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[Abstract:] Grasslands play a crucial role in European agriculture and ecology, but are often underutilized due to low-value end-products. The utilisation of late-harvest grass for biochar and heat generation on farm-level is being studied as a potential negative emissions technology. Technical (energy provision and carbon sink), economic (cost vs. benefit), political (regulatory framework) and social (SWOT) perspectives are being evaluated. Technical feasibility has been demonstrated with three different farm-scale technologies and the energetic and carbon-sink potential evaluated. When a continuously operating allothermal unit is evaluated, 35 % of the input biomass energy content can be utilized for heating a farm, in combination with the potential to provide a carbon sink. The cost-benefit analysis shows important monetary savings when including the agronomic value (based on the market price) of the produced biochar. An assessment of the regulatory framework of biochar production in Germany presents a multitude of regulations applying to such technologies some of which provide a hurdle to navigate and may incur excessive costs for farmers as small-scale biochar producers. A SWOT analysis of a case in Brandenburg, Germany highlights strengths and opportunities, but also obstacles such as lack of infrastructure and regulatory support. This study highlights the need for further development of suitable technology and research on the long-term economic and carbon sink potential of biochar. This work was performed within the GO-GRASS project and has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement number 862674. We thank all the partners who collaborated with the data collection. We would also like to thank Philipp Grundmann for the coordination of the GO-GRASS project.

Nano zero-valent iron biochar (nZVI–BC), an environmentally-friendly functional material prepared from waste biomass, has attracted extensive attention. This material has potential to solve the problem of biomass conversion. However, the lack of a method of converting biomass to the nZVI–BC involved in biomass modification and pyrolysis hinders its further production and application. In this study, we introduced the green solvent polyethylene glycol 400 (PEG400) to a biomass (rice straw, RS) modification system with FeCl3·6H2O, and activated RS was prepared to nZVI–BC by one-step pyrolysis. The addition of PEG400 promoted the hydrolysis of iron ion and improved the RS surface structure, promoting the attachment of Fe2O3 to the RS surface. The mild activation conditions with temperatures of 60, 80, 100 °C and a time of 0.5 h prevented the excessive loss of the lignin component and were conducive to the formation of carbon skeletons. Amorphous carbon and Fe2O3 were subjected to redox reactions to form nZVI–BC with the assistance of reducing gas produced from pyrolysis. In addition, the prepared nZVI–BC was tested for dye (Congo red) removal, showing rapid absorption (70.6% at 5 min) and high catalysis in advanced oxidation (75.67% at 5 min, 90% at 60 min). This work proposed a novel mechanistic strategy for preparing nZVI–BC and set a foundation for its scaled production and application.

Direct air capture (DAC) of CO2 is considered one of the most promising carbon capture methods to reduce ambient CO2 concentration for climate change mitigation. Biochar represents an attractive adsorbent for DAC because it is environmentally friendly and cost-effective. In this work, KOH-activated bamboo biochar shows the CO2 capture capacity of 3.49 mmol g−1 (25 °C, 1 bar), and it is used as an adsorbent to perform direct air capture using a fixed-bed reactor with an ambient CO2 capture capacity of up to 51.74 μmol g−1. Furthermore, the effect of relative humidity on CO2 adsorption by biochar was investigated and exhibited promising stability under 2.7% relative humidity. However, the biochar activity for CO2 capture is reduced to 63.88% under 67.1% humidity after 50 cycles.

The effects of synthetic fertilizer and nutrient leaching are causing serious problems impacting soil function and its fertility. Mitigation of nutrient leaching and use of chemical fertilizer is crucial as fertile land adds up sustainability to climate changes. Biochar produced from agricultural bio-waste and municipal solid waste has been used for crop production and when applied in combination with organic nutrients may support mitigation of nutrient loss and adverse effects of chemical fertilizers. Different types of biochar and their application for soil enhancement have been observed, pine needle and sewage sludge derived low-temperature biochar along with compost, organic fertilizer in the form of manure and microalgal biomass may interact with soil chemistry and plant growth to impact nutrient loss and compensate the hazardous effect of chemical fertilizer, but it has not been investigated yet. This present study elaborates application of sewage sludge and pine needle biochar produced at 400 °C in an application rate of 5 % w/w and 10 t h-1 in combination with compost, manure and microalgal biomasses of Closteriopsis acicularis (BM1) and Tetradesmus nygaardi (BM2) on the growth of Chickpea (Cicer arietinum) and Fenugreek (Trigonella foenum-graecum) crop assessed in a pot experiment over a two crop (Chickpea - Fenugreek) cycle in Pakistan. Results depict that the pine needle biochar with additives has increased plant height by 104.1 ± 2.76 cm and fresh biomass by 49.9 ± 1.02 g, buffered the soil pH to 6.5 for optimum growth of crops and enhance carbon retention by 36 %. This study highlights the valorization of sewage sludge and pine needle into biochar and the effect of biochar augmentation, its impact on soil nutrients and plant biomass enhancement. The greener approach also mitigates and helps in the sustainable management of solid wastes.

