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1.
Environ Monit Assess ; 194(2): 70, 2022 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-34994870

RESUMO

Biochar derived from banana peels can be used as an alternative nutrient in the soil that can promote crop growth while reducing fertiliser usage. Biochar stability has proportional relationship to biochar residence time in the soil and potassium is one of the vital nutrients needed for plant growth. This research aims at providing optimum pyrolysis operating conditions like temperature, residence time, and heating rate using banana peels as feedstock. An electrical tubular furnace was used to conduct the pyrolysis process to convert banana peels into biochar. The elemental compositions of biochar are potassium, oxygen (O), and carbon (C) content. The O:C ratio was used as the biochar stability indicator. Analysis of results showed that operating temperature has the most remarkable effect on biochar yield, biochar stability, and biochar's potassium content. In addition, a multilayer feedforward artificial neural network model was developed for the pyrolysis process. Eleven training algorithms were selected to model the multi-input multi-output neural network (MIMO). The most suitable training algorithm was identified through four performance criterions which are root mean square error (RMSE), mean absolute error (MSE), mean absolute percentage error (MAPE), and regression (R2). The results show that the Levenberg-Marquardt backpropagation training algorithm has the lowest error. From the chosen training algorithm, neural network was trained, and optimum operating parameters for banana peel were predicted at 490 °C, 110 min, and 11 °C/min with a high yield of 47.78%, O/C ratio of 0.2393, and 14.04 wt. % of potassium.


Assuntos
Musa , Pirólise , Carvão Vegetal , Monitoramento Ambiental , Redes Neurais de Computação , Nutrientes , Solo , Temperatura
2.
Environ Pollut ; 296: 118751, 2022 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-34973382

RESUMO

Straw and biochar amendments have been shown to increase soil organic carbon (SOC) stocks in arable land; however, their effects on hydrological fluxes of dissolved organic carbon (DOC), which may offset the benefits of C sequestration amounts remain uncertain. Therefore, we conducted a three-year field study that included four treatments (CK, control with no fertilizer; NPK, synthetic N fertilizer; RSDNPK, synthetic N fertilizer plus crop residues; BCNPK, synthetic N fertilizer plus biochar of crop straw) to investigate the effects of straw and biochar amendment on DOC losses through hydrological pathways of overland flow and interflow from a wheat-maize rotation system in the subtropical montane agricultural landscape. We detected substantial intra- and inter-annual variations in runoff discharge, DOC concentration, and DOC fluxes for both overland flow and interflow pathways, which were primarily attributed to variations in rainfall amount and intensity. On average, the DOC concentrations for interflow (2.98 mg C L-1) were comparable with those for overland flow (2.71 mg C L-1) throughout the three-year experiment. However, average annual DOC fluxes for interflow were approximately 2.60 times greater than those for overland flow, which probably related to higher runoff discharges of interflow than overland flow. Compared to the control, on average, the N fertilization treatments significantly decreased the annual DOC fluxes of overland flow and significantly increased annual DOC fluxes of interflow. Relative to the application of synthetic N fertilizer only, on average, crop straw amendment practice significantly increased annual DOC fluxes of interflow by 28.7%, while decreasing annual DOC fluxes of overland flow by 12.0%; in contrast, biochar amendment practice decreased annual DOC fluxes of interflow by 25.3% while increasing annual DOC fluxes of overland flow by 44.6%. Overall, considering both overland flow and interflow, crop straw amendment significantly increased hydrological DOC fluxes, whereas biochar had no significant effects on hydrological DOC fluxes throughout the three-year experiment. We conclude that crop straw incorporation strategies that aim to increase SOC stocks may enhance hydrological losses of DOC, thereby in turn offsetting its benefits in the subtropical montane agricultural landscapes.


Assuntos
Carbono , Solo , Agricultura , Carvão Vegetal , Fertilizantes
3.
Huan Jing Ke Xue ; 43(1): 398-408, 2022 Jan 08.
Artigo em Chinês | MEDLINE | ID: mdl-34989524

