RESUMO
Malignancies including ovarian cancer (OvCa) are genetically unstable. Genomic integrity is maintained by tumor suppressor p53 and DNA damage response network, which crosstalk to each other via not well characterized mechanisms. In this work, we characterize features of damage-related signals in cultured epithelial OvCa cells and tumor biopsies. We found that endogenous burden of DNA damage in OvCa tissues were ubiquitously accumulated in high-grade malignancies than lower grade of cancer that cannot be obviously explained by disturbed function of in DNA damage response (DDR). In contrast, CHK1 phosphorylation (CHK1-pS345) marking the checkpoint activation in nucleolar compartments are prevalent in high-grade OvCa, coincident to the elevated DNA damage in nucleoplasm. Generation of CHK1-pS345 requires the presence of p53 protein in addition to the well-known activities of ATM/ATR kinases. Apparently, mutant forms of p53 possess higher activity in triggering CHK1 phosphorylation than wild type, implying a potential role of p53 in maintaining rDNA integrity. Loss of p53 function would cause replication stress in nucleoli. Altogether, our study reveals endogenous nucleoli stress in OvCa that is coupled to perturbed function of p53 in DNA repair.
Assuntos
Neoplasias Ovarianas , Proteína Supressora de Tumor p53 , Proteínas Mutadas de Ataxia Telangiectasia/genética , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Carcinoma Epitelial do Ovário/genética , Proteínas de Ciclo Celular/genética , Linhagem Celular Tumoral , Quinase 1 do Ponto de Checagem/genética , Quinase 1 do Ponto de Checagem/metabolismo , Dano ao DNA/genética , Feminino , Humanos , Neoplasias Ovarianas/genética , Fosforilação , Proteínas Quinases/metabolismo , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismoRESUMO
The stability and applicability of UiO-66-(NH2)2 metal-organic framework (MOF) nanoparticles (NPs) were successfully improved in this study by incorporating them into alginate biopolymer during the manifestation of crosslinking agents-calcium chloride and glutaraldehyde-via a simple, environment-friendly, and facile approach to eradicate potentially toxic metals (PTMs) such as Cr6+, Cr3+, Cu2+, and Cd2+ from water and real electroplating wastewater. Hydrophilic functional groups (i.e., -OH, -COOH, and -NH2) are imperative in the smooth loading of UiO-66-(NH2)2 MOF- NPs into three-dimensional (3-D) membrane capsules (MCs). The X-ray photoelectron spectroscopy (XPS) results suggested that UiO-66-(NH2)2 MOF was effectively bonded in/on the capsule via electrostatic crosslinking between -H3N+ and -COO-. Scanning electron microscopy results revealed a porous honeycomb configuration of the 3-D SGMMCs (S: sodium alginate, G: glutaraldehyde, M: MOF NPs, and MCs: membrane capsules). The maximum monolayer absorption capacities for Cr6+, Cr3+, Cu2+, and Cd2+ were 495, 975, 1295, and 1350 mg/g, respectively. The results of Fourier transform infrared spectroscopy and XPS analyses showed that electrostatic attraction and ion exchange were the main processes for PTM removal used by the as-developed 3-D SGMMCs. The as-developed 3-D SGMMCs exhibited outstanding selectivity for removing the targeted PTMs under the specified pH/conditions and maintained >80% removal efficiency for up to six consecutive treatment cycles. Notably, > 60% removal efficiencies for Cr6+ and Cu2+ were observed when treating real electroplating wastewater. Therefore, the as-developed 3-D SGMMCs can be used as an exceptional multifunctional sorbent to remove and recover PTMs from real electroplating wastewater.
