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1.
Environ Res ; 253: 119124, 2024 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-38734294

RESUMO

Polyaromatic hydrocarbons (PAHs) are the most persistent compounds that get contaminated in the soil and water. Nearly 16 PAHs was considered to be a very toxic according US protection Agency. Though its concentration level is low in the environments but the effects due to it, is enormous. Advanced Oxidation Process (AOP) is an emergent methodology towards treating such pollutants with low and high molecular weight of complex substances. In this study, sulfate radical (SO4‾•) based AOP is emphasized for purging PAH from different sources. This review essentially concentrated on the mechanism of SO4‾• for the remediation of pollutants from different sources and the effects caused due to these pollutants in the environment was reduced by this mechanism is revealed in this review. It also talks about the SO4‾• precursors like Peroxymonosulfate (PMS) and Persulfate (PS) and their active participation in treating the different sources of toxic pollutants. Though PS and PMS is used for removing different contaminants, the degradation of PAH due to SO4‾• was presented particularly. The hydroxyl radical (•OH) mechanism-based methods are also emphasized in this review along with their limitations. In addition to that, different activation methods of PS and PMS were discussed which highlighted the performance of transition metals in activation. Also this review opened up about the degradation efficiency of contaminants, which was mostly higher than 90% where transition metals were used for activation. Especially, on usage of nanoparticles even 100% of degradation could be able to achieve was clearly showed in this literature study. This study mainly proposed the treatment of PAH present in the soil and water using SO4‾• with different activation methodologies. Particularly, it emphasized about the importance of treating the PAH to overcome the risk associated with the environment and humans due to its contamination.


Assuntos
Recuperação e Remediação Ambiental , Oxirredução , Hidrocarbonetos Policíclicos Aromáticos , Sulfatos , Sulfatos/química , Sulfatos/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Hidrocarbonetos Policíclicos Aromáticos/química , Recuperação e Remediação Ambiental/métodos , Poluentes Ambientais/química , Poluentes Ambientais/análise
2.
Environ Res ; 225: 115570, 2023 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-36868450

RESUMO

An integrated 1D/0D/1D hybrid nanomaterial was prepared from MWCNT supported carbon quantum dots @ MnO2 nanomaterial for a sensitive and selective electrochemical heavy metal ion sensor by hydrothermal methods. The developed nanomaterials were characterized by various analytical methods such as FESEM, HRTEM, XRD, FTIR, EDX and elemental mapping study, and also its electrochemical properties of the prepared samples were investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) analysis. Differential pulse voltammetry (DPV) analysis has been used to investigate the quantitative detection of heavy metal ions such as cadmium and chromium on modified electrodes under optimal conditions. The in-situ electrochemical sensitivity and selectivity of the samples were determined by varying various parameters, such as the concentration of heavy metal ions, different electrolytes and electrolyte pH. The observed DPV results show that prepared MWCNT (0.05 wt%) and CQD (0.1 wt%) supported MnO2 nanoparticles show effective detection response for chromium (IV) metal ion. In particular, 0D CQD, 1D MWCNT, and MnO2 hybrid nanostructures produced a synergistic effect among them, resulting in strong electrochemical performance of the prepared samples against the target metal ions.


Assuntos
Metais Pesados , Nanoestruturas , Compostos de Manganês/química , Óxidos/química , Íons , Eletrólitos
3.
Environ Res ; 216(Pt 4): 114756, 2023 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-36372148

RESUMO

Ecosystems are becoming more and more polluted, hence sustainable techniques of pollution removal are needed. In the recent times, exceedingly pure water has become ideal for several industries. Modern industry needs ultra-pure water, which is highly processed water that is devoid of colloidal particles and has a conductivity of less than 0.06 µS. A very effective method for removing ionic chemicals from polluted waters emerged recently called electrodeionization. Continuous electrodeionization (CEDI) is a technique for producing high-purity water. Besides rendering purified water, the technique has got promising wastewater treatment technologies - by facilitating the eradication of ionizable compounds, hazardous chemicals, radioactive pollutants, heavy metals and other potential contaminants. Innovative materials have been developed in order to advance and improve this technique, which would result in enormous ecological and financial benefit on a worldwide scale. In this review article, several factors that affect the performance of CEDI has been comprehended, with the impact of Ion-exchange resins and membranes as the focal point.