In the study, the layered double hydroxide (LDH) of NiZnFe and its composites with date-palm biochar (LDH-DPb) and carbon nanotubes (LDH-cnt) were synthesized for adsorbing reactive black 5 (RB5) dye from aqueous solutions. In the first 5 min, rapid adsorption was followed by a gradual increase in both dye uptake and removal efficiency of up to 60 min of starting time. In the investigated pH range (3.0–8.0), the removal efficiency linearly decreased while the sorption capacity linearly increased for all three adsorbents as their doses increased to 0.3 or 0.4 g following a decreasing trend up to 0.6 g. By increasing the initial RB5 concentration from 10 to 100 mg L−1, the removal efficiency linearly decreased. A nearly perfect fitting of the pseudo-second-order kinetic model to the adsorption data was observed; however, the Elovich kinetic model showed the heterogeneous surface of adsorbents with chemisorption. At the solid–liquid interface, from a thermodynamics point of view, we obtained the nonspontaneous nature of the adsorption of RB5 dye of the studied adsorbents with an increased disorder, which supported the endothermic nature onto the studied adsorption process. Furthermore, a nearly perfect fitting of the Langmuir model was obtained to the adsorption data, thereby suggesting the monolayer adsorption of RB5 dye onto the studied adsorbents. In the Dubinin–Radushkevich model, a good agreement of the calculated adsorption capacities to the experimental values were observed and the chemical adsorption of RB5 dye on to the studied adsorbents was proposed based on E (8 – 16 kJ mol−1).

In this study, biochar (BC) derived from pomelo was prepared via a high-temperature calcination method to modify the graphitic carbon nitride (g-C3N4) to synthesize the BC/g-C3N4 composite for the degradation of the tetracycline (TC) antibiotic under visible light irradiation. The experimental results exhibit that the optimal feeding weight ratio of biochar/urea is 0.03:1 in BC/g-C3N4 composite could show the best photocatalytic activity with the degradation rate of tetracycline is 83% in 100 min irradiation. The improvement of photocatalytic activity is mainly attributed to the following two points: (i) the strong bonding with π-π stacking between BC and g-C3N4 make the photogenerated electrons of light-excited g-C3N4 transfer to BC, quickly and improve the separation efficiency of carriers; (ii) the introduction of BC reduces the distance for photogenerated electrons to migrate to the surface and increases the specific surface area for providing more active sites. This study provides a sustainable, economical and promising method for the synthesis of photocatalytic materials their application to wastewater treatment.

Far-ranging and improper uses of pharmaceuticals and personal care products (PPCPs) over the last few decades have led to severe water contamination that imposes serious effects on human beings and the ecological system. Therefore, there is an increasing demand for a highly-efficient and environmentally friendly technology for the removal of PPCPs from aqueous solutions. Adsorption technology is an appropriate technology to solve this issue. Carbon-based composites, ranging from modified activated carbon to functionalized biochar, show great potential for this purpose. This review hence elaborates on the environmental occurrences and risks of PPCPs and summarizes the recent progress in removing PPCPs from water using carbon-based adsorbents. The pore structure, relatively large specific surface area (SSA), abundant surface functional groups, highly aromatic structures and the extra excellent characteristics of the cooperative materials contribute to their outstanding adsorption performance. Furthermore, the biochar-clay material is cost effective and more efficient compared to traditional activated carbon regarding the adsorption of PPCPs. Among the emerging adsorbents, graphene and carbon nanotubes composites show superior adsorption ability. Their adsorption mechanisms, such as electrostatic interactions, hydrogen bonding, and pore filling, are discussed in details.

The need to mitigate climate change and improve energy security has led to an increasing interest in the utilisation of renewable gas to decarbonise natural gas use. Northern Ireland serves as an interesting case study to evaluate how biomethane from manure and silage material can displace natural gas. This is because of high agricultural intensity, the low penetration of gas relative to the wider UK and the modern pipeline infrastructure. This study included spatial mapping of biomethane yield and life cycle assessment for processing scenarios. The results demonstrated that current manure management i.e., storage and application of manure to grassland, results in 344 kg CO2 equivalent/person of greenhouse gases and 9.7 kg/person of ammonia being emitted. In a second scenario where collected manure and underutilised grass silage is routed to anaerobic digestion, the estimated net energy produced is 6124 GWh, with −464 kg CO2 equivalent/person. A third scenario, combining anaerobic digestion and pyrolysis, also produces 6124 GWh and 200 kilo tonnes of biochar (retaining 64% of manure phosphorus), −563 kg CO2 equivalent/person. This research evaluates the opportunity for biomethane while acknowledging that a comprehensive approach which balances energy potentials and nutrient management is required for sustainable biomethane based decarbonisation.

High applied thermal-stability and superior structural property for activated carbon adsorbent are extremely promising, which also is the determining short slab in volatile organic compounds (VOCs) adsorption applications. Herein, we develop the outstanding engineering carbon adsorbents from waste shaddock peel which affords greatly-enhanced thermal-stability and super structural property (SLang=4962.6 m2·g−1, Vmicro=1.67 cm3·g−1). Such character endows the obtained adsorbent with ultrahigh adsorption capture performance of VOCs specific to benzene (16.58 mmol·g−1) and toluene (15.50 mmol·g−1), far beyond traditional zeolite and activated carbon even MOFs materials. The structural expression characters were accurately correlated with excellent adsorption efficiency of VOCs by studying synthetic factor-controlling comparative samples. Ulteriorly, adsorption selectivity prediction at different relative humidity was demonstrated through DIH (difference of the isosteric heats), exceedingly highlighting great superiority (nearly sixfold) in selective adsorption of toluene compared to volatile benzene. Our findings provide the possibility for practical industrial application and fabrication of waste biomass-derived outstanding biochar adsorbent in the environmental treatment of threatening VOCs pollutants.

