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In recent years biochar (BC) has gained importance for its huge carbon (C) sequestration potential and positive effects on various soil functions. However, there is a paucity of information on the long-term impact of BC on the priming effect and nutrient availability in soil with different properties. This study investigates the effects of BC prepared from rice husk (RBC4, RBC6), sugarcane bagasse (SBC4, SBC6) and mustard stalk (MBC4, MBC6) at 400 and 600 °C on soil C priming and nitrogen (N), phosphorus (P), and potassium (K) availability in an Alfisol, Inceptisol, and Mollisol. BC properties were analyzed, and its decomposition in three soil orders was studied for 290 days in an incubation experiment. Post-incubation, available N, P, and K in soil were estimated. CO2 evolution from BC and soil alone was also studied to determine the direction of priming effect on native soil C. Increasing pyrolysis temperature enhanced pH and EC of most of the BC. The pyrolysis temperature did not show clear trend with respect to priming effect and nutrient availability across feedstock and soil type. MBC6 increased C mineralization in all the soil orders while RBC6 in Alfisol and SBC6 in both Inceptisol and Mollisol demonstrated high negative priming, making them potential amendments for preserving native soil C. Most of the BC showed negative priming of native SOC in long run (290 days) but all these BC enhanced the available N, P, and K in soil. SBC4 enhanced N availability in Alfisol and Inceptisol, RBC4 improved N and P availability in Mollisol and P in Alfisol and MBC6 increased K availability in all the soils. Thus, based on management goals, tailored BC or blending different BC can efficiently improve C sequestration and boost soil fertility. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the design parameters for a filter intended to remove fluoride from groundwater. Water fluoridation notably influences groundwater, particularly in arid and semi-arid areas that exacerbate the challenge of availability of safe drinking water from Groundwater resources in numerous developing nations. Experiments were conducted to determine the fluoride concentrations in groundwater sources in the arid region of Maharashtra, India. Samples were collected from seven villages in three districts of Maharashtra. This study utilized chemically functionalized sugarcane bagasse biochar adsorbent (SCBB), which is low-cost and easily accessible, to remove fluoride from groundwater in a column setup. The recommended design parameters for the packed-bed column flow rate (Q) are 100 ml min-1 and bed height (d) is 30 cm. [ABSTRACT FROM AUTHOR]

Global warming necessitates urgent action to reduce carbon dioxide (CO2) emissions and remove CO2 from the atmosphere. Biochar, a type of carbonized biomass which can be produced from crop residues (CRs), offers a promising solution for carbon dioxide removal (CDR) when it is used to sequester photosynthetically fixed carbon that would otherwise have been returned to atmospheric CO2 through respiration or combustion. However, high‐resolution spatially explicit maps of CR resources and their capacity for climate change mitigation through biochar production are currently lacking, with previous global studies relying on coarse (mostly country scale) aggregated statistics. By developing a comprehensive high spatial resolution global dataset of CR production, we show that, globally, CRs generate around 2.4 Pg C annually. If 100% of these residues were utilized, the maximum theoretical technical potential for biochar production from CRs amounts to 1.0 Pg C year−1 (3.7 Pg CO2e year−1). The permanence of biochar differs across regions, with the fraction of initial carbon that remains after 100 years ranging from 60% in warm climates to nearly 100% in cryosols. Assuming that biochar is sequestered in soils close to point of production, approximately 0.72 Pg C year−1 (2.6 Pg CO2e year−1) of the technical potential would remain sequestered after 100 years. However, when considering limitations on sustainable residue harvesting and competing livestock usage, the global biochar production potential decreases to 0.51 Pg C year−1 (1.9 Pg CO2e year−1), with 0.36 Pg C year−1 (1.3 Pg CO2e year−1) remaining sequestered after a century. Twelve countries have the technical potential to sequester over one fifth of their current emissions as biochar from CRs, with Bhutan (68%) and India (53%) having the largest ratios. The high‐resolution maps of CR production and biochar sequestration potential provided here will provide valuable insights and support decision‐making related to biochar production and investment in biochar production capacity. [ABSTRACT FROM AUTHOR]

