Effects of biochar-based fertilizers on nutrient leaching in a tobacco-planting soil

Biochar is a soil amendment for increasing soil quality and decreasing nutrient leaching. However, there is little information on the impact of biochar-based fertilizer(BF) on soil nutrient leaching in agricultural soils. We conducted a soil column leaching experiment to study the effects of BF on the leaching of total nitrogen(TN), total phosphorus, and total potassium(TK) in tobacco soils. The distribution characteristics of NH_4^+-N, available P, and available K in soil profiles were analyzed after the application of BF. Biochar was prepared by pyrolysis of fluecured tobacco stems. It was applied at four levels, 0%, 3%,9%, and 15%(w/w), respectively, to the compound fertilizer. Compared with the control, the leaching loss of soil TN decreased by 8.36%, 6.72%, and 6.45%, and the loss of soil TK decreased by 9.18%, 9.31% and 11.82% in the 3%,9%, and 15% BF treatments, respectively. However, BF had no significant effect on the P leaching due to the low movement of P in the soil profile. In addition, the BF addition increased the immobilization of NH_4^+-N, available P, and available K in the soil profile. These results indicate that addition of BF to a tobacco-planting soil reduced nutrient leaching, and suggest that BF could be an effective method of applying biochar to agriculture fields.

Biochar-based Solid Acids as Catalysts for Carbohydrate Hydrolysis: A Critical Review

Recently, increasing interest has been focused on the hydrolysis of carbohydrates to monosaccharides, among which, glucose and xylose as typical platform sugars can be used to produce chemicals and biofuels. As heterogeneous catalysts, solid acids have gained extensive attention for biomass biorefinery and could replace the conventional process owing to their excellent properties, including acceptable acidity and easy separation. In particular, biochar-based solid acids derived from biomass are promising for biomass conversion owing to the low-cost of feedstocks and the simple preparation procedure. Herein, we attempt to provide a critical overview of biochar-based solid acids for hydrolysis of carbohydrates into glucose and xylose. The preparation methods and properties of biochar-based catalysts as well as the influence of their properties on catalytic performance were discussed in detail. We also highlight the major challenges facing the use of biochar-based solid acids for carbohydrate hydrolysis.

Effects of Combined Application of Biochar-based Organic Fertilizer and Reduced Nitrogen Fertilizer on Soil Enzyme Activity and Yield of Purple Cabbage(Brassica oleracea var.capita rubra)in Yuanmou County

[Objectives]In response to the issue of soil improvement in Yuanmou County,the effects of combined application of biochar-based organic fertilizer and reduced nitrogen fertilizer on soil nutrients,soil enzyme activity,and yield of purple cabbage(Brassica oleracea var.capita rubra)were investigated in the field base of Institute of Thermal Zone Ecological Agriculture,Yunnan Academy of Agricultural Sciences in Yuanmou County.[Methods]A total of 13 treatments were set up by applying biochar-based organic fertilizer at three levels of 15,30 and 45 t/hm^(2)(T_(1),T_(2),T_(3)),combined with top application of nitrogen fertilizer(urea)at four levels:375(N_1),300(N_(2)),225(N_(3))and 0 kg/hm^(2),with non-fertilizing treatment as control check(CK),in order to explore the optimal ratio for the combined application of biochar-based organic fertilizer with nitrogen fertilizer.[Results]The application of biochar-based organic fertilizer could significantly improve soil nutrients,enzyme activity,and purple cabbage yield.The improvement effect of combined application with nitrogen fertilizer was higher than that of single application of biochar-based organic fertilizer,and the improvement effect was enhanced with the application amount of biochar-based organic fertilizer increasing.The contents of organic matter and total nitrogen were the highest in treatment T_(3)N_(3),of which the values increased by 81.39%and 56.09%compared with the CK,respectively.The contents of soil hydrolyzable nitrogen,available phosphorus,and available potassium were all the highest under treatment T_(3)N_(2),with increases of 92.76%,171.01%and 235.50%,respectively.There was a significant positive correlation between the activity of soil catalase,urease,and sucrase and organic matter,total nitrogen,and available nutrients.The overall soil enzyme activity was relatively higher in treatment T_(3)N_(2).The yield of purple cabbage treated with biochar-based organic fertilizer combined with nitrogen fertilizer could reach 85750 kg/hm^(2),which was 94.78%higher than that treated with biochar-based organic fertilizer alone.Based on comprehensive analysis,the optimal combination ratio was 45 t/hm^(2)of biochar-based organic fertilizer and 300 kg/hm^(2)of urea(T_(3)N_(2)).[Conclusions]This study provides data support for the promotion of biochar-based organic fertilizers and reduced fertilizer in agricultural soil in the Dam area of Yuanmou County.