In this work, a modification method of H3PO4 plus H2O2 (PHP) was introduced to targetedly form abundant oxygenated functional groups (OFGs) on biochar, and methylene blue (MB) was employed as a model pollutant for adsorption to reflect the modification performance. Results indicated that parent biochars, especially derived from lower temperatures, substantially underwent oxidative modification by PHP, and OFGs were targetedly produced. Correspondingly, approximately 21.5-fold MB adsorption capacity was achieved by PHP-modified biochar comparing with its parent biochar. To evaluate the compatibility of PHP-modification, coefficient of variation (CV) based on MB adsorption capacity by the biochar from various precursors was calculated, in which the CV of PHP-modified biochars was 0.0038 comparing to 0.64 of the corresponding parent biochars. These results suggested that the PHP method displayed the excellent feedstock compatibility on biochar modification. The maximum MB adsorption capacity was 454.1 mg/g when the H3PO4 and H2O2 fraction in PHP were 65.2% and 7.0%; the modification was further intensified by promoting temperature and duration. Besides, average 94.5% H3PO4 was recovered after 10-batch modification, implying 1.0 kg H3PO4 (85%) in PHP can maximally modify 2.37 kg biochar. Overall, this work offered a novel method to tailor biochar towards OFGs-rich surface for efficient adsorption.

Lignocellulosic biomass can be circulated to produce many materials and products, including biochar. This study analyzed five different types of biochar produced from agricultural wastes. The raw materials included three agricultural by-products: corncob, cassava rhizome, rice husk, and two types of wood residues: rain tree (Samanea saman (Jacq.) Merr.) and krachid (Streblus ilicifolius (Vidal) Corner.). The biochar were made in patented retorts with locally-appropriated technology at a temperature range of 450–500°C. This research focuses on the primary physicochemical properties and biochar components, allowing biochar to become a vital material to support sustainable agriculture and the environment. Biochar properties used for agriculture consist of specific surface area, total pore volume, average pore diameter, pH, electrical conductivity (EC), and cation exchange capacity (CEC). The properties that benefit the environmental purposes are the element: carbon (C), hydrogen (H), nitrogen (N), oxygen (O), and the molar ratio of H/C, O/C, and C/N. The study found that all five types of biochar contained suitable properties for soil amendment and carbon sequestration. However, significant differences were shown in specific surface area, average pore diameter, pH, CEC, and EC of various biochar. Based on O/C and H/C ratios, all five types of biochar persisted in soil from 100 to over 1,000 years.

Herein, the aim was to develop an in-depth understanding of the kinetic behaviour of olive tree pruning residue (OTPR), an abundant agricultural waste, during pyrolysis. Thermal analysis at 1, 2, 4, 6 and 10 °C.min−1 was performed using TGA-thermogravimetric analysis, with the results subsequently used to determine the OTPR's kinetic thermal breakdown behaviour. Furthermore, advanced kinetics and technology solutions (AKTS) thermo-kinetic tool was applied to investigate the kinetic behaviour of OTPR and to generate kinetic predictions for various heating configurations. Friedman's method was the main approach used to evaluate the kinetic parameters. For comparison, other established kinetic modelling techniques, such as ASTM-E698 and Flynn-Wall-Ozawa (FWO) methods, were applied. The ASTM-E698 approach yielded an apparent activation energy (Ea) of 172.09 kJ.mol−1, whereas the FWO method yielded an Ea range from 38 to 172 kJ.mol−1. Finally, the differential iso-conversional approach yielded Ea values ranging between 85 and 191 kJ.mol−1. Kinetic predictions were then developed for isothermal, non-isothermal, and stepwise configurations using the kinetic parameters obtained via Friedman’s model. The forecasts shed light on optimising production throughput in a variety of reactor configurations.

In this study, novel iron-doped biochar (Fe-BC) was produced using a simple method, and it was used as an H2O2 activator for tetracycline (TC) degradation. Generally, iron loading can improve the separation performance and reactivity of biochar (BC). In the Fe-BC/H2O2 system, 92% of the TC was removed within 30 min with the apparent rate constant (kobs) of 0.155 min−1, which was 23.85 times that in the case of the BC/H2O2 system (0.0065 min−1). The effects of the H2O2 and Fe-BC dosage, initial pH, and TC concentration on the TC removal were investigated. The radical quenching and electron paramagnetic resonance (EPR) measurements demonstrated that the removal of TC using the Fe-BC/H2O2 process involved both radical (•OH and O2−•) and non-radical pathways (1O2 and electron transfer). In addition, the performance of the catalyst was also affected by the persistent free radicals (PFRs) and defective sites on the catalyst. Moreover, the degradation pathways of TC were proposed according to the intermediate products detected by LC-MS and the ecotoxicity of intermediates was evaluated. Finally, the Fe-BC/H2O2 showed high resistance to inorganic anions and natural organic matter in aquatic environments. Overall, Fe-BC is expected to be an economic and highly efficient heterogeneous Fenton catalyst for removing the organic contaminants in wastewater.

In rice-producing countries, the abundance of rice residue must be sustainably managed to avoid environmental problems. Moreover, repeated usage of inorganic fertilizers has caused rapid soil deterioration in these arable lands. Converting rice husk residue into rice husk biochar (RHB) and reapplying it back to paddy fields as a soil amendment can be a sustainable approach in rice production. Due to its adsorptive capability, nutrient retention capacity and high silica content, RHB can improve soil fertility and improving the effectiveness of fertilizer when mixed together due to its nutrient retention capacity and high silica content. High silica content in rice husk biochar provides better nutrient retention, turgidity, and structure for plant. The objectives of this review article are to compile studies related to rice husk biochar properties and factors affecting it and application of rice husk biochar in Asian agriculture.

