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1.
Ecotoxicol Environ Saf ; 208: 111756, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396079

RESUMO

To deeply assess the feasibility of sewage sludge-based biochars for use in soil applications, this review compared sewage sludge-based biochars (SSBBs) with lignocellulose-based biochars (LCBBs) in terms of their pyrolysis processes, various fractions and potential soil applications. Based on the reviewed literature, significant differences between the components of SSBB and LCBB result in different pyrolysis behavior. In terms of the fractions of biochars, obvious differences were confirmed to exist in the carbon content, surface functional groups, types of ash fractions and contents of potential toxic elements (PTEs). However, a clear influence of the feedstock on labile carbon and polycyclic aromatic hydrocarbons (PAHs) was not observed in the current research. These differences determined subsequent discrepancies in the soil application potential and corresponding mechanisms. The major challenges facing biochar application in soils and corresponding recommendations for future research were also addressed. LCBBs promote carbon sequestration, heavy metal retention and organic matter immobilization. The application of SSBBs is a promising approach to improve soil phosphorus fertility, immobilize heavy metals and provide available carbon sources for soil microbes to stimulate microbial biomass. The present review provides guidance information for selecting appropriate types of biochars to address targeted soil issues.


Assuntos
Carvão Vegetal/química , Recuperação e Remediação Ambiental/métodos , Metais Pesados/química , Pirólise , Poluentes do Solo/química , Biomassa , Carbono , Lignina , Metais Pesados/análise , Hidrocarbonetos Policíclicos Aromáticos , Esgotos , Solo , Poluentes do Solo/análise
2.
Ecotoxicol Environ Saf ; 208: 111552, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396093

RESUMO

A novel material that nano zero valent iron (nZVI) loaded on biochar with stable starch stabilization (nZVI/SS/BC) was synthesized and used for the removal of hexavalent chromium [Cr(VI)] in simulated wastewater. It was indicated that as the pyrolysis temperature of rice straw increased, the removal rate of Cr(VI) by nZVI/SS/BC first increased and then decreased. nZVI/SS/BC made from biochar pyrolyzed at 600 °C (nZVI/SS/BC600) had the highest removal efficiency and was suitable for a wide pH range (pH 2.1-10.0). The results showed that 99.67% of Cr(VI) was removed by nZVI/SS/BC600, an increase of 45.93% compared to the control group, which did not add soluble starch during synthesis. The pseudo-second-order model and the Langmuir model were more in line with reaction. The maximum adsorption capacity for Cr(VI) by nZVI/SS/BC600 was 122.86 mg·g-1. The properties of the material were analyzed by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) mapping, Brunauer-Emmett-Teller (BET), Fourier-transform infrared (FTIR), and X-ray diffraction (XRD). The results showed that the nZVI particles were uniformly supported on the biochar, and the BET surface areas of nZVI/SS/BC was 40.4837 m2·g-1, an increase of 8.79 times compared with the control group. Mechanism studies showed that soluble starch reduced the formation of metal oxides, thereby improving the reducibility of the material, and co-precipitates were formed during the reaction. All results indicated that nZVI/SS/BC was a potential repair material that can effectively overcome the limitations of nZVI and achieve efficient and rapid repair of Cr(VI).


Assuntos
Carvão Vegetal/química , Cromo/química , Poluentes Químicos da Água/química , Adsorção , Ferro/química , Pirólise , Amido , Temperatura , Poluentes Químicos da Água/análise , Purificação da Água , Difração de Raios X
3.
Ecotoxicol Environ Saf ; 208: 111624, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396144

