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Biochar
Number of Followers: 3  Hybrid journal (It can contain Open Access articles)ISSN (Print) 2524-7972 - ISSN (Online) 2524-7867 Published by Springer-Verlag  [2658 journals]
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- Physicochemical properties and morphology of biochars as affected by
feedstock sources and pyrolysis temperatures-
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Abstract: Feedstock sources and pyrolysis temperatures affect the physicochemical and morphological properties of biochars. We evaluated biochars derived from switchgrass (SGB) and poultry litter (PLB) pyrolyzed at 350 °C (SGB350, PLB350) and 700 °C (SGB700, PLB700) to identify their potential ability in improving soil health. Except for SGB350, the pH of biochars was high (> 10.0) and can be used as an amendment in acid soils. PLB700 had higher mineral content and nutrient availability due to its higher ash content (tenfold higher) and electrical conductivity. Surface functional groups responsible for metal retention were evidenced in all biochars. Cation exchange capacity (CEC), specific surface area (SSA), and microporosity more than doubled by increasing pyrolysis temperature from 350 to 700 °C. The pH-buffering capacity measured through acid titration curve was better than that calculated with acid/alkali additions. Biochars pyrolyzed at 700 °C have much higher pH, CEC, SSA, and stronger buffering capacity, and thus are more promising to improve soil health and reduce contaminant bioavailability.
PubDate: 2019-11-18
DOI: 10.1007/s42773-019-00028-z
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- Effects of 7 years of field weathering on biochar recalcitrance and
solubility-
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Abstract: How weathering affects the physiochemical properties of biochar and its long-term carbon (C) sequestration potential remains unclear. In this study, we measured changes in biochar recalcitrance and solubility after 7 years of weathering in a cultivated field. Biochar recalcitrance and biodegradability of weathered and unweathered hardwood biochar mixtures were determined by thermal analysis (differential scanning calorimetry) and evolved gas analysis. Differences in biochar solubility and the chemical composition of biochar-derived dissolved organic carbon (DOC) were determined by repeated laboratory leaching and UV–Vis spectroscopy. The surface carbon-oxidation state (Cox) of biochar increased by 117.6–158.2% with weathering in the field, and there was an average of 0.9–1.2% decrease in biochar C contents per year. However, thermal indices of biochar recalcitrance and biodegradability, which suggested intermediate C sequestration potential, were not significantly different between weathered and unweathered biochars. The O:C ratio increased with weathering suggesting an increase in biodegradability, however, both weathered and unweathered biochars were still estimated to have half-lives of over 1000 years. Water-soluble organic carbon (WSOC) concentrations from the unweathered biochar rapidly decreased during laboratory leaching to levels similar to the field-weathered biochars, and aromaticity (SUVA254) of WSOC increased from 5.9% in the unweathered biochar to 42% aromaticity in the biochars weathered for 7 years. We conclude that during short-term (years) weathering under field conditions, there is continued solubilization of increasingly aromatic biochar-C compounds, however, this accounts for a relatively small proportion of biochar C such that there is little-to-no change in biochar stability or C sequestration potential after field application.
PubDate: 2019-11-15
DOI: 10.1007/s42773-019-00026-1
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- Short-term impacts of biochar and manure application on soil labile carbon
fractions, enzyme activity, and microbial community structure-
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Abstract: Biochar is known to ameliorate soil fertility and increase crop yield; however, information regarding its effects on soil chemical and biological properties remains limited. The experiment was conducted to study the short-term impacts of different types of biochar on soil C fractions, enzyme activities, and microbial community structure at depositional and eroded landscape positions at different sampling times [before planting, after planting, and after harvesting of soybean (Glycine max L.)]. Three biochar materials, produced from C-optimized gasification of corn (maize, Zea mays L.) stover (CS), ponderosa pine (Pinus ponderosa Lawson and C. Lawson) wood residue (PW), and switchgrass (Panicum virgatum L.) (SG), and dairy manure (DM) and mixture of dairy manure and pinewood biochar (DMP), were applied at a rate of 10 Mg ha−1 to depositional and eroded landscape positions. Data showed that the application of DMP and sole application of DM treatments significantly increased the labile C fractions at the depositional and eroded landscapes. The addition of DM and DMP increased the activities of β-glucosidase and urease enzymes, and those are involved in C and nitrogen cycling at depositional and eroded landscape positions. There were no significant differences between different biochar materials. However, there was an increase in soil microbial community structure in the DM and DMP treatments at both the landscape positions. In conclusion, our study revealed that DMP and sole application of DM influenced the soil labile C pool, enzyme activities, and microbial community structure at both the landscape positions for different sampling times.
