Biochar
Biochar FAQ
US Forest Service Biochar Webinars
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Biochar demo project
A "Northcoast Biochar" project has emerged from the Redwood Forest Foundation, and a demo project has been set up in Branscom, focused on in-forest thinning slash, which is a highly significant problem due to the large amount of fuels treatment expected to take place in CA.
This project sponsored a webinar on March 10. The recording of the webinar is here. It is worthwhile if you have an interest in Biochar
==> https://www.rffi.org/biochar/.
This page also had a video introducing the demo project.
This demo project will generate current cost and market data to inform our biochar feasibility and prospects here.
Biochar Research
2017-Minatre-Biochar-annotated-bibliography.pdf
Volume 2 , Issue 4 , December 2020
Journal Website: https://www.springer.com/42773
Twitter: Biochar5 Facebook: Wushuang Li
Biochar and its importance on nutrient dynamics in soil and plant
Md Zahangir Hossain, Md Mezbaul Bahar, Binoy Sarkar, Scott Wilfred Donne, Young Sik Ok, Kumuduni Niroshika Palansooriya, Mary Beth Kirkham, Saikat Chowdhury, Nanthi Bolan*
Abstract:
Biochar, an environmentally friendly soil conditioner, is produced using several thermochemical processes. It has unique characteristics like high surface area, porosity, and surface charges. This paper reviews the fertilizer value of biochar, and its efects on soil properties, and nutrient use efciency of crops. Biochar serves as an important source of plant nutrients, especially nitrogen in biochar produced from manures and wastes at low temperature (≤400 °C). The phosphorus, potassium, and other nutrient contents are higher in manure/waste biochars than those in crop residues and woody biochars. The nutrient contents and pH of biochar are positively correlated with pyrolysis temperature, except for nitrogen content. Biochar improves the nutrient retention capacity of soil, which depends on porosity and surface charge of biochar. Biochar increases nitrogen retention in soil by reducing leaching and gaseous loss, and also increases phosphorus availability by decreasing the leaching process in soil. However, for potassium and other nutrients, biochar shows inconsistent (positive and negative) impacts on soil. After addition of biochar, porosity, aggregate stability, and amount of water held in soil increase and bulk density decreases. Mostly, biochar increases soil pH and, thus, infuences nutrient availability for plants. Biochar also alters soil biological properties by increasing microbial populations, enzyme activity, soil respiration, and microbial biomass. Finally, nutrient use efciency and nutrient uptake improve with the application of biochar to soil. Thus, biochar can be a potential nutrient reservoir for plants and a good amendment to improve soil properties.
James A. Ippolito, Liqiang Cui, Claudia Kammann, Nicole Wrage‑Mönnig, Jose M. Estavillo, Teresa Fuertes‑Mendizabal, Maria Luz Cayuela, Gilbert Sigua, Jef Novak, Kurt Spokas, Nils Borchard*
Abstract:
Various studies have established that feedstock choice, pyrolysis temperature, and pyrolysis type infuence fnal biochar physicochemical characteristics. However, overarching analyses of pre-biochar creation choices and correlations to biochar characteristics are severely lacking. Thus, the objective of this work was to help researchers, biochar-stakeholders, and practitioners make more well-informed choices in terms of how these three major parameters infuence the fnal biochar product. Utilizing approximately 5400 peer-reviewed journal articles and over 50,800 individual data points, herein we elucidate the selections that infuence fnal biochar physical and chemical properties, total nutrient content, and perhaps more importantly tools one can use to predict biochar’s nutrient availability. Based on the large dataset collected, it appears that pyrolysis type (fast or slow) plays a minor role in biochar physico- (inorganic) chemical characteristics; few diferences were evident between production styles. Pyrolysis temperature, however, afects biochar’s longevity, with pyrolysis temperatures>500 °C generally leading to longer-term (i.e.,>1000 years) half-lives. Greater pyrolysis temperatures also led to biochars containing greater overall C and specifc surface area (SSA), which could promote soil physico-chemical improvements. However, based on the collected data, it appears that feedstock selection has the largest infuence on biochar properties. Specifc surface area is greatest in wood-based biochars, which in combination with pyrolysis temperature could likely promote greater changes in soil physical characteristics over other feedstock-based biochars. Crop- and other grass-based biochars appear to have cation exchange capacities greater than other biochars, which in combination with pyrolysis temperature could potentially lead to longer-term changes in soil nutrient retention. The collected data also suggest that one can reasonably predict the availability of various biochar nutrients (e.g., N, P, K, Ca, Mg, Fe, and Cu) based on feedstock choice and total nutrient content. Results can be used to create designer biochars to help solve environmental issues and supply a variety of plantavailable nutrients for crop growth.