RESUMO

Phthalate esters (PAEs), such as dibutyl phthalate (DBP) and di-(2-ethylhexyl) phthalate (DEHP), are used extensively as additives and plasticizers, and have become ubiquitous in the environment. PAEs in the soil could have adverse effects on crop plants as well as humans via accumulations in food chain. Thus, it is important to explore strategies to reduce the bioavailability of phthalate esters. We investigated the effects of Fe-Mn oxide-modified biochar composite (FMBC) applications on the quality of wheat grown in DBP- and DEHP-polluted brown soil. The application of FMBC and biochar (BC) increased the wheat grain biomass by 9.71-223.01% and 5.40-120.15% in the DBP-polluted soil, and 10.52-186.21% and 4.50-99.53% in the DEHP-spiked soil in comparison to the controls. All FMBC treatments were better than the BC treatments, in terms of decreasing DBP and DEHP bioavailability for the wheat grains. The activities of the glutamine synthetase and glutamic-pyruvic transaminase in the flag leaves at the filling stage and of granule-bound starch synthase, soluble starch synthase, and adenosine diphosphate-glucose pyrophosphorylase in the grains at maturity increased significantly with increases in either the BC or FMBC applications. This, in turn, increased the starch, protein, and amino acid content in the wheat grains. Compared with the BC treatment, the FMBC amendment induced only slight increases in the aforementioned factors. This study offers novel insights into potential strategies for decreasing PAEs bioavailability in soil, with potential positive implications for crop quality and environmental health improvements.


Assuntos
Carvão Vegetal/química , Recuperação e Remediação Ambiental/métodos , Ácidos Ftálicos/química , Poluentes do Solo/metabolismo , Triticum/fisiologia , Dibutilftalato/análise , Dibutilftalato/metabolismo , Dietilexilftalato/metabolismo , Grão Comestível/química , Poluição Ambiental , Ésteres/análise , Humanos , Ferro/análise , Óxidos/análise , Plastificantes/análise , Solo/química , Poluentes do Solo/análise , Triticum/metabolismo
4.
Ecotoxicol Environ Saf ; 208: 111626, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396146

RESUMO

Soil application of biochars has been shown to effectively immobilize potentially toxic elements (PTEs). Soil water regime can also affect PTE availability. No previous studies have examined the interactive effect of biochars and soil water regime on Pb availability. Therefore, this study investigated the effect of high and low temperature (300 and 600°C) biochars derived from cow manure (CB), municipal compost (MB) and licorice root pulp (LB) applied at 3 wt%, under two soil moisture regimes (field capacity (FC) and saturation (ST)) on Pb release kinetics and chemical fractions in a Pb-contaminated calcareous soil. Results showed that CB and MB treatments significantly enhanced Pb stabilization compared to LB, attributed to their favorable chemical properties (high P, ash, carbonate, oxidizable C content and high pH) which could promote Pb conversion into stable chemical fractions. Immobilization of Pb was enhanced under saturated conditions compared to FC by the treatments, which is attributed to increased soil pH, reduction of metal oxides and possible formation of sulfides. The most significantly effective treatments were the CB300, CB600 and MB600 treatments under ST, as indicated by significant decrease in soil Pb mobility factor from 29.1% (CL+FC) to 21.2-22.9%, and 11.7-16.3% increase in non-EDTA-extractable Pb. Results of this study demonstrate that combined application of high ash biochars and soil water saturation significantly enhances Pb immobilization in calcareous soil.


Assuntos
Carvão Vegetal/química , Recuperação e Remediação Ambiental/métodos , Chumbo/química , Poluentes do Solo/química , Poluição Ambiental , Esterco , Óxidos , Solo/química , Poluentes do Solo/análise
5.
Environ Sci Pollut Res Int ; 28(2): 1574-1586, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32851523

RESUMO

Co-transport of biochar (BC) colloids with coexisting organic contaminants (OCs) in soil involves complex interactions among BC colloids, OCs, and soil particles, which is significant for the environmental application and risk assessment of BC and yet has not been well addressed. This study explored co-transports of three typical OCs (i.e., phenanthrene (PHN), atrazine (ATZ), and oxytetracycline (OTC)) and BC colloids obtained from bulk BCs with different charring temperatures (200-700 °C) and particle sizes (250 nm, 500 nm, and 1 µm) in a soil column of 9 cm in height. Considerable transport of BC colloids alone was observed and the maximum breakthrough concentration (C/Co) increased from 0.08 to 0.77 as the charring temperature decreased from 700 to 200 °C. The mobilities of PHN, OTC, and ATZ alone were very low but were greatly increased by co-transports with BC colloids, and their maximum C/Co values were within 0.05-0.33, 0.03-0.44, and 0.05-0.62, respectively, in the absence and presence of various BC colloids. The enhancement effect of BC colloids on the OC transport decreased with increasing charring temperature or particle size of BC colloids. BC colloids mainly acted as a vehicle to facilitate the transport of OCs, and dissolved organic carbon from BC colloids also contributed to the increased mobility of OCs in dissolved form. These findings provide new insights into co-transport of BC colloids and contaminants in soil.