RESUMO

In order to economically and efficiently remove dissolved organic matter (DOM) in the secondary water of wastewater treatment plants, this study adopted iron-nitrogen co-doped biochar material (Fe-N-C) as a new adsorbent and systematically analyzed the effect of this new carbon material on the secondary water DOM, as well as the adsorption performance, kinetic process, selectivity, and mechanism of action. In addition, the long-term performance and reusability of the adsorption material were thoroughly investigated through a fixed-bed adsorption device. The results show that Fe-N-C had outstanding adsorption performance for secondary water DOM. When the dosage was only 1.0 g·L-1, the removal rates of TOC, UV254, and UV280 were as high as 40.18%, 76.92%, and 78.26%, respectively, which are far higher. Regarding the adsorption effect of pure biochar and conventional activated carbon, the adsorption process conformed to the pseudo-second-order kinetics and Freundlich adsorption isotherm model, indicating that the adsorption process is a multilayer chemical adsorption involving valence electrons and the exchange of electrons. The three-dimensional fluorescence spectroscopy, molecular weight distribution, and resin analysis results, such as classification and characterization, showed that Fe-N-C had selective adsorption for different components in the secondary water DOM. The fixed bed adsorption column with Fe-N-C as the core had the maximum removal rate of secondary water TOC, UV254, and UV280 as high as 94.09%, 95.65%, and 97.18%, respectively, and had good stability. It was close to adsorption saturation when the processing capacity reached 620 times the bed volume. However, after the regeneration heat treatment, the adsorption performance was remarkably restored. These results are expected to provide reference for the further development of high-efficiency adsorption water treatment technology.


Assuntos
Carvão Vegetal , Poluentes Químicos da Água , Adsorção , Ferro , Cinética , Nitrogênio , Poluentes Químicos da Água/análise
4.
Huan Jing Ke Xue ; 43(1): 540-549, 2022 Jan 08.
Artigo em Chinês | MEDLINE | ID: mdl-34989539

RESUMO

To study changes in phosphatase activity, we examined the diversity of phoC and phoD gene microbial communities in the rhizosphere and non-rhizosphere soil of plants under the treatment of chemical fertilizer and organic fertilizer combined with biochar. These results can provide a certain theoretical guidance for the conversion of insoluble phosphorus in the soil phosphorus pool to the inorganic phosphate ion that can be absorbed by plant roots and also provide a certain experimental basis for the improvement of the availability of phosphorus in the soil and the agricultural utilization of biochar. In this study, corn stalks and rice husk stalks were used as test materials, and the pot experimental method was adopted using the following treatments:set control (CK), traditional fertilization (F), chemical fertilizer+20 t·hm-2 rice husk biochar (FP), chemical fertilizer+10 t·hm-2rice husk biochar+10 t·hm-2 corn biochar (FPM), organic fertilizer+20 t·hm-2 rice husk biochar (PP), and fresh organic fertilizer+20 t·hm-2 rice husk biochar (NPP). We determined the rhizosphere and non-rhizosphere soil acid phosphatase (ACP) activity and alkaline phosphatase (ALP) activity and used T-RFLP technology to analyze the diversity of phoC and phoD genes in order to clarify the impact of biochar on the micro-ecosystem formed by the plants, soil, and microorganisms. The results showed that:① the ALP and ACP activities of each treatment in the non-rhizosphere soil were lower than that of CK. In the rhizosphere soil, the ALP activity was significantly increased after the combined application of chemical fertilizer and organic fertilizer with biochar, and the ACP activity in the rhizosphere soil was higher than that in the non-rhizosphere soil. ② The combined application of biochar with chemical fertilizers and organic fertilizers significantly increased the diversity of phoC and phoD genes communities in rhizosphere and non-rhizosphere soils (P<0.05); the diversity and richness of microbial communities in rhizosphere soil were higher than that in non-rhizosphere soils. ③ ACP activity was negatively correlated with phoC gene microbial community, and most ALP activity was positively correlated with phoD microbial community.


Assuntos
Fertilizantes , Microbiota , Carvão Vegetal , Fertilizantes/análise , Monoéster Fosfórico Hidrolases , Rizosfera , Solo , Microbiologia do Solo
5.
J Environ Manage ; 304: 114282, 2022 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-34920283

