Ciprofloxacin, a second-generation synthetic fluoroquinolone derivative widely used in human and veterinary medicines, has the potential to pose a serious risk to aquatic organisms and humans. The ...current research investigated the removal of ciprofloxacin using biochar treated with clay mineral and subsequently activated with carbon dioxide (CO2) produced at two different pyrolysis temperatures (350 and 650 °C). Batch adsorption experiments were carried out to assess the removal efficiency of ciprofloxacin by as-synthesized materials. The effects of various factors, such as pH, contact time, adsorbent dose, initial ciprofloxacin concentration, and temperature were studied during the removal process. The physicochemical characterization results verified the successful loading of clay minerals on biochar. Non-linear adsorption models were employed to understand the nature of adsorption processes however, the Pseudo-second-order kinetic and Freudlich and Redlich Peterson isotherm models best fitted with the adsorption data. These findings indicated that the adsorption did not follow an ideal monolayer adsorption suggesting hybrid chemical adsorption process that was spontaneous and endothermic. The maximum adsorption (50.32 mg g−1) of ciprofloxacin was achieved by CO2 activated biochar-clay mineral composite prepared at 350 °C, and was almost two times higher than the pristine biochar at neutral pH and 40 °C. The possible proposed mechanisms involved for the removal of ciprofloxacin were electrostatic attraction, cation exchange, pore-filling effect, and π-π interactions. Our findings demonstrate that application of CO2 activated biochar-clay mineral composite is a promising technique for efficient removal of ciprofloxacin from aqueous solution.
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•CO2 activated biochar-clay mineral composites were synthesized and characterized.•Removal of ciprofloxacin was studied by as-synthesized materials.•Pseudo-second-order, Freundlich and Redlich-Peterson models were best fitted.•AMBC-350 exhibited maximum adsorption capacity (50.32 mg g−1).•Possible adsorption mechanisms were proposed by data modelling.
Rapid industrial development and human activities have caused a degradation of soil quality and fertility. There is increasing interest in rehabilitating low fertility soils to improve crop yield and ...sustainability. Biochar, a carbonaceous material intentionally produced from biomass, is widely used as an amendment to improve soil fertility by retaining nutrients and, potentially, enhancing nutrient bioavailability. But, biochar is not a simple carbon material with uniform properties, so appropriate biochar selection must consider soil type and target crop. In this respect, many recent studies have evaluated several modification methods to maximize the effectiveness of biochar such as optimizing the pyrolysis process, mixing with other soil amendments, composting with other additives, activating by physicochemical processes, and coating with other organic materials. However, the economic feasibility of biochar application cannot be neglected. Strategies for reducing biochar losses and its application costs, and increasing its use efficiency need to be developed. This review synthesized current understanding and introduces holistic and practical approaches for biochar application to low fertility soils, with consideration of economic aspects.
•Biochar has potential to be the best management practice for low fertility soils.•Biochar coating with organic materials can result in enhanced crop nutrient supply.•Biochar may accelerate the composting process and improve the end-product quality.•The influence of biochar varies strongly according to the types of feedstock/soil.
Returning biochar to fields: A review Tan, Zhongxin; Lin, Carol S.K.; Ji, Xiaoyan ...
Applied soil ecology : a section of Agriculture, ecosystems & environment,
08/2017, Volume:
116
Journal Article
Peer reviewed
•There is a disconnect between biochar preparation and its returning.•Return biochar from directional function for soil to directional preparation.•Returning biochar can improve the soil physical and ...chemical properties.•Returning biochar can improve the activity of soil microbes.•Returning biochar can reduce the emission of greenhouse gas.
Biochar generated from thermochemical conversion of biomass reduces greenhouse gas emissions and is useful for improving ecological systems in agriculture. However, certain biochars function well in improving soil, and other biochars do not. Why? Because it is not clear how to prepare the best biochar for soil. There is a disconnect between biochar preparation and returning the biochar to the soil. To elucidate this relationship, this paper reviews (i) technologies for preparing biochar, (ii) how preparation conditions affect biochar properties, and (iii) the effects on soil physical and chemical properties. In addition to reducing greenhouse gas emissions, biochar improves the physicochemical and microbial properties of soil and absorbs poisonous and pernicious substances. Therefore, as biochar is produced by pyrolysis, optimizing processing conditions to improve its properties for agricultural use is a key issue explored in this article.