ORIGINAL ARTICLES
Biochar from vegetable wastes: agro‑environmental characterization
Snigdhendubala Pradhan, Ali H. Abdelaal, Kamal Mroue, Tareq Al‑Ansari, Hamish R. Mackey, Gordon McKay*
Abstract:
Considering the global issue of vegetable wastes generation and its impact on the environment and resources, this study evaluated the conversion of four largely produced vegetable wastes (caulifower, cabbage, banana peels and corn cob residues) into biochar. Each waste was tested individually and as a combined blend to assess feedstock infuences on biochar properties. In addition, various pyrolysis temperatures ranging from 300 °C to 600 °C and two particle size fractions (less than 75 µm, 75–125 µm) were considered. Biochars were characterized for various properties that can infuence the biochars’ efectiveness as a soil amendment. It was found that pyrolysis temperature was the most dominant factor on biochar properties, but that individual feedstocks produced biochars with diferent characteristics. The biochars had characteristics that varied as follows: pH 7.2–11.6, ECE 0.15–1.00 mS cm−1, CEC 17–cmolc kg−1 and ζ-potential − 0.24 to − 43 mV. Based on optimal values of these parameters from the literature, caulifower and banana peels were determined to be the best feedstocks, though mixed vegetable waste also produced good characteristics. The optimum temperature for pyrolysis was around 400 °C, but difered slightly (300–500 °C) depending on the distinct feedstock. However, smaller particle size of biochar application was always optimal. Biochar yields were in the range of 20–30% at this temperature range, except for corn cobs which were higher. This study demonstrates that pyrolysis of dried vegetable wastes is a suitable waste valorization approach to produce biochar with good agricultural properties.
A composite of Ni–Fe–Zn layered double hydroxides/biochar for atrazine removal from aqueous solution
Yifan Wang, Jiaming Kang, Simeng Jiang, Hui Li, Zheyi Ren, Qinbo Xu, Qun Jiang, Wenzhu Liu, Ruizhen Li, Ying Zhang*
Abstract:
This study assembled corn stalk-derived biochar (BC) with layered double hydroxide (LDH) through a rapid coprecipitation of biochar and metal (Ni/Fe/Zn) hydroxide precipitates. A BC and LDH composite (BC-LDH) and modifed BC-LDH material after heating (BC-LDH-P) were prepared successfully for atrazine adsorptive removal. The physicochemical properties of the synthesized samples were analyzed by X-ray difraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), and X-ray photoelectron spectroscopy (XPS). Batch experiments were conducted to study the sorption of atrazine onto BC, BC-LDH, and BC-LDH-P from the aqueous solution. The adsorption of atrazine onto BC-LDH and BC-LDH-P were performed following with the pseudo-second-order kinetic model, and the sorption isotherms agreed well with the Freundlich ftting model. The adsorption amounts of the three materials are arranged in descending order is as follows: BC-LDH-P>BC-LDH>BC (143.15>123.10>95.93 mg g−1, respectively). Due to the high crystallinity of the LDH material and the high binding degree with biochar, Ni/Fe/Zn-LDH biochar composites ofer a potential alternative to a carbon-based adsorbent for atrazine removal from aqueous solution.
