Techno-economic analysis reveals the untapped potential of wood biochar

Understanding the dependence of biochar properties on different types of biomass

Owing to the diversity of biomasses and many variables in pyrolysis process, the property of biochar from varied biomass feedstock or even same biomass could differ significantly. Since the property of biochar governs the further application of biochar, this review paid particular attention to the correlation between the nature of biomass feedstock and the specifications of biochar in terms of yield, elemental composition, pH, functionalities, heating value, pore structures, morphologies, etc. The property of the biochar from the pyrolysis of cellulose, hemicellulose, lignin, woody biomass (pine, mallee, poplar, acacia, oak, eucalyptus and beech), bark of woody biomass, leaves of woody biomass, straw, algae, fruit peels, tea waste was compared and summarized. In addition, the differences of the biochar of these varied origins were also analyzed. The remaining questions, about the correlation of biomass nature with biochar characteristics, to be further investigated are analyzed in detail. The deduced information about the relationship of the nature of biochar and biomass feedstock as well as key pyrolysis parameters is of importance for further development of the methods for tailoring or production of the biochar of desirable properties. The results from this study could be interesting technically and commercially for the technology developer using biochar as the source of carbon in different applications.

A comprehensive review on unleashing the power of hydrogen: revolutionizing energy systems for a sustainable future

Population growth and environmental degradation are major concerns for sustainable development worldwide. Hydrogen is a clean and eco-friendly alternative to fossil fuels, with a heating value almost three times higher than other fossil fuels. It also has a clean production process, which helps to reduce the emission of hazardous pollutants and save the environment. Among the various production methodologies described in this review, biochemical production of hydrogen is considered more suitable as it uses waste organic matter instead of fossil fuels. This technology not only produces clean energy but also helps to manage waste more efficiently. However, the production of hydrogen obtained from this method is currently more expensive due to its early stage of development. Nevertheless, various research projects are underway to develop this method on a commercial scale.

Development of calcium-modified biochar for enhanced phytoremediation of human-induced salt pollutants (HISPs)

Soil salinization is a major environmental hazard that limits land availability. Human-induced salt pollutants (HISPs) are regularly presented in large quantities on the contaminated site (such as brine leakages and salt-water spills), causing a devastating shock with high salt stress to the ecosystem. For instance, Saskatchewan resulted in a 48% drop in wheat production and a 0.3% decline in provincial GDP. As the calcium-modified biochar can potentially ameliorate the negative effects of HISPs on plants and improve the plant, phytoremediation with calcium-modified biochar can have increased detoxification of hazardous pollutants from sites. Therefore, the objective of our study was to develop a biochar-assisted phytoremediation employing diverse approaches to calcium modification for the sustainable removal of HISPs. The co-pyrolyzed calcium biochar achieved a remarkable removal rate of 18.06%, reducing salinity from 9.44 to 7.81 dS/m. During a 90-day long-term phytoremediation, the overall reduction rate of calcium-modified biochar stimulated the germination and growth of Thinopyrum ponticum. The result of post-treatment further indicated that co-pyrolyzed biochar with Ca transferred salt into the plant compared to Ca-coated biochar, which only immobilized HISPs on its surface. These results offer two different treatment approaches for diverse situations involving HISPs contamination, addressing current in-situ spills and providing a calcium-related biochar technology for further research in desalination.

Production of bagasse fly ash-derived CO2 adsorbent by physical activation and by nitrogen-functionalization using hydrothermal treatment

The high cost of commercial CO2 capture material is one of the issues hindering the widespread adaptation of the technology. This study explored efficient ways of utilizing waste material in the form of bagasse fly ash (BFA) as CO2 adsorbent through thermochemical preparations of physical activation, and hydrothermal carbonization (HTC). The activation of BFA using flue gas was able to produce an adsorbent with good CO2 adsorption capacity, with similar results to the CO2 activation. The second approach using co-HTC of BFA with chicken manure (CM) optimized using Box-Behnken design of experiment was able to produce an adsorbent with CO2 adsorption capacity nearly on-par with commercial adsorbents. It was also found that the model was able to accurately predict the experiment outcome when verified with the additional experiments. Material characterizations showed that the increase of the CO2 adsorption capacity of the adsorbent might have been achieved through the formation of secondary amines deposited on the BFA. The results of this study showed that the utilization of waste in the form of BFA and CM could contribute to the advancement of circular and low-cost CO2 capture medium from waste materials, which could increase the adaptation and involvement of sugar industry and poultry farm.