Assuntos
Poluentes do Solo , Solo , Adsorção , Carvão Vegetal , Coloides
6.
Environ Sci Pollut Res Int ; 28(2): 2198-2208, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32875446

RESUMO

The aim of this study was to investigate the stability of heavy metals in biochar derived from rice straw with heavy metal enrichment, and the relationship between pyrolysis temperature and the stability of heavy metals in biochar. The concentrations of heavy metals of rice straw and biochar (pyrolyzed at 300 °C, 500 °C, 700 °C, and 900 °C) were measured. The experiments of extraction and leaching were conducted to evaluate the effect of pyrolysis temperature on the stability of heavy metals in biochar. A pot experiment was conducted to investigate the environmental risk of heavy metals from biochar. The pyrolysis temperature affected the pH, total C, total N, surface structure, functional groups, and the concentrations of heavy metals in biochar. After being pyrolyzed, the bioavailable DTPA fraction of total Cu, Zn, Cd, and Pb of BC500, BC700, BC900, and BC900 decreased by 72.87%, 69.45%, 48.09% and 15.89%, respectively, in comparison with levels in rice straw. In addition, the leaching potential of heavy metals in biochar was significantly reduced. The pot experiment and the correlation analysis indicated that the pyrolysis temperature was not significantly related to the accumulation of heavy metals in aerial parts of rice seedlings. Increase in the pyrolysis temperature had a positive effect on increasing the stability and decreasing the mobility of heavy metals in biochar. However, the variations in the pyrolysis temperature were not the main factor to affect the uptake of heavy metals originated from biochar into the aerial parts of rice seedlings.


Assuntos
Metais Pesados , Oryza , Poluentes do Solo , Disponibilidade Biológica , Carvão Vegetal , Pirólise , Poluentes do Solo/análise , Temperatura
7.
Water Res ; 189: 116588, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33221588

RESUMO

Granulated Activated Carbon (GAC) filtration is a common process for advanced wastewater treatment. In such filters, the removal of organic substances results from adsorptive as well as biological processes. This work investigated the potential of biological processes and their influence on GAC-filter performance. During 32 months, the removal of micropollutants,Dissolved Organic Carbon (DOC) and the spectral absorption coefficient was monitored in six GAC-filters. The effects of pre-treatment (cloth- and/or membrane-filtration), EBCT (from 6 - 35 min) and GAC-type were evaluated. Likewise, the impact of the influent´s fluctuations in temperature, flow and concentration (ammonia, nitrate, and soluble reactive phosphorus (sRP)) were analysed. Biological processes were tracked by the frequency of backwashing, oxygen consumption, removal of poorly absorbable micropollutants and production of transformation products. Pre-treatment influenced biofilm growth significantly. Membrane filtration delayed the first backwashing event by 122 d in comparison to cloth-filtration, where the first backwash was conducted after only 21 d. Removal of poorly absorbable substances was observed early on (40 - 50 d). Parallel operation contributed to a better utilisation of the GAC-capacity and the biological removal potential. Influent nitrogen species > 0.5 mg N/L promoted biofilm growth, whereas sRP seemed to have no effect. The developed biofilm and optimal operating conditions led to longer life spans of the GAC-filters, making carbon usage rates comparable to those from PAC applications. The results suggest that biological processes accounted for about 25 - 42% of the totally removed DOC at the end of the operation.