Assuntos
Metais Pesados , Poluentes Químicos da Água , Purificação da Água , Ecossistema , Purificação da Água/métodos , Poluentes Químicos da Água/análise , Água , Águas Residuárias
4.
Environ Res ; 216(Pt 3): 114696, 2023 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-36328226

RESUMO

Composite polymeric membranes with enhanced anti-fouling properties, antimicrobial activities and flux were produced via the phase inversion technique using poly (ether-ether-sulfone) (PEES)/polyethylene glycol (PEG) and n-ZnO. SEM and ATR-FTIR spectroscopy were used to study the morphological and chemical properties of the resulting ultrafiltration membranes. PEG and n-ZnO concentration has an effect on membrane morphologies, ultrafiltration performance, thermal characteristics, metal ion separation studies, surface hydrophilicity and anti-fouling capabilities. The permeate flux increased when the PEG concentration was raised. This results revealed that adding PEG and n-ZnO to membranes increased their surface hydrophilicity and anti-fouling properties. The inclusion of 1.5 wt % n-ZnO and 5 wt % PEG to the pristine PEES membrane resulted in a higher flux of 233.76 L m-2 h-1, 70.09 % of water content, 47.46° of contact angle, the porosity of 30.20 %, and hydraulic resistance of 0.22 kPa/Lm-2h-1. Anti-fouling properties of the fabricated membrane were assessed using a model foulant BSA, which revealed a high flux recovery ratio value. As a result, the PEG and n-ZnO incorporated membrane is more hydrophilic than the virgin membrane. In addition, the prepared PEES/PEG/n-ZnO membrane showed a significant increase in metal ions and protein rejection. Furthermore, an antibacterial test of the membrane revealed that the PEG and n-ZnO composite membrane outperformed the bare PEES membrane in terms of antibacterial capabilities. Overall, the findings reveal that combining n-ZnO and PEG resulted in a membrane with improved anti-fouling capabilities and hydrophilicity, making it suitable for water purification.


Assuntos
Incrustação Biológica , Óxido de Zinco , Ultrafiltração/métodos , Polietilenoglicóis/química , Éter , Incrustação Biológica/prevenção & controle , Membranas Artificiais , Sulfonas , Éteres , Água , Antibacterianos/farmacologia
5.
Environ Res ; 216(Pt 3): 114635, 2023 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-36309215

RESUMO

The emerging industrialization has resulted in the rapid growth of textile industries across the globe. The presence of xenobiotic pollutants in textile wastewater threatens the ecosystem. Applying different microbes (bacteria, fungi & algae) has paved the way for phytoremediation - the eco-friendly, cost-effective method. The present study focuses on the phytoremediation of reactive dyes - Reactive red, Reactive Brown & Reactive Black and Cr (VI) in synthetic textile wastewater using Salvinia sps. The mixed azo dyes of each 100 mg/L showed decolourization of 75 ± 0.5% and 82 ± 0.5% of removal of 20 mg/L of Cr (VI) after eight days of incubation in a phytoreactor setup. Chlorophyll analysis revealed the gradual decrease in the photosynthetic pigments during the remediation. The degraded metabolites were analyzed using FT-IR and showed the presence of aromatic amines on day zero, which were converted to aliphatic amines on day four. The GC-MS analysis revealed the disruption of -NN- bond, rupture of -CN- bond, scission of -N-N-bond, and loss of -SO3H from the Reactive Black dye leading to the formation of an intermediate p-Hydroxy phenylhydrazinyl. The rupture of Reactive red dye resulted in the formation of p-Hydrazinyl toluene sulphonic acid, Naphthyl amine -3,6-disulphonic acid and 8-Hydroxy Naphthyl amine -3,6-disulphonic acid. Decarboxylation, desulphonation, deoxygenation and deamination of Reactive Brown dye showed the presence of different metabolites and metabolic pathways were proposed for the reactive azo dyes which were phytoremediated.