There has been a ton of debate on developing goals and the conflicts regarding environmental preservation. In the wastewater treatment industry, biochar seems to appear as a low-cost and environmentally friendly alternative because of its high porosity and adsorbent capacity. This study used the Scopus database to map articles on the topic through a systematic methodology and screening. The results demonstrate the approach researchers are giving to biochar adsorbing characteristics. It was observed that research about biochar applied to wastewater is recent and shortage. China and India were the countries that most published about it. Sewage sludge was the most common biomass used for biochar production, and pyrolysis temperature remained mainly at 300° C to 700 °C. Also, the removal of heavy metals was the greater purpose of the studies. Finally, this mapping described biochar formation and its use as an adsorbent for wastewater treatment purposes, providing important data for directing future studies. [ABSTRACT FROM AUTHOR]

The manufacturing of fossil-based fertilizers by extraction of rock phosphate has contributed to carbon emissions and depleted the non-renewable phosphorus reserves. Sewage sludge, which is a waste product from Sewage Treatment Plants (STPs), is rich in phosphorus. The existing techniques for sludge management contribute to carbon emissions and ecological footprint. Struvite (raw fertilizer) and biochar recovery from sludge has emerged as viable methods to reduce carbon emission and ensure economic sustainability of STPs. In this work, the potential for phosphorus recovery and revenue generation is discussed for Rajasthan state in India. The fate of phosphorus and heavy metals in STPs is evaluated which indicates that about 70% of the phosphorus and trace amounts of metals end up in sewage sludge. Further, the power consumption is high in STPs due to industrial wastewater ingress. There is a need to bridge the gap between sewage treatment and generation in Rajasthan, improve STP performance before resource recovery inclusion at policy-level and scale-up. Mixing struvite with biochar can lead to safe application of struvite as raw fertilizer as heavy metals are sequestered by biochar. A business framework is developed to serve as a blueprint and potential model for linking technical and market viability., Competing Interests: The authors declare there is no conflict., (© 2024 The Authors This is an Open Access article distributed under the terms of the Creative Commons Attribution Licence (CC BY 4.0), which permits copying, adaptation and redistribution, provided the original work is properly cited (http://creativecommons.org/licenses/by/4.0/).)

Effluent from electroplating industries contains various toxic heavy metal ions such as chromium, nickel, lead, cadmium, copper and zinc. Recovery of the valuable heavy metals by environment friendly approach for recycling in various useful applications could be significant from the perspectives of clean process development with techno-economic viability. Zinc is an important component of electroplating effluent found in high concentration (80–750 mg/L). The present study investigates on recovery of zinc from electroplating effluent using an efficient biochar synthesized from jute industrial wastes. Biochar characteristics and metal removal mechanisms were established using BET surface area, zeta potential, FESEM-EDAX, elemental mapping, XRD, FTIR, XPS, XRF, Raman spectroscopy and roles played by functional groups. Optimum adsorption capacity of 526.32 mg g−1 was obtained for Zn(II). Zn(II) binding was achieved by ion exchange, complexation with functional groups, electrostatic interactions, adsorption and micro-precipitation. The techno-economic analysis was performed for biochar prepared by chemical carbonization process and found competitive in comparison with other reported biochar obtained by slow pyrolysis process. Further, the disposal of the toxic metal-laden spent adsorbent is a critical issue that needs to be addressed. In the present study recycling potential of the exhausted Zn(II)-laden biochar was explored for the development of micro-fertilizer for plants and soil-fertility improvement. Application of the Zn(II)-laden biochar mixed with soil revealed a positive influence on Cicer arietinum seed germination, plant growth parameters, protein and chlorophyll a and b content. Significantly, there were no changes in the antioxidant enzymes activities, superoxide dismutase (SOD) and catalase (CAT) between the plants grown in control soil and different Zn(II)-laden biochar-mixed soil, suggesting that 15% of the Zn(II)-laden biochar could not be excess condition of zinc. The present study thus addresses an important aspect of solid waste management of jute industry considering significant volume of jute waste production of ~ 0.04 MT/day in India along with the remediation of electroplating and other metal-bearing industrial effluent. Further, micro-fertilizer application of the metal-laden sludge and soil productivity improvement at low cost, environmentally safe and fruitful manner makes the study significant from ecological as well as societal perspectives. [ABSTRACT FROM AUTHOR]

