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1.
Environ Monit Assess ; 196(7): 647, 2024 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-38907768

RESUMO

In this study, the current distribution probability of Ephedra gerardiana (Somalata), a medicinally potent species of the Himalayas, was assessed, and its spatial distribution change was forecasted until the year 2100 under three Shared Socioeconomic Pathways. Here, we used the maximum entropy model (MaxEnt) on 274 spatially filtered occurrence data points accessed from GBIF and other publications, and 19 bioclimatic variables were used as predictors against the probability assessment. The area under the curve, Continuous Boyce Index, True Skill Statistics, and kappa values were used to evaluate and validate the model. It was observed that the SSP5-8.5, a fossil fuel-fed scenario, saw a maximum habitat decline for E. gerardiana driving its niche towards higher altitudes. Nepal Himalayas witnessed a maximum decline in suitable habitat for the species, whereas it gained area in Bhutan. In India, regions of Himachal Pradesh, Uttarakhand, Jammu and Kashmir, and Sikkim saw a maximum negative response to climate change by the year 2100. Mean annual temperature, isothermality, diurnal temperature range, and precipitation seasonality are the most influential variables isolated by the model that contribute in defining the species' habitat. The results provide evidence of the effects of climate change on the distribution of endemic species in the study area under different scenarios of emissions and anthropogenic coupling. Certainly, the area of consideration encompasses several protected areas, which will become more vulnerable to increased variability of climate, and regulating their boundaries might become a necessary step to conserve the regions' biodiversity in the future.


Assuntos
Mudança Climática , Ecossistema , Nepal , Índia , Butão , Ephedra , Monitoramento Ambiental , Probabilidade , Fatores Socioeconômicos , Modelos Teóricos
2.
Environ Geochem Health ; 46(3): 98, 2024 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-38393462

RESUMO

Microplastics, which have a diameter of less than 5 mm, are becoming an increasingly prevalent contaminant in terrestrial and aquatic ecosystems due to the dramatic increase in plastic production to 390.7 million tonnes in 2021. Among all the plastics produced since 1950, nearly 80% ended up in the environment or landfills and eventually reached the oceans. Currently, 82-358 trillion plastic particles, equivalent to 1.1-4.9 million tonnes by weight, are floating on the ocean's surface. The interactions between microorganisms and microplastics have led to the transportation of other associated pollutants to higher trophic levels of the food chain, where microplastics eventually reach plants, animals, and top predators. This review paper focuses on the interactions and origins of microplastics in diverse environmental compartments that involve terrestrial and aquatic food chains. The present review study also critically discusses the toxicity potential of microplastics in the food chain. This systematic review critically identified 206 publications from 2010 to 2022, specifically reported on microplastic transport and ecotoxicological impact in aquatic and terrestrial food chains. Based on the ScienceDirect database, the total number of studies with "microplastic" as the keyword in their title increased from 75 to 4813 between 2010 and 2022. Furthermore, various contaminants are discussed, including how microplastics act as a vector to reach organisms after ingestion. This review paper would provide useful perspectives in comprehending the possible effects of microplastics and associated contaminants from primary producers to the highest trophic level (i.e. human health).


Assuntos
Cadeia Alimentar , Microplásticos , Poluentes Químicos da Água , Animais , Ecossistema , Monitoramento Ambiental , Microplásticos/toxicidade , Plásticos/toxicidade , Poluentes Químicos da Água/toxicidade , Poluentes Químicos da Água/análise
4.
Environ Monit Assess ; 195(4): 523, 2023 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-36988758

RESUMO

This study reports the exhalation rates of radon and thoron from surface soil collected from 60 rural sites of district Hisar, Haryana, India. The exhalation rates of Rn222 (radon) and Rn220 (thoron) were measured by portable SMART RnDuo (AQTEK SYSTEMS) using a mass accumulation chamber which was equipped with a scintillation material-coated cell. Dose rates due to natural gamma radiations ranged from 0.526 to 1.139 mSv y-1. The Rn222 mass exhalation rate in soil samples varied from 0.14 to 94.65 mBq kg-1 h-1. Thoron surface exhalation rates ranged from 46.42 to 619.88 Bq m-2 h-1. This study gives an idea about the differences in Rn222 and Rn220 exhalation at different locations which may be due to variations in geological features of the locations and characteristics of the topsoil. The findings show that usage of study area soil as building material is safe.