Transforming to biochar provides an environmentally friendly approach for crop residue reutilization, which are usually applied as sorbent for heavy metal removal. As typical silicon-rich material, the specific sorptive mechanisms of rice straw derived biochar (RSBC) are concerned, especially at the low concentration range which is more environmentally relevant. In the present study, Cd sorption onto RSBCs at the concentration of ≤ 5 mg/L was investigated. The sorptive capacity was positively correlated with the pyrolytic temperature of the biochar and the environmental pH value. Water soluble minerals of the RSBCs played the dominant roles in Cd sorption, contributing 29.2%, 62.5% and 82.9% of the total sorption for RSBCs derived under 300°C, 500°C and 700°C, respectively. Increased number of cations, dominantly K+, were exchanged during the sorption. Coprecipitation with cations and carbonates may also be contributive to the sorption. The dissolution of silicon-containing minerals was found to be declined during sorption, suggesting its involvement in the sorption process, possibly through precipitation. Whilst, the sparingly soluble silicate crystals may impose ignorable role in the sorption. Complexation with organic groups is only a minor mechanism in Cd sorption, compared to the much more dominant roles of the inorganic ashes.

Burning lignocellulosic biomass wastes in an outdoor atmosphere has placed heavy burden on ecological environment and increased risk on human health. Converting solid agricultural wastes into functional materials is a research hotspot. In this study, N-doped and CoO-loaded carbocatalyst (CoO-N/BC) was successfully synthesized from the cotton stalk biomass via a simple synthesis process of impregnation and carbonization. Compared with cotton stalk biomass derived pristine biochar, the CoO-N/BC possessed a higher specific surface area (466.631 m2 g-1 vs 286.684 m2 g-1) as well as a better catalytic performance in the activation of peroxymonosulfate (PMS) for CIP degradation. The superior catalytic efficiency was ascribed to the directional flow of electrons on the well-organized carbon network of CoO-N/BC, which accelerated electron migration and improved electron conduction ability. Based on the results of radical quenching experiment and electron paramagnetic resonance (EPR), both radical and non-radical process conjointly led to the stepwise decomposition of CIP, and singlet oxygen (1O2) mediated non-radical pathway was discovered to play a dominant role. Besides, the carbon-bridge mediated non-radical pathway was proved to accelerate this degradation process through the experiments of prolong the time of adding CIP at different time intervals. Nitrogen doped sites and CoO active sites as well as defects formed in sp2-hybridized carbon network were supposed to be the active sites for PMS. Furthermore, EIS and LSV were employed to confirm the electron transfer mediated non-radical process of reaction system. This work provides a modified strategy for the disposition of lignocellulosic biomass wastes and illuminates the underlying mechanism of heterogeneous catalysis by CoO-N/BC.

The adsorption removal of anti-inflammatory drugs from water by diverse materials has drawn great attention. This study investigated the adsorption of sulfamethoxazole (SMX) by two types of materials, UiO-66 and UiO-66-BC composites. Highly porous MOF composites with functional groups were synthesized by combining UiO-66 with corncob-based biochar at different molar ratios. SEM results showed that macroporosity of UiO-66-BC composites was increased by increasing the ratio of biochar. It was found that UiO-66-BC composites displayed highly improved adsorption performance of SMX relative to pristine UiO-66. UiO-66-BC (5%) had the highest SMX adsorption capacity, about 2.4 times those of pristine UiO-66. It was the high surface area of UiO-66 and redundant functional groups of biochar that increased the adsorption performance of composites. Moreover, UiO-66-BC can be reused and displayed the competitive adsorption efficiency after successive adsorption, which made it a potential adsorbent for the removal of SMX from water.

Considerable research efforts have been devoted to increase phosphorus (P) availability during aerobic composting. However, there is little discussion weather the dissolved organic carbon (DOC) controls the transformation among P-fractions. Thus, we investigated the changes in DOC compositions and P-fractions during biochar-amended composting (wet weight basis, 5% and 10%). TP content continuously increased since the ‘concentration effect’ during aerobic composting. NaHCO3-Pi, NaOH-Pi and HCl-Pi were main P-fractions, and biochar can improve P-bioavailability by transforming NaOH-Pi and HCl-Pi into NaHCO3-Pi. Structure equation models (SEMs) indicated that biochar enhanced the P-bioavailability through regulating the decomposition of DOC. Our results at least hint that the activation mechanism on P under the influence of DOC during biochar-amended composting.

This study aimed to investigate the potential of three bioamendments (rice husk biochar, wheat straw biochar, and spent mushroom compost) to enhance microbial degradation of crude oil in saline soil. A soil microcosm experiment was conducted, comparing the response of soil microorganisms to crude oil under saline (1 % NaCl) and non-saline conditions. The soils were amended with different bioamendments at varying concentrations (2.5 % or 5 %), and degradation rates were monitored over a 120-day period at 20 °C. The results showed that the bioamendments significantly influenced the degradation of total petroleum hydrocarbons (TPH) in both non-saline and saline soils by 67 % and 18 % respectively. Non-saline soils exhibited approximately four times higher TPH biodegradation compared to saline soils. Among the bioamendments, rice husk biochar and spent mushroom compost had the greatest impact on biodegradation in saline soil, while wheat straw and rice husk biochar combined with spent mushroom compost showed the most significant effects in non-saline soil. The study also revealed that the bioamendments facilitated changes in the microbial community structure, particularly in the treatments with rice husk biochar and wheat straw biochar. Actinomycetes and fungi were found to be more tolerant to soil salinity, especially in the treatments with rice husk biochar and wheat straw biochar. Additionally, the production of CO2, indicating microbial activity, was highest (56 % and 60 %) in the treatments combining rice husk biochar or wheat straw biochar with spent mushroom compost in non-saline soil, while in saline soil rice husk biochar treatment (50 %) was the highest. Overall, this research demonstrates that the application of bioamendments, particularly rice husk biochar and wheat straw biochar combined with spent mushroom compost, can effectively enhance the biodegradation of crude oil in saline soil. These findings highlight the potential of such bioamendments as green and sustainable solutions for soil pollution, especially in the context of climate change-induced impacts on high-salinity soils, including coastal soils.