RESUMO

Reliable approaches for accurately assessing the performance of stormwater treatment systems is essential for their effective design, including filter media selection which can be a significant constituent in stormwater treatment systems. This study presents an innovative modelling approach integrating the Tank Model with the adsorption-desorption characteristics of the filter media. The resulting modelling approach was applied to simulate a field-scale bioretention basin where biochar was used as filter media with over ten years of rainfall records. The resulting outflow and overflow volumes were compared with observed data for calibration. The Stormwater Treatment Tank Model (STTM) was validated using the Leave-One-Out-Cross-Validation (LOOCV) method. The simulation outcomes include water outflow and overflow (quantity) from the bioretention basin as well as outflow water quality represented by three heavy metals (Pb, Cu, and Zn). The modelling approach developed was found to be capable of accurately simulating outflow and overflow volumes, with outlet water quantity being significantly influenced by the total rainfall depth. The modeling results also suggested that a sole treatment system would not be adequate, particularly for large rainfall events (>100 mm) and a treatment train would be more effective. Simulating long-term (over ten years) pollutant removal performance in the bioretention basin indicated that heavy metals outflow event mean concentration (EMCs) values calculated using simulated results of 30% biochar application rate generated the best pollutant removal with consistent values (2.7 µg/L, 3.0 µg/L, 17.2 µg/L for Pb, Cu, and Zn, respectively). These results confirm that the modelling approach is reliable for assessing long-term treatment performance, as well as a robust tool able to contribute to more effective treatment system design, particularly filter media selection and evaluation.


Assuntos
Chuva , Purificação da Água , Adsorção , Carvão Vegetal , Abastecimento de Água
6.
J Environ Manage ; 304: 114297, 2022 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-34933264

RESUMO

A magnetic nitrogen-doped sludge-based biochar (NAlSB-Fe-Si) was prepared based on waterworks sludge for raw material and dicyandiamide for nitrogen source to adsorb methylene blue (MB) from water. And the magnetic particles loaded on the adsorbent were obtained through functionalizing iron and silicon ions which were extracted from the biochar by acid and alkali impregnation. Physicochemical properties of sludge-based biochar (SB) were analyzed by SEM, BET, FTIR, XRD, XPS and VSM. Compared with the original biochar, NAlSB-Fe-Si had richer pore structure and higher pore volume, and the SiO2 and Fe3O4 loading made the specific surface area increased by 200%. Possible adsorption mechanism was proposed by exploring the initial pH, MB concentration and reaction time. Results revealed that alkaline environment was more conducive to the rapid removal of cationic dyes such as MB. Pseudo-second-order kinetic model and intra-particle diffusion model could describe the adsorption behavior of MB on NAlSB-Fe-Si. The fitting results of Langmuir model showed that adsorption temperature is positively correlated with adsorption capacity, and the maximum adsorption capacity of MB on nitrogen-doped sludge-based biochar (NSB) and NAlSB-Fe-Si at 25 °C was 26.47 and 300.36 mg/g, respectively. Finally, the MB removal rate of NAlSB-Fe-Si could still reach 70% after four cycles, indicating that the composite was an efficient cationic dye adsorbent, and its preparation could be regarded as a way of resource utilization of waterworks sludge.


Assuntos
Azul de Metileno , Poluentes Químicos da Água , Adsorção , Carvão Vegetal , Cinética , Esgotos , Dióxido de Silício , Poluentes Químicos da Água/análise
7.
Chemosphere ; 289: 133203, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34896172

RESUMO

Use of untreated municipal wastewater (WW) contains toxic trace elements that pose a serious threat to the soil-plant-human continuum. The use of biochar (BC) is a promising approach to minimize trace element induced toxicity in the ecosystem. Therefore, the present study aims to evaluate the efficacy of BC derived from wheat straw and iron oxide nanoparticles doped biochar (IO-BC) to reduce trace element buildup in soil and plants that consequently affect tomato plant growth and physiological activity under WW irrigation. The BC and IO-BC were applied at four levels (0, 0.5, 1, and 1.5%) in WW irrigated soils. The results indicated that the addition of WW + BC and WW + IO-BC resulted in significant reduction in trace element mobility in soil. Interestingly, the application of WW + IO-BC (1.5%) was more effective in reducing trace element mobility and bioavailability in soil by 78% (As), 58% (Cr), 46% (Pb) and 50% (Cd) compared to WW irrigation, and thus reduced trace element accumulation and toxicity in plants. Results revealed that WW irrigation negatively affected tomato growth, fruit yield, physiology and antioxidative response. Addition of WW + BC and WW + IO-BC ameliorated the oxidative stress (up to 65% and 58% in H2O2 and MDA) and increased plant tolerance (up to 49% in POD and APX activity). The risk indices also showed minimum human health risk (H1 < 1) from tomato after the addition of BC or IO-BC in WW irrigated soils. It is concluded that IO-BC addition in WW irrigated soil could assist in reducing trace elements accumulation and toxicity in tomato and associated human health risks.