Research and Application Effects of Biochar-based Fertilizer on Fruit Trees

Biochar and biochar-based fertilizer are effective ways to realize the resource utilization of agricultural and forestry wastes.Because of its soil improvement,yield increase,quality improvement and significant environmental effects,it has become a research hotspot,and its application in agriculture has also increased.In this paper,the preparation,types,application methods and effects of biochar-based fertilizer on fruit trees were summarized.Finally,this paper discussed the application prospects of biochar-based fertilizer on fruit trees.

Review of organic and inorganic pollutants removal by biochar and biochar-based composites

Biochar(BC)has exhibited a great potential to remove water contaminants due to its wide availability of raw materials,high surface area,developed pore structure,and low cost.However,the application of BC for water remediation has many limita-tions.Driven by the intense desire of overcoming unfavorable factors,a growing number of researchers have carried out to produce BC-based composite materials,which not only improved the physicochemical properties of BC,but also obtained a new composite material which combined the advantages of BC and other materials.This article reviewed previous researches on BC and BC-based composite materials,and discussed in terms of the preparation methods,the physicochemical properties,the performance of contaminant removal,and underlying adsorption mechanisms.Then the recent research progress in the removal of inorganic and organic contaminants by BC and BC-based materials was also systematically reviewed.Although BC-based composite materials have shown high performance in inorganic or organic pollutants removal,the potential risks(such as stability and biological toxicity)still need to be noticed and further study.At the end of this review,future prospects for the synthesis and application of BC and BC-based materials were proposed.This review will help the new researchers systematically understand the research progress of BC and BC-based composite materials in environmental remediation.

Advances in preparation,application in contaminant removal,and environmental risks of biochar-based catalysts:a review

As a carbon-rich material produced by pyrolysis of biomass,biochar features low cost,large specific surface area,and widely available feedstocks based on the functional diversity and environmental-friendly properties,it has received increasing attention in the fields of pollutant removal due to three win-win effects of water remediation,carbon sequestration and reutilization of wastes.To design excellent biochar-based catalysts for environmental applications,one must understand recent advances in the catalysts for contaminant removal.This review focuses on the current application of biochar-based catalysts in redox systems,Fenton-like systems,sonocatalytic systems and photocatalytic systems.Besides in-depth discussion in effects of preparation conditions on physicochemical characteristics of biochars,the review supplements new preparation technologies of biochar and biochar-based catalysts.Most importantly,the advantages/shortcomings,catalysis mechanisms,as well as the pollutant removal ability of different types of biochar-based catalysts are discussed.The environmental risks of the catalyst applications are also elaborated on.Future research on biochar-based catalyst production and its environmental applications is discussed.The review provides a good overview of the current advances of biochar-based catalysts in pollutant control and the future research directions.

Biochar-based materials and their applications in removal of organic contaminants from wastewater:state-of-the-art review

As a class of famous carbon materials,biochars(BCs)and their derivative materials with excellent physicochemical properties and diversified functionalities present great potential in wastewater treatment fields.This review focuses on the latest development in reported biochar-based materials as superior adsorbents or catalysts for removing harmful organic contaminants from wastewater.The construction and properties of biochar-based materials are briefly introduced at the beginning.As one of the major factors affecting the properties of BCs,the wide diversity of feedstocks,such as agricultural and forest residues,industrial by-products as well as municipal wastes,endows BCs different chemical compositions and structures.Woody and herbaceous BCs usually have higher carbon contents,larger surface areas and strong aromaticity,which is in favor of the organic contaminant removal.Driven by the desire of more cost-effective materials,several types of biochar-based hybrid materials,such as magnetic BC composites(MBC),nanometal/nanometallic oxides/hydroxide BC composites and layered nanomaterial-coated BCs,as well as physically/chemically activated BCs,have also been developed.With the help of foreign materials,these types of hybrid BCs have excellent capacities to remove a wide range of organic contaminants,including organic dyestuff,phenols and chemical intermediates,as well as pharmaceutically active compounds,from aquatic solutions.Depending on the different types of biochar-based materials,organic contaminants can be removed by different mechanisms,such as physical adsorption,electrostatic interaction,π-πinteraction and Fenton process,as well as photocatalytic degradation.In summary,the low cost,tunable surface chemistry and excellent physical-chemical properties of BCs allow it to be a potential material in organic contaminant removal.The combination of BCs with foreign materials endows BCs more functionalities and broader development opportunities.Considering the urgent demand of practical wastewater treatment,we hope more researches will focus on the applications and commercialization of biochar-based materials.