The energy transition in agriculture must be accompanied by agronomic practices that shift production towards organic regimes. Among the energy consuming processes that today find resistance in organic conversion there is certainly the removal of weeds from crops, that is mainly carried out through herbicides. This analysis evaluates the economic and environmental implications that the introduction of innovative thermal weeding systems, powered by biomass gasification, can have in the substitution of traditional chemical and mechanical weeding technologies. The comparison is carried out through a combination of cost–benefit analysis, environmental analysis and sensitivity analysis applied to the case study of vineyard management in northern Italy. The results show that the biomass-powered weeding system is economically feasible when it can benefit from economic incentives that reward organic production. In all cases, biomass-powered weeding system provides for a reduction in equivalent CO2 emissions which reaches −75% in the case of replacement of glyphosate-based chemical weeding methods. The analysis points out that gasification-powered weeding process can also achieve carbon neutrality through the co-production of biochar, which should lead policy makers to support this practice under the environmental objectives at national and European level.

To alleviate the salinity and drought stresses faced in agricultural production, and to improve crop water use efficiency (WUE) in drought-prone regions, novel management strategies are needed. The combination of biochar amendment and reduced irrigation regimes could mitigate the negative effects of salinity and drought stresses and improve WUE of cotton plants. A split-root pot trial was performed in order to investigate the effects of two biochar amendments [wheat straw pellets biochar (WSP) and soft wood pellets biochar (SWP)] combinedwith three irrigation schemes [full irrigation (FI), deficit irrigation (DI), and partial root-zone drying irrigation (PRD)] on the growth, physiology and WUE of cotton plants under two salinity levels [0 mM NaCl (S0) and 200 mM NaCl (S1)]. The results showed that salt stress depressed plant growth and physiology, and reduced seed cotton yield and lint yield by 19.33–47.22% and 40.43–58.81%, respectively. However, the biochar amendment alleviated salt stress and increased plant dry biomass allocation ratio by 3.85%–12.54%, 5.07%–14.39% and 9.78%–46.62% in boll, seed cotton and lint cotton under S1, respectively, and also increased lint ginning out turn (GOT), harvest index (HI), WUE at plant and yield level (WUEp and WUEy) by 0.21%–28.69%, 5.07%–14.39%,􀀀 0.30%–15.71% and 5.83%–32.44%, respectively. Moreover, WSP was superior to SWP in terms of improving plant growth and yield. PRD showed better growth and physiological effects than DI, especially WUEp and WUEy were 6.88%–13.73% and 9.16%–22.78% greater under PRD than under DI. The combined application of biochar and PRD counteracted the decrease in WUE caused by biochar application alone under S0. Collectively, WSP combined with PRD could be a promising strategy in sustainable cotton production under drought and salinitystress.

International audience; The present research deals with the global challenge of managing industrial sludge with respect to sustainability and circular economy principles. It focuses on raw industrial sludge (IS-R) conversion into valuable biochars that can serve as efficient adsorbents for pharmaceuticals in industrial wastewater. Three biochars were produced through sludge pyrolysis at 750 degrees C either without modification (IS-R-B), or after pre-treatment with 1 M solution of ZnCl2 (IS-ZnCl2-B) or FeCl3 (IS-FeCl3-B). Compared to the pristine biochar, the modified sludge-derived biochars (SDBs) showed improved structural, textural, and surface chemical properties. As a result, ISZnCl2-B and IS-FeCl3-B had AMX adsorption capacities of 31.9 and 32.1 mg g-1 which were 41.2% and 42.0% higher than the non-modified biochar, respectively. Moreover, both modified SDBs effectively removed AMX under various experimental conditions, including the presence of competitive ions and over a wide pH range. The AMX removal was found to be spontaneous, endothermic, and primarily controlled by chemical reactions on a monolayer system. These findings suggest that biochars generated from pyrolysis of salt-modified industrial sludge can be used as effective materials for removing pharmaceuticals from water. Therefore, this study supports the concepts of circular economy and sustainable development by offering engineering solutions.

Absract Pyrolysis is a promising technology for the treatment of refinery waste activated sludge (rWAS). In this study, attapulgite as a natural clay was used to enhance the pyrolysis of rWAS. The yields, characteristics of pyrolytic products, pyrolytic kinetics and mechanisms were investigated. The attapulgite improved the conversion of rWAS into non-condensable gases and pyrolytic liquids. The bio-oil quality improved and the biochar yield reduced. The average activation energy of Stage I (230–400 °C) and Stage II (400–500 °C) decreased by 36.5% and 49.7%, respectively, compared to rWAS alone. Al2O3 and Fe2O3 in attapulgite enhanced the dealkylation reaction and cracking of C–C bonds. The content of the gasoline (

Technologies that can effectively address the environmental issues arisen from the use of agrochemicals and P fertilizers are needed for the development of green agriculture. Here, we report a new core–shell P-laden biochar/ZnO/g-C3N4 composite (Pbi-ZnO-g-C3N4) used both as an efficient photocatalyst for degrading atrazine and a promising slow-release fertilizer for improving the P utilization efficiency. In comparison with P-laden biochar/ZnO (Pbi-ZnO), Pbi-ZnO-g-C3N4 exhibits enhanced photocatalytic activity with the maximum atrazine degradation efficiency of 85.3% after 260 min. Pbi-ZnO-g-C3N4 also shows superior P slow-release performance with the cumulative P release concentration of 216.40 g/L in 260 min. Besides, it is found that the coating of g-C3N4 on the surface of Pbi-ZnO improves the utilization of visible light and separation of photoinduced electron-hole pairs, producing more radicals (•OH and •O2–) under visible light irradiation. The mechanistic study reveals that Z-shaped heterojunction is formed between ZnO and g-C3N4 in Pbi-ZnO-g-C3N4, and biochar serves as an electron-transfer bridge that promotes the separation of electron-hole pairs. Finally, pot experiments reveal that the P utilization efficiency for pepper seedlings fertilized by Pbi-ZnO-g-C3N4 is higher than that by Pbi-ZnO. The application of Pbi-ZnO-g-C3N4 is beneficial for the growth of native soil microorganism.