Assuntos
Poluentes Radioativos do Ar , Poluição do Ar em Ambientes Fechados , Monitoramento de Radiação , Radônio , Radônio/análise , Solo , Expiração , Poluentes Radioativos do Ar/análise , Índia , Poluição do Ar em Ambientes Fechados/análise , Habitação
5.
Environ Sci Pollut Res Int ; 30(60): 124884-124901, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36596976

RESUMO

Zinc and magnesium oxide nanoparticles were fabricated using green synthesis method for the sequestration of hexavalent chromium Cr(VI) from the aqueous medium. The biogenically prepared ZnO@EC and MgO@EC nanoparticles were successfully loaded on the Eucalyptus. The prepared nanomaterials were characterized using various techniques such as FESEM, TGA, XRD, EDX, FTIR, BET, and elemental mapping. FE-SEM analysis has revealed the surface morphology of ZnO nanoparticles, which were rod-like and spherical in shape, whereas MgO nanoparticles were of irregular shape. Batch mode was selected to remove the hexavalent chromium from aqueous solution using the prepared nanomaterials. The Cr(VI) adsorption was carried out under optimized conditions, viz., pH (3.0), adsorbent dose (0.05 g), contact time (150 min), temperature (25 ± 2 °C), and initial concentration (50 mg/L). The experimental results were compared using the different isotherm models; The observations have indicated that experimental data fit better with Freundlich (R2 = 0.99) and Langmuir (R2 = 0.99) isotherms, respectively. The maximum adsorption capacity of ZnO@EC and MgO@EC for Cr(VI) was found to be 49.3 and 17.4 mg/g, respectively. The regeneration study of the adsorbents was conducted using different desorbing agents viz., ethanol, NaOH, and NaCl. The desorbing agent NaOH performed better and showed removal percentage of 34.24% and 20.18% for ZnO@EC and MgO@EC, respectively, after the three reusability cycles. The kinetics of reaction was assessed using the pseudo-first-order and pseudo-second-order kinetic models. The experimental data of both the nanomaterials ZnO@EC and MgO@EC obeyed pseudo-second-order model with correlation coefficient values 0.999 and 0.983, respectively. The thermodynamic study confirmed that adsorption was feasible, spontaneous, and endothermic. The adsorbents were tested for spiked real water which confirms their applicability and potential in real water systems also. The results indicated fair removal of chromium suggesting applicability of both adsorbents.


Assuntos
Eucalyptus , Poluentes Químicos da Água , Purificação da Água , Óxido de Zinco , Água , Óxido de Zinco/química , Óxido de Magnésio , Hidróxido de Sódio , Termodinâmica , Cromo/química , Extratos Vegetais , Adsorção , Poluentes Químicos da Água/análise , Cinética , Concentração de Íons de Hidrogênio , Purificação da Água/métodos
6.
Environ Sci Pollut Res Int ; 30(34): 81319-81332, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35672639

RESUMO

This study deals with heavy metal ions removal from simulated water using biosynthesized silica-supported iron oxide nanocomposites (nano-IOS). Agricultural and garden wastes have been utilized to prepare nano-IOS through a green synthesis process. Nano-IOS was characterized by XRD, SEM, FTIR, and zeta potential analysis. The nanocomposites were used to remove five heavy metals, viz., Pb2+, Cd2+, Ni2+, Cu2+, and Zn2+, with optimization of reaction parameters including pH, the concentration of heavy metals, adsorbent dosage, and contact time in batch mode experiments. The optimized dose of nano-IOS was 0.75 g/L for the adsorption of Pb2+, Cd2+, Ni2+, Cu2+, and Zn2+ (10.0 mg/L) with a contact duration of 70 min at pH 5.0 for Pb2+, Cd2+, and Cu2+ and 6.0 for Ni2+ and Zn2+. The adsorption behavior of the nano-adsorbent was well described by Langmuir adsorption isotherm and pseudo-second-order kinetic model indicating chemisorption on the surface of nano-IOS. The adsorption was also found spontaneous and endothermic. Thus, the environmentally benign and bio-synthesized nano-IOS can be utilized as an effective nano-adsorbent for the rapid sequestration of heavy metal ions from water and wastewater.