Assuntos
Poluentes Químicos da Água , Purificação da Água , Carvão Vegetal , Filtração , Águas Residuárias , Poluentes Químicos da Água/análise
8.
Environ Pollut ; 268(Pt A): 115684, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33010549

RESUMO

Anaerobic digestate and biochar are by-products of the biogasification and pyrolysis of agricultural wastes. This study tested the hypothesis that combined application of anaerobic pig/cattle manure digestate and coconut husk (CH) biochar can improve soil nutrient conditions, whilst minimizing atmospheric and groundwater pollution risks. Microcosms simulated digestate application to agricultural soil with and without CH biochar. Ammonia volatilization and nutrient leaching were quantified after simulated heavy rainfalls. Archaeal and bacterial community and abundance changes in soils were quantified via next generation sequencing and qPCR of 16S rRNA genes. Nitrifying bacteria were additionally quantified by qPCR of functional genes. It was found that CH biochar retarded nitrate leaching via slower nitrification in digestate-amended soil. CH biochar reduced both nitrifying archaea and bacteria abundance in soil by 71-83 percent in the top 4 cm soil layer and 66-80 percent in the deeper soil layer one month after the digestate application. Methanotroph abundances were similarly reduced in the CH biochar amended soils. These findings demonstrate combined benefits of anaerobic digestate and CH biochar application which are relevant for the development of a more circular rural economy with waste minimization, renewable energy production, nutrient recycling and reduced water pollution from agricultural land.


Assuntos
Nitrificação , Solo , Anaerobiose , Animais , Bovinos , Carvão Vegetal , Cocos , Nutrientes , RNA Ribossômico 16S , Microbiologia do Solo , Suínos
9.
Sci Total Environ ; 758: 143643, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33246719

RESUMO

Magnetic biochar has been widely used in the removal of aquatic pollutants due to its strong adsorption capacity and recyclability. However, the nutrient deficiency caused by magnetic biochar reduces plant performance and limits its use. The effects of magnetic biochar (derived from either eucalyptus wood or pig manure compost) on soil Cd, Zn, and Pb bioavailability to Phragmites australis L. (reed) and soil microbial community were investigated in a pot experiment. We also examined treatments of magnetic biochar with P supplementation and unmodified biochar with Fe addition to elucidate the mechanism by which magnetic biochar affects plant growth. We found that the addition of magnetic biochar significantly reduced the concentrations of available heavy metals in soil and inhibited heavy metal uptake by reeds. It also promoted the formation of iron plaque on reed roots to inhibit metal translocation. However, compared to unmodified biochar, magnetic biochar reduced reed performance, as indicated by the reduced plant biomass and photosynthetic ability, and it also reduced the biomass of soil bacteria and fungi. This was due to the interception of P by the iron plaque and the reduced concentration of soil available P. Collectively, although magnetic biochar exhibited a strong potential for heavy metal remediation, P supplementation is recommended to maintain plant performance and soil health when applying magnetic biochar.


Assuntos
Metais Pesados , Poluentes do Solo , Animais , Carvão Vegetal , Fenômenos Magnéticos , Metais Pesados/análise , Fósforo , Solo , Poluentes do Solo/análise , Suínos
10.
Sci Total Environ ; 758: 143657, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33250256

RESUMO

As a promising soil amendment, biochar has demonstrated its potential for influencing soil nutrient transformations. The effects of biochar on soil phosphorus (P) transformations have received much less attention than its effects on carbon cycling. A review of the literature reveals that biochar applications to soils may have notable effects on the abundance, speciation, availability, and leaching loss of soil P. However, a comprehensive and systematic understanding of the biochar-induced environmental behavior of soil P has not been obtained so far. Therefore, in this review, we analyzed and identified the known and potential mechanisms through which biochar affects P behavior in soils: (1) biochar as a source of P provides soluble and exchangeable P to soil; (2) biochar enhances the availability of endogenic soil P by influencing P-related complexation and metabolism effects; and (3) biochar affects P leaching losses directly or indirectly by adsorbing P, improving P retention by soil, and facilitating P assimilation by plants. By presenting a broad and detailed illustration of P behaviors in biochar-amended soils, this paper suggests that the application of biochar to soils will help enlarge soil P pools, increase soil P availability, and decrease P leaching losses from soil. Additional studies are needed to further elucidate the long-term effects of biochar addition on soil P transformations, explore how biochar-derived dissolved organic matter (BDOM) affects the mobility and availability of soil mineral-associated P, and examine the transport of particulate P in biochar-amended soils.