Assuntos
Compostos Azo , Poluentes Químicos da Água , Compostos Azo/metabolismo , Águas Residuárias , Ecossistema , Espectroscopia de Infravermelho com Transformada de Fourier , Poluentes Químicos da Água/análise , Indústria Têxtil , Corantes/metabolismo , Biodegradação Ambiental , Têxteis , Aminas
6.
Environ Res ; 218: 115006, 2023 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-36493810

RESUMO

The marine ecosystem contains a solution for food, shelter, pharmaceutical problems and has a key role in the economy of the country as tourism. The Gulf of Kachchh, known for its high tides and the coral reefs are less explored for its antibiotic activity due to the coral bleaching and diseases. The bacterial strains in the coral Porites lutea are determined to possess antibiotic activity against bacterial strains such as E.coli, P. aeruginosa, S. aureus and S. faecalis. Among thirty bacterial strains isolated from the tissue, skeleton and mucus, two bacterial strains resulted in the better antagonistic activity. The antibiotic compound extracted from both the bacteria elucidated to be 4-[(2E)-4-hydroxypent-2-en-1-yl]-5,6-dihydro-2H-pyran-2-one. Further, through ADMET prediction it was inferred that it is an effective drug lead as it reports less toxicity and better drug-likeliness. The study also includes the effect of Poly Hydroxy Butarate (PHB) production by the isolated bacterial strain.


Assuntos
Antozoários , Animais , Antozoários/microbiologia , Ecossistema , Staphylococcus aureus , Recifes de Corais , Bactérias , Antibacterianos/toxicidade
7.
Environ Res ; 236(Pt 2): 116735, 2023 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-37517489

RESUMO

In the current study, an attempt was made to synthesize coffee husk (CH) activated carbon by chemical modification approach (sulphuric acid-activated CH (SACH) activated carbon) and was used as a valuable and economical sorbent for plausible remediation of Methylene blue (MB) dye. Batch mode trials were carried out by carefully varying the batch experimental variables: SACH activated carbon (SACH AC) dosage, pH, initial dye concentration, temperature, and contact time. The optimum equilibrium time for adsorption by SACH activated carbon was obtained as 60 min, and the maximum adsorption took place at 30 °C. Morphological and elemental composition, crystallinity behaviour, functional groups, and thermal stability were examined using SEM with EDX, XRD, FTIR, BET, TGA, and DTA and these tests showed successful production of activated carbon. The outcomes showed that chemical activation enhanced the number of pores and roughness which possibly maximized the adsorptive potential of coffee husk. The Box-Benken design (BBD) was used to optimize the MB dye adsorption studies and 99.48% MB dye removed at SACH AC dosage of 4.83 g/L at 30 °C for 60 min and pH 8.12, and the maximum adsorption was yielded for sulphuric acid-activated coffee husk carbon carbon with 88.1 mg/g maximum MB adsorption capacity. Langmuir- Freundlich model deliberately provided a better fit to the equilibrium data. The SACH AC-MB dye system kinetics showed a high goodness-of-fit with pseudo second order model, compared to other studied models. Change in Gibbs's free energy (ΔGo) of the system indicated spontaneity whereas low entropy value (ΔSo) suggested that the removal of MB dye on the SACH activated carbon was an enthalpy-driven process. The exothermic nature of the sorption cycle was affirmed by the negative enthalpy value (ΔHo). The adsorptive-desorptive studies reveal that SACH AC could be restored with the maximum adsorption efficiency being conserved after the fifth cycles. Overall, the outcomes revealed that sulphuric acid-activated coffee husk activated carbon (SACH AC) can be used as prompt alternative for low-cost sorbent for treating dye-laden synthetic wastewaters.


Assuntos
Coffea , Poluentes Químicos da Água , Azul de Metileno/análise , Carvão Vegetal , Adsorção , Poluentes Químicos da Água/análise , Concentração de Íons de Hidrogênio , Termodinâmica , Cinética , Água/química
8.
Environ Res ; 216(Pt 4): 114766, 2023 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-36370813