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 limitations. 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.
Antibiotics have been used in massive quantities for human and animal medical treatment, and antibiotic resistance genes (ARGs) are of great concern worldwide. Antibiotics and ARGs are exposed to the ...natural environment through the discharge of medical wastewater, causing great harm to the environment and human health. Biochar has been widely used as a green and efficient adsorbent to remove pollutants. However, pristine and unmodified biochars are not considered sufficient and efficient to cope with the current serious water pollution. Therefore, researchers have chosen to improve the adsorption capacity of biochar through different modification methods. To have a better understanding of the application of modified biochar, this review summarizes the biochar modification methods and their performance, particularly, molecular imprinting and biochar aging are outlined as new modification methods, influencing factors of biochar and modified biochar in adsorption of antibiotics and ARGs and adsorption mechanisms, wherein adsorption mechanism of ARGs on biochar is found to be different than that of antibiotics. After that, the directions of biochar and modified biochar worthy of research and the issues that need attention are proposed. It can be noted that under the current dual carbon policy, biochar may have wider application prospects in future.
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•Adsorption performances of biochar for antibiotics and ARGs are summarized.•Adsorption mechanisms of antibiotics and ARGs by biochar are proposed.•Influencing factors of antibiotics and ARGs adsorption by biochar are discussed.•Challenges in the removal of antibiotics and ARGs by biochar are elaborated.
Production and utilization of biochar: A review Cha, Jin Sun; Park, Sung Hoon; Jung, Sang-Chul ...
Journal of industrial and engineering chemistry (Seoul, Korea),
08/2016, Volume:
40
Journal Article
Peer reviewed
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Biochar produced during the thermochemical decomposition of biomass not only reduces the amount of carbon emitted into the atmosphere, but it is also an environment-friendly ...replacement for activated carbon and other carbon materials. In this review paper, researches on biochar are discussed in terms of production method and application. Different processes for biochar production, such as pyrolysis, gasification, hydrothermal carbonization, etc., are compared. Physical and chemical activation methods used to improve the physicochemical properties of biochar and their effects are also compared. Various environmental application fields of biochar including adsorption (for water pollutants and for air pollutants), catalysis (for syngas upgrading, for biodiesel production, and for air pollutant treatment), and soil conditioning are discussed. Recent research trend of biochar in other applications, such as fuel cell, supercapacitor, and hydrogen storage, is also reviewed.
•Biochar of ≤0.5 and 0.5–1mm sizes were applied to soil.•Migration rate to deeper soil was higher for finer biochar but limited to few cm.•Biochar downward migration was higher in sandy loam with ...lower Ksat than in loamy sand.•55–76% of applied biochar was recovered in soil leaving 24–45% unaccounted.•The unaccounted for biochar was transported away by erosion.
Field experiments were conducted in Arenosols (loamy fine sand) and Acrisols (sandy loam) in Zambia to quantify vertical and lateral transport of biochar (BC) using the BC and soil 13C isotope signatures and total organic carbon contents. There were three experimental treatments composing of no BC, ≤0.5 and 0.5–1mm BCs each with three replicates arranged in completely randomized design. The applied BCs were made from rice husk, except 0.5–1mm BC in sandy loam, which was from maize cob. One year after mixing BC homogeneously in the 0–5cm surface layer, soil down to 20cm depth was sampled. The downward migration of BC was significant down to 8cm depth in sandy loam and down to 6cm in loamy fine sand. Below these depths, there was no significant difference in BC amounts between the BC amended and the reference plots. There was a general tendency for greater downward migration for the ≤0.5mm than for 0.5–1mm BC. Total BC recovery at 0–5cm depth in the BC-treated soils amounted to 45–66% of the total applied amount of BC. As only 10–20% was recovered in the deeper soil layers, 24–45% of the applied BC could not be accounted for in the soil profile. Although, decomposition and downward migration to below 20cm depth may contribute to the loss of BC from the surface soil, much can be attributed to lateral transfer through erosion. This is the first study that explicitly focuses on the theme of BC dispersion and shows that in Arenosols and Acrisols of the tropics, the downward migration of BC is limited.