Assuntos
Poluentes do Solo , Solo , Carvão Vegetal , Fósforo , Poluentes do Solo/análise
11.
Sci Total Environ ; 758: 143584, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33272600

RESUMO

In this study, a heterogeneous activator was prepared via the Fe/Mn modification of sludge-derived biochar (Fe/MnBC) to achieve high-efficiency activation of persulfate (PS) for reactive blue 19 (RB19) degradation. The morphologies and chemical states of Fe/MnBC were examined by various characterizations. A comprehensive assessment was conducted to reveal the effects of biochar preparation conditions and system reaction conditions. According to the results of scavenger quenching experiments and electron paramagnetic resonance (EPR) testing, the mechanisms of Fe/MnBC combined PS system on RB19 degradation were proposed, including radical and non-radical mechanisms. The formation and involvement of sulfate radical (SO4·-), hydroxyl radical (OH·), and singlet oxygen (1O2) were proved in this system, and Fe(IV)/Mn(VII) was also speculated to participate in the non-radical degradation process. These findings give a new insight into the mechanisms of PS activated by metal-biochar composite. Besides, fixed-bed reactor (FBR) experiments indicated that the Fe/MnBC has considerable PS activation potential for dyes removal. The degradation process was further modeled by the central composite design (CCD-RSM) and artificial neural networks (ANN) methods. The statistical metrics and prediction indicated that the prediction results of ANN model were better than CCD-RSM model, and the ANN model could perfectly predict the reaction process of Fe/MnBC FBR for engineering applications.


Assuntos
Poluentes Químicos da Água , Antraquinonas , Carvão Vegetal , Oxirredução , Poluentes Químicos da Água/análise
12.
Sci Total Environ ; 758: 143664, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33288263

RESUMO

To solve the problem of limited adsorption efficiency of pristine biochar for phosphate, a novel biochar composite was prepared from different feedstocks and coal gangue by one facile-step pyrolysis method. The effects of pyrolysis temperature, adsorbent dosage, pH of the solution, and coexisting ions on phosphate adsorption were analyzed. The adsorption performance and mechanism of phosphate in water were investigated. The application of the phosphorus-laden (P-laden) composite as slow-release fertilizer was evaluated by a germination test. The results showed that the maximum phosphate adsorption capacity of coal gangue modified oilseed rape straw biochar prepared at 700 °C (CG-OR700) was 7.9 mg/g at pH 4.0, which is 4.6 times that of pristine biochar. The adsorption process can be well fitted by the pseudo-second-order kinetic and Langmuir isotherm adsorption model. The mechanism of phosphate adsorption mainly includes surface precipitation, ligand exchange, and electrostatic attraction. The P-laden biochar can be used as a slow-release fertilizer to promote seed germination and growth. This study shows that the coal gangue modified biochar composite can not only be used to remove phosphate from wastewater, but also be used as a slow-release fertilizer, providing a new way for the phosphorus recovery and resource utilization of solid wastes.


Assuntos
Fosfatos , Poluentes Químicos da Água , Adsorção , Carvão Vegetal , Carvão Mineral , Fertilizantes , Cinética , Água , Poluentes Químicos da Água/análise
13.
Sci Total Environ ; 758: 143957, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33333296