PubDate: 2019-10-24
DOI: 10.1007/s42773-019-00025-2
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- Biochar insights from laboratory incubations monitoring O 2 consumption
and CO 2 production-
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Abstract: Biochar has been touted as a long-term carbon sequestration tool. However, there are no studies evaluating biochar’s effect on oxygen (O2) consumption as a measure of the microbial respiration response to biochar. To gain insight into this aspect, we evaluated O2 consumption rates to test the hypothesis that biochar is an efficient agent for carbon dioxide (CO2) sequestration in soils. Four different biochar types and one activated charcoal were incubated alone and associated with three different soils for approximately 2 months in laboratory incubations. Headspace concentration of CO2 and O2 was periodically quantified. The data presented here confirm that the CO2 production following biochar’s addition to soils results in a process that is correlated to oxygen consumption. However, this overall stimulation is not clearly related to biochar type. Activated carbon resulted in the highest statistically significant stimulation of activity, despite it possessing the lowest quantity of volatile carbon and mineral nutrient sources. Taking into consideration our results, we conclude that using biochar does achieve total carbon sequestration. However, the amount of available soil organic carbon following soil incorporation appears to be reduced following biochar addition and its long-term implication on this mineralizable soil organic carbon pool does deserve more research attention.
PubDate: 2019-09-10
DOI: 10.1007/s42773-019-00021-6
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- Impacts of chicken manure and peat-derived biochars and inorganic P alone
or in combination on phosphorus fractionation and maize growth in an
acidic ultisol-
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Abstract: The forms of phosphorus (P) in animal manure and peat are different from synthetic P fertilizers and will affect soil P fractions when they are used as P amendments. Effects of chicken manure (CMB) and peat (PB) derived biochars (CMB and PB) alone or in combination with P fertilizer (KH2PO4) and rock phosphate (RP) on plant/soil health and soil P fractions in an acidic ultisol were examined with greenhouse pot experiments. The total P rate was constant at 120 mg kg−1 in all treatments. Soil P fractions, P uptake, and maize growth were determined after 56 days. Application of CMB combined with P fertilizer or alone significantly increased soil pH, water extractable and relatively labile P, dry matter yield of maize, chlorophyll contents in maize leaves, while decreasing the Fe and Al binding P. Moreover, sole application of CMB and PB showed greater effects than application of P fertilizer alone regarding plant growth and P fractionation. Integration of synthetic inorganic P sources with CMB or sole application of CMB is more beneficial than application of inorganic P sources to improve plant growth and P availability.