Rojimul Hussain*, Sanandam Bordoloi*, Piyush gupta*, Ankit Garg*, K. Ravi*, S. Sreedeep*, Lingaraj Sahoo*
Abstract:
Biochar is a carbon-rich material obtained after thermochemical conversion of biomass under no oxygen environment. The efect of biochar amendment on soil properties, such as water retention, infltration and desiccation crack potential was studied in the recent years. However, the efect of biochar or feedstock type on these properties is not explicit. This study investigates the efect of two diferent (in terms of feedstock) types of biochar on the water retention, infltration and desiccation cracking behavior of compacted silty sand. Water retention characteristics, infltration rate and the progression of desiccation cracks were measured after compacting soil amended with 5–10% (w/w) biochar produced from water hyacinth (WHB) and mesquite. Measurements were also taken for an unpyrolyzed material coir pith (CP, sourced from coconut husk)-amended soil for comparing the results of biochar-amended soil. The results show that the amendment of 5% to 10% biochar increased the maximum water holding capacity (θs), air entry value (AEV) and water content at 1500 kPa (θ1500) of the soil, whereas decreased the infltration rate and peak crack intensity factor (CIF) of the soil. Moreover, the application of CP increased the infltration rate. The amendment of WHB showed the highest increment in AEV and θ1500 and the highest decrement in infltration rate and CIF compared to the other amendments. Based on the results, it is advisable to use the WHB-amended soil in bioengineered structures that could promote the growth of vegetation by higher water retention and could reduce the potential of leachate formation by decreasing water infltration and desiccation crack potential.
Efects of biochar amendments on soil water retention characteristics of red soil at south China
Zhuangzhuang Qian, Luozhong Tang, Shunyao Zhuang*, Yan Zou, Delong Fu, Xue Chen
Abstract:
Biochar has been extensively used for the improvement of soil water retention. However, the efects of various biochars were not well determined. The objectives of this study were to investigate the efects of three biochars [biochars made from bamboo (Bambusaceae), rice straw (Oryza sativa), and tobacco stem (Nicotiana L.)] on soil physical properties and the water retention characteristics of red soil at southeast China. The air-dried soil samples were mixed with ratios of 2%, 5%, and 10% (w w−1) BC (bamboo biochar), RC (rice straw biochar), and TC (tobacco biochar), respectively, and evaluated for changes in soil bulk density (BD), soil saturated water content, feld capacity, capillary porosity and soil hygroscopic coefcient. The results showed that BD decreased signifcantly with the application of the three types of biochar, total soil porosity and capillary porosity increased with the increase of the biochar ratio. The soil hygroscopic coefcient, wilting moisture capacity, saturated water content, and feld capacity were signifcantly afected by the application of the three types of biochar. Compared with the other two treatments, the BC showed the best efects on soil water characteristics. BC treatments with addition ratios of 2%, 5%, and 10% signifcantly decreased BD by 6.55%, 18.03%, and 36.07%, respectively. Moreover, saturated water content and feld capacity were increased by BC. BC treatments signifcantly increased the readily available water by 32.65%, 42.49%, and 50.01%, respectively. However, the increased non-readily available water induced by the high ratio of biochar addition was not easily utilized by plants. Our results suggested that the biochar amendment can improve soil structure, decrease soil BD, boost soil porosity and capillary porosity, and increase soil moisture constant, and 2–5% of BC was recommended in the feld condition.
Cogon grass biochar amendment and Panicum coloratum planting improve selected properties of sandy soil under humid lowland tropical climatic conditions
Patrick S. Michael*
Abstract:
Biochar amendment improves the physical, chemical and biological characteristics of diferent soil types under diferent climatic and environmental conditions. In this study, efects of biochar or live pasture plants existing alone or co-existing on selected soil properties of sandy loam soil under humid lowland tropical climatic conditions were investigated. The changes measured in the amended soil, with or without plants, were compared to the unamended and unplanted soils. Biochar amendment with or without pasture improved moisture retention, lowered bulk density, increased pH and kept the electrical conductivity within ranges conducive for pasture growth. Generally, contents of all the nutrients increased following biochar amendment, however pasture establishment without amendment resulted in depletion of available potassium and magnesium. Under all treatment conditions, soil organic carbon and soil organic matter were signifcantly depleted. Cogon grass is invasive under all land use systems and contributes to greenhouse gas emissions through slash-and-burn. Using biomass from the grass instead of burning would mitigate CO2 emissions from the tropics.