RESUMO

The present study aimed at the synthesis of cobalt oxide nanoparticles (CONPs) mediated by leaf extract of Muntingia calabura using a rapid and simple method and evaluation of its photocatalytic activity against methylene blue (MB) dye. UV-vis absorption spectrum showed multiple peaks with an optical band gap of 2.05 eV, which was concordant with the literature. FESEM image signified the irregular-shaped, clusters of CONPs, and EDX confirmed the existence of the Co and O elements. The sharp peaks of XRD spectrum corroborated the crystalline nature with a mean crystallite size of 27.59 nm. Raman spectrum substantiated the purity and structural defects. XPS signified the presence of Co in different oxidation states. FTIR image revealed the presence of various phytochemicals present on the surface and the bands at 515 and 630 cm-1 designated the characteristic Co-O bonds. VSM studies confirmed the antiferromagnetic property with negligible hysteresis. The high BET specific surface area (10.31 m2/g) and the mesoporous nature of the pores of CONPs signified the presence of a large number of active sites, thus, indicating their suitability as photocatalysts. The CONPs degraded 88% of 10 mg/L MB dye within 300 min of exposure to sunlight. The degradation of MB dye occurred due to the formation of hydroxyl free radicals on exposure to sunlight, which followed first-order kinetics with rate constant of 0.0065 min-1. Hence, the CONPs synthesized herein could be applied to degrade other xenobiotics and the treatment of industrial wastewater and environmentally polluted samples.


Assuntos
Cobalto , Nanopartículas , Óxidos , Nanopartículas/química , Azul de Metileno/química
9.
Environ Res ; 216(Pt 2): 114622, 2023 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-36279912

RESUMO

Coral reefs are constantly subjected to multiple stresses like diseases and fish predation, which can profoundly influence the coral microbiome. This study investigated the differences in bacterial community structure of healthy, white syndrome affected and blenny nipped coral colonies of Porites lutea, collected from the coral reefs of Gulf of Kachchh, north-west coast of India. Present study observed that the stressed coral colonies harbored more OTUs and contained higher diversity values compared to healthy corals colonies. Similarly, beta diversity analysis indicated the dissimilarities among the three coral samples analyzed. Though the taxonomy analysis indicated bacterial phyla like Proteobacteria, Firmicutes, Bacteroidetes, and Actinobacteria among the entire coral samples studied, there was a variation in their relative abundances. Huge variations were observed in the relative dominance at the bacterial genera level. About 13phyla and 11 genera was identified in healthy coral. The PBN sample was found to contain Proteobacteria, Cyanobacteria, Verrucomicrobia, and Lentisphaerae as dominant phyla and Endozoicomonas, Dyella, Woeseia, and Winogradskyella as dominant genera. The PWS sample contained Proteobacteria, Lentisphaerae, Spirochaetes, and Tenericutes as dominant phyla and Endozoicomonas, Arcobacter, Sunxiuqinia, and Carboxylicivirgia as dominant genera. Among the healthy samples, sequences belonging to Uncultured Rhodospirillaceae were dominant, while Woeseia and sequences belonging to Uncultured Rhodovibrionaceae were dominant among the blenny nipped white syndrome infected corals. Although any previously established pathogen was not identified, present study revealed the presence of a potentially pathogenic bacterium, Arcobacter, among the diseased corals. It also demonstrated a dynamic microbiome among the Porites lutea colonies on subjecting to various stresses.


Assuntos
Antozoários , Microbiota , Animais , Antozoários/microbiologia , Prevalência , Recifes de Corais , Bactérias/genética
10.
Artigo em Inglês | MEDLINE | ID: mdl-36817164

RESUMO

Management of hospital wastewater is a challenging task, particularly during the situations like coronavirus 2019 (COVID-19) pandemic. The hospital effluent streams are likely to contain many known and unknown contaminants including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) along with a variety of pollutants arising from pharmaceuticals, life-style chemicals, drugs, radioactive species, and human excreta from the patients. The effluents are a mixed bag of contaminants with some of them capable of infecting through contact. Hence, it is essential to identify appropriate treatment strategies for hospital waste streams. In this work, various pollutants emerging in the context of COVID-19 are examined. A methodical review is conducted on the occurrence and disinfection methods of SARS-CoV-2 in wastewater. An emphasis is given to the necessity of addressing the challenges of handling hospital effluents dynamically involved during the pandemic scenario to ensure human and environmental safety. A comparative evaluation of disinfection strategies makes it evident that the non-contact methods like ultraviolet irradiation, hydrogen peroxide vapor, and preventive approaches such as the usage of antimicrobial surface coating offer promise in reducing the chance of disease transmission. These methods are also highly efficient in comparison with other strategies. Chemical disinfection strategies such as chlorination may lead to further disinfection byproducts, complicating the treatment processes. An overall analysis of various disinfection methods is presented here, including developing methods such as membrane technologies, highlighting the merits and demerits of each of these processes. Finally, the wastewater surveillance adopted during the COVID-19 outbreak is discussed. Supplementary Information: The online version contains supplementary material available at 10.1007/s13762-023-04803-1.