RESUMO

A recyclable magnetic rape straw biochar (MRSB) catalyst was synthesized by a high value-added and energy-saving method using abandoned rape straw as the raw material. The MRSB catalyst showed high catalytic activity and recyclability for activating persulfate (PS) to degrade tetracycline hydrochloride (TC) in water. The Fe3O4 in the MRSB greatly promoted the activation of PS. More importantly, the MRSB catalyst exhibited high catalytic performance over a wide pH range (2.99-11.01) for activating PS to degrade TC in water. Moreover, MRSB still had good catalytic activity for TC degradation after 8 recycling cycles and was easily separated by an external magnetic field for reuse. The electron spin resonance (ESR) analysis indicated that the generation of the sulfate radicals (SO4-), hydroxyl radicals (OH) and superoxide radicals (O2-) was greatly promoted in the MRSB/PS system. As a result, MRSB exhibited 13.24-fold higher reaction rate for activating PS than those of rape straw biochar (RSB). Both radical mechanism and non-radical mechanism existed in the MRSB/PS system, and SO4- and singlet oxygen (1O2) played a determinative role. This study might give a new way to reuse abandoned rape straw and synthesize new recyclable catalysts for activating PS to degrade organic pollutants in water.


Assuntos
Tetraciclina , Água , Carvão Vegetal , Fenômenos Magnéticos
14.
Sci Total Environ ; 758: 143883, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33338792

RESUMO

Mercury (Hg) is toxic and can affect human health through soil entering food chain. Spinach absorb easily heavy metals. Corn stover biochar can improve soil structure and physicochemical property. This study wanted to establish a Hg-corn stover biochar-soil-spinach model including 1 control group (without HgCl2 and corn stover biochar) and 24 treatment groups (with HgCl2 or/and corn stover biochar). Hg concentration was 0, 1, 2, 4, and 6 mg kg-1, respectively. Corn stover biochar contents were 0%, 1%, 3%, 5%, and 7% w/w, respectively. The results showed that residual Hg concentrations was the largest and water soluble and exchangeable Hg as well as carbonate bound Hg concentrations were the lowest among five Hg forms. Hg concentrations in four Hg treatment groups were higher than the control group in dose-dependent manner. The deposition of 6 mg kg-1 Hg was the highest. Corn stover biochar decreased Hg migration from soil to leaching solution and spinach, and passivation effect of 7% concentration of corn stover biochar was the best. Besides, corn stover biochar relieved the increase of methyl Hg caused by Hg in soil. Moreover, Hg concentration in roots was the highest and Hg concentration in stems was the lowest in spinach. Furthermore, Hg absorbed by roots was more than the sum of Hg absorbed by stems and leaves. In addition, we also found that the measured soil Hg concentrations were coincided with the predicted soil Hg concentrations under 1, 2, and 4 mg kg-1 Hg concentrations, except 2 mg kg-1 Hg at 7% C. Under 6 mg kg-1 Hg concentration, measured soil Hg concentrations was lower than that of the predicted soil Hg concentrations. Taken together, our findings indicated that corn stover biochar can increase edible safety of spinach by immobilizing Hg in soil and be used as an organic amendment.


Assuntos
Mercúrio , Poluentes do Solo , Carvão Vegetal , Humanos , Mercúrio/análise , Solo , Poluentes do Solo/análise , Spinacia oleracea , Zea mays
15.
J Environ Manage ; 279: 111685, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33321351

RESUMO

In this work, chemical and structural properties of various biochars were analyzed and compared with those from a highly stable anthropic soil, Terra Preta de Índio (TPI). TPI is believed to be responsible for the fertility of Amazonian soils and their stability; therefore, the production of a synthetic TPI would be of great interest for agricultural applications. Biochar produced from different raw biomasses were comprehensively characterized and, based on the obtained results, a preliminary study was performed testing three different routes of chemical activation using nitric acid, phosphoric acid, and potassium hydroxide as activating agents. After chemical activations, metal contents in the biochars decreased, as expected, and high degrees of carbonization were observed. In the case of the activation performed with HNO3, intense signals related to carboxylic groups in TG-MS analysis and in potentiometric titrations point out to a highly oxygenated biochar. Structural analysis showed that activations generated point defects in sp2-carbon structures of biochar, with the material obtained after KOH activation showing a high surface area (569 m2 g-1), an important feature for the use as soil amendment.