Tigist Melaku, Gebermedihin Ambaw, Abebe Nigussie*, Amsalu Nebiyu Woldekirstos, Eshetu Bekele, Milkiyas Ahmed
Abstract:
There is little understanding as to whether the addition of biochar requires less fertilizer to obtain the potential yield. Furthermore, the additional yield ascribed to the non-nutrient efects of biochar is ambiguously quantified. Therefore, this study is aimed to elucidate the infuence of biochar application rate and production temperature on (i) marginal agronomic efficiency (AELN), (ii) potential yield (Yopt), (iii) the amount of mineral fertilizer required to obtain the potential yield (Fopt); and (iv) nutrient use efficiency. AELN, Yopt and Fopt were calculated after ftting the yield response at diferent levels of mineral fertilizer with a second-degree polynomial. Application of biochar reduced marginal agronomic efciency, implying that the plant utilized the applied nutrient more efficiently without biochar at a low dose of mineral fertilizer. Biochar increased potential yield but required more mineral fertilizer to obtain the optimum yield. The non-nutrient associated f of biochar reached to 39% and is mainly attributed to its liming efect. The efect of biochar on AELN, Yopt, Fopt, fertilizer use efciency and soil pH were more pronounced at the higher application rate. Addition of biochar, however, increased soil Mehlich-P and carbon content, irrespective of production temperature and application rate. This study demonstrated that the shortterm efect of biochar application on fertilizer utilization should be examined with caution in low-input cropping systems because the biochar efects were dependent on fertilizer level, biochar application rate, production temperature and their interactions. Further manipulative experiments are recommended to identify the mechanisms that explain the non-nutrient effect of biochar on yield.
Volume 3 , Issue 1 , March 2021
Fei Lian, Zhenyu Wang*, Baoshan Xing*
Abstract:
Nano-black carbon (BC) is one of the most active fractions in the pyrogenic carbonaceous matter continuum. The majority of recent studies mainly focus on the role of nano-BC in the global carbon cycle. However, based on literature and our recent studies, we suggest that nano-BC may also serve as a super suspending agent, carrier, and redox mediator for sorbates during its migration from terrestrial to water bodies due to its unique properties such as high colloidal stability, strong sorption capacity, and high surface reactivity. The full implications of nano-BC in water/soil environments are far more than we expected. Thus, we call for more detailed investigations on the activity and reactivity of nano-BC in water/soil environments.
Woody biochar potential for abandoned mine land restoration in the U.S.: a review
Carlos Rodriguez‑Franco*, Deborah S. Page‑Dumroese
Abstract:
There are thousands of abandoned mine land (AML) sites in the U.S. that need to be restored to reduce wind and water erosion, provide wildlife forage, shade streams, and improve productivity. Biochar created from woody biomass that would normally be burned in slash piles can be applied to soil to improve soil properties and is one method to restore AML soil productive capacity. Using this ‘waste’ biomass for biochar and reclamation activities will reduce wildfre risk, air pollution from burning, and particulates released from burning wood. Biochar has the potential to improve water quality, bind heavy metals, or decrease toxic chemical concentrations, while improving soil health to establish sustainable plant cover, thereby preventing soil erosion, leaching, or other unintended, negative environmental consequences. Using forest residues to create biochar also helps reduce woody biomass and improves forest health and resilience. We address concerns surrounding organic and inorganic contaminants on the biochar and how this might afect its’ efcacy and provide valuable information to increase restoration activities on AMLs using biochar alone or in combination with other organic amendments. Several examples of AML biochar restoration sites initiated to evaluate short- and long-term above- and belowground ecosystem responses are presented.