11.
Environ Res ; 212(Pt A): 113114, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35331699

RESUMO

The presence of pollutants and toxic contaminants in water sources makes it unfit to run through. Though various conventional techniques are on deck, development of new technologies are vital for wastewater treatment and recycling. Polymers have been intensively utilized recently in many industries owing to their unique characteristics. Biopolymers resembles natural alternative to synthetic polymers that can be prepared by linking the monomeric units covalently. Despite the obvious advantages of biopolymers, few reviews have been conducted. This review focuses on biopolymers and composites as suitable adsorbent material for removing pollutants present in environment. The classification of biopolymers and their composites based on the sources, methods of preparation and their potential applications are discussed in detail. Biopolymers have the potentiality of substituting conventional adsorbents due to its unique characteristics. Biopolymer based membranes and effective methods of utilization of biopolymers as suitable adsorbent materials are also briefly elaborated. The mechanism of biopolymers and their membrane-based adsorption has been briefly reviewed. In addition, the methods of regeneration and reuse of used biopolymer based adsorbents are highlighted. The comprehensive content on fate of biopolymer after adsorption is given in brief. Finally, this review concludes the future investigations in recent trends in application of biopolymer in various fields in view of eco-friendly and economic perspectives.


Assuntos
Poluentes Ambientais , Poluentes Químicos da Água , Purificação da Água , Adsorção , Biopolímeros , Polímeros , Águas Residuárias , Poluentes Químicos da Água/análise , Purificação da Água/métodos
12.
Environ Res ; 214(Pt 2): 113958, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-35921904

RESUMO

Brackish lake systems and estuaries are unique aquatic systems that support diversified life forms and strongly influence a region's economy. Major chemical water quality parameters of India's second-largest brackish water lake, Pulicat were assessed. Physico-chemical parameters like pH, temperature, suspended solid concentrates, total dissolved solids, salinity, nitrogenous nutrients, phosphate, silicate, and chlorophyll a were analysed. The results obtained for different parameters were compared and interpreted with statistical software SPSS version 20 and images were plotted using the Arc GIS spatial analyst tool. During the summer months, the nitrogen to phosphorus ratio ranges from a minimum of 1.96 to a maximum of 16.64 (9.55 ± 4.01) while it ranges from a minimum of 7.98 to a maximum of 15.52 (12.47 ± 2) during the pre-monsoon. In the monsoon season, the nitrogen to phosphorus ratio of surface water suggests a range from a minimum of 8.64 to a maximum of 17.58 (13.87 ± 2.14). During the post-monsoon season, the nitrogen to phosphorus ratio ranges from 4.98 to 17.34 (11.77 ± 3.68). The average nitrogen to phosphorus ratios were 9.6, 12.5, 13.9 and 11.8 in summer, pre-monsoon, monsoon, and post-monsoon respectively. The nitrogen to phosphorus ratio was lower than the Redfield ratio for all the seasons. The average concentration of chlorophyll a was 14.9, 13.4, 12.8 and 11.8 in summer, pre-monsoon, monsoon, and post-monsoon respectively. As per the Pearson Correlation Coefficient, there was no significant correlation among nitrogen, phosphorus, and chlorophyll a. This suggests the influence of suspended solid concentrates, and nitrogen and phosphorus flux in the sediment-water interface might be interfering with the nutrient cycles and primary productivity.


