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1.
Environ Sci Pollut Res Int ; 30(59): 123643-123656, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37991616

RESUMO

The global "copper-poor and aluminum-rich" situation has made the possibility of "copper saving with aluminum" an important topic. This study established a framework for analyzing multiple substances' coupled flows at the product level based on material flow analysis (MFA), and took the household air conditioning system of the Chinese mainland in 2020 as an example to characterize the coupled flows of aluminum and copper. The results showed that the system consumed 0.69 million tons of aluminum and 2.10 million tons of copper, and discharged 0.17 million tons of aluminum and 0.43 million tons of copper to the environment cumulatively to achieve 13.2 million terajoules of final heat exchanged and serve 1.24 billion square meters during lifetime in mainland China alone, secondary aluminum and copper accounted for only 22.61% and 24.83% of the total consumption, and the in-use stocks increased by 0.19 million tons of aluminum and 0.70 million tons of copper. The external dependency of copper ore was 92.83%, which was significantly higher than the 44.29% of bauxite. The comprehensive utilization efficiency of copper reached 77.88%, which was slightly higher than the 70.80% of aluminum. The conclusion indicates that under the premise of meeting use requirements, promoting "replacing copper with aluminum" can improve the stability and safety of China's material supply chain, but there is a need to further boost the production efficiency of aluminum in primary production.


Assuntos
Alumínio , Cobre , Alumínio/análise , Cobre/análise , Ar Condicionado , China , Óxido de Alumínio/análise
2.
Photodiagnosis Photodyn Ther ; 43: 103691, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37429459

RESUMO

AIM: To investigate the effect of different cavity disinfectants, Phycocyanin (PC), Ocimum Sanctum (OS), and Ti Sapphire Laser, on the bond integrity and microleakage of resin restorations. MATERIAL AND METHOD: 60 human mandibular molars were extracted and prepared based on ICDAS scores of 4 and 5. To obtain the CAD surface, a visual examination was supported by tactile sensation and a dye for caries detection. Samples were randomly allocated into 4 groups based on cavity disinfectants applied (n = 15). Group 1: Specimens disinfected with CHX, Group 2: Specimens disinfected with Ti sapphire laser, Group 3: Specimens disinfected with Phycocyanin activated by Photodynamic therapy, and Group 4: Specimens disinfected with OS. Following the disinfection of the CAD surfaces, composite bulk-fill restorative material was bonded to each specimen and all samples were subjected to thermocycling. Ten samples from each group underwent SBS testing performed on a universal testing machine. Five samples were subjected to a microleakage analysis. RESULT: The maximum microleakage scores were displayed by Group 3: PC (0.521 nm) treated specimens. Whereas, and minimum microleakage was exhibited by Group 4: OS (0.471 nm). Group 4: OS (23.06±0.21 MPa) treated group displayed the maximum bond scores of resin adhesive to the CAD surface. However, Group 3: PC (21.67±0.24 MPa) treated specimens exhibited the lowest bond scores. Failure mode analysis revealed that among all the investigated groups the predominant type of failure was cohesive failure i.e., Group 1 (80%), Group 2 (80%), Group 3 (70%), and Group 4 (90%). CONCLUSION: Ocimum Sanctum, Phycocyanin activated by Photodynamic therapy, and Ti-sapphire laser for disinfection of caries-affected dentin have shown promise in terms of improved bond strength and reduced microleakage.


Assuntos
Desinfetantes , Fotoquimioterapia , Humanos , Ocimum sanctum , Ficocianina/uso terapêutico , Resinas Compostas/química , Óxido de Alumínio/análise , Desinfecção , Suscetibilidade à Cárie Dentária , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/uso terapêutico , Dentina/química , Titânio , Lasers , Teste de Materiais
3.
Environ Sci Pollut Res Int ; 29(27): 40893-40902, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35084677