Assuntos
Lycopersicon esculentum , Poluentes do Solo , Oligoelementos , Carvão Vegetal , Ecossistema , Humanos , Peróxido de Hidrogênio , Nanopartículas Magnéticas de Óxido de Ferro , Solo , Poluentes do Solo/análise , Poluentes do Solo/toxicidade
8.
Chemosphere ; 289: 133243, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34896417

RESUMO

Dual functional innovative approaches were developed to tackle the algal scum problem in water by utilizing the algal (Spirogyra sp.) biomass waste for organic dye-laden industrial wastewater treatment, a global problem, and challenge. Therefore, an algal biochar-based nanocomposite (nAgBC) was synthesized and employed as a low-cost adsorbent for Congo red (CR) removal. Surface morphology, physicochemical characteristics, elemental composition, phase, and stability of the nanocomposite was analyzed using BET, FESEM-EDX, FTIR, XRD, XPS, and TGA. The nanocomposite was found to be thermostable, mesoporous with large and heterogeneous surface area, containing nAg as doped material, where -OH, NH, CO, CC, SO, and CH are the surface binding active functional groups. Maximum adsorption efficiency of 95.92% (18 mg L-1 CR) was achieved (qe = 34.53 mg g-1) with 0.5 g L-1 of nanocomposite after 60 min, at room temperature (300 K) at pH 6. Isotherm and kinetic model suggested multilayer chemisorption, where adsorption thermodynamics indicated spontaneous reaction. Fluorescens spectral analysis of CR confirmed the formation of CR supramolecule, supporting enhanced adsorption. Furthermore, the result suggested a 5th cycle reusability and considerable efficacy towards real textile industrial effluents. Synergistic effects of the active surface functional groups of the biochar and nAg, along with the overall surface charge of the composite lead to chemisorption, electrostatic attraction, H-bonding, and surface complexation with CR molecules. Thus, synthesized nAgBC can be applicable to mitigate the wastewater for cleaner production and environment.


Assuntos
Nanocompostos , Poluentes Químicos da Água , Purificação da Água , Adsorção , Biomassa , Carvão Vegetal , Concentração de Íons de Hidrogênio , Cinética , Águas Residuárias , Poluentes Químicos da Água/análise
9.
Chemosphere ; 289: 133251, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34896419

RESUMO

Production of cost-efficient composite materials from low-cost modified biochar for the removal of Cd (II) from wastewater is much needed to meet the growing needs of industrial wastewater treatments. A novel chitosan-modified kiwi branch biochar (CHKB) was fabricated as low-cost modified biochar for the removal of Cd (II) from aqueous solution. Batch adsorption and characterization experiments indicated that the modification of kiwi biochar (KB) by chitosan remarkably improved its adsorption performance. The results revealed that the adsorption isotherms can be best described by a Langmuir model and that a pseudo-second-order model fits the Cd (II) adsorption kinetics well, which indicates that it is a monolayer process controlled by chemisorption. CHKB exhibited a Langmuir maximum adsorption capacity of Cd (II) (126.58 mg g-1), whereas that of KB was only 4.26 mg g-1. The adsorption ability of CHKB was improved by increasing the surface area and an abundance of surface functional groups (-OH, -NH, CO, etc.). The cation exchange, electrostatic interaction, surface complexation, and precipitation were the main mechanisms in the sorption of Cd (II) on CHKB. Excellent adsorption performance, low cost, and environmental-friendliness made CHKB a fantastic adsorbent for the removal of Cd (II) in wastewater.


Assuntos
Quitosana , Poluentes Químicos da Água , Adsorção , Cádmio/análise , Carvão Vegetal , Cinética , Poluentes Químicos da Água/análise
10.
Chemosphere ; 289: 133262, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34906528

RESUMO

High electron transfer rates and a higher number of electron transfer active sites play important roles in inhibiting the recombination of photogenerated electron-hole pairs. In the experiments described in this article, the g-C3N4/BC/Bi25FeO40 composite material was prepared to use biochar (BC) as the conductive channel. The presence of BC significantly increases the electron transfer rate due to its excellent electrical conductivity and can provide more electron transfer active sites. At the same time, BC provides a larger surface area and has a loose porous structure, which lead to excellent adsorption performance. Based on various characterization results, it was confirmed that the Z-scheme heterojunction was successfully constructed between g-C3N4 and Bi25FeO40. The photocatalytic experiment results showed that the degradation efficiency of g-C3N4/BC/Bi25FeO40 on the tetracycline hydrochloride (TCH) could reach 92.2% within 60 min. Parameters such as circulation stability, pH value of the solution and the amount of composite materials were studied. The synthesized composite material has good reusability and high efficiency in a wide pH range of 3-11. Its excellent photocatalytic activity is attributed to the formation of an effective Z-scheme heterostructure, as well as the rapid photoelectron transfer and excellent adsorption capacity of BC. This work provides a way to design new photocatalysts using semiconductor composite materials and BC materials.