Assuntos
Metais Pesados , Nanocompostos , Poluentes Químicos da Água , Purificação da Água , Dióxido de Silício/química , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/química , Metais Pesados/análise , Metais Pesados/química , Adsorção , Águas Residuárias/química , Eliminação de Resíduos Líquidos/métodos , Purificação da Água/métodos , Íons/química
7.
Chemosphere ; 289: 133101, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34863719

RESUMO

Herein, for the adsorption and detection of As (III), multifunctional nanohybrid have been synthesized using a solvothermal approach. Structural and functional characterizations confirmed the impregnation of the ZnO over graphene oxide. Nanohybrid exhibits a remarkable qmax (maximum adsorption capacity) of 8.17 mg/g, at an adsorbent dose of 3 g/L and pH of 8.23. Higher adsorption with nanohybrid was attributed to a large BET surface area of 32.950 m2/g. The chemical nature and adsorption behaviour of As(III) on ZnO-GO were studied by fitting the data with various adsorption isotherms (Langmuir & Freundlich) and kinetics models (six models). It is observed from the findings that removal of As(III) with ZnO-GO nanocomposite appears to be technically feasible with high removal efficiency. The feasibility of the nanocomposite to function as a sensor for the detection of As(III) was also evaluated. The fabricated sensor could detect As(III) with a lower limit of detection of 0.24 µM and linear range up to 80 µM. Overall, this study is significant in nanohybrid as a multifunctional composite for the adsorption and detection of As (III) from wastewater.


Assuntos
Arsênio , Grafite , Nanocompostos , Poluentes Químicos da Água , Purificação da Água , Adsorção , Arsênio/análise , Concentração de Íons de Hidrogênio , Cinética , Poluentes Químicos da Água/análise
8.
Pathogens ; 10(8)2021 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-34451467

RESUMO

Currently, there is a massive debate on whether meteorological and air quality parameters play a crucial role in the transmission of COVID-19 across the globe. With this background, this study aims to evaluate the impact of air pollutants (PM2.5, PM10, CO, NO, NO2, and O3) and meteorological parameters (temperature, humidity, wind speed, and rainfall) on the spread and mortality due to the COVID-19 outbreak in Delhi from 14 Mar 2020 to 3 May 2021. The Spearman's rank correlation method employed on secondary data shows a significant correlation between the COVID-19 incidences and the PM2.5, PM10, CO, NO, NO2, and O3 concentrations. Amongst the four meteorological parameters, temperature is strongly correlated with COVID-19 infections and deaths during the three phases, i.e., pre-lockdown (14 March 2020 to 24 March 2020) (r = 0.79), lockdown (25 March 2020 to 31 May 2020) (r = 0.87), and unlock (1 June 2020 to 3 May 2021) (r = -0.75), explaining the variability of about 20-30% in the lockdown period and 18-19% in the unlock period. NO2 explained the maximum variability of 10% and 7% in the total confirmed cases and deaths among the air pollutants, respectively. A generalized linear model could explain 80% and 71% of the variability in confirmed cases and deaths during the lockdown and 82% and 81% variability in the unlock phase, respectively. These findings suggest that these factors may contribute to the transmission of the COVID-19 and its associated deaths. The study results would enhance the ongoing research related to the influence of environmental factors. They would be helpful for policymakers in managing the outbreak of COVID-19 in Delhi, India.

9.
Chemosphere ; 280: 130792, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34162093

RESUMO

Environmental deterioration due to anthropogenic activities is a threat to sustainable, clean and green environment. Accumulation of hazardous chemicals pollutes soil, water and air and thus significantly affects all the ecosystems. This article highlight the challenges associated with various conventional techniques such as filtration, absorption, flocculation, coagulation, chromatographic and mass spectroscopic techniques. Environmental nanotechnology has provided an innovative frontier to combat the aforesaid issues of sustainable environment by reducing the non-requisite use of raw materials, electricity, excessive use of agrochemicals and release of industrial effluents into water bodies. Various nanotechnology based approaches including surface enhance scattering, surface plasmon resonance; and distinct types of nanoparticles like silver, silicon oxide and zinc oxide have contributed significantly in detection of environmental pollutants. Biosensing technology has also gained significant attention for detection and remediation of pollutants. Furthermore, nanoparticles of gold, ferric oxide and manganese oxide have been used for the on-site remediation of antibiotics, organic dyes, pesticides, and heavy metals. Recently, green nanomaterials have been given more attention to address toxicity issues of chemically synthesized nanomaterials. Hence, nanotechnology has provided a platform with tremendous applications to have sustainable environment for present as well as future generations. This review article will help to understand the fundamentals for achieving the goals of sustainable development, and healthy environment.