PubDate: 2019-09-03
DOI: 10.1007/s42773-019-00022-5
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- Exploring the benefits of biochar over other organic amendments for
reducing of metal toxicity in Withania somnifera-
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Abstract: Biochar is considered as a good metal sequester and ameliorates the metal toxicity and uptake in plants. However, its effectiveness over other organic amendments is not well discussed. The aim of this study is to compare the biochar amendments alleviating the levels of Pb and Cd in Withania somnifera L. Dunal with other organic manure. Farmyard manure, vermicompost, and biochar were applied in the field spiked with highly available Pb and Cd. Metal bioavailability and accumulation, plant growth and plant physiology, antioxidant enzymes and metabolite content of W. somnifera along with soil properties were evaluated in all treatments. Study indicates that the application of organic manures significantly alleviated the metal levels (33–72%) in the plant in comparison with control. The herbage yield was significantly higher (33–69%) under different organic manures as compared to the metal treatments. Secondary metabolite contents and antioxidant enzymes were higher in metal treatments in comparison with control. Organic manures were not only able to restrain the Pb and Cd in soil but also enhanced the soil microbial activities. Results indicate that biochar amendments were more promising than farmyard manure and vermicompost due to the presence of more stable carbon in biochar and more alleviation in metal uptake. In addition, net profit in the cultivation of W. somnifera was higher for biochar amendments (50% higher) compared to control. The study recommended that biochar could be a better option for commercial and safer production of W. somnifera. Graphic abstract
PubDate: 2019-08-31
DOI: 10.1007/s42773-019-00023-4
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- Fertilizer and soil conditioner value of broiler manure biochars
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Abstract: Pyrolysis is an option for enhancing the sustainable management of broiler manure surpluses by producing a concentrated, hygienic char product with a fertilizer and soil conditioner value. In this study, the impacts of pyrolysis conducted at 350, 400 and 450 °C on total nutrient and harmful element concentrations in biochars derived from peat-bedded broiler manure were examined. Emphasis was placed on the availability of phosphorus (P). In addition, the pore structures of these biochars were explored using X-ray microtomography and image analysis. During pyrolysis, 35–50%, 40–55% and 35–45% of the original carbon, nitrogen and sulfur contents, respectively, of the feedstock biomass were lost as volatiles. Mineral elements, including P, were concentrated in the biochar. Although water-extractable P was found to be converted to less labile forms due to charring, the concentration effect and notable increase in sodium bicarbonate-extractable P rendered broiler manure biochars richer in total labile P in comparison with feedstock manure (7.1, 10.0, 11.1 and 14.8 g labile P kg−1 in feedstock and biochars produced at 350, 400 and 450 °C, respectively). The pore volume of the micrometer-scale porosity of the broiler manure biochar was comparable to that found earlier in wood-based biochars. In comparison with wood-based biochars, the pore structure of broiler manure biochars was more versatile, and the pore size distribution was wider. Consequently, part of the porosity was too large to store plant-available water, which may reduce the potential of broiler manure biochars to improve soil water storage capacity.
PubDate: 2019-08-27
DOI: 10.1007/s42773-019-00020-7
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- Biochar-induced changes in metal mobility and uptake by perennial plants
in a ferralsol of Brazil’s Atlantic forest-
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Abstract: Despite an abundance of short-term studies focusing on biochar’s effects on annual plants, the long-term effects of biochar on perennial plants and the effects of the biochar on the mobility and speciation changes of metals/metalloids not limited to main plant nutrients in soils are poorly constrained. This study reports on the amelioration a sloped orthic ferralsol by biochar from Tibouchina wood and the resulting effects on perennial crops and microbiota, including a comprehensive analysis of metals/metalloids speciation changes. Fields were amended with biochar and urine-amended biochar (2 kg/m2) and were planted with papaya, banana, and manioc. Soil and plant materials were analyzed using acid digestions, sequential extractions, and 16S rRNA gene sequencing. Biochar applications led to decreased soil acidity, shifted the cation exchange capacity from being Al-influenced to being Mg/K/Ca-dominated, and elevated the concentrations of Mg, K, Ca, Zn, and Ba in soils. The exchangeable/acid-soluble fraction of Ca, P, and S notably increased. The soil microbial biome became more species rich and diverse in the biochar-amended fields. Manioc benefited from biochar applications, demonstrating increased growth, which resulted in generally decreased concentrations of trace elements in most plant parts, however, with an increased total elemental uptake. Urine amendment contributed to higher concentrations of P, S, and K in soils, but did not further increase plant growth. Biochar was shown to be a promising soil amendment for agricultural use of orthic ferralsols of the Brazil’s Atlantic forest region, but the accumulation of potentially harmful metals needs to be considered.