Assuntos
Elétrons , Tetraciclina , Catálise , Carvão Vegetal , Luz
11.
Environ Pollut ; 295: 118687, 2022 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-34920043

RESUMO

Remediation of hydrophobic organic contaminants using activated carbon is an effective means by which to clean up contaminated areas. Predicting remediation success using laboratory experimentation with soil, however, is unclear. Current remediation efforts involving activated carbon addition to floodplain soils downstream of the Velsicol Chemical Corporation Superfund Site (VCCSS) have offered the opportunity to directly compare in situ activated carbon remediation with laboratory experimentation. The objective of the current study was to compare bioaccumulation of DDT, DDD, and DDE (DDX) residues by earthworms (Eisenia fetida) exposed to laboratory-aged (LA) or field-aged (FA) soils from four locations. Samples were evaluated at 0-, 3-, and 9-months post-remediation to determine the ability of laboratory studies to predict in situ remediation. Floodplain soils downstream from the VCCSS were amended with 2% by weight activated carbon in the field and the laboratory, and then aged for 3- or 9-months. At 0-, 3-, and 9-months bioaccumulation assays were conducted with LA and FA soils and tissue concentrations were compared within study sites. In both LA and FA soils, activated carbon caused significant reductions (37.01-92.94%) in bioaccumulated DDX in earthworms. Field-collected worms showed a similar trend in reduction of bioaccumulated DDX, suggesting activated carbon remediation was successful in reducing bioavailable DDX for native organisms within the floodplain soils. The rate of reduction in bioavailable DDX, however, was significantly faster in LA soils (ß = -0.189, p < 0.0001) compared to FA soils (ß = -0.054, p < 0.0038). Differences in temperature and methods of activated carbon incorporation between LA and FA soils may account for the differences in remediation rate, suggesting laboratory experiments may overpredict the extent or speed in which remediation occurs in the field. Therefore, use of laboratory studies in predicting success of activated carbon remediation may be most effective when conditions mimic field remediation as closely as possible.


Assuntos
Oligoquetos , Poluentes do Solo , Animais , Carvão Vegetal , DDT/análise , Solo , Poluentes do Solo/análise
12.
Environ Pollut ; 295: 118707, 2022 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-34923062

RESUMO

Biochar application into paddy is an improved strategy for addressing methane (CH4) stimulation of straw biomass incorporation. Whereas, the differentiative patterns and mechanisms on CH4 emission of straw biomass and biochar after long years still need to be disentangled. Considering economic feasibility, a seven-year of field experiment was conducted to explore the long-term CH4 mitigation effect of annual low-rate biochar incorporation (RSC, 2.8 t ha-1), with annual rice straw incorporation (RS, 8 t ha-1) and control (CK, with no biochar or rice straw amendment incorporation) as a comparation. Results showed that RSC mitigated CH4 emission while RS stimulated CH4 significantly (p < 0.05) and stably over 7 experimental years compared with CK. RSC mitigated 14.8-46.7% of CH4 emission compared with CK. In comparison to RSC, RS increased 111-950.5% of CH4 emission during 7 field experimental years. On the 7th field experimental year, pH was significantly increased both in RS and RSC treatment (p < 0.05). RSC significantly (p < 0.05) increased soil nitrate (NO3--N) compared with RS while RS significantly (p < 0.05) increased dissolved carbon (DOC) compared to RSC. Soil NO3--N inhibition on methanogens and promotion on methanotrophs activities were verified by laboratory experiment, while soil pH and DOC mainly promoted methanogens abundance. Significantly (p < 0.05) increased DOC and soil pH enhanced methanogens growth and stimulated CH4 emission in RS treatment. Higher soil NO3--N content in RSC than CK and RS contributed to CH4 mitigation. Soil NO3--N and DOC were identified as the key factors differentiating CH4 emission patterns of RS and RSC in 2019. Collectively, soil NO3--N impacts on CH4 flux provide new ideas for prolonged effect of biochar amendment on CH4 mitigation after years.


