar - a carbon-rich product from biomass pyrolysis, moinha (local charcoal residue), traditional fertiliser containing nitrogen, phosphorus and potassium, lime, and forage peanut (Arachis pintoi cv. Amarillo). Considering the total biomass produced over the experiment (sum of four harvests), the highest dry biomass production was observed for Brachiaria brizantha cv. Piatã (14.1 Mg ha−1) and cv. Marandu (12.7 Mg ha−1), for biochar application of 30 Mg ha−1. Paiaguás had the highest dry matter production (12.4 Mg ha−1) for the treatment with forage peanut plus 15 Mg ha−1 of biochar. The increases in dry mass production translated to additional income, as compared with the control, of U$ 1 291, U$ 1 183 and U$ 991 per year for Marandu, Piatã and Paiaguás, respectively. The increases in forage grass productivity were reflected by positive changes in soil characteristics such as improvement in cation exchange capacity, pH and nutrient contents. Improved management of tropical pasturelands holds opportunity for more sustainable food production, and for ecosystem services protection and recuperation, for example, biodiversity net-gain, water regulation and carbon sequestration. [ABSTRACT FROM AUTHOR]

In this research, the atrazine adsorption onto activated biochar produced from corn straw was evaluated based on kinetic and equilibrium studies and physical, chemical and morphological analyses. Batch adsorption experiments were performed to obtain kinetic and equilibrium parameters which were used to simulate the process' performance on fixed-bed column. The activated biochar showed specific surface area, total pore volume and average pore radius of 573 m2 g−1, 0.3054 cm3 g−1 and 10.7 Å, respectively, while the non-activated biochar exhibited lower specific surface area (504 m² g−1) in comparison with the activated biochar. The atrazine adsorption mechanism was predominantly driven by hydrogen bonds and π-π stacking. The experimental equilibrium data was adequately described by Langmuir isotherm, showing high adsorbate-adsorbent affinity (K L = 4.287 L mg−1). The adsorbent also showed favorable kinetics which was well described by the intraparticle diffusion model. The atrazine adsorption dynamics on fixed-bed column packed with the produced biochar was investigated by using an experimental design associated to phenomenological mathematical modeling. The approach was able to predict the column behavior from the batch parameters and was experimentally validated, showing an efficiency of 72% and breakthrough time of 520 min. The results evidenced the effectiveness of the produced biochar to remove atrazine from water as well as the model to adequately predict the batch and column's performance. [Display omitted] • Biochar produced from an abundant waste material (corn straw) in Brazil. • A major contribution of micropores was observed in porous structure. • Robustness identification of kinetic and equilibrium parameters from batch studies. • Phenomenological-statistical modeling was successfully used in fixed-bed study. • Biochar was efficient in atrazine removal on fixed-bed column. [ABSTRACT FROM AUTHOR]

The objective of this study was the full characterization of pruning residue from macrophyte Cyperus giganteus from tertiary wastewater treatment plant (WTP), Ponte dos Leites, located in Araruama, RJ, Brazil. Analyses aimed to systematically assess the feasibility of using the pruning residues as an energy resource. To do so, macrophytes were submitted to experimental analyses of their physical properties (real density: 0.44–0.77 g cm−3, bulk density: 0.08–0.09 g cm−3, among other characteristics), chemical and proximate analyses, and thermal analysis. Results of thermal behavior characterized the biomass as a viable energy source (high heat value, 14–16 MJ kg−1). C. giganteus different samples fractions analyses confirmed that molecular structures of the macrophyte (lignin: 17.3–26.8 wt %, cellulose: 27.8–32.6 wt %, hemicellulose: 30.1–31.5 wt %; depending on the plant part) affect thermal decomposition behavior. Maximum mass losses ranged from 83.43 to 75.91%. Energy production potential from biomass pruning residues generated at Ponte dos Leites was estimated to be around 92,400 MJ mês−1. This shows the effectiveness of using pruning residues biomass from macrophyte Cyperus giganteus for energy production, highlighting its energy potential, and support its use as inputs in thermal conversion processes. [Display omitted] • Physical-chemical characterization of Cyperus giganteus pruning residues from CW. • Assessment of C. giganteus biomass thermal properties (TGA, LHV, HHV and UHV). • Potential use of C. giganteus biomass for bioenergy production (biochar). • Potential use of biochar from C. giganteus biomass for agricultural purposes. [ABSTRACT FROM AUTHOR]

Production of biofuels via biomass pyrolysis has received a strong emphasis since it may produce a wide variety of renewable fuels in liquid (bio-oil), solid (biochar), and gas (syngas) forms. Sugarcane bagasse, waste from the sugar-alcohol industry, is largely produced in Brazil, India, and Thailand and appears as a great biomass option for pyrolysis due to its properties, abundance, and current underutilization. However, sugarcane bagasse properties and pyrolysis operating conditions may directly affect the product properties, distribution, and further application as fuels and chemicals. Thus, it is necessary a thorough study of these subjects. This review brings an overview of biomass and pyrolysis concepts, as well as a collection of improvements in the production of products (bio-oil, biochar, and gas) via sugarcane bagasse pyrolysis. In addition, this review discusses the interaction between process operating conditions and this biomass type to address how the products' properties and yields are affected. • Fast Pyrolysis: an efficient thermochemical process for bio-oil, biochar, and gas production. • Fast Pyrolysis concepts, operational conditions, and reactor configurations were reviewed. • Bio-oil, biochar, and gas production as an alternative for renewable energy world matrix. • Focus on sugarcane bagasse as a raw material for bio-oil, biochar, and gas production. • Upgrading methods for bio-oil, challenges, and future works in the pyrolysis field. [ABSTRACT FROM AUTHOR]

Greenhouse gas removal technologies are needed to reach the targets of the UNFCCC Paris Agreement. Among existing technologies, the use of biochar is considered promising, particularly biochar derived from the large quantities of sugarcane residues available in South America and elsewhere. However, the net greenhouse gas removal potential of sugarcane biochar has not been assessed hitherto. We use a scenario-based anticipatory life cycle assessment to investigate the emissions associated with a change from the combustion of sugarcane residues in a combined heat and power plant to the pyrolysis of these residues for biochar production and field application in São Paulo State, Brazil. We define scenarios based on different mean marginal electricity production and biochar production share. The results indicate that emissions from covering the electricity deficit generated by partial combustion of biomass during biochar production is the main emitting process. Overall, the processes associated with biochar production lower the net greenhouse gas benefits of the biochar by around 25%. Our analysis suggests that allocating 100% of the available sugarcane residues to biochar production could sequester 6.3 ± 0.5 t CO 2 eq ha−1 yr−1 of sugarcane in São Paulo State. Scaled up to the entire State, the practice could lead to the removal of 23% of the total amount of GHGs emitted by the State in 2016. • First LCA of sugarcane biochar for GHG removal in Brazil. • Covering the energy deficit created by pyrolysis is the most GHG emitting process. • Lifecycle emissions reduce the net carbon sequestration benefits of biochar by 25%. • Sugarcane residue biochar in São Paulo State, Brazil could sequester 36 Mt CO 2 eq yr−1. [ABSTRACT FROM AUTHOR]