Assuntos
Estruturas Metalorgânicas , Poluentes Químicos da Água , Adsorção , Alginatos , Cádmio , Cloreto de Cálcio , Cápsulas , Galvanoplastia , Glutaral , Concentração de Íons de Hidrogênio , Ácidos Ftálicos , Águas Residuárias/química , Água , Poluentes Químicos da Água/análiseRESUMO
Currently, the occurrence of toxic levels of metals in soils is a serious environmental issue worldwide. Phytoremediation is getting much attention to control metals soil pollution because it is economic and environmentally friendly. However, the methods used to detect metals in plants are not uniform and have depicted poor comparability of the research investigations. Therefore, the present overview is designed to discuss the possible chemical forms of metals in various environmental matrixes and the detection methods employed to identify the chemical forms of metals in plants. Moreover, the in situ and indirect methods to detect metals in plants have also been discussed herein. In addition, the pros and cons of the available techniques have also been critically analyzed and discussed. Finally, key points/challenges and future perspectives of these methods have been highlighted for the scientific community.Novelty statementIn the current review, the possible chemical forms of metals in various environmental matrixes are discussed in detail. Various extraction agents and their efficiency for extracting metals from plants have been clearly illustrated. Further, all the available methods for analyzing the chemical forms of metals in plants have been compared.
Assuntos
Metais Pesados , Poluentes do Solo , Biodegradação Ambiental , Plantas , SoloRESUMO
In this study, a novel extraction and safety evaluation method for heavy metals based on different functions of plants was proposed, and an edible plant (pea) was used as the research material to explore the feasibility of the novel method. Pea sprouts were cultured in cadmium (Cd) concentrations of 0, 1.0, 3.0, and 5.0 mg L-1, respectively. The Cd in pea sprouts was continuously extracted with 100 °C distilled water, 60% ethanol, 6% acetic acid, and simulated gastric juice. It was observed that highest amount of Cd (48.65-58.87%) was found in the extraction of roots with 6% acetic acid, followed by 100 °C distilled water (28.68-37.61%). While in stems, most of the Cd (70.73-85.39%) was extracted by 6% acetic acid. The recovery rate of the sequential chemical extraction technique employed in this experiment was between 93 and 106%. Compared with traditional methods, this study has its development potential in two aspects. First, it can determine which steps of sequential extractions of heavy metals in plants are the most harmful to humans. Secondly, corresponding measures can be taken to reduce heavy metals in vegetables used daily, such as soaking edible vegetables in vinegar for a short time. Novelty statement: In this study, a novel extraction and safety evaluation method for heavy metals based on different functions of plants was proposed, and an edible plant (pea) was used as the research material to explore the feasibility of the novel method. Compared with the commonly used extraction methods, the novel method is more reasonable and has greater development potential.
Assuntos
Metais Pesados , Poluentes do Solo , Biodegradação Ambiental , Cádmio/análise , Humanos , Metais Pesados/análise , Pisum sativum , Medição de Risco , Plântula/química , Poluentes do Solo/análiseRESUMO
Impairment of genome instability drives the development of cancer by disrupting anti-cancer barriers. Upon genotoxic insults, DNA damage responsive factors, notably ATM kinase, is crucial to protect genomic integrity while promoting cell death. Meanwhile, cytotoxic therapy-inducing DNA lesions is double-edged sword by causing cancer metastasis based on animal models and clinical observations. The underlying mechanisms for the procancer effect of cytotoxic therapies are poorly understood. Here, we report that cancer cells subjected to cytotoxic treatments elicit dramatic alteration of gene expression controlling the potential of epithelium-mesenchyme transition (EMT). Resultantly, EMT-dependent cell mobility is potently induced upon DNA damage. This stimulation of EMT is mainly Ataxia-Telangiectasia-mutated (ATM)-dependent, as the chemical inhibitor specifically inhibiting ATM kinase activity can suppress the EMT gene expression and thus cell mobility. At last, we show that cancer cells with ATM activation display increased metastatic potential in ovarian cancer tissues. Taken together, we reveal a novel role of ATM in promoting metastatic potential of cancer cells by favoring EMT gene expression.