Enhanced heavy metal stabilization and phosphorus retention during the hydrothermal carbonization of swine manure by in-situ formation of MgFe2O4

Hydrothermal carbonization is an efficient technique for the disposal of livestock manure, enabling its harmless treatment, quantity reduction, and resourceful utilization. Co-hydrothermal of modified materials facilitates the production of more valuable carbonaceous materials. However, further exploration is needed to understand their potential impact on the environmental risks associated with livestock manure disposal and the application of products derived from it. Therefore, the carbonization degree, heavy metals stabilization, and phosphorus retention during the hydrothermal treatment of swine manure were systematically investigated in this study under the influence of in-situ formed MgFe2O4. The results revealed that the in-situ formation of MgFe2O4 improved the dehydration and decarboxylation of organic components in swine manure, thereby improving its carbonization degree. Furthermore, both hydrothermal carbonization and MgFe2O4 modified hydrothermal carbonization resulted in an enhanced stabilization of heavy metals, leading to a significant reduction in their soluble/exchangeable fraction and reducible fraction. Phosphorus was predominantly retained in the hydrochars, with the highest retention rate reaching 88%, attributed to the significant decrease in soluble and exchangeable phosphorus fractions facilitated by the in-situ formation of MgFe2O4. Moreover, MgFe2O4 modified hydrochars exhibited remarkable adsorption capacity for Pb(II) and Cu(II) without any leaching of heavy metals. Overall, the findings indicated that the in-situ formation of MgFe2O4 positively influenced the hydrothermal of swine manure, improving certain economic benefits in its practical application.

Co-pyrolysis of sewage sludge and biomass waste into biofuels and biochar: A comprehensive feasibility study using a circular economy approach

Enormous annual sewage sludge (SS) volumes pose global environmental challenges owing to contamination and significant greenhouse gas emissions. Here, we investigated the economic viability of co-pyrolyzing SS and biomass waste to produce biofuels (bio-oil and gas) and biochar. Net present worth (NPW) analysis, the sale product break-even price, and sludge handling price (SHP) were used to determine the profitability of co-pyrolysis compared with SS pyrolysis alone and conventional treatment methods. In this study, the sale prices of biochar based on quality (i.e., stability, carbon sequestration effectiveness, and heavy metal content) were estimated to be 2.24, 1.44, and 0.98 CAD/kg for high-, medium-, and low-grade biochar. The bio-oil prices, estimated based on the higher heating values of bio-oil and diesel, ranged from 0.80 to 1.22 CAD/kg. Sawdust (SD) and wheat straw (WS) were the chosen co-pyrolysis feedstocks, with four mixing ratios (20, 40, 60, and 80 wt%). Economically, SD (40 wt% mixing ratio) co-pyrolysis achieved the best performance, with a maximum NPW of 8.71 million CAD. SD single and co-pyrolysis were the only profitable scenarios. Moreover, SS single pyrolysis and WS co-pyrolysis exhibited higher profitability than conventional SS treatment methods, with SHPs of 65 and 40 CAD/1000 kg dry sludge, respectively. Sensitivity analysis highlighted the dependence of economic performance on biochar and bio-oil market value. This study offers the first economic analysis of this approach and enhances our understanding of the potential of co-pyrolysis for biofuel and biochar production, providing innovative solutions for the environmental challenges of SS disposal.

Application of biochar in microbial fuel cells: Characteristic performances, electron-transfer mechanism, and environmental and economic assessments

Biochar is a by-product of thermochemical conversion of biomass or other carbonaceous materials. Recently, it has garnered extensive attention for its high application potential in microbial fuel cell (MFC) systems owing to its high conductivity and low cost. However, the effects of biochar on MFC system performance have not been comprehensively reviewed, thereby necessitating the evaluation of the efficacy of biochar application in MFCs. In this review, biochar characteristics were outlined based on recent publications. Subsequently, various applications of biochar in the MFC systems and their probable processes were summarized. Finally, proposals for future applications of biochar in MFCs were explored along with its perspectives and an environmental evaluation in the context of a circular economy. The purpose of this review is to gain comprehensive insights into the application of biochar in the MFC systems, offering important viewpoints on the effective and steady utilization of biochar in MFCs for practical application.

A critical review on biochar production from pine wastes, upgradation techniques, environmental sustainability, and challenges

Pine wastes, including pine needles, cones, and wood, are abundantly produced as an agroforestry by-product globally and have shown tremendous potential for biochar production. Various thermochemical conversion technologies have exhibited promising results in converting pine wastes to biochar, displaying impressive performance. Hence, this review paper aims to investigate the possibilities and recent technological advancements for synthesizing biochar from pine waste. Furthermore, it explores techniques for enhancing the properties of biochar and its integrated applications in various fields, such as soil and water remediation, carbon sequestration, battery capacitor synthesis, and bio-coal production. Finally, the paper sheds light on the limitations of current strategies, emphasizing the need for further research and study to address the challenges in pine waste-based biochar synthesis. By promoting sustainable and effective utilization of pine wastes, this review contributes to environmental conservation and resource management.

Adsorption properties of active biochar: Overlooked role of the structure of biomass

Vascular plants account for more than 80% of all biomass on earth and are potential precursors of biochar. However, the changes of vascular bundle have received less attention during the preparation of biochar. In this study, loofah sponge (LS), tangerine pith (TP), and rhodiola rosea (RR), were selected to show the role of vascular bundle in biochar through the pretreatment of vascular bundle. The results showed that the active biochar prepared with vascular bundle protection had high adsorption capacity for methylene blue (LS: 953.53 mg/g, TP: 714.77 mg/g, RR: 583.49 mg/g). The Brunauer-Emmett-Teller method was used to measure the specific surface area (SSA) of active biochar. The SSA of LS active biochar prepared by vascular bundle protection was 2262.67 m2/g, and has high adsorption properties under different conditions. In conclusion, the protection of vascular bundle during biochar preparation is important to improve the utilization of biological resources and environmental adsorption.