RESUMO

The aim of this work is study of physical and chemical properties of dust of the Pre-Aral region of Uzbekistan such as Karakalpakstan and Khorezm that are located near the three deserts such as the Aralkum, Karakum, and Kyzylkum. The dust particles fell on glass have been collected in Karakalpakstan and Khorezm and studied systematically by employing wide range of methods. Particle volume vs size distribution has been measured with maximum around 600 nm and ~ 10 µm. The major and minor constituent materials present in the dust have been studied systematically by X-ray fluorescence spectroscopy, energy dispersive X-ray diffraction, and inductively coupled plasma optical emission spectroscopy. Main characteristic absorption bands corresponding to Si-O, Si-O-Si bonding in quartz and Fe-O bonds in hematite Fe2O3 have been identified by infrared and Raman spectroscopy. Quartz, hematite, lime, corundum, magnesia, and several other trace minerals have been identified in the dust particles. X-ray diffraction peaks corresponding to quartz, hematite, and corundum are sharp and are found to be more crystalline with some level of disorder. Analysis of the particle size and crystallinity on human being has been performed: disordered or crystalline quartz can create the lung disease; the particles in the size of 0.5-0.7 µm may produce diseases such as chronic silicosis, silicosis, and silica tuberculosis whereas hematite might create lung disease. Dust particles worsen optical transmittance of glass of the panels.


Assuntos
Poeira , Silicose , Óxido de Alumínio/análise , Poeira/análise , Humanos , Tamanho da Partícula , Quartzo , Uzbequistão
4.
Artigo em Inglês | MEDLINE | ID: mdl-33720803

RESUMO

Measurement of skin exposure to particles using interception (e.g., cotton gloves) and removal (e.g., wiping) sampling techniques could be inaccurate because these substrates do not have the same topography and adhesion characteristics as skin. The objective of this study was to compare particle transfer and adherence to cotton gloves, cotton gloves with artificial sebum, and a pre-moistened polyvinyl alcohol (PVA) material with bare human skin (fingertip, palm). Experiments were performed with aluminum oxide powder under standardized conditions for three types of surfaces touched, applied loads, contact times, and powder mass levels. In the final mixed model, the fixed effects of substrate, surface type, applied load, and powder mass and their significant two-way interaction terms explained 71% (transfer) and 74% (adherence) of the observed total variance in measurements. For particle mass transfer, compared with bare skin, bias was -77% (cotton glove with sebum) to +197% (PVA material) and for adherence bias ranged from -40% (cotton glove) to +428% (PVA material), which indicated under- and over-sampling by these substrates, respectively. Dermal exposure assessment would benefit from sampling substrates that better reflect human skin characteristics and more accurately estimate exposures. Mischaracterization of dermal exposure has important implications for exposure and risk assessment.


Assuntos
Exposição Ambiental/análise , Pele/metabolismo , Manejo de Espécimes , Adesividade , Óxido de Alumínio/análise , Óxido de Alumínio/química , Óxido de Alumínio/metabolismo , Fibra de Algodão , Humanos , Álcool de Polivinil/química , Pós/análise , Pós/química , Pós/metabolismo , Absorção Cutânea
5.
Biotechnol Appl Biochem ; 68(6): 1257-1270, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33016525

RESUMO

Nanoparticles are the magic bullets and at the leading edge in the field of nanotechnology, and their unique properties make these materials indispensable and superior in many areas, including the electronic field. Extensive applications of nanomaterials are incontrovertibly entering our living system. The increasing use of nanomaterials into the ecosystem is one of the crucial environmental factors that human being is facing. Nanomaterials raise noticeable toxicological concerns; particularly their accumulation in plants and the resultant toxicity may affect the food chain. Here, we analyzed the characterization of nanomaterials, such as graphene, Al2 O3 , TiO2 , and semi-insulating or conducting nanoparticles. Quantitative evaluation of the nanomaterials was conducted and their commercialization aspects were discussed. Various characterization techniques, scanning electron microscopy, X-ray diffraction, and ultraviolet rays were utilized to identify the morphology, phase, absorbance, and crystallinity. In addition, we analyzed the effects of nanomaterials on plants. The toxicity of nanoparticles has severe effects on loss of morphology of the plants. Potential mechanisms including physical and physiological effects were analyzed. In future studies, it is indispensable to assess widely accepted toxicity evaluation for safe production and use of nanomaterials.