The augmentation of biochar (BC) during anaerobic digestion (AD) has been identified as a potential strategy for improving the AD of complex feedstocks. This study evaluates the influence of oak wood biochar 450 °C and fermentation conditions during the AD of the invasive aquatic plant, water hyacinth (WH). Factorial 22 design of experiments (DOE) allowed the evaluation of the effect of the crucial processing conditions, inoculum-to-substrate ratio (ISR) and biochar load. Further optimisation was performed to identify the best processing conditions for the AD of WH, at an ideal ISR of 1. The contour plots suggested that methane yield is favoured at biochar loads of ≤0.5%, whereas the production rate is favoured by increasing biochar loads. However, biochar addition offered no further improvement or significant effect on the digestion of WH. The subsequent AD of WH samples collected from different locations in India and Uganda exhibited variable biochemical methane potential (BMP) yields. BC addition had little effect on BMP performance, and in some cases, it even reduced the BMP. This study concludes that the amendment potential of biochar is influenced by digestion conditions and the substrate, particularly when working with complex substrates. [ABSTRACT FROM AUTHOR]

Organic matter management is key to sustain ecosystem services provided by soils. However, it is rarely considered in a holistic view, considering local resources, agro-environmental effects and harmonization with farmers' needs. Organic inputs, like compost and biochar, could represent a sustainable solution to massive current challenges associated to the intensification of agriculture, in particular for tropical regions. Here we assess the potential of agricultural residues as a resource for farmer communities in southwestern India to reduce their dependency on external inputs and sustain ecosystem services. We propose a novel joint evaluation of farmers' aspirations together with agro-environmental effects of organic inputs on soils. Our soil quality evaluation showed that biochar alone or with compost did not improve unilaterally soils in the tropics (Anthroposol, Ferralsol and Vertisol). Many organic inputs led to an initial decrease in water-holding capacities of control soils (-27.3%: coconut shell biochar with compost on Anthroposol). Responses to organic matter inputs for carbon were strongest for Ferralsols (+33.4% with rice husk biochar), and mostly positive for Anthroposols and Vertisols (+12.5% to +13.8% respectively). Soil pH responses were surprisingly negative for Ferralsols and only positive if biochar was applied alone (between -5.6% to +1.9%). For Anthroposols and Vertisols, highest increases were achieved with rice husk biochar + vermicomposts (+7.2% and +5.2% respectively). Our socio-economic evaluation showed that farmers with a stronger economical position showed greater interest towards technology like biochar (factor 1.3 to 1.6 higher for farmers cultivating Anthroposols and/or Vertisols compared to Ferralsols), while poorer farmers more skepticism, which may lead to an increased economical gap within rural communities if technologies are not implemented with long-term guidance. These results advocate for an interdisciplinary evaluation of agricultural technology prior to its implementation as a development tool in the field. [ABSTRACT FROM AUTHOR]