Effects of saline water on soil properties and red radish growth in saline soil as a function of co-applying wood chips biochar with chemical fertilizers

BACKGROUND

Currently, using unconventional water sources in agriculture has become necessary to face overpopulation worldwide. Therefore, a pot experiment was carried out to evaluate the effects of irrigation with saline water in the presence of co-applied wood chips biochar (WCB) with chemical fertilizers on physicochemical properties and nutrient availability as well as growth parameters, and yield of red radish (Raphanus sativus L.) grown in the saline sandy soil.

METHODS

The WCB was added to the saline sandy soil at levels of 0 (control), 2.5, and 5% w/w. Then, this soil was cultivated by red radish plants and irrigated with saline water (5 dS m- 1). This experiment was performed in a randomized complete block design with three replicates.

RESULTS

Compared with the control treatment, WCB treatments increased significantly soil water holding capacity by 34.8% and 73.2% for levels of 2.5 and 5%, respectively. Soil pH decreased significantly in all WCB treatments. The relative increase in the total available nitrogen over the control was 30.1 and 103.5% for 2.5 and 5% wood chips biochar, respectively. Compared to the control, applying WCB at 2.5% led to an increase in the fresh root weight of red radish plants by 142.7%, while 5% caused a decrease in the fresh root weight of red radish plants by 29.4%.

CONCLUSION

Recently, WCB represents an interesting approach to the rehabilitation of saline soils and the management of using saline water sources. It is recommended that combined application of WCB at a level of 2.5% with chemical fertilizers in order to improve red radish growth and nutrient retention in the saline sandy soil which preserves the ecosystem as well as increases productivity leading to the reduction of costs.

Assessment of agriwaste derived substrates to grow ornamental plants for constructed wetland

Burning of surplus residues in agricultural fields is a common practice in many countries of the world. This practice adds emissions into the atmosphere and results in the loss of essential plant nutrients, hence, there is a need for developing technologies for the sustainable management of agri-residues. Constructed wetlands offer excellent nature-based, low-cost green technologies for the treatment of wastewater using surplus agricultural residues as wetland substrates to grow ornamental plants as a source of income. This study was conducted to investigate the use of agricultural residues and biochar as substrates to grow ornamental plants in constructed wetlands. Four ornamental plants (Canna Indica, Gerbera jamesonii, Liliumwallichianum, and Tagetes erecta) were grown in six different substrate combinations for 120 days. Data on plant growth parameters were collected for each plant and compared to select the best substrate combination. Canna Indica and Lilium wallichianum resulted in significantly higher growth and nutrient uptake (P<0.001) with the substrate of 15% rice straw, 80% soil, 5% biochar (T4), and 25% sugarcane bagasse, 70% soil, 5% biochar (T5) compared to other plants. The result concluded that agricultural waste-derived substrates are viable alternatives having fertilizing effects with the potential for nutrient recovery. The present study provides an alternative approach to utilize agricultural waste sustainably to grow ornamental plants in the constructed wetland which reduces the overall cost of the wetland unit making it more cost-efficient.

A dual bacterial alliance removed erythromycin residues by immobilizing on activated carbon

Removing erythromycin from the environment is a major challenge. In this study, a dual microbial consortium (Delftia acidovorans ERY-6A and Chryseobacterium indologenes ERY-6B) capable of degrading erythromycin was isolated, and the erythromycin biodegradation products were studied. Coconut shell activated carbon was modified and its adsorption characteristics and erythromycin removal efficiency of the immobilized cells were studied. It was indicated that alkali-modified and water-modified coconut shell activated carbon and the dual bacterial system had excellent erythromycin removal ability. The dual bacterial system follows a new biodegradation pathway to degrade erythromycin. The immobilized cells removed 95% of erythromycin at a concentration of 100 mg L^-1 within 24 h through pore adsorption, surface complexation, hydrogen bonding, and biodegradation. This study provides a new erythromycin removal agent and for the first time describes the genomic information of erythromycin-degrading bacteria, providing new clues regarding bacterial cooperation and efficient erythromycin removal.

Motivators and barriers of circular economy business model adoption and its impact on sustainable production in Malaysia

The circular economy concept is popular among developed countries contributing to sustainable production, efficient resource utilization, a new economic model, and higher skill job creation. In production and consumption, it is inevitable in our modern life that we are used to the traditional linear economy cradle-to-cradle model. With the gap in developing countries within the Southeast Asia region, this research aims to understand the motivators and barriers to circular economy business model adoption among the manufacturing firms in Malaysia. Subsequently, the impact of sustainable production will be studied based on the circular economy business model adoption. Using the Theory of Planned Behavior and Partial Least Squares Structural Equation Modeling, this study assesses the responses of 102 respondents from various industries with environmental management systems within Malaysia. Survey-based primary data was gathered to understand motivators and barriers that negatively influence the circular economy business adoption, affecting sustainable production. The findings show that motivators have a positive impact while barriers have a negative impact on circular economy business model adoption. Apart from the barriers and motivators, the research also assesses the level of circular economy adoption among manufacturing firms with certified environmental management systems. This implies a general overview for manufacturing firms in Malaysia regarding circular economy adoption and contributes to the studies done in developing nations. In conclusion, motivators positively impact the adoption of the circular economy business model, while barriers have a negative effect. In addition, adopting the circular economy model has a positive relationship with sustainable production.