Assuntos
Poluentes Ambientais , Recuperação e Remediação Ambiental , Nanoestruturas , Ecossistema , Nanotecnologia
10.
Chemosphere ; 275: 130051, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33676273

RESUMO

Monocrotophos (MCP) is an organophosphate insecticide with broad application in agricultural crops like rice, maize, sugarcane, cotton, soybeans, groundnut and vegetables. MCP solubilize in water readily and thus reduced sorption occurs in soil. This leads to MCP leaching into the groundwater and pose a significant threat of contamination. The MCP's half-life depends on the temperature and pH value and estimated as 17-96 d. But the half-life of technical grade MCP can exceed up to 2500 days if properly stored at 38 °C in a glass or polyethylene container in a stable condition. It causes abnormality, ranging from mild to severe confusion, agitation, hypersalivation, convulsion, pulmonary failure, senescence in mammals and insects. MCP affects humans by inhibiting the activity of the acetylcholine esterase enzyme. MCP is accountable for the catalytic degradation of acetylcholine and affects the neurotransmission between neurons. This review discusses MCP's various aspects and fate on aquatic and terrestrial life forms, quantification methods for monitoring, various degradation processes, and their mechanisms. Different case studies related to its impact on the human population in different parts of the world have been discussed. Efforts have also been made to summarize and present different microbial population's role in its degradation and mineralization.


Assuntos
Inseticidas , Monocrotofós , Animais , Produtos Agrícolas , Ecossistema , Humanos , Inseticidas/toxicidade , Monocrotofós/toxicidade , Solo
11.
Environ Sci Pollut Res Int ; 27(28): 34862-34905, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32656757

RESUMO

This review discusses a fresh pool of research findings reported on the multiple roles played by metal-based, magnetic, graphene-type, chitosan-derived, and sonicated nanoparticles in the treatment of pharmaceutical- and agrochemical-contaminated waters. Some main points from this review are as follows: (i) there is an extensive number of nanoparticles with diverse physicochemical and morphological properties which have been synthesized and then assessed in their respective roles in the degradation and mineralization of many pharmaceuticals and agrochemicals, (ii) the exceptional removal efficiencies of graphene-based nanomaterials for different pharmaceuticals and agrochemicals molecules support arguably well a high potential of these nanomaterials for futuristic applications in remediating water pollution issues, (iii) the need for specific surface modifications and functionalization of parent nanostructures and the design of economically feasible production methods of such tunable nanomaterials tend to hinder their widespread applicability at this stage, (iv) supplementary research is also required to comprehensively elucidate the life cycle ecotoxicity characteristics and behaviors of each type of engineered nanostructures seeded for remediation of pharmaceuticals and agrochemicals in real contaminated media, and last but not the least, (v) real wastewaters are extremely complex in composition due to the mix of inorganic and organic species in different concentrations, and the presence of such mixed species have different radical scavenging effects on the sonocatalytic degradation and mineralization of pharmaceuticals and agrochemicals. Moreover, the formulation of viable full-scale implementation strategies and reactor configurations which can use multifunctional nanostructures for the effective remediation of pharmaceuticals and agrochemicals remains a major area of further research.


Assuntos
Poluentes Ambientais , Nanoestruturas , Poluentes Químicos da Água , Purificação da Água , Adsorção , Agroquímicos
12.
Environ Sci Pollut Res Int ; 26(14): 14024-14035, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30852751

RESUMO

Present study aimed to evaluate the vermicomposting of lignocellulosic wastes employing Eisenia fetida earthworms. The study examined the effectiveness of vermicomposting for 105 days by mixing lignocellulosic waste (LW) with cattle manure (CM) in five different proportions. Results revealed that TOC and C/N ratio decreased gradually till end and in vermicomposts varied between 268-320 g/kg and 12.26-16.85, respectively. Nutrient content (NPK) in the vermicomposts increased with time in all the mixtures. Heavy metals' content also increased in vermicomposts and benefit ratio for heavy metals ranged between 0.06 and 5.1. Increase in earthworm biomass (22.38-39.64 g) and reproduction (21.27-31.60 hatchlings/worm) was also satisfactory in all the waste mixtures. Based on results, it can be inferred that lignocellulosic waste can successfully be converted into good quality manure employing earthworms.