Assuntos
Lagos , Poluentes Químicos da Água , Ásia , Clorofila A/análise , Monitoramento Ambiental , Lagos/análise , Nitrogênio/análise , Fósforo/análise , Águas Salinas , Estações do Ano , Poluentes Químicos da Água/análise
13.
Environ Res ; 204(Pt A): 111916, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34428450

RESUMO

Management of basic natural resources and the spent industrial and domestic streams to provide a sustainable safe environment for healthy living is a magnum challenge to scientists and environmentalists. The present remedial approach to the wastewater focuses on recovering pure water for reuse and converting the contaminants into a solid matrix for permanent land disposal. However, the ground water aquifers, over a long period slowly leach the contaminants consequently polluting the ground water. Synthetic adsorbents, mainly consisting of polymeric resins, chelating agents, etc. are efficient and have high specificity, but ultimate disposal is a challenge as most of these materials are non-biodegradable. In this context, it is felt appropriate to review the utility of adsorbents based on natural green materials such as agricultural waste and restricted to few model contaminants: phenols, and heavy metals chromium(VI), and cadmium(II) in view of the vast amount of literature available. The article discusses the features of the agricultural waste material-based adsorbents including the mechanism. It is inferred that agricultural waste materials are some of the common renewable sources available across the globe and can be used as sustainable adsorbents. A discussion on challenges for industrial scale implementation and integration with advanced technologies like magnetic-based approaches and nanotechnology to improve the removal efficiency is included for future prospects.


Assuntos
Poluentes Químicos da Água , Purificação da Água , Adsorção , Cádmio , Cromo/análise , Fenóis , Eliminação de Resíduos Líquidos , Águas Residuárias , Poluentes Químicos da Água/análise
14.
Environ Res ; 215(Pt 1): 114180, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36057335

RESUMO

In the present study, surface-active compounds (SAC) were extracted from biosolids using an alkaline treatment process. They were tested for their remediation efficiency of crude oil-contaminated sediment soil and was compared with Triton x-100. The SAC exhibited a similar soil washing efficiency to that of the commercial Triton x-100, and under the optimized soil washing parameters, SAC exhibited a maximum of 91% total polycyclic aromatic hydrocarbons removal. Further, on analysing the toxicity of the soil residue after washing, it was observed that SAC from biosolids washed soil exhibited an average of 1.5-fold lesser toxicity compared to that of Triton x-100 on different test models-earthworm, a monocot, and dicot plants. The analysis of the key soil parameters revealed that the commercial surfactant reduced the soil organic matter and porosity by an average of 1.3-fold compared to SAC. Further, the ability of surfactants to induce toxicity was confirmed by the adsorption of the surfactants on the surface of the soil particles which was in the order of Triton x-100 > SAC. Thus, this study suggests that SAC can be applied as an effective bioremediation approach for contaminated soil for a greener and sustainable ecosystem.


Assuntos
Petróleo , Hidrocarbonetos Policíclicos Aromáticos , Poluentes do Solo , Biodegradação Ambiental , Biossólidos , Ecossistema , Octoxinol , Petróleo/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Solo , Poluentes do Solo/análise , Tensoativos/análise
15.
Environ Res ; 201: 111626, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34217718

RESUMO

The present work explains the sorption ability of a novel nano-composite, Polypyrrole -iron oxide-seaweed (PPy - Fe3O4 - SW), for Cr(VI) removal. The influence of operating parameters, namely pH, contact time, nanocomposite dosage, initial Chromium concentration and operating temperature, on the hexavalent chromium removal was studied. The novel nano-composite was analyzed using FTIR, SEM and EDS to confirm the sorption of Cr(VI) and to understand the mechanism of sorption. PPy - Fe3O4- SW nano-composite removed 96.36% of Cr(VI) at the optimized conditions of pH = 2, temperature = 30 °C, initial Cr(VI) concentration = 50 mg/L, nanocomposite dosage = 100 mg and contact time = 30min. PPy-Fe3O4-SW nanocomposite has a maximum sorption capacity of 144.93 mg/g. The kinetic studies revealed that the metal adsorption obeys pseudo second order (PSO) model and the sorption was found to be monolayer in nature as confirmed by Langmuir isotherm (R2 > 0.9985). Electrostatic interaction and ion-exchange are identified as the fundamental mechanisms for Cr(VI) sorption on PPy-Fe3O4-SW composite.