PubDate: 2019-07-12
DOI: 10.1007/s42773-019-00018-1
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- Impact of sole and combined application of biochar, organic and chemical
fertilizers on wheat crop yield and water productivity in a dry tropical
agro-ecosystem-
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Abstract: Agriculture under changing climate scenario is facing major challenges of water scarcity and resource imbalances. Crop water productivity (WP) may act as an indicator of crop responses to water limitation. Organic amendments such as biochar and manure application to soil are suggested for improving soil quality and reducing water requirements from agricultural sector. However, studies exploring the impact of biochar as sole or in combination with organic and/or chemical fertilizers on WP in dry tropical agro-ecosystems are limited. In this study, we observed the effect of rice-husk ash (RHA, biochar) along with farm-yard manure (FYM) and chemical fertilizers (CF) under varying water conditions on soil hydro-physical properties, yield and WP of wheat crop. Water-filled pore space (WFPS), grain and straw yield, irrigation and total water productivity varied significantly (at P < 0.001) at treatment level. Grain and straw yield were found higher under sole and combined CF applied treatments. Sole and combined RHA and FYM amendment improved water holding capacity (WHC) and WFPS, whereas a decrease in crop yield was observed as compared to the control. Irrigation and total water productivity were found higher under combined RHA + FYM and sole CF treatments with reduced water supply (except sole CF) as compared to control and sole RHA treatments with full water irrigation. Crop water productivity was found positively correlated with grain and straw yields, however, significant correlations were not observed with WHC and WFPS. Results indicate that increasing soil hydro-physical properties in silty-loam soil may hinder crop yield and WP under sole biochar applied soils. Overall, the implications of the study would help in devising agro-management practices based on combined application of RHA and FYM with reduced chemical fertilizer and water inputs to mitigate the impacts of climate change without compromising crop yield in the highly vulnerable dry tropical agro-ecosystem of India. Moreover, long-term studies are needed in these ecosystems to identify the appropriate agricultural package for mitigating the forthcoming water scarcity conditions.
PubDate: 2019-06-01
DOI: 10.1007/s42773-019-00013-6
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- Short-term effects of maize residue biochar on kinetic and thermodynamic
parameters of soil β-glucosidase-
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Abstract: Soil β-glucosidase (BG), the rate-limiting enzyme in the final step of cellulose hydrolysis, plays a key role in microbial metabolism, carbon (C) cycling and sequestration in terrestrial ecosystems. Biochar application is known to affect soil BG activity; however, most of the biochar studies have focused on the potential activity of BG, and it is not clear how biochar influences the kinetic and thermodynamic behavior of BG in the soil. The objective of this study was to investigate the effect of maize residue biochar on soil BG kinetic and thermodynamic parameters. Soil BG kinetic (Vmax and Km) and thermodynamic (Ea, ΔHa and Q10) parameters were determined within soils (clayey and sandy loam soils) amended with either maize residue (as positive control) or its biochar (600 °C) at 0.5 and 1.0% ratios (w/w), and the mixtures were incubated for 90 days. BG showed an increase in potential enzymatic activity (81%), enzyme concentration (higher Vmax value) (25%) and substrate affinity (lower Km value) (32%) in the biochar-amended sandy loam soil only at high addition rates compared with the control, and an increase by about 86% of the catalytic efficiency (Vmax/Km). In the clayey soil, biochar addition decreased potential BG activity (by 10–29%), increased the Vmax value (by 20–25%) and had no impact on enzyme–substrate binding affinity, but still increased the catalytic efficiency by 47–72%. Adsorption of soil BG by biochar particles did not affect the catalytic efficiency in the soil. Generally, application of maize residue biochar to the soil decreased the Ea, ΔHa and Q10 values of BG compared with the negative controls at both biochar rates in the light-textured soil and only at low biochar rate in heavy-textured soil. The direction and magnitude of BG responses (activity, kinetics, and thermodynamics) to biochar were more related to the soil characteristics. Biochar would increase soil BG thermal stability and decrease its sensitivity to increasing temperature and global warming.