Assuntos
Óxido de Alumínio/análise , Grafite/análise , Jasminum/química , Nanopartículas/análise , Titânio/análise , Humanos , Tamanho da Partícula
6.
Anal Bioanal Chem ; 413(2): 555-564, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33156401

RESUMO

Hybrid material surfaces on microparticles are emerging as vehicles for many biomedical multiplexing applications. Functionalization of these hybrid surface microparticles to biomolecules presents unique challenges related to optimization of surface chemistries including uniformity, repeatability, and sample sparring. Hybrid interfaces between microlevel surfaces and individual biomolecules will provide different microenvironments impacting the surface functionalization optimization and efficiency. Here, we propose and validate the first demonstration of streptavidin adsorption-based antibody functionalization on unmodified, hybrid surface microparticles for in vitro analysis. We test this analytical technique and fabricate hybrid surface microparticles with a polystyrene core and aluminum oxide semi-coating. Additionally, we optimize the streptavidin-biotin functionalization chemistry in both assay implementation and sample sparring via analytical mass balances for these microparticles and subsequently conjugate anti-human CD11b antibodies. Result confirmation and characterization occurs from ultraviolet protein absorbance and ImageJ processing of fluorescence microscopy images. Additionally, we design and implement the multi-sectional imaging (MSI) approach to support functionalization uniformity on the hybrid surface microparticles. Finally, as a proof-of-concept performance, we validate anti-CD11b antibodies functionalization by visualizing hybrid surface microparticles conjugate to human neutrophils isolated from blood samples collected from potentially septic patients. Our study introduces and defines a category of functionalization for hybrid surface microparticles with the intent of minuscule sample volumes, low cost, and low environmental impact to be used for many cellular or proteomic in vitro multiplexing applications in the future. Graphical abstract.


Assuntos
Óxido de Alumínio/análise , Microesferas , Neutrófilos/metabolismo , Estreptavidina/análise , Adsorção , Biotina/química , Antígeno CD11b/análise , Humanos , Técnicas In Vitro , Microscopia de Fluorescência , Tamanho da Partícula , Poliestirenos , Propriedades de Superfície
7.
Ecotoxicol Environ Saf ; 206: 110949, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-32882571

RESUMO

A better comprehensive understanding of the influence of soil/solution properties on cadmium (Cd) phytotoxicity is essential for soil Cd ecological risk assessment. The toxicity of soil spiked Cd to Ligustrum japonicum 'Howardii' seedling growth was conducted by the greenhouse pot experiments using 13 typical forest soils selected from mainland of China. The results showed that the ranges of Cd toxicity thresholds of 10% seedling growth inhibition (EC10) and 50% inhibition (EC50) followed the order: soil pore water Cd (EC10 on average 0.88 mg L-1 with the variation of 54.9 folds and EC50 on average 2.28 mg L-1 with variation of 41.8 folds), DTPA extractable Cd (EC10 on average 5.4 mg kg-1 with 20.9 folds variation and EC50 on average 17.86 mg kg-1 with 6.6 folds variation), total added Cd (EC10 on average 6.55 mg kg-1 with 16.7 folds variation and EC50 on average 22.11 mg kg-1 with 5.1 folds variation), which suggested that whatever the available Cd expressed, its toxicity is largely affected by soil properties. The empirical multiple equations were well developed between different fractions of Cd toxicity thresholds ECx (x = 10 or 50) and soil/solution. The results also showed that the pH inversely correlated with EC10 (r2 = 0.54, P < 0.01) and EC50 (r2 = 0.63, P < 0.001) based on soil pore water, indicating the ECx decreased with more toxicity as pH increased. No single significant soil solution properties were found for ECx in DTPA extractable Cd. For the ECx of DTPA extractable and total Cd, the content of aluminum oxides in soil and soil pH were the two significant factors inversely related with ECx, which explained 68%-79% of the inter-soil variation, respectively. Overall, soil or solution pH was the most important factor controlling Cd toxicity thresholds. Meanwhile, significant negative correlations existed between the soil solution pH and the slopes of parameter (b) of the dose-response curves for different fractions of Cd, implying that the growth of toxic effect enhanced as unit Cd dosage increased in low pH soils. These results will be helpful to evaluate the metal ecological risk in forest soils.