Assuntos
Proteínas Mutadas de Ataxia Telangiectasia/genética , Proliferação de Células/genética , Transição Epitelial-Mesenquimal/genética , Neoplasias/genética , Movimento Celular/genética , Proliferação de Células/efeitos dos fármacos , Dano ao DNA/genética , Regulação Neoplásica da Expressão Gênica/genética , Instabilidade Genômica/genética , Humanos , Metástase Neoplásica , Neoplasias/patologiaRESUMO
To enhance the inferior removal capability of aqueous Cr(VI) by commercial activated carbon under neutral conditions. The emerging ball milling technology was employed and the removal efficiency of Cr(VI) by ball-milled highly activated carbon (HAC) increased from 68.3% to 99.0% under pH 6 and from 42.7% to 77.8% under pH 7 compared to pristine activated carbon (AC), respectively. Raman spectra and Boehm's titration results signified that the enhanced Cr(VI) removal performance of HAC under neutral conditions was associated with the enriched surface acid functional groups, in which the content of COOH groups increased from 0.31 mmol/g to 0.97 mmol/g. Two Cr(VI) removal mechanisms were proposed established on the acid and alkalic solution washed chromium-loaded HAC, involving the reduction of Cr(VI) to Cr(III) subsequently accompany with the formation of chromium hydroxides on the surface and inside the pores of HAC, and the bonding of CrO42- on the surface COOH groups, as confirmed by SEM-EDX element mapping and specific surface area and porosity measurements. The Pseudo-second order model and Freundlich model fitted the adsorption kinetic and isotherm of AC and HAC well severally, suggesting that the specific interaction of Cr(VI) with the HAC surface and the Cr(VI) removal was multi-layer adsorption. Thermodynamic study exhibited the spontaneity of Cr(VI) removal on ball-milled HAC was increased. Reusability and regeneration studies of HAC denoted the potential application on Cr(VI) uptake under neutral conditions.
Assuntos
Carvão Vegetal , Poluentes Químicos da Água , Adsorção , Cromo/análise , Concentração de Íons de Hidrogênio , Cinética , Poluentes Químicos da Água/análiseRESUMO
Activated carbon has been widely used to remove hazardous Cr(VI); however, the impact of Cr2O3 precipitate on gradually declining removal ability as pH increases has received little attention. Herein, to investigate the effect of Cr2O3, SEM-EDX (scanning electron microscope-energy dispersive X-ray analysis) coupling elements mapping of chromium-loaded powdered activated carbon (PAC) revealed that a chromium layer was formed on the PAC exterior after being treated with Cr(VI) at pH 7. XPS (X-ray photoelectron spectroscopy) study confirmed that 69.93% and 39.91% Cr2O3 precipitated on the PAC surface at pH 7 and pH 3, respectively, corresponding to 17.77 mg/g and 20 mg/g removal capacity. Exhausted PAC had a removal efficiency of 92.43% after Cr2O3 being washed by H2SO4 solution, which was much higher than the removal efficiency of 51.27 % after NaOH washing. This further verified that the intrinsically developed Cr2O3 precipitate on PAC under neutral conditions limited the durability of PAC as an adsorbent. Consecutive elution assessments confirmed that adsorption and reduction ability both declined as pH increased. Raman spectroscopy and C 1s spectra of materials demonstrated two distinct Cr(VI) removal mechanisms under pH 3 and pH 7. In conclusion, the exhausted AC after Cr(VI) adsorption can be rejuvenated after the surface coated Cr2O3 is washed by the acid solution, which can expand the longevity of AC and recover Cr(III).
Assuntos
Carvão Vegetal , Poluentes Químicos da Água , Adsorção , Cromo/análise , Concentração de Íons de Hidrogênio , Cinética , Poluentes Químicos da Água/análiseRESUMO
BACKGROUND: Loss of the genomic stability jeopardize genome stability and promote malignancies. A fraction of ovarian cancer (OvCa) arises from pathological mutations of DNA repair genes that result in highly mutagenic genomes. However, it remains elusive why the ovarian epithelial cells are particularly susceptible to the malfunction of genome surveillance system. METHODS: To explore the genotoxic responses in the unique context of microenvironment for ovarian epithelium that is periodically exposed to high-level steroid hormones, we examined estrogen-induced DNA damage by immunofluorescence in OvCa cell lines, animal and human samples. RESULTS: We found that OvCa cells are burdened with high levels of endogenous DNA damage that is not correlated with genomic replication. The elevation of damage burden is attributable to the excessive concentration of bioactive estrogen instead of its chemomimetic derivative (tamoxifen). Induction of DNA lesions by estrogen is dependent on the expression of hormone receptors, and occurs in G1 and non-G1 phases of cell cycle. Moreover, depletion of homologous recombination (HR) genes (BRCA1 and BRCA2) exacerbated the genotoxicity of estrogen, highlighting the role of HR to counteract hormone-induced genome instability. Finally, the estrogen-induced DNA damage was reproduced in the epithelial compartments of both ovarian and fallopian tubes. CONCLUSIONS: Taken together, our study disclose that estrogen-induced genotoxicity and HR deficiency perturb the genome stability of ovarian and fallopian epithelial cells, representing microenvironmental and genetic risk factors, respectively.