PubDate: 2019-06-01
DOI: 10.1007/s42773-019-00016-3
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- A 2-year study on the effect of biochar on methane and nitrous oxide
emissions in an intensive rice–wheat cropping system-
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Abstract: The impacts of biochar addition with nitrogen fertilizer (Urea-N) on greenhouse gas (GHG) fluxes and grain yields are not comprehensively understood. Therefore, we designed a field experiment in an intensive rice–wheat cropping system located in the Taihu Lake region of China and measured CH4 and N2O emissions for 2 consecutive years to examine the impacts of biochar combined with N-fertilizer on rice production and GHG flux. Three field experimental treatments were designed: (1) no N-fertilizer application (N0); (2) 270 kg N ha−1 application (N270); and (3) 270 kg N-fertilizer ha−1 plus 25 t ha−1 biochar application (N270 + C). We found that, compared with urea application alone, biochar applied with Urea-N fertilizer increased N use efficiency (NUE) and resulted in more stable growth of rice yield. In addition, biochar addition increased CH4 emissions by 0.5–37.5% on average during the two consecutive rice-growing seasons, and decreased N2O–N loss by ~ 16.7%. During the first growing season, biochar addition did not significantly affect the global warming potential (GWPt) or the greenhouse gas intensity (GHGI) of rice production (p > 0.05). By contrast, during the second rice-growing season, biochar application significantly increased GWPt and GHGI by 28.9% and 18.8%, respectively, mainly because of increased CH4 emissions. Our results suggest that biochar amendment could improve grain yields and NUE, and increased soil GWPt, resulting in a higher potential environmental cost, but that biochar additions enhance exogenous carbon sequestration by the soil, which could offset the increases in GHG emissions.
PubDate: 2019-06-01
DOI: 10.1007/s42773-019-00011-8
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- Development of the straw biochar returning concept in China
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Abstract: 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.
PubDate: 2019-06-01
DOI: 10.1007/s42773-019-00019-0
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- Biochar colloids and their use in contaminants removal
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Abstract: In this study, we report on the extraction, characterization, and potential applications of colloidal biochar derived from pyrolyzed wood—an untapped source of carbonaceous particles. A series of characterizations was performed on biochar colloids to unravel their colloidal properties and surface chemistry through which it was found that they have a net negative charge and are stable between pH 3 and 10. Moreover, our initial toxicity tests showed that biochar colloids themselves are not toxic and they can be used in remediation applications, which led us to investigate (1) their copper sorption, a model inorganic contaminant, in a scenario that biochar colloids are released into the environment and (2) their potential use in organic pollutants adsorption and degradation. Copper sorption studies showed that biochar colloids have a copper sorption capacity as high as 22 mg \(\hbox {g}^{-1}\) in sub-ppm copper solutions. This increased the acute 48 h lethal concentration ( \(\hbox {LC}_{50}\) ) of copper for Daphnia magna by 21 ppb, which is comparable to the previously reported effect by dissolved organic matter. Adsorption and degradation of methylene blue (MB), an often-used proxy for organic contaminants in water, were studied by coupling the biochar colloids to positively charged \(\hbox {TiO}_{2}\) nanoparticles and using it as a photocatalyst. The hybrid MB photodegradation efficiency was \(21\%\) higher than that of \(\hbox {TiO}_{2}\) nanoparticles alone. Enhancement of demethylation is proposed as the main degradation mechanism of MB, as confirmed by liquid chromatography–mass spectroscopy (LC/MS), and the positive impact of biochar colloids is ascribed to their abundant adsorption sites, which may facilitate MB adsorption and its photocatalytic degradation.