Acid mine drainage (AMD) is a multi-factor pollution formed from complex chemical, physical, and biological interactions that takes place under ambient conditions in abandoned and active mines. Over the years, researchers have been investigating ways to mitigate its potential impact on the environment through various treatment technologies. The aim of this review was to critically analyze the broad spectrum of treatment methods that have been engaged in published literature on the remediation of AMDs. Adsorption treatment using zeolites, fly ash, biochar activated carbon, clay-based minerals and biomass-based adsorbents was discussed. Given an appropriate choice of adsorbent, ions in AMD can be reduced between 50% and 99%. Membrane separation processes like nanofiltration, reverse osmosis and hybrid systems were discovered to be more effective than adsorption and can effect over 90% rejection at optimized conditions. Biological processes showed a far wider range of performance amongst all treatment types due to the selectivity in performance of the different micro-organisms used although Advanced Oxidation Process (AOPs) have been shown to achieve>80% ions removal. In all biological processes studied ranging from wetlands to bioreactors, algal bioreactors seemed the most effective in this domain. Most of these treatment technologies are corrective while preventive techniques can be explored to prevent the production of AMD. Despite the positive outcomes of the different types of treatment, they have associated technical issues. It is recommended that more preventive techniques be explored to reduce the production of AMD. The review discussed how AMD treatment would affect environmental protection and water resource management.

Now a days disposal of plastic, rubber and Aluminium are big problem. Burning of agricultural wastes in open field is also gives serious threat to the environment. But they can be converted into useful products like heat, power, oil, gas, and biochar using Pyrolysis process. Many research works have been carried out to convert the harmful materials into useful by products. In this paper, pyrolyser used by various researchers are reviewed under the topics the various raw materials, temperature obtained and application. Some of the modified pyrolysers are also reviewed.

A direct carbon solid oxide fuel cell is a new technology for clean and efficient utilization of carbon resources to generate electricity, with the advantages of high power generation efficiency and wide available fuel flexibility. Biomass, in virtue of large specific surface area, numerous oxygen-containing functional groups which can promote the electrooxidation of carbon, and low ash content which can increase the cell stability, reveals promising feasibility as a fuel for direct carbon fuel cells. Here we report a high-performance direct carbon fuel cell utilizing Chinese parasol leaf biochar as fuel, among which Ag–Gd0.1Ce0.9O2-δ and Al2O3 doped yttria-stabilized zirconia are employed as symmetrical electrodes and electrolyte materials, respectively. The cell with pure leaf biochar fuel gives a maximum power density of 249 mW cm−2 and an open circuit voltage (OCV) of 1.008 V at 850 °C while an improved performance of 272 mW cm−2 and OCV of 1.01 V are achieved for the cell fuelled by Fe catalyst-loaded leaf biochar. The above results demonstrate that Chinese parasol leaf biochar can be applied as a potential fuel for high performance direct carbon solid oxide fuel cells.

Recently, biochar-related phosphate sorbents have been extensively investigated and achieved significant progress; however, there is still much room for enhancement on capturing performance and recovery of powdery ones after sorption. Herein, a new kind of adsorbent, in which biochar/Mg-Al spinel encapsulated in carboxymethyl cellulose-La hydrogels with cationic polymeric layers, was fabricated, aiming for integrating multi-advantages of each component for enhanced phosphate capture. Batch static experiments were correlated to the phosphate adsorption performance of the adsorbent. The maximum phosphate adsorption capacity of the adsorbent was 89.65 mg P/g at pH = 3. The Langmuir isotherm model and the pseudo-second-order kinetic model fitted well with the adsorption behavior of the adsorbent. More importantly, this composite adsorbent that integrated with biochar, Mg-Al spinel, cationic polymeric components exhibited favorable selectivity over coexisting anions (Cl-, SO42-, HCO3– and NO3–) and performed good reusability after five consecutive cycles. By virtue of the bead-like feature, fixed-bed column experiments demonstrated that the Thomas model fitted the breakthrough curves well under varied experimental conditions. The adsorption mechanism of phosphate on the designed composite adsorbent with multi-components could be described as the electrostatic attraction, ligand exchange and inner-sphere complexation, which might account for the efficient phosphate capturing performance.

A significant amount of chlorine, and alkali and alkaline earth metal (AAEM) in food waste has been a major limitation to the utilization of food waste as fuel. The present study aims to investigate the behavior of chlorine and AAEM in food waste biochar during pyrolysis, demineralization, and combustion. Food waste compost (FWC) and food waste feedstock (FWF) were selected as raw materials. Three different pyrolysis temperatures from 300 to 500 °C and two demineralization processes, water and CO2–saturated water, were employed. As the pyrolysis temperature increased, crystallized salt was removed through demineralization, which further increased the heating value. Effective removal of chlorine was demonstrated in both demineralization methods. During demineralization, re-adsorption of Ca on food waste biochar occurred, which was alleviated by CO2-water demineralization. The total amounts of volatilized Cl and AAEM after CO2–water demineralization were reduced by 74.79–99.38% for FWF and 98.34–99.9% for FWC compared to raw biochar. Furthermore, slagging and fouling potentials for all food waste biochar samples were estimated using various indices. The proposed behavior of Cl and AAEM in food waste biochar during various fabrication conditions provides insight into how food waste biochar can be applied in thermos-electric power plant for co-firing with coal.