Assuntos
Dano ao DNA , Estrogênios/toxicidade , Tubas Uterinas/efeitos dos fármacos , Neoplasias Ovarianas/genética , Ovário/efeitos dos fármacos , Animais , Proteína BRCA1/genética , Proteína BRCA2/genética , Linhagem Celular Tumoral , Epitélio/efeitos dos fármacos , Epitélio/metabolismo , Tubas Uterinas/metabolismo , Feminino , Recombinação Homóloga , Humanos , Camundongos , Neoplasias Experimentais , Especificidade de Órgãos , Neoplasias Ovarianas/tratamento farmacológico , Ovário/metabolismo , Receptores de Estrogênio/metabolismo , Receptores de Progesterona/metabolismoRESUMO
In the present study, 12 indigenous diesel-oil-degrading bacteria were isolated from the petroleum-contaminated soils of the Changqing oil field (Xi'an, China). Measurement of the diesel-oil degradation rates of these strains by the gravimetric method revealed that they ranged from 42% to 66% within 2 weeks. The highest degradation rates were observed from strains CQ8-1 (66%), CQ8-2 (62.6%), and CQ11 (59%), which were identified as Bacillus thuringiensis, Ochrobactrum anthropi, and Bordetella bronchialis, respectively, based on their 16S rDNA sequences. Moreover, the physiological and biochemical properties of these three strains were analyzed by Gram staining, catalase, oxidase, and Voges-Proskauer tests. Transmission electron microscopy showed that all three strains were rod shaped with flagella. Gas chromatography and mass spectrometric analyses indicated that medium- and long-chain n-alkanes in diesel oil (C11-C29) were degraded to different degrees by B. thuringiensis, O. anthropi, and B. bronchialis, and the degradation rates gradually decreased as the carbon numbers increased. Overall, the results of this study indicate strains CQ8-1, CQ8-2, and CQ11 might be useful for environmentally friendly and cost-effective bioremediation of oil-contaminated soils.
Assuntos
Bactérias/classificação , Bactérias/metabolismo , Campos de Petróleo e Gás/microbiologia , Petróleo/metabolismo , Microbiologia do Solo , Poluentes do Solo/metabolismo , Alcanos/metabolismo , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Biodegradação Ambiental , China , DNA Bacteriano/genética , Flagelos , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNARESUMO
Current research is based on an innovative approach of the fabrication of encapsulated sustainable, green, phytogenic magnetic nanoparticles (PMNPs), to inhibit the generation of secondary pollutants (Iron/Feo) during water treatment applications. These novel bio-magnetic membrane capsules (BMMCs) were prepared using two-step titration gel crosslink method, with polyvinyl alcohol and sodium alginate matrix as the model encapsulating materials to eliminate potentially toxic metals (Pb2+ and Cd2+) from water. The development of BMMCs was characterized by FTIR, XRD, XPS, SEM, VSM, TGA and EDX techniques. The effects of various operating parameters, adsorbent dose, contact time, solution pH, temperature, initial concentration of metals cations and co-existing ions were studied. The hysteresis loops have illustrated an excellent super-paramagnetic nature, demonstrating the smooth encapsulation of PMNPs without losing their magnetic properties. The maximum monolayer adsorptive capacities estimated at pH 6.5 by the Langmuir isotherm model were 548 and 610.67â¯mg/g for Pb2+ and Cd2+, respectively. The novel BMMCs did not only control oxidation of PMNPs but also sustained the adsorptive removal over a wide range of pH (3-8), and the electrostatic interaction and ion-exchange were the core adsorption mechanisms. The BMMCs could easily be regenerated using 25% HNO3 as an eluent for successful usage in seven repeated cycles. Therefore, the BMMCs as a material can be used as an excellent sorbent or composite material to remove toxic metals Pb2+ and Cd2+, showing strong potential for improving water and wastewater treatment technologies.