Application of biochar-based photocatalysts for adsorption-(photo)degradation/reduction of environmental contaminants:mechanism,challenges and perspective

The fast increase of population results in the quick development of industry and agriculture.Large amounts of contaminants such as metal ions and organic contaminants are released into the natural environment,posing a risk to human health and causing environment ecosystem problems.The efficient elimination of contaminants from aqueous solutions,photocatalytic degradation of organic pollutants or the in-situ solidification/immobilization of heavy metal ions in solid phases are the most suitable strategies to decontaminate the pollution.Biochar and biochar-based composites have attracted multidisciplinary interests especially in environmental pollution management because of their porous structures,large amounts of functional groups,high adsorption capacities and photocatalysis performance.In this review,the application of biochar and biochar-based composites as adsorbents and/or catalysts for the adsorption of different contaminants,adsorption-photodegradation of organic pollutants,and adsorption-(photo)reduction of metal ions are summarized,and the mechanism was discussed from advanced spectroscopy analysis and DFT calculation in detail.The doping of metal or metal oxides is the main strategy to narrow the band gap,to increase the generation and separation of photogenerated e−-h+pairs,to produce more superoxide radicals(·O_(2)^(−))and hydroxyl radicals(·OH),to enhance the visible light absorption and to increase photocatalysis performance,which dominate the photocatalytic degradation of organic pollutants and(photo)reduction of high valent metals to low valent metals.The biochar-based composites are environmentally friendly materials,which are promising candidates in environmental pollution cleanup.The challenge and perspective for biochar-based catalysts are provided in the end.

Application of biochar-based materials in environmental remediation:from multi-level structures to specific devices

The development of biochar has triggered a hot-spot in various research fields including agriculture,energy,environment,and materials.Biochar-based materials provide a novel approach against environmental challenging issues.Considering the rapid development of biochar materials,this review serves as a valuable platform to summarize the recent progress on the theoretical investigation and engineering applications of biochar materials in environmental remediation.For a better understanding of the structure-application relationships,the structural properties of biochar from macroscopic and microscopic aspects are summarized.The multilevel structures including elements,phases,surface chemistry,and molecular are highlighted to elucidate the multi-functional properties of biochars.Sorption,catalysis,redox reaction,and biological activity of biochar are briefly illustrated,which influence the transport,transformation,and removal of organic and inorganic pollutants in the environments.According to the multi-level structures and structure-application relationships of biochar,specific biochar-based materials and devices have been designed for practical environmental application.The important progress on the functionalization and device of biochar-based materials,including magnetic biochars,2D and 3D biochar-based macrostructures,immobilized microorganism on biochar,and biochar-amended biofilters are highlighted.The environmental friendliness and sustainability of biochar-based materials,considering the whole cycle from synthesis to application,are evaluated.

Biochar-based materials in environmental pollutant elimination,H_(2) production and CO_(2) capture applications

Biochar and biochar-based materials have been studied extensively in multidisciplinary areas because of their outstanding physicochemical properties.In this review article,biochar and biochar-based materials in the removal of environmental pollutants,hydrogen generation and carbon dioxide capture were summarized and compared.The interaction mechanisms were discussed from the experimental results and characterization analysis.The high porous structures,active surface sites,(co)doping of single metals/nonmetals,and incorporation of metal oxides or other materials improved the high activity of biochar-based materials in their applications.However,there are still some challenges such as:(1)the fact that H_(2) generation with high selectivity or the produced syngas to meet the real application requirement in industrial is the main challenge in H_(2) production;(2)the fact that the selective capture of CO_(2) with high stability,high adsorption capacity and recyclability at low-cost should be considered and focused on;(3)the sorption-(photo)degradation of the organic chemicals;and(4)the fact that the sorption-reduction-extraction/solidification of metals/radionuclides are efficient methods for the elimination of environmental pollutants.In the end,the perspectives,challenges and possible techniques for biochar-based materials’real application in future were described.

Metagenome analysis reveals potential microbial functions in topsoil of wheat-maize rotation system with five-year application of fertilizers

Fertilization mode affects soil quality and ecological health.The effects of four fertilization regimens on lignocellulose content,readily degradable carbohydrate decomposition,and potential microbial functions in the topsoil of a wheat-maize rotation system between 2012 and 2017 were investigated.The fertilization regimens of control(control NFNB),high chemical fertilizer(HCF),high biochar plus low chemical fertilizer(HBLCF),and biochar-based fertilizer(BBF)were compared on soil fundamental properties,microbial structure,and potential function in soil carbohydrate degradation based on metagenome analysis.The diversity of carbohydrate-active enzyme genes in the topsoil microbial consortia in the four trials was primarily distributed within the ten ecologically most dominant phyla.Application of BBF was associated with the lowest decline in total nitrogen and P2O5(2012-2017:6.5%and 28.1%,respectively)and the most effective carbohydrate decomposition(2015-2017:67.0%for cellulose and 59.9%for readily degradable carbohydrate).Carbohydrate transport and metabolism accounted for 6.0%of reads assigned functional classification under the BBF regimen.These findings reveal the ecologically functional diversity of topsoil microorganisms and suggest BBF application as a promising strategy for sustainable agriculture and beneficial to soil health.