Assuntos
Óxido Nitroso , Oryza , Agricultura , Carvão Vegetal , Metano , Óxido Nitroso/análise , Solo
13.
Environ Pollut ; 295: 118714, 2022 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-34942291

RESUMO

The objective of this work was to evaluate the adsorption capacity of alkylated modified porous biochar prepared by esterification and etherification (PSAC-2) for low concentrate volatile organic compounds (VOCs, toluene and ethyl acetate) in high humidity environment by experiments and theoretical calculations. Results showed that PSAC-2 has a large specific surface area and weak surface polarity, at 80% relative humidity, its capacities for toluene and ethyl acetate adsorption could be maintained at 92% and 87% of the initial capacities (169.9 mg/g and 96.77 mg/g). The adsorption behaviors of toluene, ethyl acetate, and water vapor were studied by adsorption isotherms, and isosteric heat was obtained. The desorption activation energy was obtained by temperature programmed desorption experiment. The outcomes manifested that the PSAC-2 can achieve strong adsorption performance for weakly polar molecules. Through density functional theory (DFT) simulations, owing to the interaction of hydrogen bonds, oxygen-containing groups became a significant factor influencing the adsorption of VOCs in humid environments. These results could provide an important reference for VOCs control in a high humidity environment.


Assuntos
Pistacia , Compostos Orgânicos Voláteis , Adsorção , Alquilação , Carvão Vegetal , Umidade
14.
J Sci Food Agric ; 102(1): 167-174, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34080199

RESUMO

BACKGROUND: Nowadays a significant amount of land contaminated with toxic elements is being used for agriculture, posing a serious risk of crop contamination and toxicity. Several methodologies are being used to remediate soil contamination, including the use of amendments such as biochar. This work evaluated the effects of biochar combined with different fertirrigations (water, a conventional fertilizer solution, or a fertilizer solution with a commercial biostimulant derived from leonardite) on the availability of toxic elements and nutrients for pepper cultivated in a soil contaminated with As, Cd, Pb, and Zn. RESULTS: Irrigation with fertilizer solutions improved plant growth regardless of the biochar amendment. Biochar decreased the bioavailability of Cu and Pb in soil and the Cu content in pepper leaves. Combined with fertilization, biochar also decreased plant As and Pb content. Biochar combined with biostimulant decreased the bioavailable content of Cd in soil and its uptake by pepper plants. CONCLUSION: The use of biochar and biostimulant presented advantages for plant production in a non-suitable scenario of nutrient scarcity and contamination. © 2021 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.


Assuntos
Capsicum/metabolismo , Carvão Vegetal/química , Produção Agrícola/métodos , Fertilizantes/análise , Nutrientes/química , Poluentes do Solo/metabolismo , Adsorção , Transporte Biológico , Cádmio/química , Cádmio/metabolismo , Capsicum/química , Capsicum/crescimento & desenvolvimento , Chumbo/análise , Chumbo/química , Chumbo/metabolismo , Nutrientes/metabolismo , Folhas de Planta/química , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Solo/química , Poluentes do Solo/química , Zinco/química , Zinco/metabolismo
15.
Chemosphere ; 286(Pt 1): 131583, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34293558

RESUMO

Chemical degradation is one of the crucial methods for the remediation of hydrophobic organic compounds (HOCs) in soil/sediment. The sequestration effect of black carbon (BC) can affect the adsorption state of HOCs, thereby affecting their chemical degradability. Our study focused on the chemical degradability of 2-Chlorobiphenyl (PCB1) sequestrated on the typical BC (fly ash (FC), soot (SC), low-temperature biochar (BC400) and high-temperature biochar (BC900)) by iron-nickel bimetallic nanomaterials (nZVI/Ni) based on TENAX desorption technology. The results showed that PCB1 adsorbed in various states were simultaneously dechlorinated by nZVI/Ni. Specifically, rapid-desorption-state PCB1 tended to degrade more easily than resistant-desorption-state PCB1. Moreover, the degradation mechanism varied according to the type of BC. In the case of FC and SC, the degradation rate was lower than the desorption rate for the PCB1 in rapid and slow desorption states, and the degradation rate of PCB1 in the resistant desorption state was negligible. The PCB1 on FC and SC was first desorbed from BC and then degraded. However, in terms of BC400 and BC900, the degradation rate was higher than the desorption rate, and the degradation rate of the resistant-desorption-state PCB1 was 1.4 × 10-2 h-1 and 4.1 × 10-2 h-1, respectively. The graphitized structure of BC900 can directly transfer electrons, so more than 90% of the resistant-desorption-state PCB1 could be degraded. In addition, BC may affect the longevity of nZVI/Ni, thereby affecting its degradability. Therefore, the chemical degradability of BC-adsorbed HOCs should be comprehensively evaluated based on the adsorption state and the properties of BC.