Remediation of mercury‑contaminated soils and sediments using biochar: a critical review
Qian Yang, Yongjie Wang, Huan Zhong*
Abstract:
The transformation of mercury (Hg) into the more toxic and bioaccumulative form methylmercury (MeHg) in soils and sediments can lead to the biomagnifcation of MeHg through the food chain, which poses ecological and health risks. In the last decade, biochar application, an in situ remediation technique, has been shown to be efective in mitigating the risks from Hg in soils and sediments. However, uncertainties associated with biochar use and its underlying mechanisms remain. Here, we summarize recent studies on the efects and advantages of biochar amendment related to Hg biogeochemistry and its bioavailability in soils and sediments and systematically analyze the progress made in understanding the underlying mechanisms responsible for reductions in Hg bioaccumulation. The existing literature indicates (1) that biochar application decreases the mobility of inorganic Hg in soils and sediments and (2) that biochar can reduce the bioavailability of MeHg and its accumulation in crops but has a complex efect on net MeHg production. In this review, two main mechanisms, a direct mechanism (e.g., Hg-biochar binding) and an indirect mechanism (e.g., biochar-impacted sulfur cycling and thus Hg-soil binding), that explain the reduction in Hg bioavailability by biochar amendment based on the interactions among biochar, soil and Hg under redox conditions are highlighted. Furthermore, the existing problems with the use of biochar to treat Hgcontaminated soils and sediments, such as the appropriate dose and the long-term efectiveness of biochar, are discussed. Further research involving laboratory tests and feld applications is necessary to obtain a mechanistic understanding of the role of biochar in reducing Hg bioavailability in diverse soil types under varying redox conditions and to develop completely green and sustainable biochar-based functional materials for mitigating Hg-related health risks.
Quantitative analysis of Pb adsorption on sulfhydryl‑modifed biochar
Juan Xiong, Mengge Zhou, Chenchen Qu, Daohai Yu, Chang Chen, Mingxia Wang, Wenfeng Tan*
Abstract:
Biochar is an efective absorbent for remediating heavy metal contaminated soil, but functional optimization is still needed to improve its performance in feld application. Here, we characterized the physical structures and surface chemical properties of raw wood biochar and palm biochar (WB and PB) and the corresponding sulfhydryl-modifed biochar (SWB and SPB). Their adsorption capacity for Pb was evaluated by combining thermodynamic and kinetic adsorption at 0.01 mol/L KCl and corresponding model simulation. The results demonstrated successful grafting of sulfhydryl groups onto the biochar, which dramatically reduced the specifc surface area (SSA) and pore volume of biochar. The pKa in the surface complexation model (SCM) indicated similar proton afnity between sulfhydryl groups and original functional groups on the biochar. SCM could satisfactorily ft the Pb adsorption behaviors, and model analysis revealed that Pb tended to be adsorbed on low-proton afnity sites at low pH, but high-proton afnity sites became dominant in Pb adsorption with increasing pH and adsorbed almost all Pb ions at pH>7.0. Besides, the Pb adsorption density of SWB and SPB was improved by 8.86 and 3.64 folds relative to that of WB and PB, respectively. Over 90% of initially added Pb ions were removed in 1440 and 720 min by raw and sulfhydryl-modifed biochar, respectively, indicating that sulfhydryl modifcation accelerated the Pb adsorption of biochar. These results suggest that site density, SSA and pore structure of biochar play crucial roles in heavy metal adsorption, and sulfhydryl modifcation may improve the performance of biochar in remediating heavy metal contaminated soil.