Assuntos
Nanopartículas de Magnetita , Poluentes Químicos da Água , Purificação da Água , Adsorção , Cádmio , Concentração de Íons de Hidrogênio , Cinética , Chumbo , ÁguaRESUMO
Treatment of toxic and emerging pollutants (T&EPs) is increasing the threats to the survival of conventional wastewater treatment (WWTs) technologies. The high installation and operational costs of advanced treatment technologies have shifted the research interest to the development of economical and reliable technology for management of T&EPs. Thus, recently biogenic nanoparticles (BNPs) fabricated using microbes/microorganisms are getting tremendous research interest due to their unique properties (i.e. high specific surface area, desired morphology, catalytic reactivity) for the biodegradation and biosorption of T&EPs. In addition, BNPs can be manufactured using metal contaminated water which indicates a hidden potential for resource recovery and utilization. Therefore, the present study discusses the adsorptive and catalytic performance of BNPs in the removal of T&EPs from water (W) and wastewater (WW). In addition, inspired by the superior performance of BNPs in advance WWT, a model of BNPs based WWT resource recovery and utilization process is also proposed. Finally, main issues i.e. mass production, leaching, poisoning/toxicity, regeneration, reusability and fabrication costs and process optimization are discussed which are main hinders in the transfer of BNPs based WWT technologies from laboratory to commercial scale.
Assuntos
Nanopartículas , Águas Residuárias , Água/metabolismo , Adsorção , Biodegradação AmbientalRESUMO
Magnetotactic bacteria (MTB) are getting much attention in the recent years due to the biomineralization in their magnetosomes (MS). MS are unique organelles that are bio-mineralized due to MTB. MS contains nanosized crystal minerals of magnetite or greigite covered by bilayer lipid membrane, which are originated from cytoplasmic membrane (CM). MS are organized as an ordered chain into the cell which acts as a miniature compass needle. Furthermore, the biodiversity of MTB and their distribution is principally linked with the characteristics and growths of the MS. MTB are often considered as a part of the bacterial biomass from all of the aquatic environments. There have been a lot of genes that control the functions of MTB by accumulating as clusters of genomes such as magnetosomes genomic island (MAI). Therefore, in the present review, the function of the genes and proteins has been highlighted, which are mainly associated with the construction and formation of MS. In addition, the biodiversity, morphology and cell biology of MTB is discussed in greater detail to understand the formation of MS crystals by MTB.
Assuntos
Bactérias/citologia , Bactérias/genética , Biodiversidade , Magnetossomos/genética , Magnetossomos/metabolismo , Bactérias/classificação , Bactérias/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Membrana Celular , Óxido Ferroso-Férrico , Genes Bacterianos/genética , Ilhas Genômicas , Ferro/metabolismo , Magnetismo , Magnetossomos/química , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Filogenia , SulfetosRESUMO
Magnetotactic bacteria (MTB) have started to be employed for the biosynthesis of magnetic nanoparticles, due to the rapidly increasing demand for nanoparticles in biomedical, biotechnology and environmental protection. MBT are the group of prokaryotes that have the ability to produce bio-magnetic minerals or bio-magnetic crystals of either magnetite (Fe3 O4 ) or greigite (Fe3 S4 ) in numerous shapes and size ranges, known as magnetosomes (MS). MS compel MTB to respond to the applied external magnetic field. However, it is extremely difficult to grow MTB and produce high yield of MS under artificial environmental conditions, thus creating a major hurdle to relocate MTB technology from laboratory scale to industrial or commercial level. Therefore, to best of our knowledge this review is the first attempt to highlight existing research developments about the laboratory scale and mass production of MS by MTB. Moreover, the optimum culture media and environmental conditions used for the cultivation of MTB were also considered. Finally, future research is encouraged for the improvement of MS yield which will result in the development of advanced nanotechnology/magnetotechnology.