Assuntos
Poluentes do Solo , Fuligem , Adsorção , Carvão Vegetal , Solo , Poluentes do Solo/análise , Tecnologia
16.
Chemosphere ; 286(Pt 1): 131490, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34293561

RESUMO

Excessive phosphate run-off with total phosphorus concentration greater than 20 µg P L-1 triggers the growth of harmful algal species in waterbodies and potentially leads to eutrophication. This has severe negative implications on aquatic environment and impacts human health. The annual economic impact of harmful algal blooms is reported to be as high as $25 million for public health and commercial fishery sector, $29 million for recreation/tourism sector and $2 million for monitoring and management. Adsorption is widely considered as an effective and economic strategy to achieve extremely low concentration of phosphorus. The char produced by valorizing various waste biomasses have been gaining attention in phosphorus remediation owing to their availability, their ability to regenerate and reuse. This review paper exclusively focuses on utilizing hydrochar and biochar synthesized from waste biomass, respectively, through hydrothermal carbonization and slow pyrolysis to mitigate phosphorus concentration and potential strategies for handling the spent char. The key mechanisms involved in phosphate adsorption are electrostatic interaction, ion exchange and complexation. The maximum adsorption capacity of hydrochar and biochar ranges from 14-386 mg g-1 and 3-887 mg g-1, respectively. Hydrochar and biochar are cost-effective alternative to commercial activated carbon and spent char can be used for multiple adsorption cycles. Furthermore, extensive research studies on optimizing the feedstock, reaction and activation conditions coupled with technoeconomic analysis and life cycle assessment could pave way for commercialization of char-based adsorption technology.


Assuntos
Carvão Vegetal , Águas Residuárias , Adsorção , Biomassa , Humanos , Fosfatos
17.
Chemosphere ; 286(Pt 1): 131591, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34303053

RESUMO

Drinking water safety cannot be overemphasized. Filamentous fungi have many excellent features for metal removal. Both graphene oxide (GO) and activated carbon (AC) are conventional metal adsorbents, but they are not suitable for large-scale use due to high cost. In this study, a low dosage of conidia (2.0 × 104 conidia/mL) of metal-resistant/adapted filamentous fungus Penicillium janthinillum strain GXCR were co-immobilized with a low dosage of 0.5 mg/L GO or 0.5 mg/L AC by embedding in 2% polyvinyl alcohol (PVA)-3% sodium alginate (SA), generating six types of microbead adsorbents (MBAs) to remove metals from a low concentration of either single metal (100 mg/L) or mixed metals (100 mg/L each) of Pb (II), Fe (III) and Cu (II) in drinking water. Fungus GXCR-containing MBAs had higher specific surface areas (SSAs), better mesoporous structures, and a higher removal rate (85-98.99%) of single or mixed metals. Singl-metal adsorptions of MBAs were almost unaffected by temperature changes. MBAs showed a stable removal rate of 87-94% during four cycles of adsorption-desorption of single metal. Single-metal adsorptions were well described by multiple models of Freundlich isotherm with constant values of 0.21-0.432, Langmuir isotherm with constant values of 0.037-0.17, Pseudo-fist-order, Pseudo-second-order, and intra-particle diffusion (IPD). In conclusion, co-immobilization between GXCR, GO and AC can make metal removal more efficient. Adsorption capacity is increased with SSAs but not in the same proportion. Single-metal adsorptions involve multiple mechanisms of monolayer and multilayer adsorptions, external mass transfer, and IPD. IPD is important but not the only one rate-controlling step for single-metal adsorptions.