Assuntos
Compostagem/métodos , Lignina , Oligoquetos/fisiologia , Animais , Biomassa , Bovinos , Poluentes Ambientais/análise , Lamiaceae , Esterco , Metais Pesados/análise , Folhas de Planta , Reciclagem , Solo/química
13.
Environ Sci Pollut Res Int ; 24(24): 19938-19945, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28689288

RESUMO

Present investigation aims on the vermicomposting of the excreta of different ruminants to convert it into manure employing earthworm species, Eisenia fetida. A total of 11 feedstocks (FS1-FS11) with different ratios were prepared from the excreta of different ruminants, viz., sheep, cow, buffalo, and goat. Semi-composted feedstocks were fed to E. fetida for 90 days under laboratory conditions. Vermicomposting enhanced the nutrient contents of ruminant excreta and converted it into odor-free and homogenous vermicompost. The growth of E. fetida was significant in all the feedstocks, but largest biomass gain was achieved in buffalo excreta followed by [sheep + buffalo] > [goat + buffalo] and [cow + buffalo] feedstocks. Highest fecundity (782 ± 23.3) was also recorded in buffalo excreta followed by [goat + buffalo] excreta feedstock (484.6 ± 15.7). In vermicomposted feedstocks, total organic carbon and organic matter was lesser, while NPK and heavy metals were higher as compared to raw feedstocks. C/N ratios of vermicomposts ranged from 15.37 to 38.56, which indicate a good level of maturity and stabilization of feedstocks.


Assuntos
Compostagem/métodos , Esterco/análise , Oligoquetos/metabolismo , Ruminantes , Solo/química , Animais , Biomassa , Metais Pesados/análise , Oligoquetos/crescimento & desenvolvimento , Poluentes do Solo/análise
14.
Bioresour Technol ; 236: 11-19, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28390272

RESUMO

This is the first-ever study of its kind for an extensive assessment and comparison of maturity indexes between compost and vermicompost that have been derived from Municipal Solid Waste (MSW). The spectroscopic (Fourier transform infrared spectroscopy: FT-IR), thermogravimetric analysis (TG), differential scanning calorimetry (DSC) and structural characterization (scanning electron microscope: SEM) were recorded. FT-IR spectra showed an increase in conversion of polysaccharides species and aliphatic methylene groups in vermicompost compared to compost as depicted from the variation of the intensity of the peaks. TG curves of final vermicompost showed a much lower mass loss when compared to compost, indicating higher stability in feedstock. SEM micrographs of the vermicompost reflected strong fragmentation of material than composts which revealed the extent of intra-structural degradation of MSW. These findings elucidate on a clear comparison between composts and vermicomposts in terms of maturity indexes for soil enhancement and in agriculture as organic fertilizer.


Assuntos
Solo/química , Resíduos Sólidos , Varredura Diferencial de Calorimetria , Fertilizantes , Eliminação de Resíduos , Espectroscopia de Infravermelho com Transformada de Fourier
15.
Waste Manag ; 64: 51-62, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28302524

RESUMO

Waste management strategies for organic residues, such as composting and vermicomposting, have been implemented in some developed and developing countries to solve the problem of organic solid waste (OSW). Yet, these biological treatment technologies do not always result in good quality compost or vermicompost with regards to sanitation capacity owing to the presence of bacterial pathogenic substances in objectionable concentrations. The presence of pathogens in soil conditioners poses a potential health hazard and their occurrence is of particular significance in composts and/or vermicomposts produced from organic materials. Past and present researches demonstrated a high-degree of agreement that various pathogens survive after the composting of certain OSW but whether similar changes in bacterial pathogenic loads arise during vermitechnology has not been thoroughly elucidated. This review garners information regarding the status of various pathogenic bacteria which survived or diffused after the composting process compared to the status of these pathogens after the vermicomposting of OSW with the aim of achieving sanitation goals. This work is also indispensable for the specification of compost quality guidelines concerning pathogen loads which would be specific to treatment technology. It was hypothesized that vermicomposting process for OSW can be efficacious in sustaining the existence of pathogenic organisms most specifically; human pathogens under safety levels. In summary, earthworms can be regarded as a way of obliterating pathogenic bacteria from OSW in a manner equivalent to earthworm gut transit mechanism which classifies vermicomposting as a promising sanitation technique in comparison to composting processes.


