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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: 111600, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396120

RESUMO

Field experiments was conducted to evaluate the effectiveness of sepiolite (S), sepiolite + fungi residues (SFR) and sepiolite + vermicompost (SVC) on in situ immobilization remediation of Cd contaminated soils. The results showed that treatments of S, SFR and SVC decreased soil Cd availability by 15.2-47.8%, 17.5-44.9% and 13.2-44.9%, respectively, when compared with the control groups. Moreover, the content of Cd in edible parts of Lactuca sativa L., Cichorium endivia L. and Brassica campestris L. was experienced a decrease of 15.9-41.9%, 1.6-38.0% and 29.0-37.4% reduction, respectively, under the amended soil. The improvement of soil fertility was obtained under addition of SVC and SFR, while the amounts of available P, K, organic matter, microbial carbon, microbial nitrogen and dehydrogenase activity were increased by 9.6-68.2%, 1.2-28.3%, 37.5-70.5%, 4.1-121.0%, 220-640% and 6.8-56.8%, respectively, in contrast to CK. Moreover, high-throughput sequencing analysis showed that the combined treated soils got higher values of alpha diversity indices, Chao1, ACE and Shannon. The number of dominant phyla (Proteobacteria, Acidobacteria, Gemmatimonadetes, Crenarchaeota) and genera (Aquicella, Lysobacter, Candidatus Nitrososphaera, Sphingopyxis, Mesorhizobium) were enhanced. Therefore, the use of sepiolite and organic amendments could be an adequate strategy to immobilization remediation of Cd-contaminated soils.


Assuntos
Cádmio/análise , Recuperação e Remediação Ambiental , Poluentes do Solo/análise , Brassica , Poluição Ambiental , Silicatos de Magnésio , Solo/química , Microbiologia do Solo
3.
Ecotoxicol Environ Saf ; 208: 111734, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396063

RESUMO

Hexavalent chromium [Cr(VI)] has strong mobility and it can enter into deep regions of soil. Cr(VI)-contaminated soil remediation is the process of removing Cr(VI) present in deep soils and any residual Cr(VI). In this study, the Cr(VI)-contaminated soil in Chongqing was investigated, and the remediation and economic feasibility of chemical leaching and reduction combined with a soil repairing approach was explored. The results showed that the leaching reagent, liquid-solid ratio, leaching time, reduction agent dosage, reduction temperature and reduction time had significant (P < 0.05) effects on the remediation of Cr(VI). At 0.02 mol/L oxalic acid and citric acid using a liquid-solid ratio of 5:1 and leaching time of 45 min, the removal rate of Cr(VI) was 62.7%, the residual Cr(VI) in soil was 126 mg/kg, and the soil pH was 4.09 after leaching. Between 25 and 90 °C, and at a molar ratio of 25:1 of FeSO4•7 H2O to Cr(VI), the reduction rate of Cr(VI) in soil after reduction was 54.0-98.4%, and the leaching concentration of Cr(VI) in soil was 0.01-0.29 mg/L. The optimal reduction was at 90 °C for 60 min, resulting in only 2.7 mg/kg of residual Cr(VI) in soil. The cost of this technology to treat the area studied was 826 ¥/ton of soil, which represents an economically feasible method for Cr(VI)-contaminated soil remediation.


Assuntos
Cromo/química , Recuperação e Remediação Ambiental/métodos , Poluentes do Solo/química , Ácido Cítrico , Poluição Ambiental , Ácido Oxálico , Solo , Poluentes do Solo/análise
4.
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
5.
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
6.
Water Res ; 189: 116688, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33278722