Assuntos
Água Potável , Penicillium , Poluentes Químicos da Água , Adsorção , Carvão Vegetal , Compostos Férricos , Grafite , Cinética , Chumbo , Poluentes Químicos da Água/análise
18.
Chemosphere ; 286(Pt 1): 131622, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34303903

RESUMO

The widespread use of per- and polyfluoroalkyl substances (PFASs)-related products such as aqueous film-forming foams (AFFF) has led to increasing contamination of groundwater systems. The concentration of PFASs in AFFF-impacted groundwater can be several orders of magnitude higher than the drinking water standard. There is a need for a sustainable and effective sorbent to remove PFASs from groundwater. This work aims to investigate the sorption of PFASs in groundwater by biochar column. The specific objectives are to understand the influences of PFASs properties and groundwater chemistry to PFASs sorption by biochar. The PFASs-spiked Milli-Q water (including 19 PFASs) and four aqueous film-forming foams (AFFF)-impacted groundwater were used. The partitioning coefficients (log Kd) of long chain PFASs ranged from 0.77 to 4.63 while for short chain PFASs they remained below 0.68. For long chain PFASs (C ≥ 7), log Kd increased by 0.5 and 0.8 for each CF2 moiety of PFCAs and PFSAs, respectively. Dissolved organic matter (DOM) was the most influential factor in PFASs sorption over pH, salinity, and specific ultraviolet absorbance (SUVA). DOM contained hydrophobic compounds and metal ions which can form DOM-PFASs complexes to provide more sorption sites for PFASs. The finding is useful for executing PFASs remediation by biochar filtration column, especially legacy long chain PFASs, for groundwater remediation.


Assuntos
Fluorcarbonetos , Água Subterrânea , Poluentes Químicos da Água , Carvão Vegetal , Fluorcarbonetos/análise , Água , Poluentes Químicos da Água/análise
19.
Chemosphere ; 286(Pt 1): 131470, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34311401

RESUMO

Heavy metals in the soil are major global environmental problems. Waste cotton was used to synthesize a novel ß-CD/hydrothermal biochar (KCB), which is a low-cost and environment-friendly adsorbent for heavy metal soil remediation. KCB were used as reactive materials of electrokinetic-permeable reactive barrier (EK-PRB) to explore the removal characteristics of heavy metals. FTIR and XPS analysis revealed that KCB contained large numbers of surface functional groups. Adsorption of KCB for Pb2+ and Cd2+ reached 50.44 mg g-1 and 33.77 mg g-1, respectively. Metal ions in contaminated soil were removed by reactive barrier through electromigration, electrodialysis and electrophoresis, the removal efficiency of Pb2+ and Cd2+ in soil reached 92.87% and 86.19%. This finding proves that KCB/EK-PRB can be used as a cheap and green process to effectively remediate soils contaminated with heavy metals.


Assuntos
Recuperação e Remediação Ambiental , Metais Pesados , Poluentes do Solo , Carvão Vegetal , Metais Pesados/análise , Solo , Poluentes do Solo/análise
20.
Chemosphere ; 286(Pt 1): 131631, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34315073

RESUMO

Conventional thermochemical conversion techniques for biofuel production from lignocellulosic biomass is often non-selective and energy inefficient. Microwave assisted pyrolysis (MAP) is cost and energy-efficient technology aimed for value-added bioproducts recovery from biomass with less environmental impacts. The present review emphasizes the performance of MAP in terms of product yield, characteristics and energy consumption and further it compares it with conventional pyrolysis. The significant role of biochar as catalyst in microwave pyrolysis for enhancing the product selectivity and quality, and the influence of microwave activation on product composition identified through sophisticated techniques has been highlighted. Besides, the application of MAP based biochar as soil conditioner and heavy metal immobilization has been illustrated. MAP accomplished at low temperature creates uniform thermal gradient than conventional mode, thereby producing engineered char with hotspots that could be used as catalysts for gasification, energy storage, etc. The stability, nutrient content, surface properties and adsorption capacity of biochar was enhanced by microwave activation, thus facilitating its use as soil conditioner. Many reviews until now on MAP mostly dealt with operational conditions and product yield with limited focus on comparative energy consumption with conventional mode, analytical techniques for product characterization and end application especially concerning agriculture. Thus, the present review adds on to the current state of art on microwave assisted pyrolysis covering all-round aspects of production followed by characterization and applications as soil amendment for increasing crop productivity in addition to the production of value-added chemicals, thus promoting process sustainability in energy and environment nexus.


Assuntos
Carvão Vegetal , Micro-Ondas , Biomassa , Pirólise , Solo
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