Assuntos
Bactérias/crescimento & desenvolvimento , Bactérias/isolamento & purificação , Magnetossomos/metabolismo , Bactérias/metabolismo , Técnicas Bacteriológicas , Meios de Cultura , Óxido Ferroso-Férrico/metabolismo , Ferro/metabolismo , Magnetismo , Nanopartículas/química , Nanotecnologia , Filogenia , Sulfetos/metabolismoRESUMO
Recently, phytoremediation has been regarded as a green and environment friendly technique to treat metals contaminated soils. Thus, in this study, pot experiments were designed to investigate the combine effects of biochar and magnesium (MPs) to purify cadmium (Cd)-contaminated soils by Medicago sativa L. (alfalfa). The results showed that the combined use of biochar and Mg significantly increased the accumulation of Cd and promoted the transport of Cd from root to shoot in alfalfa, simultaneously. Importantly, the combined use of biochar and Mg could increase the accumulation of Cd in shoot and whole plant (shoot + root) of alfalfa up-to 59.1% and 23.1%, respectively. Moreover, the enhancement mechanism can be analyzed from several aspects. Firstly, the photosynthesis was enhanced, which was beneficial to plant growth. The product of photosynthesis provided energy for uptake and transport of Cd. Meanwhile, its transport in phloem could promote the transport of Cd. Secondly, the enhancement of antioxidant capacity of alfalfa effectively protected the membrane structure of alfalfa, which indicated that Cd could enter alfalfa from the channel on the cell membrane. Lastly, the chemical form of Cd and microbial community structure in soil were changed. Overall, these changes reduced the Cd toxicity in soil, enhanced the resistance capability of alfalfa, increased the Cd uptake by alfalfa and promoted the growth of alfalfa. Thus, the obtained results suggested that the combined use of biochar and Mg is an effective approach to enhance phytoremediation performance for purifying Cd-contaminated soils.
Assuntos
Biodegradação Ambiental , Cádmio , Carvão Vegetal , Magnésio , Medicago sativa , Fotossíntese , Poluentes do Solo , Medicago sativa/metabolismo , Medicago sativa/efeitos dos fármacos , Cádmio/metabolismo , Poluentes do Solo/metabolismo , Carvão Vegetal/química , Magnésio/química , Magnésio/metabolismo , Fotossíntese/efeitos dos fármacos , Solo/química , Raízes de Plantas/metabolismoRESUMO
Sodium alginate (SA) biopolymer has been recognized as an efficient adsorbent material owing to their unique characteristics, including biodegradability, non-toxic nature, and presence of abundant hydrophilic functional groups. Accordingly, in the current research work, UiO-66-OH and UiO-66-(OH)2 metal organic framework (MOF) nanoparticles (NPs) have been integrated into SA biopolymer-based three-dimensional (3-D) membrane capsules (MCs) via a simple and facile approach to remove toxic metal cations (Cu2+ and Cd2+) from water and real sewage. The newly configured capsules were characterized by FTIR, SEM, XRD, EDX and XPS analyses techniques. Exceptional sorption properties of the as-developed capsules were ensured by evaluation of the pertinent operational parameters, i.e., contents of MOF-NPs (1-100 wt%), adsorbent dosage (0.001-0.05 g), content time (0-360 h), pH (1-8), initial concentration of metal cations (5-1000 mg/L) and reaction temperature (298.15-333.15 K) on the eradication of Cu2+ and Cd2+ metal cations. It was found that hydrophilic functional groups (-OH and -COOH) have performed an imperative role in the smooth loading of MOF-NPs into 3-D membrane capsules via intra/inter-molecular hydrogen bonding and van der waals potencies. The maximum monolayer uptake capacities (as calculated by the Langmuir isotherm model) of Cd2+ and Cu2+ by 3-D SGMMCs-OH were 940 and 1150 mg/g, respectively, and by 3-D SGMMCs-(OH)2 were 1375 and 1575 mg/g, respectively, under optimum conditions. The as-developed capsules have demonstrated superior selectivity against targeted metal cations under designated pH and maintained >80 % removal efficiency up to six consecutive treatment cycles. Removal mechanisms of metal cations by the 3-D SGMMCs-OH/(OH)2 was proposed, and electrostatic interaction, ion-exchange, inner-sphere coordination bonds/interactions, and aromatic ligands exchange were observed to be the key removal mechanisms. Notably, FTIR and XPS analysis indicated that hydroxyl groups of Zr-OH and BDC-OH/(OH)2 aromatic linkers played vital roles in Cu2+ and Cd2+ adsorption by participating in inner-sphere coordination interactions and aromatic ligands exchange mechanisms. The as-prepared capsules indicated >70 % removal efficiency of Cu2+ from real electroplating wastewater in the manifestation of other competitive metal ions and pollutants under selected experimental conditions. Thus, it was observed that newly configured 3-D SGMMCs-OH/(OH)2 have offered a valuable discernment into the development of MOFs-based water decontamination 3-D capsules for industrial applications.