RESUMO

Fe-based materials used to adsorb P are commonly considered to be limited by the increased Fe lability, while Fe in drinking water treatment residue (DWTR) shows stable P adsorption abilities. Accordingly, this study aimed to gain insight into Fe lability in DWTR as compared to FeCl3 and Fe2(SO4)3 using Fe fractionation, EXAFS, and high-throughput sequencing technologies. The results showed that compared to Fe2(SO4)3 and FeCl3, Fe was relatively stable in the DWTR under the effects of organic matter, sulfides, and anaerobic conditions. Typically, the addition of FeCl3 and Fe2(SO4)3 enhanced Fe mobility in sediment and overlying water, promoting the formation of Fe-humin acid and ferrous sulfides (FeS and FeS2). However, the addition of DWTR, even at relatively high doses of Fe, has limited impact on Fe mobility. The addition remarkably increased oxidizable Fe in sediment (by approximately 63%), causing Fe to be dominated by oxidizable and residual fractions (like those in raw DWTR); EXAFS analysis also suggested that Fe-humin acid increased substantially with the addition of DWTR, becoming the main Fe species in sediment (with a relative abundance of 50.1%). Importantly, the Fe distributions were stable in sediment with DWTR added, which demonstrated that organic matter stabilized the Fe in the DWTR. Further analysis indicated that all materials promoted the enrichment of bacterial genera potentially related to Fe metabolism (e.g., Bacteroides, Dok59, and Methanosarcina). Fe2O3 in the FeCl3 and Fe2(SO4)3 groups and Fe-HA in the DWTR group were the key species affecting the microbial communities. Overall, the stabilizing effect of organic matter on Fe in DWTR could be used to develop Fe-based materials to enhance Fe stability for environmental remediation.


Assuntos
Água Potável , Recuperação e Remediação Ambiental , Purificação da Água , Adsorção , Água Potável/análise , Reciclagem
7.
Water Environ Res ; 93(1): 136-147, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32495995

RESUMO

Electrokinetic remediation (EKR) is one of the most successful remediation techniques to treat the sediments contaminated with heavy metals. EDTA is the most widely used enhancing agent to improve the transport process in EKR. But often the generated effluents from EKR contains a high concentration of heavy metals, which cannot be disposed of without treatment. The major objective of this study includes the estimation of optimal concentration of chelating agent EDTA, followed by treatment of contaminated sediments by EKR technique for heavy metal removal. The effluents generated from EKR were further studied for recovery and reuse of EDTA and for safe discharge of heavy metals. The optimum concentration of EDTA was found as 0.05 M with a solid-to-liquid ratio as 1:10. When fresh EDTA was used as enhancing agent the average removal of heavy metals obtained as 74.8% with EKR, whereas the application of recovered EDTA in treatment process in first, second, and third cycle showed the slight reduction of heavy metals of about 71.1%, 63.5%, and 52.1%, respectively. The heavy metal removal by recovered EDTA was effective in reduction of heavy metals up to three cycles of re-use while reducing the ecological risk in sediments. PRACTITIONER POINTS: Treatment of contaminated sediments with heavy metals achieved by electrokinetic remediation (EKR) technique enhanced with EDTA. The recovery of EDTA and heavy metal reduction from the generated effluents during EKR treatment were performed by the addition of FeCl3 and Na2 PO4, and optimized concentration was evaluated. This study found that the use of recovered EDTA in EKR treatment has effectively reduced the risk associated with heavy metals.


Assuntos
Recuperação e Remediação Ambiental , Metais Pesados , Poluentes do Solo , Quelantes , Ácido Edético , Sedimentos Geológicos , Metais Pesados/análise , Poluentes do Solo/análise
8.
Chemosphere ; 266: 128969, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33220980

RESUMO

The in-situ treatment of solid wastes might be regarded as cost-effective and minimum environmental fingerprint solution, particularly with reference to contaminated soils, offering several benefits compared to ex-situ methods. In this short communication it is described the study of a lab-scale coaxial dielectric barrier discharge (DBD) plasma reactor simulating the in-situ soil remediation conditions for the first time. In this conceptual design, the contaminated medium is handled as a part of the electrical discharge, while the plasma discharges are produced directly within the contaminated porous medium under treatment, thus scattering reactive species directly in the air contained inside its interconnected pores. The in-situ cold plasma setup was used to remediate bauxite samples highly contaminated by oil sludge contaminants. A very high TOC removal (∼70%) was achieved after 30 min of plasma treatment time with the corresponding energy consumption being 0.53 kWh kg-1. Carbon balance analysis of the exhaust gases revealed that 61% of the removed pollutant was converted to CO2, 19% was decomposed to CO, and 20% was emitted as VOCs. The scale-up of the presented in-situ cold plasma approach could lead to a promising alternative for the fast, cost-effective, and green in-situ remediation of granular porous, heavily contaminated with hydrocarbons contaminated sites.