Preparation and application of biochar from co-pyrolysis of different feedstocks for immobilization of heavy metals in contaminated soil

Co-pyrolysis is a potentially effective method for both biomass waste management and multi-functional biochar-based product design. It involves the thermochemical decomposition of biomass waste under anoxic conditions, which can reduce the cost of disposal and produce biochar with beneficial properties. Herein, this study aimed to investigate the properties and environmental applications of biochar from single- and mixed- feedstocks of wheat straw, rice husk, pig manure, and oyster shell at 450 ℃, respectively. A pot experiment with Chinese cabbage was carried out to compare the effects of biochars with limestone on soil Cd and Pb immobilization at two harvest periods. The results indicated that co-pyrolysis of various biomasses exhibited synthetic effects on promoting the calorific value of syngas and enhancing the quality of produced biochar. The pot experiment revealed a significant promotion on soil pH, soil organic matter, cation exchange capacity, and soluble Ca, which consequently reduced Cd and Pb availability. In contrast with limestone treatment, soil amendment with single biomass-derived and co-pyrolysis-derived (COPB) biochars had a significant positive impact on soil fertility and microbial biomass. Application of COPB at a 0.5% dosage consistently and most effectively enhanced the shoot biomass, increased leaf Vitamin C content but reduced leaf content of nitrate and heavy metals in both harvests. Using COPB for soil remediation would be financially visible due to the enhancement of crop yield. Therefore, this study proposes a strategy for targeted enhancement of the functions of biochar derived from co-pyrolysis of selected biomass waste for soil remediation and agricultural production.

Composted Bagasse and/or Cyanobacteria-Based Bio-Stimulants Maintain Barley Growth and Productivity under Salinity Stress

Soil and water salinity are among the most fatal environmental challenges that threaten agricultural production worldwide. This study investigated the potential impact(s) of soil amendment using composted bagasse and/or foliar application of cyanobacteria-based bio-stimulants (Arthrospira platensis, also known as Spirulina platensis) to combat the harmful effect(s) of using saline water to irrigate barley plants grown in salt-affected soils during 2020/2021 and 2021/2022. Briefly, the dual application of composted bagasse and cyanobacteria-based bio-stimulants significantly improved the soil properties, buffered the exchangeable sodium percentage (ESP), and enhanced the activity of soil enzymes (urease and dehydrogenase). Moreover, both treatments and their combination notably augmented the water relations of barley plants under salinity stress. All treatments significantly decreased stomatal conductance (gs) and relative water content (RWC) but increased the electrolyte leakage (EL) and balanced the contents of Na⁺ and K⁺, and their ratio (K⁺/Na⁺) of barley leaves under salinity stress compared with those irrigated with fresh water during the 2020/2021 and 2021/2022 seasons. Additionally, composted bagasse and cyanobacteria-based bio-stimulants diminished the oxidative stress in barley plants under salinity stress by improving the activity of antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), and peroxidase (POX). Consequently, the combination of composted bagasse and cyanobacteria extract resulted in superior yield-related traits such as spike length, number of grains per spike, 1000-grain weight, grain yield, straw yield, and harvest index. Collectively, our findings suggest that the integrative application of composted bagasse and cyanobacteria is promising as a sustainable environmental strategiy that can be used to improve soil properties, plant growth, and productivity of not only barley plants but also maybe other cereal crops irrigated with saline water in salt-affected soil.

Abattoir residues as nutrient resources: Nitrogen recycling with bone chars and biogas digestates

Abattoirs produce by-products that may become valuable resources for nutrient recycling and energy generation by including pyrolysis and biogas production in the value creation chain. This study investigated the potential of bone chars as sorbents for ammonium in order to produce a soil amendment useful for fertilizing purposes. Ammonium enriched from the digestate by membrane distillation or from pure ammonium sulphate solutions accommodated the nitrogen sorption to the bone chars. The plant availability of the sorbed nitrogen was studied by a standardized short-term plant test with rye (Secale cereale L.). The results showed that ammonium, both from biogas digestate and from pure salt solutions, could be sorbed successfully to the bone chars post-pyrolysis and increased the nitrogen concentration of the chars (1.6 ± 0.3%) by 0.2-0.4%. This additional nitrogen was desorbed easily and supported plant growth (+17 to +37%) and plant nitrogen uptake (+19-74%). The sorption of ammonium to the bone chars had a positive effect on the reversal of pure bone char phytotoxicity and on nitrogen availability. In summary, this study showed that abattoir wastes are useful pyrolysis input materials to produce bone chars and to provide ammonium source for sorption to the chars. This innovation offers the possibility to produce nitrogen-enriched bone chars as a new type of fertilizer that upgrades the known value of bone char as phosphorus fertilizer by an additional nitrogen fertilizer effect.