Recent industrial development and research progress in nanotechnology have led to the release of a number of nanomaterials with particle sizes (1–10 nm) which are categorized as quantum dots (QDs) in aquatic system. Disposal away of such QDs will cause potential pollution to the environment. Therefore, removal of disposed QDs from wastewater represents a challenging research subject for scientists and engineers. Hence, the objective of this study is devoted to assess the process of coagulative removal of silver quantum dots (Ag-QDs), as an example, from water by a novel super magnetic nanocomposite. Such material was aimed to prepare from the chemical combination and reaction of a generated Citrus sinensis and Citrus reticulata peels biochar (SMCsr-B) with spinel cobalt ferrite (CoFe2O4) as a super-magnetic source. The produced (SMCsr-B) was then crosslinked with polyurea-formaldehyde polymer (PUF) using EDA in only two minutes via microwave irradiation to produce (SMCsr-B/PUF). The SEM, EDX, FT-IR, XRD, and XPS analyses of the assembled (SMCsr-B/PUF) nanocomposite were acquired to confirm surface morphology and chemical structure. Controlling experimental factors were investigated as pH, time, and Ag-QDs pollutant concentration using microwave irradiative removal technique to establish the efficiency of coagulative adsorption of Ag-QDs onto (SMCsr-B/PUF). The solution (pH 5) was proved to exhibit the higher removal percentages of Ag-QDs in 15–25 s. SMCsr-B/PUF nanocomposite exhibited high removal efficiency as 93.12%, 92.39% and 92.48% upon using 20, 40 and 60 mg L−1 of Ag-QDs, respectively in presence of 10 mM NaCl. The kinetic and equilibrium adsorption data were best fitted to Freundlich model. The prepared SMCsr-B/PUF was successfully utilized as an efficient super magnetic nanocomposite for removal and recovery of Ag-QDs from aqueous environment.

Nowadays, the harm of antibiotics residues in environments to human health and ecological safety has been causing more and more attention. In this paper, a biochar based iron material (MBC) was used to activate persulfate (PS) for the removal of sulfadiazine (SDZ) from aqueous solution. Experiment results indicate that the degradation and mineralization of SDZ by MBC/PS system reached 91.79 and 60 % within 60 min under the optimal reaction conditions, respectively. MBC/PS system exhibited a better performance on SDZ removal compared with MBC/H2O2 system. The addition of Cu2+ ion could enhance the degradation of SDZ by MBC/PS system. PO43-, Cl- and SO42- had a certain degree of inhibitory effect on the SDZ degradation. Both radicals and non-radical species such as SO4•-, •OH and 1O2 participated in the degradation reaction of SDZ by MBC/PS system, but •OH was the main radical species responsible for SDZ degradation. The liquid chromatograph-mass spectrometer (LC-MS) technique was used to identify the intermediate products of SDZ, and it was proposed that the degradation of SDZ might be achieved through hydrolyzation, hydroxylation, deamination and amino-oxidization processes. A possible reaction mechanism involving a synergistic effect between PS homogeneous and heterogeneous activation processes as well as both radicals and non-radicals reactions was finally proposed.

Superfluous low-frequency microwave radiation becomes a serious problem gradually at current age, herein, the Sn-Fe-O multiphase compounds were combined with novel biochar by using Salvia miltiorrhiza Bunge's leaves as carbon source, which can realize the recycling of this useless Chinese medicinal waste for economy. Also, the influence of preparation process on the final components, structures and properties in composites have been evaluated, the P2 composite possesses the optimal electromagnetic absorbing property i.e. the maximum reflection loss achieves −45.09 dB at 0.48 GHz with efficient absorbing bandwidth of 0.14–1.16 GHz at the matching thickness of 2 mm, moreover, a broad efficient absorbing bandwidth of 0.86–3 GHz can obtained for only 0.71 mm as well. The outstanding absorption of this sample can be ascribed to the synergistic effect of multiple low-frequency absorption mechanisms such as nature resonance, eddy current, conduction and electron hopping, multi-ply interfacial polarization etc., suggesting its superiority for being applied as a new-type low frequency electromagnetic wave absorber for practical use.

Metal-free carbon photocatalysts hold great promise in future visible-light-driven selective photocatalytic organic synthesis. However, designing ideal carbon photocatalysts from sustainable strategies to further improve the photo-efficiency and economic nature is crucial for portable industrial applications. Herein, a clean and economic strategy to fabricate hydrochar microspheres as the first metal-free biochar potocatalysts is reported by a facile hydrothermal post-treatment approach from biowaste. The obtained hydrochars present excellent photocatalytic activity and reusability toward the selective oxidative coupling reactions of various amines under visible-light irradiation. Experimental studies and theoretical calculation revealed that the abundant oxygenated functional groups built-in on the surface could function as photocatalytic active sites. In particular, the diphenolic hydroxyl functional groups and quinone moieties attached to the large π-electronic-system were the main active sites involved in the photocatalytic activity. This research highlights that the utilization of sustainable biowaste-derived hydrochar materials as a low-cost and eco-environmental carbocatalysts, may open up a new avenue for light-driven diverse organic transformations.