Assuntos
Recuperação e Remediação Ambiental , Gases em Plasma , Poluentes do Solo , Características da Família , Solo , Poluentes do Solo/análise
9.
Chemosphere ; 266: 128988, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33243569

RESUMO

Remediation of soils contaminated with hydrocarbon materials is of particular importance due to their association with food chain. One of the remediation methods, which has been taken into account in recent years by researchers, is the electrokinetic technique. In this study, the electrokinetic method was used in combination with the Fenton technique to remove phenanthrene from clay soil. Oxidizing agent and catalyst used in the Fenton technique greatly influenced the efficiency of the remediation process. To investigate the effect of these two factors on the remediation process, it was made use of three different types of electrodes as catalyst, including graphite, iron, and copper, as well as hydrogen peroxide and sodium persulfate with different concentrations as oxidizing agent. During the 9 experiments designed, factors affecting removal efficiency, such as remediation time, electric current intensity, electroosmotic flow rate, and pH of the cathode and anode reservoirs were also investigated. Overall, the use of the electrokinetic-Fenton method with 15% hydrogen peroxide and copper electrode exhibited a 100% increase in the process efficiency over the same time period required to perform the conventional electrokinetic method and removed 93% of the soil phenanthrene, these findings indicated that combining the Fenton technique with the electrokinetic method enhanced the efficiency of this method in removing organic pollutants from the soil. Also, the use of sodium persulfate as an oxidizing agent in the electrokinetic method increased the removal efficiency by more than 95% over the half time period required to perform the conventional electrokinetic method.


Assuntos
Recuperação e Remediação Ambiental , Fenantrenos , Poluentes do Solo , Oxidantes , Solo , Poluentes do Solo/análise
10.
Chemosphere ; 266: 128934, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33246700

RESUMO

Environmental biotechnology is the use of biotechnology to develop and regulate biological systems for the remediation of environmental contamination. Nature has gifted ample material for remediation of its resources, among which chitosan is one of the most important and largely available biomaterial globally. Chitosan is a biopolymer obtained by deacetylation of chitin extracted from marine waste and its applications from drug delivery to food additives are broadly available. Chitosan exhibit several properties such as availability, low cost, high biocompatibility, and biodegradability. These properties make it biologically and chemically acceptable for use in various fields. Due to some limitations of pure chitosan, there has been a growing interest in modifying the chitosan in order to improve the original properties and widen the applications of pure phase chitosan. Various modified forms of chitosan and their associated applications are reviewed here with emphasis on their use in environmental remediation. The demand of chitosan in the global industrial market is growing which is briefly explained in this paper. Chitosan is used for water purification since a long time and still progress is going on for making it more efficient in the removal process. It can be used as a flocculent and coagulant, as an adsorbent for removing the contaminants like heavy metals, dyes, pesticides, antibiotics, biological contaminants from wastewater. Soil remediation using chitosan material is explained in this review. Various other applications such as drug delivery, food additives, tissue engineering are thoroughly reviewed.


Assuntos
Quitosana , Recuperação e Remediação Ambiental , Metais Pesados , Purificação da Água , Águas Residuárias
11.
J Environ Manage ; 278(Pt 2): 111567, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33129029