Tran Thi Thu Hien*, Toshiki Tsubota, Tomoyuki Taniguchi, Yoshiyuki Shinogi
Abstract:
Rapid expansion of cultivated bamboo negatively impacts on biodiversity and soil microbial community. As such, it is important to properly manage and use bamboo to prevent and control such issues. This study focuses on optimizing pyrolysis conditions to produce bamboo biochar for agricultural soil amendment, particularly soil potassium (K) and water holding capacity. Bamboo chips were pyrolyzed under nitrogen gas at 400, 600, and 800 °C for 1 and 2 h of retention. A total of six biochar products were created: 400-1 (i.e., 400 °C in 1 h), 400-2, 600-1, 600-2, 800-1, and 800-2. The 600 °C bamboo biochar products were observed to have the greatest potential in increasing soil K and water holding capacity. The 600-1 product had the highest potassium content (4.87%), with a water holding capacity of 3.73 g g−1, while the 600-2 product had the second-highest potassium content (4.13%) and the highest water holding capacity (4.21 g g−1) and cation exchange capacity. The K release in 600 °C products was larger and slower than that of the 400 °C and 800 °C products, respectively. The results also indicated that the physicochemical characteristics of bamboo biochar, such as yield, pH, surface area, water holding capacity, and K content, were signifcantly impacted by temperature, retention time, or a combination of these parameters. The outcomes from this study are a valuable reference for bamboo biochar production targeting agricultural soil amendment, particularly when it is directed at increasing soil K and water holding capacity.
Libing Pan, Fanzhen Xu, Huizhu Mo, Richard T. Corlett, Liqing Sha*
Abstract:
Biochar can enhance crop production and sequester carbon, but there have been few studies with tree crops. Rubber plantations cover more than 8 million hectares in Southeast Asia, so we assessed the feasibility of biochar application in these plantations with a pot trial. Rubber seedlings were planted in soil with four concentrations (0, 1.25%, 2.5% and 5%, w/w) of biochar combined with two concentrations of compound fertilizer (0 kg/ha and 300 kg/ha). Soil properties and seedling growth were measured, and a leaching experiment was conducted in the rainy season. Our results show that biochar increased pH, water content (27.4–65.1%), total carbon (25.4–53.6%), nitrate nitrogen, and available phosphorus in the soil, and decreased bulk density (3.2–23.9%). Biochar treatment reduced leaching of ammonium nitrogen and ortho-P. Biochar increased seedling nutrient uptake (C, N, P and K), with 2.5% and 5% biochar showing the largest efects, but seedling biomass was the highest with 1.25%, and declined in 2.5% and 5%. Our results suggest that biochar addition is an efective way to improve rubber plantation soils, sequester more carbon and decrease nutrient leaching, but the optimum application rate under feld conditions needs further research.
Biochars reduce irrigation water sodium adsorption ratio
Saima Awan, James A. Ippolito*, J. L. Ullman, Kamran Ansari, Liqiang Cui, A. A. Siyal
Abstract:
Irrigation water quality plays a vital role in sustaining crop productivity and feeding a growing world population. In many countries, continued agricultural water reuse can lead to greater water-soluble salt concentrations, and in particular Na; fnding means by which irrigation water Na, and thus sodium adsorption ratios (SAR), can be reduced would reduce the rate at which soil sodifcation occurs. Four biochars, containing a variety of organic functional groups and electrochemistries, were examined for their potential to sorb and remove Na from simulated irrigation water, and subsequently reduce water SAR. Two batch experiments examined the role that wheat straw biochar, lodgepole pine biochar, Kentucky bluegrass biochar, and hemp biochar played in terms of sorbing sodium over time or application rate. Of the four biochars examined, hemp biochar had the lowest oxidation–reduction potential (ORP;~0–100 mV), sorbed the greatest Na amount (up to 923 mg kg−1), and released Ca and Mg (up to 115 and 63 mg kg−1, respectively) into solution, all of which led to a signifcant reduction in water SAR (from 8.8 to 7.3; 17% decrease). Sodium sorption onto hemp biochar better ft a Langmuir versus a Freundlich isotherm, yet followed a pseudo-second-order model better than a pseudo-frst-order kinetic model. The data suggest that Na ions formed a monolayer on the hemp biochar surface, infuenced by associations with π electrons, but given time the Na ions may difuse into biochar pores or more slowly interact with biochar-borne π electrons. Hemp biochar shows promise in reducing the SAR of Na-impacted waters. Future investigations should focus on additional laboratory, greenhouse, and feld trials with hemp biochar and other biochars designed to have similar or superior properties for sorbing excess irrigation water Na and improving crop growth.