Nutrient deficiencies in soil–crop contexts and inappropriate managements are the important reasons for low crop productivity, reduced nutritional quality of agricultural produce and animal/human malnutrition, across the world. The present investigation was carried out to evaluate nutrient deficiencies of sulphur (S) and micronutrients [zinc (Zn), boron (B), iron (Fe), copper (Cu) and manganese (Mn)] in agricultural soils of India for devising effective management strategies to achieve sustainable crop production, improved nutritional quality in crops and better animal/human health. A total of 2,42,827 surface (0–15 cm depth) soil samples were collected from agriculture fields of 615 districts lying in 28 states of India and were analysed for available S and micronutrients concentration. The study was carried out under the aegis of All India Coordinated Research Project on Micro- and Secondary-Nutrients and Pollutant Elements in Soils and Plants. The mean concentrations were 27.0 ± 29.9 mg kg−1 for available S, 1.40 ± 1.60 mg kg−1 for available Zn and 1.40 ± 4.70 mg kg−1 for available B, 31.0 ± 52.2 mg kg−1 for available Fe, 2.30 ± 3.50 mg kg−1 for available Cu and 17.5 ± 21.4 mg kg−1 for available Mn. There were variable and widespread deficiencies of S and micronutrients in different states. The deficiencies (acute deficient + deficient + latent deficiency) of S (58.6% of soils), Zn (51.2% of soils) and B (44.7% of soils) were higher compared to the deficiencies of Fe (19.2% of soils), Cu (11.4% of soils) and Mn (17.4% of soils). Out of 615 districts, > 50% of soils in 101, 131 and 86 districts were deficient in available S, available Zn and available B, respectively. Whereas, > 25% of soils in 83, 5 and 41 districts had deficiencies of available Fe, available Cu and available Mn, respectively. There were occurrences of 2-nutrients deficiencies such S + Zn (9.30% of soils), Zn + B (8.70% of soils), S + B (7.00% of soils) and Zn + Fe (5.80% of soils) to a greater extent compared to the deficiencies of Zn + Mn (3.40% of soils), S + Fe (3.30% of soils), Zn + Cu (2.80% of soils) and Fe + B (2.70% of soils). Relatively lower % of soils were deficient in 3-nutrients (namely S + Zn + B, S + Zn + B and Zn + Fe + B), 4-nutrients (namely Zn + Fe + Cu + Mn) and 5-nutrients (namely Zn + Fe + Cu + Mn + B) simultaneously. The information regarding the distribution of deficiencies of S and micronutrients (both single and multi-nutrients) could be used by various stakeholders for production, supply and application of right kind of fertilizers in different districts, states and agro-ecological regions of India for better crop production, crop nutritional quality, nutrient use efficiency, soil health and for tackling human and animal malnutrition. [ABSTRACT FROM AUTHOR]

Biochar is a growing tool for bioremediation and soil improvement applications. Researchers are focusing on biochar due to its efficacy, eco-friendly composition, and cost-effective solutions to a variety of environmental issues. In recent times biochar has been used in enhancing the soil, increasing nutrient content, and sequestering carbon in paddy cultivation soils. India and Southeast Asian countries consume paddy as a major source of food in large quantities. Therefore, improving the growth condition of paddy fields using an easily available and safe technique will help increase the production rate. This will fulfill the needs of the growing population. Biochar is developed by the thermal decomposition of organic materials in low or no oxygen through pyrolysis, gasification, and co-pyrolysis methods. It improves paddy soil fertility due to its special physicochemical properties such as porosity, high surface area, efficient slow release, nutrient holding capacity, and maintenance of soil microbiota. Considering the importance of biochar in paddy soil fertility, the present work reviews the sources of biochar, functionalization of biochar, mechanism, and beneficial role of biochar. [ABSTRACT FROM AUTHOR]

Coal is the predominant global energy source, where its consumption as metallurgical coke from fast-depleting prime coking coal is vital. In India, the complete depletion of prime coking coal and ultimate dependence on low-grade low-volatile coking coal reserves are the primary concern, so the need to explore alternative fuels, preferably with less climatic concern. Accordingly, a process for the synthesis of bio-coke, a novel product, using varying blending ratios (90:10, 80:20, 70:30, 60:40, and 50:50) of such inferior grade coal and biochars (derived at 550°C) of coconut shell (CSC), groundnut shell (GSC), sawdust (SDC), and sugarcane bagasse (SBC) in the presence of starch and molasses binders was developed via carbonization (at 800–1100°C). Obtained bio-cokes from coal and biochars with molasses possess better strength and plastic properties for metallurgical applications than those prepared with starch, and can be a sustainable substitute for metallurgical coke. [Display omitted] • Assessing the potential of selected biomass residues as feedstock for biochar preparation at 550 °C. • Blend of LVC coal with biochar has potential for synthesis of bio-coke - a substitute for metallurgical coke. • Optimum coal-to-biochar ratio for bio-coke is 70:30 at 1000 °C for CSC and 900 °C for GSC; and 80:20 at 900 °C for SDC. • Molasses imparted better binding properties than starch relating to bio-coke mechanical strength. • Biocoke is a less pollutant-emitting sustainable fuel than metallurgical coke. [ABSTRACT FROM AUTHOR]