RESUMO

Communities with contaminated lands are also often the most vulnerable to the impacts of a changing climate such as sea-level rise, increased temperatures, and extreme storms and hurricanes due to socio-economic and historic reasons - some of the very factors that enable the creation of these contaminated sites in these communities. In spite of, and arguably because of, this double exposure and impact, the ability of these communities to clean up and reuse their contaminated lands has not kept up with their need. Researchers have often attributed this discrepancy to a lack of technical capacity and human resource. To address this lack, since January 2018, students enrolled in planning-related courses offered by the University of West Florida Department of Earth and Environmental Sciences have engaged with stakeholders on the redevelopment of superfund sites located in Pensacola, FL under the auspices of the USEPA's College Underserved Community Partnership Program. The engagement centered on the reuse of two of these superfund sites for the betterment of the stakeholders' socio-economies and their biophysical environments. I focus in this paper on four examples of engaging with students in planning for superfund site remediation and redevelopment. The examples are of engaging with county staff; collaboratively engaging with city staff and a private firm; engaging with county commissioners; and engaging with a private firm between two superfund sites over the course of one year. I highlight the contextual, unique needs, of each stakeholder group yet emphasize the applicable lessons across all four examples. I also focus on best practices to develop plans and outlines for mutually beneficial products and outcomes for both students and stakeholder groups in the process of land revitalization.


Assuntos
Recuperação e Remediação Ambiental , Eliminação de Resíduos , Florida , Substâncias Perigosas , Humanos , Estudantes
12.
Chemosphere ; 265: 129071, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33248732

RESUMO

Electrokinetic remediation is a widely admitted technology forrectifying heavy metal-contaminated soil. Various technologies have been effectively developed to improve the metal removal efficiency of contaminated soil by electrochemical treatment alone or in combination with other remediation technologies. The working components for electrokinetic system, such as supplying power for electric fields, installing electrodes to generate electric fields, introducing electrolytes and other potential materials as a reactive medium are crucial. This review focuses on the specific functions of the working components in electrokinetic systems and their effects on the efficiency of heavy metal removal using electrochemical process. The advancements in working components were systematically summarized, such as power for electric fields, electrodes, electrolytes and ion exchange membrane, which have various impacts on the effectiveness of electrokinetic remediation. Additionally, this study introduces the application of dominating technologies at present coupled with electrokinetics. Overall, a judicious design and reasonable operation in the application of electrokinetic-coupled remediation should be implemented to enhance the removal process of heavy metals from contaminated soil.


Assuntos
Recuperação e Remediação Ambiental , Metais Pesados , Poluentes do Solo , Poluição Ambiental , Metais Pesados/análise , Solo , Poluentes do Solo/análise
13.
Chemosphere ; 265: 129070, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33257048

RESUMO

Phenanthrene contaminated soil was remediated by the photochemical process of ferrous oxalate. Without using H2O2 and adjusting soil pH, phenanthrene in contaminated soil was degraded effectively by the ferrous oxalate under visible light irradiation. Ferrous oxalate possesses excellent visible light absorption ability which benefits the degradation of phenanthrene in soil under visible light irradiation. Via the Fe(II)/Fe(III) catalytic cycle of ferrous oxalate, H2O2 and Fe(II) could be produced continuously and H2O2 was further catalyzed by Fe(II) and released hydroxyl radicals (•OH) to degrade the phenanthrene in soil. The dosage of ferrous oxalate, moisture content of soil, and soil thickness were most important factors for degradation of phenanthrene in soil. In addition, a good mixing of ferrous oxalate and soil was vital for enhancing the degradation ratio of phenanthrene. After phenanthrene contaminated soil was treated by ferrous oxalate, the toxicity of treated soil was evaluated via the lettuce cultivation experiments. It was demonstrated the toxicity of phenanthrene contaminated soil was significantly reduced by ferrous oxalate according to the growth indexes of lettuces, including root length, leaf length, and fresh weight. This environment-friendly soil remediation method based on ferrous oxalate has huge potential in the remediation of organic pollutant contaminated soil.