Assuntos
Nanocompostos , Polímeros , Cromo , Cinética , Fenômenos Magnéticos , Pirróis
16.
Environ Res ; 202: 111707, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34274329

RESUMO

Metal ion pollution poses serious threat to environment. Analysis of Cd (II) and Pb (II) ions using chemically modified mercury free electrode is a feasible routine analytical tool. Developing an electrode surface modified with conductive 2D carbon and metal complexing ligand created a synergetic effect towards sensitive and selective electrochemical determination of metal ions. The present study focused on green chemistry approach towards synthesis of reduced graphene oxide using a natural flavonoid (Quercetin) that acts as a reducing, functionalizing agent and also as metal complexing agent. This quercetin reduced graphene oxide (Q-rGO) was surface modified over paraffin wax impregnated graphite electrode. The resulting Q-rGO electrode was used as a mercury-free electrode for simultaneous analysis of Pb (II) and Cd (II) ions. Physico-chemical parameters of the synthesized Q-rGO and modified electrodes were characterized using X-ray diffraction, UV-Vis, FT-IR, and Raman spectrometer. The morphology of the material and surface topography of the modified electrode was observed using HR-TEM and FESEM, respectively. Cyclic voltammetry (CV) and AC impedance (EIS) were adopted for electrochemical characterization and Differential pulse anodic stripping voltammetry (DPASV) was chosen for simultaneous sensing of metal ions using Q-rGO electrode. Analytical parameters such as effect of electrolyte, effect of pH, preconcentration time and deposition potential were optimized. The experimental results suggested that the Q-rGO electrode is capable of sensing Pb (II) and Cd (II) ions individually and simultaneously. Inference from the calibration plot showed that the Q-rGO electrode was capable of sensing the concentration range of Cd (II) ion form 0.19 to 2.5 µgL-1 with LOD-0.05 µgL-1 and Pb (II) ions from 0.19 to 3.1 µgL-1 with LOD 0.06 µgL-1.


Assuntos
Mercúrio , Cádmio , Eletrodos , Grafite , Íons , Chumbo , Quercetina , Espectroscopia de Infravermelho com Transformada de Fourier
17.
Environ Res ; 199: 111364, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34033830

RESUMO

This research study reported the feasibility of cadmium removal using green algae, Caulerpa scalpelliformis, under controlled environmental conditions. The algal biosorbent could effectively remove cadmium under broad range of test conditions, namely, initial pH (3-6), adsorbent mass (0.5-2.5 gL-1) and shaking speed (60-100 rpm). The best operating conditions were identified using Central Composite Design under Response Surface methodology and found to be pH - 4.9, adsorbent mass - 2.1 gL-1 and shaking speed - 90 rpm. Equilibrium studies were conducted and monolayer sorption was identified as the mechanism, confirmed by Langmuir isotherm (R2 = 0.9920). The maximum Cd uptake achieved at optimal conditions was 111.11 mg g-1. The kinetic constants of the best fit model (pseudo second order) were determined. The thermodynamic feasibility was verified (ΔG ͦ < 0) and the biosorption process was found to be endothermic (ΔH ͦ > 0). The mass transfer studies shows that the mass transfer coefficient was inversely related to the temperature. Presence of favorable surface functional groups and enhanced surface area confirmed the suitability of the synthesized biosorbent for effective removal of cadmium.


Assuntos
Clorófitas , Poluentes Químicos da Água , Adsorção , Cádmio , Concentração de Íons de Hidrogênio , Cinética , Termodinâmica , Água , Poluentes Químicos da Água/análise
18.
Environ Res ; 199: 111310, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34000271