Assuntos
Alginatos , Estruturas Metalorgânicas , Esgotos , Poluentes Químicos da Água , Purificação da Água , Alginatos/química , Estruturas Metalorgânicas/química , Poluentes Químicos da Água/química , Poluentes Químicos da Água/isolamento & purificação , Adsorção , Purificação da Água/métodos , Biopolímeros/química , Esgotos/química , Cobre/química , Membranas Artificiais , Cápsulas/química , Nanopartículas/química , Cátions/química , Concentração de Íons de Hidrogênio , Cádmio/química , Cádmio/isolamento & purificação , Água/químicaRESUMO
Zero-valent iron (ZVI) materials have been developed and applied to treat various pollutants due to their strong reducing properties and large specific surface area. Red mud contains a large amount of iron oxide and therefore can be used as a source of iron base for the preparation of ZVI materials. Industrial reduction of iron oxides to prepare ZVI materials requires high temperatures resulting in high energy consumption and high costs. Biomass can be pyrolyzed at low temperatures to release large amounts of reducing gas, which can efficiently reduce red mud to obtain ZVI at lower temperatures. Therefore, this paper studied the pyrolysis of five biomasses, corn straw, wheat straw, rice husk, pine wood and coffee grounds, and compared the reduction of iron oxide in red mud at different temperatures for different biomass feedstocks. The results showed that the biomass could reduce most of the iron oxide in red mud to ZVI at 800 °C, which was at least 100 °C lower than the conventional iron reduction temperature. The reducing gas greatly facilitated the conversion of iron oxide to ZVI in this process. Moreover, the material has a good removal effect on both gentian violet and methylene blue. A low-energy and low-cost method was explored for the preparation of ZVI materials, and the resource utilization of biomass and red mud was realized.
Assuntos
Ferro , Poluentes Químicos da Água , Biomassa , Pirólise , Compostos FérricosRESUMO
Microplastics and nanoplastics are being assumed as emerging toxic pollutants owing to their unique persistent physicochemical attributes, chemical stability, and nonbiodegradable nature. Owing to their possible toxicological impacts (not only on aquatic biota but also on humans), scientific communities are developing innovative technologies to remove microplastics and nanoplastics from polluted waters. Various technologies, including adsorption, coagulation, photocatalysis, bioremediation, and filtration, have been developed and employed to eliminate microplastics and nanoplastics. Recently, adsorption technology has been getting great interest in capturing microplastics and nanoplastics and achieving excellent removal performance. Therefore, this review is designed to discuss recent innovations in developing promising adsorbents for the remediation of microplastics and nanoplastics from wastewater and natural water. The developed adsorbents have been classified into four main classes: sponge/aerogel-based, metal-based, biochar-based, and other developed adsorbents, and their performance efficiencies have been critically examined. Further, the influence of various pertinent factors, including adsorbents' characteristics, microplastics/nanoplastics' characteristics, solution pH, reaction temperature, natural organic matter, and co-existing/interfering ions on the removal performance of advanced adsorbents, have been critically assessed. Importantly, the particle application of the developed adsorbents in removing microplastics and nanoplastics from natural water has been elucidated. In addition, barriers to market penetration of the developed adsorbents are briefly discussed to help experts transfer adsorption-based technology from laboratory-scale to commercial applications. Finally, the current knowledge gaps and future recommendations are highlighted to assist scientific communal for improving adsorption-based technologies to battle against microplastics and nanoplastics pollution.