Post COP-15, the push is to reduce coal dependence for electricity generation and GHG emissions from the national electrical grid. Phasing out coal-based thermal power plants (TPPs) does not favour India's economic and social interests. Therefore, it becomes imperative to make coal-based power plants clean. Biochar derived from crop residues has been considered a clean fuel and an economical substitute for coal. The present study investigated the biochar potential of crop residues from rice, wheat, maize and sugarcane cultivation, accounting for 89% of total agro production, for coal replacement in TPPs using primary & secondary data and ArcGIS for mapping agro-residue collection point and TPP. Results show that biochar produced from the identified agro resources in the temperature range of 400 °C–500 °C are suitable for cofiring with coal. 121 MT surplus residues of the selected crops could produce 40 MT biochar having 90 TWh electricity generation potential. Biochar produced from surplus residues is equivalent to 69 MT of coal, about 11% of coal consumed annually in Indian TPPs. Also, biochar cofiring could reduce 165 MT annual CO 2 emissions from coal-burning in TPPs, about 14% of CO 2 emissions by the energy sector and 7% of overall CO 2 emissions by India. Techno-economic analysis showed that the infrastructure development & operation cost for the biochar conversion facility is in the range of 2–3 USD/MWh, which is significantly lower than that of the new biomass to electricity generation facility (43–53 USD/MWh). The results would provide baseline data for policy decisions to avoid net GHG emissions from TPPs, and site identification for additional infrastructure to develop alternative clean fuels for India's coal-based TPPs. [Display omitted] • India produces 398 MT gross & 121 MT surplus RS, WS, MS, STL & SB. • Surplus residues could produce 40 MT biochar having 90 TWh EGP. • Biochar can reduce 11% of annual coal consumption in thermal power plants. • Biochar cofiring can reduce 14% CO 2 e emission from energy sector. • The estimated cost of establishing biochar production facility was 2–3 USD/MWh. [ABSTRACT FROM AUTHOR]

Applications of biochar to degraded soils have attracted considerable interest because of its capacity to enhance nutrients availability to the plants, sequester C and immobilize organic and inorganic pollutants. A five-year field experiment was conducted in a cotton-wheat system to investigate the effect of different levels of irrigation water salinity (0.3, 5, 10, and 15 dS m−1) and rice straw biochar (0, 2, 4, and 8 t ha−1) on the crop yield and soil functions. Rice straw-derived biochar was applied every year to cotton and its residual effect was observed on wheat. Results of the study indicated that regular irrigation with saline water (5–15 dS m−1) reduced both seed cotton (12–44%) and wheat grain (7–27%) yield. However, application of biochar (2–8 t ha−1) to plots irrigated with saline water showed 6–23% and 13–27% greater seed cotton and wheat grain yield compared with unamended plots, respectively. Likewise, biochar application to soil irrigated with canal or saline water showed significant beneficial effects on soil pH, EC, nutrient metabolism and availability, bulk density, infiltration rate and microbial biomass carbon. Our results indicated that biochar amendment especially at the optimum rate of 4 t ha−1 effectively promoted crop performance by ameliorating soil physical, chemical, and biological properties. In the absence of any chemical amendment for alleviating salinity stress, the results of the present study established that the biochar holds promising potential as a soil amendment in ameliorating soil functions and promoting plant productivity under saline water irrigated conditions. • Rice straw biochar promoted crop performance and soil functionality under saline water irrigation. • Biochar application at 4 t ha−1 was optimum to facilitate saline water use in a cotton-wheat system. • Long-term biochar application did not adversely affect soil electrical conductivity. [ABSTRACT FROM AUTHOR]