PubDate: 2019-06-01
DOI: 10.1007/s42773-019-00014-5
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- Effects of biochar amendment and nitrogen fertilization on soil microbial
biomass pools in an Alfisol under rain-fed rice cultivation-
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Abstract: Field studies were conducted over 2 years to determine the response of soil microbial biomass pool to biochar and N fertilizer combinations in a rain-fed rice cropping system. Biochar was applied at four doses: 0 t ha−1, 3 t ha−1, 6 t ha−1 and 12 t ha−1 in combination with N fertilizer at four rates: 0 kg ha−1, 30 kg ha−1, 60 kg ha−1 and 90 kg ha−1 to a Typic Paleustalf Alfisol. Soil samples from two depths (0–10 and 10–20 cm) were collected to determine microbial biomass C (MBC), N (MBN), P (MBP), MBC/N ratio, MBC/P ratio, soil CO2 flux, microbial qCO2, cultivable bacterial and fungal abundance. Biochar and N fertilizer combination effects on MBC, MBN and MBP pools were dependent on biochar doses, N fertilizer rates and soil depth. MBC/N and MBC/P ratios were decreased after 2 years. Soil CO2 flux was maximum at post-seeding stage of rice plant, while decreasing trends occurred at active tillering and harvest stage. Increasing doses of biochar irrespective of its combination with N fertilizer rates decreased CO2 flux and microbial qCO2. Combinations of biochar and N fertilizer increased fungal/bacterial ratio and induced a shift to a more fungal-dominated population after 2 years. Our results suggest that combination of biochar doses (3–12 t ha−1) with N fertilizer rates had stimulatory effects on microbial biomass pools and activity with positive implications for organic carbon accumulation, nitrogen (N) and phosphorus (P) retention in tropical soils.
PubDate: 2019-06-01
DOI: 10.1007/s42773-019-00017-2
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- Effect of biochar fertilizers on amino acid variability of Secale cereale
and Lupinus angustifolius-
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Abstract: Little is known on the effects of biochar on N uptake and amino acid variability in crops such as winter rye and narrow-leafed lupine despite the fact that amino acids are important indicators, for food quality and plant stress. N uptake of both crops showed contrasting results when treated with different biochar fertilizers. Total amino acid contents referred to total nitrogen generally tend to decrease in rye grains in the presence of biochar; whereas lupine seeds were more or less unaffected by biochar combined with mineral fertilizer or compost. In lupine seeds, total amino acid contents significantly increased when biochar was mixed with digestate but decreased when mixed with fermented digestate. Lysine, one of the most limiting amino acids in cereals, reached the recommended value of 4 g kg−1 in rye grain for most biochar fertilizers. In lupine seeds, lysine decreased when biochar had been applied but were still in the recommended range when used as animal feed. Proline, an indicator for plant stress, significantly decreased (− 49%) in rye when 2 Mg biochar ha−1 was added in combination with mineral fertilizer. In contrast, proline increased when biochar was added to organic (digestate and compost) fertilizers (up to 43%). Further biochar research should focus much more on food quality, which is a key challenge for global food production.
PubDate: 2019-06-01
DOI: 10.1007/s42773-019-00012-7
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- The applicability of biochar and zero-valent iron for the mitigation of
arsenic and cadmium contamination in an alkaline paddy soil-
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Abstract: In paddy fields, the opposing transformation of arsenic (As) and cadmium (Cd) poses many challenges for their simultaneous remediation. In our previous study, we reported that combined biochar and zero-valent iron (ZVI) amendment had great potential for the simultaneous alleviation of As and Cd bioavailability in contaminated acid paddy soil. In this study, an As- and Cd-contaminated alkaline paddy soil was further studied, and the same ZVI–biochar mixtures amendments were applied to evaluate the impact of the mixtures on As and Cd transformation and translocation in the soil–rice system by performing pot experiments with rice. In line with our previous study, the ZVI–biochar composites significantly reduced As and Cd accumulation in different rice tissues, leading to a 42% and 47% decrease in rice grain As and Cd levels, respectively, compared with the control values. The ZVI–biochar mixtures exhibited synergistic effects of biochar and ZVI by enhancing the transformation of bioavailable As and Cd fractions into less bioavailable fractions, and by increasing iron plaque formation to reduce As and Cd bioavailability. Although the bioaccumulation and translocation factors of As and Cd in alkaline paddy soil were generally lower than those in acid paddy soil, particularly in the presence of the ZVI–biochar mixtures, the grain As and Cd levels did not achieve the desired food safety standard levels, probably related to the high soil As content and the small changes in soil pH. Nevertheless, for treating lightly and moderately contaminated paddy soils, ZVI–biochar mixtures can still be a good choice in the future.