Assuntos
Carvão Vegetal , Solo , Agricultura , Biomassa
16.
J Environ Manage ; 279: 111824, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33333381

RESUMO

Conversion of sewage sludge (SS) into biochar through pyrolysis is an alternative to make this residue useful for agricultural purposes. Despite advances in interpreting the functions of SS biochar (SSB) for improving soil quality, it is still necessary to understand its residual effect on the dynamics of heavy metals (HM), especially under field conditions in tropical soils. Therefore, the objective of this study was to evaluate the residual effect of the application of SSB obtained at different pyrolysis temperatures on the accumulation, availability and bioaccumulation of HMs by corn cultivated in a tropical soil. For this purpose, a field experiment was conducted for three years to assess the total and available levels of HMs in the soil and the leaf concentration after suspending the application of 30 t ha-1 of SSB produced at 300 °C (BC300) and 500 °C (BC500). In general, the HM contents were below the maximum allowed by environmental legislation in several countries. SSB, regardless of temperature, was effective in immobilizing non-essential HMs for plants, such as Cd, Co, Cr and Pb, in the soil. On the other hand, SSB was able to supply micronutrients to corn plants after amendment ceased. Thus, the lack of negative long-term effects confirms the feasibility and safety of using SSB in agricultural areas with regards to contamination by HM, and makes it an alternative for the disposal of domestic SS.


Assuntos
Metais Pesados , Poluentes do Solo , Bioacumulação , Carvão Vegetal , Metais Pesados/análise , Esgotos , Solo , Poluentes do Solo/análise
17.
Chemosphere ; 266: 129175, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33341701

RESUMO

Schwertmannite was successfully loaded onto biochar (Sch@BC) using a biosynthetic method. The physicochemical properties and structural morphology of Sch@BC were explored using XRD, SEM, BET, and XPS. The results showed that introducing biochar can effectively prevent the agglomeration of Sch. The catalytic activity of Sch@BC in the Fenton-like degradation of sulfamethoxazole (SMX) was also systematically investigated under different reaction conditions. Under optimum conditions ([SMX] = 10 mg L-1, [H2O2] = 2.0 mM, Sch@BC = 1.0 g L-1 and initial pH = 3.0), the removal efficiencies of the SMX and total organic carbon (TOC) were 100% and 45.9%, respectively, within 60 min of the reaction. The results of the radical scavenger effect and ESR studies suggested that the SMX degradation in the Sch@BC/H2O2 system was dominated by a heterogeneous Fenton-like reaction. The repeated use of Sch@BC for SMX degradation demonstrated its reusability and stability in Fenton-like reactions. There was also speculation about the degradation mechanism and pathways of SMX. Furthermore, under the same conditions, the removal efficiencies of sulfadiazine (SD) and sulfisoxazole (SIZ) under Fenton-like degradation in the Sch@BC system were 91% and 93%. The results provide a theoretical basis and practical guidance for the creation of a new catalyst using biochar as a support material for the degradation of sulfanilamide antibiotics.


Assuntos
Antibacterianos , Peróxido de Hidrogênio , Catálise , Carvão Vegetal , Compostos de Ferro , Sulfanilamida
18.
Pest Manag Sci ; 77(2): 834-843, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32926587

RESUMO

BACKGROUND: Allelochemicals can act as biopesticides or enhance the action of synthetic pesticides. In this work, we assessed the bioavailability of the allelochemical coumarin in soils amended with fresh or field-aged biochars (BCs). The fresh BC from oak wood (Fresh BC) was prepared at 550 °C and was buried for aging in two different places: in a sandy loam soil in Spain for 15 months (Aged BC_1) and a sandy loam soil in USA for six months (Aged BC_2). RESULTS: Sorption experiments showed that all BCs were able to increase the affinity of soil towards coumarin, with the distribution coefficient following the order: unamended soil < Aged BC_2-amended soil < Aged BC_1-amended soil < Fresh BC-amended soil. All biochars ensure greater persistence of coumarin and the effect was more pronounced at high chemical dose (10 mg kg-1 ). Conversely, leaching studies in soil columns revealed that BCs were able to maintain coumarin within the first 5 cm of top-soil with total amount extracted ranging between 17% and 22% for BC-amended soil and <1% for unamended soil. Leaching was only observed when coumarin was added at the highest rate. Likewise, the bioefficacy of coumarin against lettuce was enhanced only at 10 kg ha-1 with BC-amended soil. CONCLUSIONS: Biochar application to agricultural soils is a promising tool for the management of natural compounds with potential use as biopesticides, such as coumarin, because it increases sorption, persistence and, in some cases, bioefficacy. The results reveal that this effect still persists with aging of BC in soils.