Biochar is the name given to charcoal produced from pyrolyzed biomass with the purpose to add into soils to enhance soil properties and sequestrate carbon. Biochar has been a very popular research ...topic and a large amount of scientific literature has been produced in the last decade. Papers show biochar production from almost any type of biomass available using diverse types of thermochemical processes which have variations in technology, design, and conditions. All this variability in biomass feedstock and production has made biochar a very heterogeneous product, making it difficult to understand the biochar characteristics and qualities and what are the benefits and risks of its application in soils. This review presents a comprehensive vision of biochar properties, and their impact when biochar is applied to soils. To better understand this impact, biochar-collected data were classified in six types according to the main biomass used in its production, and divided into two thermochemical treatments: convectional pyrolysis methods and Hydrothermal Carbonization (HTC). Four biochar properties were studied: (i) physical and structural characteristics, (ii) chemical properties, (iii) agronomical properties, and (iv) contaminants. Outcomes of this review suggest that biochar can be a good soil amendment with capacity to enhance physical, chemical, and agronomic soil qualities. Nevertheless, results show the current lack of appropriate methodological analytical determination of some of the biochar characteristics. This can mislead to erroneous biochar characterization which could lead to future environmental issues. The review of the data suggested that some types of biomass could be not suitable for biochar soil application due to high levels of contaminants, although the information about solubility and availability of these contaminants in many cases is not clear. A consistent methodology, protocol, or index to measure biochar carbon stability in soils was not found; data suggest that a small proportion of biochars would not be suitable for carbon sequestration in soils but they could have good agronomical properties-this finding suggested that biochar production can be customized based on its final use. However, before proceeding to recommend massive use of biochar in soil, more research is necessary to have enough knowledge and understanding of biochar properties to develop models to predict biochar transport, fate, and impact.
•Biochar creates habitat and alters the soil environment for microorganisms.•Rapid change in microbial community structure and function after biochar application.•Long-term shifts in microbial ...communities depend on biochar source and soil texture.•Microorganisms are more sensitive to biochar source in sandy than clayey soils.
Soil microbial communities are responsive to biochar amendments. As the residence time of biochar in soil is expected to be hundreds to thousands of years, the changes in microbial community structure and functions could persist for a long period of time. Given that biochar is being applied as a soil amendment in many parts of the world, the long-term consequences for soil microbial communities need to be considered. The objective of this review is to document how biochar creates new habitats and changes the soil environment for microorganisms, which may lead to changes in microbial abundance, community structure and activities. Our meta-analysis revealed that slow pyrolyzed biochars produced from various feedstocks at temperatures from 300°C to 600°C consistently increased some physico-chemical properties (i.e., pH, cation exchange capacity and aggregation) and microbial parameters (i.e., abundance and community structure of microorganisms) in a vast number of soils during short (≤90days) laboratory incubations and longer (1–3years) field studies. The biochar-mediated changes in soil physico-chemical and biological properties appeared to be a function of soil texture and biochar type based on its feedstock and production temperature, which determines key biochar characteristics such as surface area, porosity and pH. Biochars derived from manure or crop residue feedstocks tend to promote microbial abundance more than wood-derived biochars. Biochars derived from wood and other lignocellulosic-rich feedstocks tend to exhibit beneficial effects on soil microbial abundance later (≥60days) than biochars from manure or crop residue feedstocks. Coarse textured soils tend to have less aggregation, lower microbial biomass and lower enzyme activities when amended with slow pyrolyzed biochars produced at high temperatures (>600°C), but these biochars did not affect the physico-chemical and biological properties of clayey soils. Further research is needed to evaluate the magnitude of biochar influence on soil microbial abundance and activities considering (1) the biochar particle size, surface area, porosity, nutrient content and pH, and (2) the soil organic matter (SOM) content and microbial abundance of the soil matrix. Once the microbial activities in the biochar–soil system are understood, they can be manipulated through organic and inorganic fertilizer applications to sustain or improve agricultural crop production.
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