Assuntos
Recuperação e Remediação Ambiental , Fenantrenos , Poluentes do Solo , Compostos Férricos , Peróxido de Hidrogênio , Oxalatos , Fenantrenos/análise , Fenantrenos/toxicidade , Solo , Poluentes do Solo/análise , Poluentes do Solo/toxicidade
14.
Sci Total Environ ; 756: 143865, 2021 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-33293085

RESUMO

Bioelectrochemical approaches offer a simple, effective, and environmentally friendly solution to pollutant remediation. As a versatile technology, although many studies have shown its potential in soil heavy metal(loid) remediation, the mechanism behind this process is not simple or well-reviewed. Thus, in this review we summarized the impacts of the microbial fuel cells (MFCs) on metal (loids) movement and transformation in the soil environment in terms of changes in soil pH, electromigration, and substrate competition between anode-respiring bacteria and the soil microbial community. Furthermore, the progress of MFCs in the fixation/removal of different elements from the soil environment is described. Hence, this review provides critical insight into the use of the MFC for soil metal(loid) bioremediation.


Assuntos
Fontes de Energia Bioelétrica , Recuperação e Remediação Ambiental , Metais Pesados , Poluentes do Solo , Metais Pesados/análise , Solo , Poluentes do Solo/análise
15.
Sci Total Environ ; 756: 144142, 2021 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-33302075

RESUMO

Oil leakage, which is inevitable in the process of extraction, processing, transportation and storage, seriously undermines the soil and groundwater environment. Surfactants can facilitate the migration and solution of oil contaminants from nonaqueous phase liquid (NAPL) or solid phase to water by reducing the (air/water) surface tension, (oil/water) interfacial tension and micellar solubilization. They can effectively enhance the hydrodynamic driven remediation technologies by improving the contact efficiency of contaminants and liquid remediation agents or microorganism, and have been widely used to enhance the remediation of oil-contaminated sites. This paper summarizes the characteristics of different types of surfactants such as nonionic, anionic, biological and mixed surfactants, their enhancements to the remediation of oil-contaminated soil and groundwater, and examines the factors influencing surfactant performance. The causes of tailing and rebound effects and the role of surfactants in suppressing them are also discussed. Laboratory researches and actual site remediation practices have shown that various types of surfactants offer diverse options. Biosurfactants and mixed surfactants are superior and worth attention among the surfactants. Using surfactant foams, adding shear-thinning polymers, and combining surfactants with in-situ chemical oxidation are effective ways to resolve tailing and rebound effects. The adsorption of surfactants on soils and aquifer sediments decreases remediation efficiency and may cause secondary pollution, Therefore the adsorption loss should be noticed and minimized.


Assuntos
Recuperação e Remediação Ambiental , Água Subterrânea , Poluentes do Solo , Poluição Ambiental , Solo , Poluentes do Solo/análise , Solubilidade , Tensoativos
16.
Chemosphere ; 262: 127803, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32755694

RESUMO

Mine tailings pose a huge hazard for environmental and human health, and the establishment of vegetation cover is crucial to reduce pollutant dispersion for the surroundings. However, their hostile physicochemical conditions hamper plant growth, compromising phytoremediation strategies. This study aims to investigate the role of organo-mineral amendments and plant growth-promoting rhizobacteria (PGPR) on the improvement of mine tailings properties and Lolium perenne L. (ryegrass) growth. Plants were grown in mine tailings mixed with an agricultural soil (1:1), 10% compost, and supplied with two different inorganic amendments - rock phosphate (6%) or lime (3%), and inoculated with the rhizobacterial strains Advenellakashmirensis BKM20 (B1) and Mesorhizobium tamadayense BKM04 (B2). The application of organo-mineral amendments ameliorated tailings characteristics, which fostered plant growth and further enhanced soil fertility and microbial activity. These findings were consistent with the increase of total organic carbon levels, with the higher numbers of heterotrophic and phosphate solubilizing bacteria, and higher dehydrogenase and urease activities, found in these substrates after plant establishment. Plant growth was further boosted by PGPR inoculation, most noticeable by co-inoculation of both strains. Moreover, inoculated plants showed increased activities for several antioxidant enzymes (catalase, peroxidase, polyphenoloxidase, and glutathione reductase) which indicate a reinforced antioxidant system. The application of agricultural soil, compost and lime associated with the inoculation of a mixture of PGPR proved to enhance the establishment of vegetation cover, thus promoting the stabilization of Kettara mine tailings. Nonetheless, further studies are needed in order to confirm its effectiveness under field conditions.