Development of the straw biochar returning concept in China

Biochar produced from straw has been shown to improve soil physicochemical properties.This review introduces the fundamental concepts,the broad applications,and underlying theory of straw biochar returning.Current developments in biochar industry and the production practices prevalent among enterprises in China are critiques.This review analyzes current knowledge gaps,challenges,and opportunities in the industrial application of straw biochar returning.Biochar standards,the quantitative and qualitative analysis methods for biochar,and high-value-added products that are based on biochar are critically examined with goal of providing recommendations for future studies.We propose production and modification of biochar that is application oriented to enhance its fitness for purpose as well as long-term and large-space-scale field study to better understand its impact on soil properties and ecotoxicology.Finally,we make prospects for the future development of SBR,including constructing a standard system about straw biochar returning and promoting self-discipline of biochar industry and the establishment of a biochar-based agricultural production model.

Challenges of organic pollutant photocatalysis by biochar‑based catalysts

With the fast development of industrialization and urbanization,large amounts of organic pollutants are released into the natural environment.The efficient elimination of organic pollutants is thereby crucial for environmental pollution treatment and human health.In the last decades,photocatalytic degradation of persistent organic pollutants has attracted multidisciplinary interest because of its simple operation on a large scale.However,the whole processes for the photocatalytic degradation of organic pollutants are still unclear.In this perspective,the contribution of reactive species,the contribution of photocatalysts,the analysis of intermediate products,the charge transfer and fast carrier recombination are discussed on biochar-based photocatalysts.

Facile one-step synthesis of graphitic carbon nitride-modified biochar for the removal of reactive red 120 through adsorption and photocatalytic degradation

Converting waste biomass into value-added biochar has been considered as a green and sustainable strategy for resource management and pollution control.In this study,graphitic carbon nitride(g-C_(3)N_(4))modified biochars(BCs)were produced through one-pot pyrolysis of urea and hickory chips in differential ratios at 520℃.The resulting BC/g-C_(3)N_(4)composites were evaluated in laboratory for their physicochemical,adsorptive,and photocatalytic properties.The characterization tests showed the successful synthesis of the BC/g-C_(3)N_(4)composites that introduced g-C_(3)N_(4)structure,N-containing surface func-tional groups,reduced surface area,and better thermal stability to the biochar.After modification,the BC/g-C_(3)N_(4)composites showed better adsorption ability to reactive red 120(RR120)than the pristine BC,due to the strong electrostatic attrition between N-containing functional groups of g-C_(3)N_(4)on biochar surface and anionic RR120.The BC/g-C_(3)N_(4)composites also inherited g-C_(3)N_(4)’s photocatalytic activity,which is visible light responsive to generate free radicals for RR120 degradation.In addition,the composites with higher urea modification ratios were more effective in the degradation of RR120.Overall,this study demonstrates the feasibility and promising potential of combining biochar and photocatalyst for the removal of aqueous dye.Because of the synergistic adsorption and photodegradation ability,BC/g-C_(3)N_(4)composites present a novel and cost-effective solution for the removal of aqueous dye and other photodegradable contaminants under natural conditions.

Conversion of biochar into sulfonate-bearing solid acids used for the hydrolysis of tylosin:the effect of aromaticity and degree of condensation

In the last few decades,sulfonated carbon materials have garnered significant attention as Brøsted solid acid catalysts.The sulfonation process and catalytic activity of sulfonated biochar can be influenced by the aromaticity and degree of condensation exhibited by biochar.However,the relationships between the aromaticity,sulfonating ability,and resultant catalytic activity are not fully understood.In this study,biochar samples pyrolyzed at 300-650℃ exhibiting different aromaticity and degrees of condensation were sulfonated and employed as sulfonate-bearing solid catalysts for hydrolytically removing tylosin.They exhibited excellent hydrolytic performance and their kinetic constants were positively correlated with the total acidity and negatively correlated with their aromaticity.This study has uncovered the relationship between the structure,properties,sulfonating ability,and subsequent hydrolytic performance of biochar samples.It was observed that the aromaticity of biochar decreased as the pyrolysis temperature increased.Lower pyrolysis temperatures resulted in a reduced degree of condensation,smaller ring size,and an increased number of ring edge sites available for sulfonation,ultimately leading to enhanced catalytic performance.These findings provide valuable insights into the fundamental chemistry behind sulfonation upgrading of biochar,with the aim of developing functional catalysts for mitigating antibiotics in contaminated water.