Assuntos
Compostagem , Oligoquetos , Saneamento , Solo , Resíduos Sólidos , Animais , Objetivos , Humanos , Reciclagem
16.
Environ Sci Pollut Res Int ; 24(12): 11228-11239, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28299564

RESUMO

This work was conducted to evaluate and compare the responses of Phaseolus vulgaris to three types of composts and vermicomposts derived from municipal solid waste (MSW). Different amendment rates were used and evaluated for their effect on germination, growth, and marketable yield. MSW-derived vermicomposts and composts were substituted into mineral brown-earth soil, applied at rates of 0 (control), 10, 20, 30, 40, 50, and 100% (v/v) in plastic pots of 7.2-L capacity. Green beans which are grown in 40% vermicompost/soil mixtures and compost/soil mixtures yielded 78.3-89.5% higher fruit weights as compared to control. Results showed that MSW vermicomposts consistently outperformed equivalent quantities of composts in terms of fruit yield, shoot, and root dry weights, which can be attributed to the contributions of physicochemical properties and nutrients content (N, P, and K) in the potting experiments. Consequently, it seemed likely that MSW vermicompost provided other biological inputs such as plant growth regulators (PGRs) and plant growth hormones (PGHs), which could have a considerably positive effect on the growth and yields of P. vulgaris as compared to composts. More in-depth scientific investigation is required in order to identify the distinctive effects and the exact mechanisms of these PGRs in MSW vermicomposts which influenced plant growth responses.


Assuntos
Phaseolus/crescimento & desenvolvimento , Solo/química , Resíduos Sólidos , Animais , Oligoquetos
17.
Waste Manag ; 39: 130-45, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25708402

RESUMO

This study was undertaken to have comparative assessment of heavy metals content during composting and vermicomposting processing of Municipal Solid Waste (MSW). Six scenarios were set up in which three experiments were for composting (controls) denoted as S1 for food waste, S2 for paper waste and S3 for yard waste and the corresponding replicates for vermicomposting processes were S4, S5 and S6. Vermicomposting caused significant reduction in Cd (43.3-73.5%), Cr (11.3-52.8%), Cu (18.9-62.5%), Co (21.4-47.6%), Zn (34.6%) and Ni (19.9-49.6%) compared to composting which showed a progressive increase. Addition of worms did not show any effect on Fe and Mn, most probably from the genesis of organic-bound complexes. The efficacy of utilizing Eudrilus eugeniae was indicated by the high values of bioconcentration factors (BCFs) which were in the order of Cd>Ni>Cu>Co>Cr>Zn and the increase amount of these metals in the earthworms' tissue after the vermicomposting processes. Different values of BCFs were obtained for different heavy metals and this accounted that earthworms exert different metabolic mechanisms. Regression analysis of the reduction percentages (R) in relation to BCF showed that RCdtot.S6, RCrtot.S5 and RCutot.S6 were significantly correlated with BCFCd.S6, BCFCr.S5 and BCFCu.S6 respectively. Thus, in comparison to simple composting processes, data analysis suggested the feasibility of inoculating E. eugeniae to MSW in order to mitigate the content of toxic heavy metals.


Assuntos
Monitoramento Ambiental , Metais Pesados/metabolismo , Oligoquetos/metabolismo , Eliminação de Resíduos/métodos , Resíduos Sólidos/análise , Animais , Disponibilidade Biológica , Modelos Lineares
18.
J Environ Manage ; 91(4): 949-57, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20042266

RESUMO

This paper reports the adsorption of Cr(VI) ions from aqueous solution by sulphuric acid treated sunflower waste. Two adsorbents, namely SHC and SSC, were prepared from sunflower plant head and stem waste. The adsorbents were characterized by FT-IR, SEM and EDX. The surface areas of SHC and SSC were 1.17 and 1.28 m(2)g(-1), respectively. The effect of various process parameters namely pH, temperature, initial metal ion concentration, adsorbent dosage and contact time has been studied. The optimum conditions for removal of Cr (VI) were found to be pH=2, contact time=2h, adsorbent dosage=4.0 g/L, concentration=250 mg/L, temperature=25+/-1 degrees C, rpm=180. The percent removal at these optimum conditions was found to be 75.7% and 85.4% for SHC and SSC respectively. The Freundlich, Langmuir and D-R models were applied for mathematical description of adsorption equilibrium. Adsorption data were well described by the Langmuir isotherm with maximum adsorption capacities of 53.76 mg/g and 56.49 mg/g for SHC and SSC, respectively. Overall, the experimental results suggest that SHC and SSC could be used as low cost alternative adsorbents for the treatment of Cr(VI) containing wastewater. A comparison of different kinetic models showed that our data fitted well to the pseudo-second order model.


Assuntos
Carbono/química , Cromo/química , Helianthus , Eliminação de Resíduos Líquidos/métodos , Gerenciamento de Resíduos , Purificação da Água/métodos , Adsorção , Inflorescência/química , Íons , Cinética , Modelos Teóricos , Caules de Planta/química
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