The global energy matrix and use of agricultural residues for bioenergy production: A review with inspiring insights that aim to contribute to deliver solutions for society and industrial sectors through suggestions for future research

Promoting the use of renewable energy sources has become an important policy strategy for mitigating climate change and for providing better energy security and financial sustainability. To overcome the problems generated by non-renewable energy sources, it is essential to use new energy sources. A literature review was conducted to investigate and understand the opportunities for implementing new renewable energy sources. Agricultural residues have great potential to receive significant consideration worldwide as an alternative, sustainable, and green energy source. The use of agricultural residues for bioenergy generation is a broad and favourable scenario for exploration. This review identified potential and almost unexplored research approaches with the aim of contributing and promoting researchers to deliver technological solutions for the society and industrial sectors. For example, a potentially promising technological solution would be for industries that produce machinery and agricultural implements to adapt their harvesters for different grain crops, to collect these agricultural residues simultaneously during harvest and readily perform granulation, compaction (pressing), pelletizing or briquetting directly on the property. Further studies are required to investigate the use of agricultural residues for bioenergy generation, which can contribute to the diversification of the energy matrix. Accordingly, in this review, several challenges and future research perspectives have been presented, such as suggestions for future research on how to collect, transport, process, market and use these agricultural residues to generate bioenergy, aiming at reducing the dependence on fossil fuels.

Impact of different structures of biochar on decreasing methane emissions from sewage sludge composting

Methane (CH₄) emissions from sewage sludge composting can be reduced by using biochar more effectively. This study investigates the impact of different structure of biochar on CH₄ emissions during sewage sludge composting. Corncob biochar (CB, pore size = 35.3990 nm), rice husk biochar (RB, pore size = 3.4242 nm) and wood biochar (WB, pore size = 1.6691 nm) were applied to the composting. The results showed that biochar decreased CH₄ emissions, mainly through the indirect effect of improving the pile environment. Compared with the control group (CK), the biochars with smaller pore structures, WB and RB, reduced CH₄ emissions by 41.83% and 33.59%, respectively, compared to only 8.20% for CB, which has a larger pore structure. In addition, RB and WB increased the free air space (FAS) by more than 10% and CB improved the microbial diversity. Methanothermobacter was reported in WB and RB, with an abundance of 45.45% in WB. Redundancy analysis (RDA) showed that pore size was positively correlated with the CH₄ emission rate. The results of this study can provide a theoretical reference for CH₄ reduction from biochar co-composting of sewage sludge.

Effect of Red Mud Addition on Electrical and Magnetic Properties of Hemp-Derived-Biochar-Containing Epoxy Composites

Waste stream valorization is a difficult task where the economic and environmental issues must be balanced. The use of complex metal-rich waste such as red mud is challenging due to the wide variety of metal oxides present such as iron, aluminum, and titanium. The simple separation of each metal is not economically feasible, so alternative routes must be implemented. In this study, we investigated the use of red mud mixed with hemp waste to produce biochar with high conductivity and good magnetic properties induced by the reduction of the metal oxides present in the red mud through carbothermal processes occurring during the co-pyrolysis. The resulting biochar enriched with thermally-reduced red mud is used for the preparation of epoxy-based composites that are tested for electric and magnetic properties. The electric properties are investigated under DC (direct current) regime with or without pressure applied and under AC (alternating current) in a frequency range from 0.5 up to 16 GHz. The magnetic measurements show the effective tailoring of hemp-derived biochar with magnetic structures during the co-pyrolytic process.

New sustainable and robust catalytic supports for palladium nanoparticles generated from chitosan/cellulose film and corn stem biochar

The production of sustainable catalytic supports for palladium nanoparticles is always desired, even more so through the recovery of biomass residues. In this sense, two different solids were investigated - chitosan/cellulose film and corn stem biochar - as catalytic supports of palladium nanoparticles. The solids were carefully characterized and tested in the Suzuki-Miyaura reaction, a typical cross-coupling reaction. The developed catalytic systems proved to be efficient and sustainable, promoted the formation of target products very well, and demanded green reactants under environmentally appropriate conditions. With the results shown in the manuscript, it is expected to contribute to the valorization of biomass and agro-industrial residues in the development of new catalysts for the chemical industry.