PubDate: 2019-06-01
DOI: 10.1007/s42773-019-00015-4
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- Inaugural editorial: pioneering the innovation and exploring the future
for biochar technology-
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PubDate: 2019-03-01
DOI: 10.1007/s42773-019-00010-9
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- Synergistic effects of biochar/microbial inoculation on the enhancement of
pig manure composting-
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Abstract: With the aim to comparatively investigate the effect of the addition of additives such as biochar (BC), microbial inoculation (MI) and biochar/microbial inoculation (BCMI) on composting enhancement, nitrogen conservation, greenhouse gas emissions, the quality improvement of pig manure compost were comparatively investigated in a 42-day aerobic pig manure composting experiment. The results showed that the duration of the thermophilic stage, the degradation of organic matter and the detoxification of the compost were enhanced in the BC, MI and BCMI treatments compared with those in the control (without additive). Moreover, the content of total Kjeldahl nitrogen in the BC, MI and BCMI treatments was increased by 38.1, 48.9 and 59.0%, respectively, through the reduction of NH3 volatilization and N2O production, which were higher than those of the control (31.8%). A reduction in CH4 release during composting was not observed with the MI and BCMI treatments. Following 42 days of composting, the final product of the three treatments exhibited acceptable potential for use as a fertilizer in agriculture; the BCMI treatment showed an especially synergistic effect on pig manure composting enhancement. Graphical
PubDate: 2019-03-01
DOI: 10.1007/s42773-019-00003-8
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- Biochar-based materials and their applications in removal of organic
contaminants from wastewater: state-of-the-art review-
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Abstract: 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–π interaction 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.
PubDate: 2019-03-01
DOI: 10.1007/s42773-019-00006-5
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- Response of microbial communities to biochar-amended soils: a critical
review-
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Abstract: Application of biochar to soils changes soil physicochemical properties and stimulates the activities of soil microorganisms that influence soil quality and plant performance. Studying the response of soil microbial communities to biochar amendments is important for better understanding interactions of biochar with soil, as well as plants. However, the effect of biochar on soil microorganisms has received less attention than its influences on soil physicochemical properties. In this review, the following key questions are discussed: (i) how does biochar affect soil microbial activities, in particular soil carbon (C) mineralization, nutrient cycling, and enzyme activities' (ii) how do microorganisms respond to biochar amendment in contaminated soils' and (iii) what is the role of biochar as a growth promoter for soil microorganisms' Many studies have demonstrated that biochar-soil application enhances the soil microbial biomass with substantial changes in microbial community composition. Biochar amendment changes microbial habitats, directly or indirectly affects microbial metabolic activities, and modifies the soil microbial community in terms of their diversity and abundance. However, chemical properties of biochar, (especially pH and nutrient content), and physical properties such as pore size, pore volume, and specific surface area play significant roles in determining the efficacy of biochar on microbial performance as biochar provides suitable habitats for microorganisms. The mode of action of biochar leading to stimulation of microbial activities is complex and is influenced by the nature of biochar as well as soil conditions.
PubDate: 2019-03-01
DOI: 10.1007/s42773-019-00009-2
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