Marlene C. Ndoun*, Herschel A. Elliott, Heather E. Preisendanz, Clinton F. Williams, Allan Knopf, John E. Watson
Abstract:
Biochars produced from cotton gin waste (CG) and guayule bagasse (GB) were characterized and explored as potential adsorbents for the removal of pharmaceuticals (sulfapyridine-SPY, docusate-DCT and erythromycin-ETM) from aqueous solution. An increase in biochar pyrolysis temperature from 350 ℃ to 700 ℃led to an increase in pH, specifc surface area, and surface hydrophobicity. The electronegative surface of all tested biochars indicated that non-Coulombic mechanisms were involved in adsorption of the anionic or uncharged pharmaceuticals under experimental conditions. The adsorption capacities of Sulfapyridine (SPY), Docusate (DCT) and Erythromycin (ETM) on biochar were infuenced by the contact time and solution pH, as well as biochar specifc surface area and functional groups. Adsorption of these pharmaceutical compounds was dominated by a complex interplay of three mechanisms: hydrophobic partitioning, hydrogen bonding and π–π electron donor–acceptor (EDA) interactions. Despite weaker π–π EDA interactions, reduced hydrophobicity of SPY− and increased electrostatic repulsion between anionic SPY− and the electronegative CG biochar surface at higher pH, the adsorption of SPY unexpectedly increased from 40% to 70% with an increase in pH from 7 to 10. Under alkaline conditions, adsorption was dominated by the formation of strong negative charge-assisted H-bonding between the sulfonamide moiety of SPY and surface carboxylic groups. There seemed to be no appreciable and consistent diferences in the extent of DCT and ETM adsorption as the pH changed. Results suggest the CG and GB biochars could act as efective adsorbents for the removal of pharmaceuticals from reclaimed water prior to irrigation. High surface area biochars with physico-chemical properties (e.g., presence of functional groups, high cation and anion exchange capacities) conducive to strong interactions with polar-nonpolar functionality of pharmaceuticals could be used to achieve signifcant contaminant removal from water.
Allahyar Khadem*, Fayez Raiesi*, Hossein Besharati*, Mohammad Ali Khalaj*
Abstract:
Biochar as an organic amendment improves soil attributes, with a potentially signifcant efect on soil chemical fertility and quality. The main objective of this study was to quantify the efect of biochar addition on nutrients, carbon sequestration and microbial activity and understand the mechanisms of controlling biochar efects in calcareous soils. Maize residue biochars produced at 200, 400 and 600 °C were added at 5 and 10 g kg−1 rates to sandy loam and clayey texture calcareous soils. The soil properties measured were pH and electrical conductivity (EC), plant-available potassium (K) and available phosphorus (P), total nitrogen (TN), C sequestration; and the fuorescein diacetate (FDA) hydrolysis activity. Addition of raw material and biochars increased pH (0.15–0.46 units), EC (0.14–0.38 dS m−1), TN (63–120%), K (12–41%) and FDA activity (27–280%), but tended to decrease plant-available P (23–86%). Increasing pyrolysis temperature increased soil C pool index (CPI), but decreased the FDA and the changes depended largely upon the application rate and soil texture. The positive efects of biochar addition and its pyrolysis temperature on soil C sequestration potential were more pronounced at high than low application rate and in sandy loam than clayey soils. Nevertheless, the efect of biochar addition and pyrolysis temperature on the FDA activity was higher at high than low application rates, but lower in sandy loam than clayey soils. Although biochar application may successfully improve soil processes and attributes and have a high potential for C sequestration, its efects are controlled by soil texture, pyrolysis temperature and application rate.