Screening tests for N sorption allow to select and engineer biochars for N mitigation during biomass processing

Biochar amendment during biomass processing can improve those processes and products, and reduce the emissions of greenhouse gases and NH₃, resulting in ecologic and economic benefits. The potential positive effects of biochar are related to NH₄⁺-N and NH₃ sorption, which in turn are depending on different biochar characteristics. By knowing the relationship between biochar characteristics and NH₄⁺-N and NH₃ sorption, biochar production can be steered towards a higher N sorption or existing biochars can be selected for targeted applications for high N sorption. Therefore, this study aims to develop fast screening tests to estimate the potential for both NH₄⁺-N and NH₃ sorption of biochar, before application in biomass processing. Further, the effects of feedstock, pyrolysis temperature, biochar characteristics and biochar treatments on N sorption are studied. The results show that NH₄⁺-N sorption varied between 0 and 1.54 mg NH₄⁺-N/g fresh biochar and was highest for manure-based biochars with a high nutrient content and cation exchange capacity, produced at lower temperatures (300-450 °C). For some biochars, the feedstock itself had a higher NH₄⁺-N sorption than the biochar. Grinding and washing increased the NH₄⁺-N sorption. In addition, a general linear model was proposed to predict the NH₄⁺-N sorption based on three chemical characteristics_· NH₃ sorption varied between 0 and 100 % of the negative control and showed a linear positive relationship with the NH₄⁺-N sorption, moisture retention factor and cation exchange capacity. Pyrolysis temperature and feedstock type did not significantly affect NH₃ sorption. NH₄⁺-N and NH₃ desorption varied amongst biochar type.

Exploration of CO2 emission reduction pathways: identification of influencing factors of CO2 emission and CO2 emission reduction potential of power industry

Low-carbon development of China's power sector is the key to achieving carbon peaking and carbon neutrality goals. Based on the logarithmic mean divisor index (LMDI) model, considering the carbon transfer caused by inter-provincial electricity trading, this paper analyzes the influencing factors of CO2 emissions in the provincial power sector and uses K-means clustering method to divide 30 provinces into four categories to analyze the differences in regional carbon emission characteristics. In addition, by establishing different development scenarios, the carbon emission trends and emission reduction potentials of each cluster under different emission reduction measures from 2020 to 2040 are studied, in order to explore the differentiated emission reduction paths of each cluster. The results show that the contribution of influencing factors shows great differences in different provinces. Trends in CO2 emissions vary widely across scenarios. In the reference scenario, the CO2 emissions of each cluster will continue to increase; in the existing policy scenario, the total power industry will peak at 6.1Gt in 2030; in the advance peak scenario that puts more emphasis on the development of advanced technologies and renewable energy under the clean development model, the carbon emission peak will be brought forward to 2025, and the peak will be reduced to 5.2Gt. Finally, differentiated emission reduction paths and measures are proposed for the future low-carbon development of different cluster power industries, providing theoretical reference for the deployment of provincial-level emission reduction work, which is of great significance to the global green and low-carbon transformation.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s10098-022-02456-1.

Impact of Drip Irrigation and Nitrogen Fertilization on Soil Microbial Diversity of Spring Maize

Given the shortage of water resources and excessive application of nitrogen fertilizers in irrigated areas, we explored the effect of water−nitrogen coupling on soil microbial diversity in maize fields irrigated using shallow buried droppers. A field experiment (split-plot design) was used with irrigation amounts set at 40%, 50%, and 60% of the conventional amount; furthermore, 13 water and nitrogen coupling treatments were designed. The secondary area was the nitrogen application level, corresponding to 50%, 70%, and the original conventional application amounts. The results showed that the effect of irrigation amount on bacterial community composition was greater than that of nitrogen, whereas the effect of nitrogen on fungi was greater than that on bacteria. No significant difference was detected in the α diversity index or species richness of bacteria and fungi. Available phosphorus and organic carbon contents significantly correlated with the community structure of soil bacteria (p < 0.05). The relative abundances of bacteria and fungi were stable with the decrease of nitrogen application rate at the irrigation rate of 2000 m3 ha−1. With the decrease of irrigation amount, the relative abundance of bacteria and fungi was stable under the treatment of 210 kg ha−1 nitrogen fertilizer. Moreover, the relative abundance of nitrogen-fixing bacteria related to the nitrogen cycle was increased by irrigation of 2000 m3 ha−1 and nitrogen application of 210 kg ha−1. Moderate reduction of subsequent N supply should be as a prior soil management option in a high N input agroecosystem.

From waste to fertilizer: Nutrient recovery from wastewater by pristine and engineered biochars

Biochar application for the recovery of nutrients from wastewater is a sustainable method based on a circular economy. Wastewater, food wastewater, and stormwater are valuable sources of nutrients (i.e., PO₄^3-, NO₃^-, and NH₄⁺). The unique properties of biochar, such as its large specific surface area, pH buffering capacity, and ion-exchange ability, make it a cost-effective and environmentally friendly adsorbent. Biochar engineering improves biochar properties and provide targeted adsorbents. The biochar-based fertilizers can be a sustainable alternative to traditional fertilization. The aim of the study was to compare the potential of pristine and engineered biochars to recover nutrients from wastewater and to determine the factors which may affect this process. Engineered biochar can be used as a selective adsorbent from multicomponent solutions. Adsorption on engineered biochar can be also regulated by additional mechanisms: surface precipitation and ligand/ion exchange. Metal modification (e.g. Mg, Fe) enhances PO₄^3- and NO₃^- adsorption capacity, and thus may provide the extra plant macro-/micronutrients. The desorption mechanism, which is the basis for nutrient release are strongly pH depended. The use of biochar-based fertilizer can have economic and agricultural benefits when using waste materials and reducing pyrolysis energy costs.