Assuntos
Poluentes do Solo , Solo , Adsorção , Disponibilidade Biológica , Carvão Vegetal , Cumarínicos , Feromônios , Poluentes do Solo/análise , Espanha
19.
Bioresour Technol ; 322: 124430, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33383476

RESUMO

Biochar was utilized to intensify constructed wetland (CW) for further organic and nitrogen removal from secondary wastewater. Four sets of non-aerated biochar amended vertical flow CW (VFCW) were developed to investigate the synergistic effects of biochar and microbes on pollutant removal. Results showed that the average COD and nitrogen removal efficiencies of VFCW1 (with 1% w/w biochar with microbe and plants) achieved 89.1 ± 5.6% and 90.2 ± 3.1% respectively, and their corresponding removal rates of 10.2 ± 0.8 mg-COD/(m3.d) and 3.57 ± 0.3 mg-TN/(m3.d) which were 35 and 52.3% higher than control. The biochar's dissolved organic carbon release in VFCWs indicated that water and acidic media portray the optimum conditions for nitrogen removal. The 16S RNA gene sequencing analysis indicated that in the biochar-amended VFCWs, bacterial phylum Proteobacteria (24.13-51.95%) followed by Chloroflexi (5.64-25.01%), Planctomycetes (8.48-14.43%), Acidobacteria (2.29-11.65%) were abundantly enhanced. Conclusively, incorporating biochar in non-aerated VFCWs is an efficient technique for enhancing nitrogen removal from secondary effluent.


Assuntos
Microbiota , Áreas Alagadas , Carbono , Carvão Vegetal , Desnitrificação , Nitrogênio/análise , Eliminação de Resíduos Líquidos , Águas Residuárias
20.
Huan Jing Ke Xue ; 42(1): 274-282, 2021 Jan 08.
Artigo em Chinês | MEDLINE | ID: mdl-33372479

RESUMO

In order to study the performance and mechanisms of bioretention pond media (Enteromorpha prolifera biochar) for NH4+-N removal in rainfall runoff, three kinds of alkali modified biochars (marked as BC1, BC2, and BC3) were prepared with various concentrations of NaOH solution (1, 2, and 3 mol·L-1) to explore their adsorption performance for NH4+-N. The results showed that:① Appropriate modifications of the NaOH concentration increased the specific surface area and surface microstructure of biochar, with the content of O and the surface functional groups being enriched. In addition, BC2 possessed the best adsorption performance. ② The adsorption capacity reached a maximum when the pH was 9.0 and the dosage of biochar was 0.5 g·L-1. Compared with BC, the adsorption capacity of BC1 and BC2 increased by 6.4% and 10.8%, respectively, while BC3 decreased by 13.7%. Moreover, BC2 had an optimal adsorption efficiency with a saturated adsorption capacity of 16.76mg·g-1. ③ The adsorption mechanism of biochar belonged to chemical adsorption with a monomolecular layer. The adsorption process was promoted by the high pH of biochar, the electrostatic attraction of biochar pores, the complexation and oxidization of the functional groups of hydroxyl (-OH), carboxyl (-COOH), and carbon-oxygen single bond (C-O). To sum up, the proper amount of NaOH to modify biochar can improve the adsorption performance of NH4+-N, and the modified biochar can be used as media of the bioretention pond to remove NH4+-N.


Assuntos
Amônia , Carvão Vegetal , Adsorção , Nitrogênio
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