A sustainable, easy to operate, scalable, and chemically pre-treatments free method has been explored for rice straw (RS) biomass conversion to furfural, 5-hydroxymethylfurfural (5-HMF), lignin and bio-char production. Initially, the RS was dipped into liquid nitrogen in a thermos flask and grinded easily to fine powder for better handling of biomass under reaction conditions in a reactor. The process also reduces the volume of biomass and enhances the surface area of RS biomass which was further analysed by SEM, TEM, IR, TGA and DSC, and further validated by its fruitful conversion to furfural, 5-HMF, lignin and bio-char synthesis in satisfied yields. The developed acidic process was performed at 130 °C for 6 hrs under a closed reaction system in reflux conditions. The ultra-performance liquid chromatography (UPLC) purity of furfural and 5-HMF was measured to >90% without additional purification technique. Moreover, the method was also examined in 250-gram scale and found to perform well.

Plant growth-promoting rhizobacteria (PGPR) represent an important microbial community group and have beneficial effects on plant growth and development. A pot experiment was conducted to study the effect of biochar applied with PGPR on the soil microbial community composition and nitrogen use efficiency (NUE) of tomato, which could provide a theoretical basis for rational fertilization. Six treatments were designed: no nitrogen (N), PGPR, or biochar control (CK); biochar without N or PGPR (BCK); N without PGPR or biochar (U); N and PGPR without biochar (UP); N and biochar without PGPR (UB); and N, PGPR, and biochar (UBP). The tomato yield in the UP treatment was 9.09% lower than that in the U treatment, whereas that in the UB treatment was 19.93% higher than that in the U treatment. The tomato yield in the UBP treatment was 32.45%, 45.69%, and 10.44% higher than those in the U, UP, and UB treatments, respectively. Biochar combined with PGPR increased the relative abundance of Nitrospira and Bradyrhizobium in the soil. At the tomato maturity stage, the soil NO3–-N content in the UBP treatment was 87.12%, 88.12%, and 31.04% higher than those in the U, UP, and UB treatments, respectively. The NUE in the UP treatment was 4.03% lower than that in the U treatment, and that in the UBP treatment was 13.63%, 17.66%, and 10.77% higher than those in the U, UP, and UB treatments, respectively. This study showed that biochar combined with PGPR can improve soil microbial community structure and increase the NUE of tomato.

The elevated presence of metal(loid)s in the environment significantly impacts ecosystems and human health and is generally largely due to industrial and mining activities. Thus, in the current study, we investigated and proposed an environmentally friendly method (phytomanagement) aimed at reducing the negative impacts associated with metal(loid) pollution through the use of soil amendments (biochar and compost) to permit Ailanthus altissima growth on a highly contaminated mining Technosol, with arsenic (As) and lead (Pb) contents of 539.06 and 11 453 mg kg–1, respectively. The objective was to examine the impacts of three biochars and compost on i) the physicochemical characteristics of soil, ii) metal(loid) immobilization in soil, and iii) A. altissima growth. We revealed that the application of biochar as a soil amendment improved soil conditions by increasing soil electrical conductivity, pH, and water-holding capacity. Moreover, concomitantly, we observed a large reduction (99%) in Pb mobility and availability following application of the hardwood biochar in combination with compost (HBCP). Thus, this combined soil amendment was most effective in promoting A. altissima growth. In addition, the HBCP treatment prevented As translocation in the upper parts of plants, although soil pore water As concentration was not diminished by amendment application.

In this study, a Ni-based sludge coke catalyst was prepared by mechanical ball-milling and mild injection to produce high-quality hydrogen-rich gas through the gasification of sludge. The effects of different factors, such as ball milling time, gasification temperature, NiO loading rate and steam flow rate on the gasification characteristics of the Ni-based sludge coke were investigated. The results showed that the optimum process conditions were the ball-milling time of 10 min, gasification temperature of 900 °C, NiO loading rate of 20% and steam flow rate of 1 g min−1. Under these conditions, the gas production efficiency was improved, with gas and H2 production rates of 0.76 m3 kg−1 and 0.34 m3 kg−1, respectively. Temperature is a key factor of gasification. The gas yield and H2 yield at 900 °C were 38 times and 85 times higher than those at 500 °C, respectively. The FTIR and XRD analysis further revealed that the selection of an appropriate ball-milling time caused the NiO to be evenly distributed on the biochar, thereby improving its catalytic performance. While, increasing the temperature promoted the full pyrolysis of organic matter and the secondary decomposition of tar, which improved the gasification efficiency. The results obtained here allow optimization of the technical parameters for the generation of hydrogen-rich gas by sludge gasification, thereby providing a theoretical basis for the production of high-quality gas through the catalytic gasification of Ni-based biochar.

Acetaminophen (ACT) is an effective and widely available analgesic and antipyretic used in medical practice. It can get into water from veterinary use, medical waste and pharmaceutical effluents. The aim of this review was to elaborate on the recent progress on ACT adsorption from water, present the findings in a structured written report and identify interesting new foundations for further work. ZnAl/biochar had the highest potential of removing ACT and can adsorb more than its weight of the pollutant ( q max > 1000 mg/g). The Langmuir and Freundlich isotherm models and the pseudo-second-order kinetics model were best-fits in most cases (usually at R2 > 0.99 threshold). It was observed that the key mechanisms of ACT uptake are π-π interactions, hydrogen bonds and electrostatic interaction. For most of the adsorbents, a >30% ACT removal efficiency was achievable after the 4 cycles. Effects as salting-out, electrostatic screening, and accumulation of moieties at sorbent-sorbate interfaces due to the competitive adsorption of ions and co-pollutants are profound in the uptake of ACT from aqueous solutions. Future perspectives were discussed in the area of process costing, adsorbent regeneration, mechanistic investigations and fixed-bed column adsorption.