An Optimal Decision Support System Based on Crop Dynamic Model for N-Fertilizer Treatment

The efficient handling of nitrogen has become a critical issue in modern agriculture, from a financial standpoint, as well as in regard to reducing the environmental impacts of using an excessive amount of nitrogen fertilizer. Manure compost is useful for maintaining or raising soil chemical levels without excessive NO3- accumulation; however, for the best grain yield, it should be combined with N fertilizer. Via this study, we aimed to develop an optimal decision support system that indicates when to initiate fertilization based on nitrogen-limited (N-limited) crop growth dynamics. An optimal nitrogen fertilizer (N-fertilizer) management system increases crop yield while maintaining a balance between fertilizer supply and crop demand. This study used the N-limited crop growth model (LINTUL3) to develop an optimal decision support system. In this work, we formulated and resolved two optimization challenges: (i) maximization of biomass growth; and (ii) maximization of growth with the least cost paid on N-fertilizer and its application. Furthermore, two case studies were developed based on the number of fields: (i) optimization for a single field, and (ii) optimization for multiple fields. In the case of multiple fields, it is hypothesized that a fertilizer treatment for one field can leak to other fields and affect the nitrogen dynamics of different fields. Finally, numerical simulations were carried out supporting the theory developed in the paper. The simulations showed that when the proposed work was employed to achieve the goal of optimal nitrogen management for a crop, a 28% to 53% increase in biomass growth under certain scenarios was attained.

Pyrolysis of citrus wastes for the simultaneous production of adsorbents for Cu(II), H2, and d-limonene

A route based on pyrolysis and physical activation with H₂O and CO₂ was proposed to reuse citrus waste traditionally discarded. The citrus wastes were orange peel (OP), mandarine peel (MP), rangpur lime peel (RLP), and sweet lime peel (SLP). The main aim was to use the solid products of this new route as adsorbents for Cu(II) ions. Copper ions are among the most important water pollutants due to their non-degradability, toxicity, and bioaccumulation, facilitating their inclusion and long persistence in the food chain. Besides the solid products, the liquid and gaseous fractions were evaluated for possible applications. Results showed that the citrus waste composition favored the thermochemical treatment. In addition, the following yields were obtained from the pyrolysis process: approximately 30 % wt. of biochar, 40 % wt. of non-condensable gases, and 30 % wt. of bio-oil. The biochars did not present a high specific surface area. Nevertheless, activated carbons with CO₂ and H₂O presented specific surface areas of 212.4 m²/g and 399.4 m²/g, respectively, and reached Cu(II) adsorption capacities of 28.2 mg g^-1 and 27.8 mg g^-1. The adsorption kinetic study revealed that the equilibrium was attained at 60 min and the pseudo-second-order model presented a better fit to the experimental data. The main generated gases were CO₂, which could be employed as an activating agent for activated carbon production. d-limonene, used for food and medicinal purposes, was the main constituent of the bio-oil.

Optimizing nitrogen management reduces mineral nitrogen leaching loss mainly by decreasing water leakage in vegetable fields under plastic-shed greenhouse

Excessive fertilization leads to high nitrogen (N) leaching under intensive plastic-shed vegetable production systems, and thereby results in the contaminations of ground or surface water. Therefore, it is urgent to develop cost-effective strategies of nitrogen management to overcome these obstacles. A 15-year experiment in annual double-cropping systems was conducted to explore impacts of N application rate and straw amendment on mineral N leaching loss in plastic-shed greenhouse. The results showed that seasonal mineral N leaching was up to 103.4-603.4 kg N ha^-1, accounting for 12%-41% of total N input under conventional N fertilization management. However, optimized N application rates by 47% and straw addition obviously decreased mineral N leaching by 4%-86%, while had no negative impacts on N uptake and tomato yields. These large decreases of N leaching loss were mainly due to the reduced leachate amount and followed by N concentration in leachate, which was supported by improved soil water holding capacity after optimizing N application rates and straw addition. On average, 52% of water leachate and 55% of mineral N leaching simultaneously occurred within 40 days after planting, further indicating the dominant role of water leakage in regulating mineral N leaching loss. Moreover, decreasing mineral N leaching was beneficial for reducing leaching loss of base cations. Therefore, optimized N application rates and straw amendment effectively alleviates mineral N leaching losses mainly by controlling the water leakage without yield loss in plastic-shed greenhouse, making this strategy promising and interesting from environmental and economical viewpoints.

Fast pyrolysis characteristics and its mechanism of corn stover over iron oxide via quick infrared heating

The harm done to the environment by fossil fuels was serious, and it is urgent to find effective methods and adopt carbon-neutral feedstock to prevent further environmental damage. An innovative infrared heating reactor was developed for the generation of high-yield bio-oil and cleaner pyrolysis gases. This work was devoted to exploring the fast pyrolysis characteristics and its mechanism of corn stover over the iron oxide in a novel infrared heating (IH) reactor and a traditional electric heating (EH) reactor. In the IH reactor, the bio-oil yield increased initially and then decreased with increasing pyrolysis temperature, reaching a maximum yield of 29 wt% at 600 °C. The yield of pyrolysis bio-oil and water decreased as the reusability number rose, whereas the char yield increased. Bio-oil yields decreased less from R0 to R3 and the catalyst was more effective in IH. IH produced more char and gas but considerably less water than EH, and its bio-oil had fewer phenols. Raman spectroscopy demonstrated that the aromatic structure of biochar increased as the pyrolysis temperature increased. Cellulose and hemicellulose can be completely cleaved at lower temperatures in IH. In addition, Fe₂O₃ catalysts have shown the advantages of low cost, efficient cycling, and long action time. Infrared heating coupled with iron oxide catalyst shows the potential to increase bio-oil yield and is more promising for industrial production than EH.