Assuntos
Biodegradação Ambiental , Recuperação e Remediação Ambiental/métodos , Mesorhizobium/fisiologia , Desenvolvimento Vegetal , Poluentes do Solo/análise , Bactérias , Compostos de Cálcio , Lolium/crescimento & desenvolvimento , Minerais , Mineração , Óxidos , Solo/química
17.
Chemosphere ; 262: 127955, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33182160

RESUMO

As common advanced oxidation processes, Fenton-like and peroxymonosulfate (PMS) processes have received enormous attention due to their high efficiency in the pollutants degradation. In this study, the Co/g-C3N4 photocatalyst was prepared by facial calcination strategy and used to evaluate the behavior of the Co/g-C3N4/H2O2 and Co/g-C3N4/PMS systems for norfloxacin (NOR) photocatalytic degradation under visible light irradiation. The composite photocatalysts exhibited better performance compared to that of pure g-C3N4 due to the efficient separation of electron-hole pairs and visible light absorption. The Co/g-C3N4/PMS system possessed better photocatalytic performance than the Co/g-C3N4/H2O2 system, where the degradation ratio of NOR and removal ratio of total organic carbon (TOC) were 96.4% and 54%, respectively, in 10 min. The photocatalytic mechanism was investigated using reactive species trapping experiments and electron spin-resonance spectroscopy (ESR). ⋅OH and SO4⋅- were the dominant reaction species in the Co/g-C3N4/H2O2 and Co/g-C3N4/PMS systems, respectively. According to the analysis of the NOR degradation path, SO4⋅- could attack the C-H bond on the piperazine ring or quinolone group of NOR, which resulted in it more active and accelerating the destruction of NOR with SO4⋅- and ⋅OH. The destruction of the quinolone group was the main pathway in the H2O2 process, while the destruction of the piperazine ring was the main pathway in the PMS process. In sum, the Co/g-C3N4/PMS process had a higher photocatalytic activity and economic applicability.


Assuntos
Cobalto/química , Grafite/química , Peróxido de Hidrogênio/química , Luz , Nitrilos/química , Norfloxacino/análise , Peróxidos/química , Catálise , Recuperação e Remediação Ambiental , Modelos Teóricos , Norfloxacino/química , Norfloxacino/efeitos da radiação , Oxirredução
18.
Chemosphere ; 263: 127981, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32822946

RESUMO

Hydrothermal carbonization technology has attracted wide attention in recent years owing to its advantages, e.g., high yield and clean production, compared with traditional pyrolysis. Anaerobic fermentation (AF) is a new method to modify carbon materials, which may improve the surface properties of hydrochar (HC). To explore whether AF has effects on different feedstocks based HCs, two kinds of HCs derived from wheat straw and poplar sawdust were treated with AF for different time in this study. By comparing the changes in physicochemical properties of anaerobic fermentative hydrochars (AFHCs), adsorption behaviors of Cadmium (Cd2+) on AFHCs were evaluated. The results showed that the surface electrical characteristics, specific surface area, and oxygen-containing functional groups of HCs improved significantly after AF treatment, which confirmed our hypothesis that AF is suitable for improving the adsorption of different feedstocks based HCs. The adsorption capacity of Cd2+ on AFHCs was significantly enhanced by a 3.1-3.4 times increase after AF treatment. The effect of AF treatment on wheat straw hydrochar (WHC) was more evident than poplar sawdust hydrochar (SHC). WHCs treated with AF own higher adsorption capacity of Cd2+, which was attributed to the higher negative charge, more exchangeable cations, and more oxygen-containing functional groups. The adsorption process was found to be a spontaneous endothermic reaction dominated by chemisorption and controlled by electrostatic attraction, ion exchange, functional groups complexation, and π-bonding coordination. These results were contributed to understanding the modification of HC by AF and its application in heavy metal pollution remediation.