Assuntos
Microplásticos , Poluentes Químicos da Água , Humanos , Plásticos , Poluentes Químicos da Água/análise , Águas Residuárias , Adsorção , ÁguaRESUMO
Recently, microplastics (MPs) and nanoplastics (NPs) contamination is a worldwide problem owing to the immense usage of plastic commodities. Thus, the environmental risks by MPs and NPs demand the application of innovative, efficient, and sustainable technologies to control the pollution of plastic particles. Regarding this, numerous technologies, including adsorption, coagulation, filtration, bioremediation, chemical precipitation, and photocatalysis, have been engaged to eradicate MPs and NPs from contaminated waters. However, the coagulation technique is getting much attention owing to its simplicity, higher removal performance, low carbon footprint, and low operational and maintenance cost. Therefore, this paper has been designed to critically summarize the recent innovations on the application of coagulation process to eradicate MPs and NPs from both synthetic and real sewage. More importantly, the effect of pertinent factors, including characteristics of coagulants, MPs/NPs, and environmental medium on the elimination performances and mechanisms of MPs/NPs have been critically investigated. Further, the potential of coagulation technology in eliminating MPs and NPs from real sewage has been critically elucidated for the first time, for better execution of this technique at commercial levels. Finally, this critical review also presents current research gaps and future outlooks for the improvement of coagulation process for eradicating MPs and NPs from water and real sewage. Overall, the current review will offer valuable knowledge to scientists in selecting a suitable technique for controlling plastic pollution.
RESUMO
Microalgae show great potential for nutrient removal from piggery digestate. However, full-strength piggery digestate have been found to severely inhibit microalgal growth. In this study, microalgae were coupled into the electric field (EF)system to form an electric field-microalgae system (EFMS). The effects of EF characteristics and environmental conditions on the growth of Desmodesmus sp. CHX1 and the removal of nitrogen and phosphorus in EFMS were explored. The results indicated that the optimal EF parameters for forming a fine EFMS were electrode of Zn (anode)/graphite (cathode), electric frequency of three times per day (10â min/time) and voltage of 12â V. The suitable light intensity and microalgae inoculation concentration for the EFMS were 180â µmol photons/(m2·s) and 0.2â g/L, respectively. Ammonium nitrogen and total phosphorus removal efficiencies were 65.38% and 96.16% in the piggery digestate by EFMS under optimal conditions. These results indicate that EFMS is a promising technology for nutrient removal from piggery digestate.
Assuntos
Microalgas , Águas Residuárias , Biomassa , Nutrientes , Nitrogênio , FósforoRESUMO
Fe-based catalysts as low-cost, high-efficiency, and non-toxic materials display superior catalytic performances in activating hydrogen peroxide, persulfate (PS), peracetic acid (PAA), percarbonate (PC), and ozone to degrade organic contaminants in aqueous solutions. They mainly include ferrous salts, zero-valent iron, iron-metal composites, iron sulfides, iron oxyhydroxides, iron oxides, and supported iron-based catalysts, which have been widely applied in advanced oxidation processes (AOPs). However, there is lack of a comprehensive review systematically reporting their synthesis, characterization, and applications. It is imperative to evaluate the catalytic performances of various Fe-based catalysts in diverse AOPs systems and reveal the activation mechanisms of different oxidants by Fe-based catalysts. This work detailedly summarizes the synthesis methods and characterization technologies of Fe-based catalysts. This paper critically evaluates the catalytic performances of Fe-based catalysts in diverse AOPs systems. The effects of solution pH, reaction temperature, coexisting ions, oxidant concentration, catalyst dosage, and external energy on the degradation of organic contaminants in the Fe-based catalyst/oxidant systems and the stability of Fe-based catalysts are also discussed. The activation mechanisms of various oxidants and the degradation pathways of organic contaminants in the Fe-based catalyst/oxidant systems are revealed by a series of novel detection methods and characterization technologies. Future research prospects on the potential preparation means of Fe-based catalysts, practical applications, assistive technologies, and impact in AOPs are proposed.