Resource and Environmental Pressures on the Transformation of Planting Industry in Arid Oasis

Controlling environmental pollutant discharge and water resource demand is crucial for the sustainable development of agriculture and rural areas in arid oases. Taking Ganzhou, an arid oasis in Northwest China, as an example, we established an analysis framework for the relationship between the planting industry transformation and the resource and environmental pressures, from 2011 to 2020, through the methods of inventory, coefficient and quota accounting. The results showed that the planting scale of crops in oases has continuously expanded, with a structural dominance of corn seed production. Pollutant discharge showed a “Z”-type evolution trend, and the demand for water consumption continued to increase. The transformation of the planting industry and pollutant discharge showed coupled trade-offs and a synergetic alternating fluctuations coupling relationship, which was highly co-evolutionary with the demand for water resources. Crop planting exhibited four spatial patterns, namely the mixed planting area of grain and cash crops grown in mountain areas (GCPA), suburban scale vegetable planting (SVPA), planting of seed production corn (MSPA), and the compound planting area of grain crops, oil crops, vegetables, and other characteristic crops (CMPA). MSPA and SVPA had the highest total and average volume per unit area, respectively. The planting industry transformation and evolution of resource and environment pressures are closely related to changes in national strategies, regional agricultural policies, and environmental regulations. Therefore, studying their relationships provides a scientific basis for the formulation of suitable countermeasures, according to the development stage of a region.

Building Envelope and the Outdoor Microclimate Variable of Vernacular Houses: Analysis on the Environmental Elements in Tropical Coastal and Mountain Areas of Indonesia

Temperature and humidity are essential factors in analyzing a building’s thermal performance. This research presents the differences in field measurements of vernacular houses in coastal and mountain areas in Indonesia. Field measurements were taken for five consecutive days in four vernacular houses. The variables were measured at the beginning and at the peak of the rainy season. Analysis included a combination of graphic and descriptive methods. The research results show that the location difference between coast and mountain results in a relatively high difference in temperature (43.6%). The outdoor temperature in the mountain area is lower than that of the coastal area. The outdoor humidity of the mountain area is 0.69% higher than that of the coastal area. In the tropical coastal area, the outdoor temperature of the exposed-brick house is 0.94% lower than that of the coastal wooden house. The outdoor air humidity of the brick house is 0.89% higher than that of the coastal wooden house. In the tropical mountain area, the outdoor temperature of the exposed-stone house is 2.47% lower than that of the wooden house. The outdoor air humidity of the stone house is 0.4% lower than that of the wooden house. The outdoor conditions affect the indoor conditions of the respective houses. These microclimatic differences are influenced by micro-environmental factors, such as the density of surrounding buildings, amount of vegetation, and shading. The research shows that height difference is the most dominant factor influencing outdoor microclimate. Regional microclimate becomes the basis for determining the most suitable envelope materials in different areas. The innovative contribution of the work is, among other benefits, the identification of factors that influence the wellbeing of the buildings’ users in the researched geographical area and the analysis of the interaction of the external and internal environment of buildings. From the above facts, it follows that the results of this work can contribute to the development of prediction models to determine the type of cover, material, shape, and load-bearing elements needed to create comfortable and energy-efficient buildings.

A Standard-Based Concept of the Integration of the Corporate Recovery Management Systems: Coping with Adversity and Uncertainty during a Pandemic

The aim of this study is to develop a conceptual model for the better coordination of recovery management systems to improve organizational performance in light of the new challenges of the COVID-19 pandemic. The author provides a revision of “the corporate recovery prism” model by presenting an extended standard-based concept of the integration of the corporate recovery management systems. It offers, among others, two new dimensions which result in a “pentagonal pyramid”. They emphasize the type of events in the individual elements of the concept and highlight the basis of the concept on standardization. The concept has been designed in order to develop the planning, preparation, and response to incidents from an event up to a crisis and, ultimately, to improve the company’s ability to thrive and prosper in an uncertain environment. For the initial validation of the concept, empirical research was conducted in Polish enterprises. The methodology of the survey is based on a questionnaire of the best practices in addressing the COVID-19 crisis in organizations. It is used for checking the relationships between organizational performance and a triad of the concept elements, such as organizational resilience (OR), crisis management (CM), and business continuity management (BCM). Using the survey results, a strong correlation was found between the triad and the performance. Therefore, the main finding of the survey shows that elements of the concept build better performance and sustainability in enterprises during a pandemic.