RESUMO

Wastewater treatment is the most important criteria that will deliberately reduce the water scarcity and to remove the organic pollutants from water. In this study, pure copper hydroxide (Cu(OH)2), 1% sodium dodecyl sulphate (SDS) and 2% sodium dodecyl sulphate (SDS) assisted Cu(OH)2 was prepared through co-precipitation technique. The prepared samples was investigated employing standard characterization studies. The X-Ray diffraction (XRD) pattern was confirmed with JCPDS card # 80-0656 with crystallite size of 25, 23 and 21 nm for pure Cu(OH)2, 1% SDS and 2% SDS assisted Cu(OH)2. The bandgap energy obtained for Cu(OH)2, 1% SDS and 2% SDS assisted Cu(OH)2 were 2.86 eV, 2.81 eV and 2.72 eV. The narrow bandgap of 2% SDS assisted Cu(OH)2 enhanced the photocatalytic activity than other two samples. The formation of nanoclusters and nanosheets were confirmed with Scanning Electron Microscopic (SEM) analysis. The thick clumsy nanosheets are formed as large nanoclusters in pure Cu(OH)2. Addition of SDS reduced the thickness of nanosheets and formed a little cluster. The prepared product photocatalytic performance was examined employing degradation of Methylene Blue (MB) dye. 2% SDS assisted Cu(OH)2 added MB dye solution was completely degraded with 98% efficiency. The reduce in particle size, high recombination of electron-hole pair with narrow bandgap made the 2% SDS assisted Cu(OH)2 candidate to give out potential output in eliminating the organic pollutants.


Assuntos
Águas Residuárias , Purificação da Água , Cobre , Hidróxidos , Tensoativos
19.
Environ Res ; 202: 111720, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34297938

RESUMO

Generation of unprocessed effluents, municipal refuse, factory wastes, junking of compostable and non-compostable effluents has hugely contaminated nature-provided water bodies like rivers, lakes and ponds. Therefore, there is a necessity to look into the water standards before the usage. This is a problem that can greatly benefit from Artificial Intelligence (AI). Traditional methods require human inspection and is time consuming. Automatic Machine Learning (AutoML) facilities supply machine learning with push of a button, or, on a minimum level, ensure to retain algorithm execution, data pipelines, and code, generally, are kept from sight and are anticipated to be the stepping stone for normalising AI. However, it is still a field under research. This work aims to recognize the areas where an AutoML system falls short or outperforms a traditional expert system built by data scientists. Keeping this as the motive, this work dives into the Machine Learning (ML) algorithms for comparing AutoML and an expert architecture built by the authors for Water Quality Assessment to evaluate the Water Quality Index, which gives the general water quality, and the Water Quality Class, a term classified on the basis of the Water Quality Index. The results prove that the accuracy of AutoML and TPOT was 1.4 % higher than conventional ML techniques for binary class water data. For Multi class water data, AutoML was 0.5 % higher and TPOT was 0.6% higher than conventional ML techniques.


Assuntos
Inteligência Artificial , Qualidade da Água , Algoritmos , Análise de Alimentos , Humanos , Aprendizado de Máquina
20.
Microb Pathog ; 115: 146-153, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29278781

RESUMO

Actinobacteria is the most widely distributed organism in the mangrove environment and produce a large amount of secondary metabolites. A new environmental actinobacterial stain exhibited strong antimicrobial activity against vancomycin and methicillin resistant actinobacteria. The active producer strain was found to be as Brevibacillus brevis EGS9, which was confirmed by its morphological, biochemical characteristics and 16S rRNA gene sequencing. It was deposited in NCBI GeneBank database and received with an accession number of KX388147. Brevibacillus brevis EGS9 was cultivated by submerged fermentation to produce antimicrobial compounds. The anti-proliferative agent was extracted from Brevibacillus brevis EGS9 with ethyl acetate. The bioactive metabolites of mangrove actinobacteria was identified by Liquid chromatography with mass spectrometry analysis. The result of the present investigation revealed that actinobacteria isolated from mangroves are potent source of anticancer activity. The strain of Brevibacillus brevis EGS9 exhibited a potential in vitro anticancer activity. The present research concluded that the actinobacteria isolated from mangrove soil sediment are valuable in discovery of novel species.


Assuntos
Actinobacteria/crescimento & desenvolvimento , Antibacterianos/farmacologia , Antibiose/fisiologia , Antineoplásicos/farmacologia , Brevibacillus/metabolismo , Proliferação de Células/efeitos dos fármacos , Acetatos/química , Actinobacteria/efeitos dos fármacos , Brevibacillus/isolamento & purificação , Linhagem Celular Tumoral , Farmacorresistência Bacteriana Múltipla , Células HeLa , Células Hep G2 , Humanos , Meticilina/farmacologia , Testes de Sensibilidade Microbiana , Microbiologia do Solo , Vancomicina/farmacologia
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