Assuntos
Cádmio/metabolismo , Recuperação e Remediação Ambiental/métodos , Adsorção , Anaerobiose , Cádmio/análise , Carbono , Carvão Vegetal/química , Fermentação , Metais Pesados , Triticum
19.
Ecotoxicol Environ Saf ; 207: 111292, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32919193

RESUMO

As a hydrophobic pollutant, benzo(a)pyrene (BaP) is difficult to be degraded by microbes due to its poor water solubility. To improve its water solubility, this study harvested a biosurfactant from swine wastewater. The role of the biosurfactant in BaP biodegradation in contaminated water and soil were investigated. The biodegradation kinetics of BaP in contaminated water and the improvement of soil properties were determined. Results showed that critical micelle concentration (CMC) of the biosurfactant was 46.8 mg/L. The biosurfactant has a high pH stability in range of 3-9 and a strong salt stability in NaCl concentration range of 0-20%. At concentrations of 1, 2, 3, 4 and 5 CMC, the biosurfactant increased BaP water solubility by 1.4, 2.6, 4.0, 5.2 and 6.6 times. BaP biodegradation in contaminated water was effectively promoted by the biosurfactant, and the concentrations of BaP in sludge phase decreased to 1.015 mg/L (47.9% decrement) and 0.675 mg/L (65.4% decrement) when the dosed biosurfactant were 1 and 3 CMC, respectively. The biodegradation kinetics of BaP in contaminated water by the biosurfactant fitted well with the two-compartment kinetic model well (R2 > 0.90). For the bioremediation of BaP contaminated soil, adding 0.1%-0.5% (w/w) biosurfactant biodegraded 39.2%-84.8% of BaP, while the control without biosurfactant was 24.2%. In addition, the application of the biosurfactant significantly improved the properties of the contaminated soil, behaved as the increase in microbial quantity, water holding capacity (WHC) and dehydrogenase (DH) activity of the soil. To sum up, the biosurfactant facilitated the BaP biodegradation and can be effectively used in in-site remediation of polycyclic aromatic hydrocarbons (PAHs) (BaP in this study) contaminated water and soil.


Assuntos
Benzo(a)pireno/análise , Recuperação e Remediação Ambiental/métodos , Poluentes do Solo/análise , Tensoativos/química , Águas Residuárias/química , Poluentes Químicos da Água/análise , Animais , Biodegradação Ambiental , Cinética , Pseudomonas/metabolismo , Solo/química , Solubilidade , Tensoativos/metabolismo , Suínos , Águas Residuárias/microbiologia
20.
Ecotoxicol Environ Saf ; 207: 111275, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32920316

RESUMO

In-situ immobilization is an effective and economically viable strategy for remediation of soil extensively polluted with heavy metals. The long-term sustainability is critical for the remediation practice. In the present study, a ten-year experiment was performed in a Cd-polluted agricultural field to evaluate the long-term stability of lime, silicon fertilizer (SF), fused calcium magnesium phosphate fertilizer (FCMP), bone charcoal, steel slag, and blast furnace slag with one-off application. All amendments had no significant effect on biomass but significantly reduced Cd uptake by Artemisia selengensis at higher dose. Among them, SF and FCMP applied at 1% could reduce Cd uptake by more than 40% to meet the Chinese maximum permissible limit for Cd content in food products (50 µg kg-1). These amendments stimulated high Cd immobilization by increasing the soil pH and decreasing the soil acid-extractable Cd content, which were closely associated with Cd uptake. In addition, the two amendments altered the soil microbial structure and stimulated metabolism pathways, including amino acid, carbohydrate, and lipid metabolism, which are beneficial for soil function and quality. The results proved that SF and FCMP at 1% are stable and ecologically safe amendments, suitable for long-term Cd immobilization, and provide a strategy to mitigate the risk of food product contamination in heavy-metal-polluted soil.


Assuntos
Cádmio/análise , Monitoramento Ambiental , Poluentes do Solo/análise , Biomassa , Cádmio/metabolismo , Compostos de Cálcio , Carvão Vegetal/química , Poluição Ambiental , Recuperação e Remediação Ambiental , Fertilizantes , Metais Pesados/química , Óxidos , Fosfatos , Solo/química
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