Assuntos
Cádmio/toxicidade , Florestas , Ligustrum/efeitos dos fármacos , Poluentes do Solo/toxicidade , Solo/química , Óxido de Alumínio/análise , Cádmio/análise , China , Monitoramento Ambiental , Concentração de Íons de Hidrogênio , Ligustrum/crescimento & desenvolvimento , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Poluentes do Solo/análise
8.
Ecotoxicol Environ Saf ; 201: 110847, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32554203

RESUMO

Bauxite residues (BR), commonly named red muds, are the saline-sodic waste produced during the extraction of alumina from bauxite. In this study, four kinds of BR were mixed at increasing concentrations with two soils in a mesososm experiment. Unamended BR from Provence (PRO) and Guinea (GUI) bauxite were selected, and Modified Bauxite Residues from PRO and GUI (MBR-PRO and MBR-GUI) were obtained by gypsum application and repeated leaching, in order to reduce their pH, electrical conductivity (EC) and exchangeable sodium percentage (ESP). Several indicators of microbial community functions and structure (growth of culturable bacteria; enzymatic activities; C-sourced substrates degradation (Biolog®); bacteria and fungi PCR-RFLP fingerprints) were measured after 35 days of incubation. Results showed that PRO residue had stronger negative effects than GUI on all the tested indicators. Residues modified by gypsum addition (MBR-PRO, MBR-GUI) were equally or sometimes less harmful compared to unamended residues. Microbial activities (bacterial growth and enzyme activities) were more inhibited than the diversity of microbial functions (Biolog®), and the structure of bacterial and fungal communities was not affected by increasing concentrations of bauxite residues. EC and ESP were the main factors explaining the inhibition of microbial activities, although the origin of bauxite residue is of great importance too.


Assuntos
Óxido de Alumínio/toxicidade , Sulfato de Cálcio/toxicidade , Microbiota/efeitos dos fármacos , Microbiologia do Solo , Poluentes do Solo/toxicidade , Solo/química , Óxido de Alumínio/análise , Óxido de Alumínio/química , Bactérias/efeitos dos fármacos , Bactérias/crescimento & desenvolvimento , Sulfato de Cálcio/análise , Sulfato de Cálcio/química , Fungos/efeitos dos fármacos , Fungos/crescimento & desenvolvimento , Poluentes do Solo/análise , Poluentes do Solo/química
9.
Int J Mol Sci ; 21(4)2020 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-32074956

RESUMO

Aluminum (Al) is extensively used for the production of different consumer products, agents, as well as pharmaceuticals. Studies that demonstrate neurotoxicity and a possible link to Alzheimer's disease trigger concern about potential health risks due to high Al intake. Al in cosmetic products raises the question whether a possible interaction between Al and retinol (vitamin A) and cholecalciferol (vitamin D3) metabolism might exist. Understanding the uptake mechanisms of ionic or elemental Al and Al nanomaterials (Al NMs) in combination with bioactive substances are important for the assessment of possible health risk associated. Therefore, we studied the uptake and distribution of Al oxide (Al2O3) and metallic Al0 NMs in the human keratinocyte cell line HaCaT. Possible alterations of the metabolic pattern upon application of the two Al species together with vitamin A or D3 were investigated. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) imaging and inductively coupled plasma mass spectrometry (ICP-MS) were applied to quantify the cellular uptake of Al NMs.


Assuntos
Óxido de Alumínio/análise , Alumínio/análise , Colecalciferol/farmacologia , Nanoestruturas/química , Vitamina A/farmacologia , Alumínio/química , Alumínio/metabolismo , Óxido de Alumínio/química , Óxido de Alumínio/metabolismo , Linhagem Celular , Membrana Celular/química , Membrana Celular/metabolismo , Humanos , Queratinócitos/citologia , Queratinócitos/efeitos dos fármacos , Queratinócitos/metabolismo , Espectrometria de Massa de Íon Secundário
10.
Plant Biol (Stuttg) ; 22(2): 323-330, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31642146

RESUMO

Bauxite mining on karst generates numerous ecological and environmental problems, including metal pollution, water and soil erosion and destruction of vegetation. Among these, the most important environmental problem is soil metal pollution. Higher plants have a great ability to adsorb metals and can be used as biological indicators. However, the study of bioindicators for soil contamination in karst bauxite is not clear. Plants and their soil were collected from an abandoned karst bauxite area at Shangdong, Guizhou Province, southwestern China. Plants were collected and identified as Pteris vittata, Pinus massoniana, Miscanthus floridulus, Coriaria nepalensis, Artemisia argyi and Senecio scandens. The content of metals in plant roots were in the order: P. vittata > M. floridulus > C. nepalensis, other plants roots had no consistent pattern. Concentrations of metal in plants (P. vittata and M. floridulus) and soil were: soil > root > leaf > stem. Levels of metals in soil samples easily exceeded background values, indicating that soil had been contaminated. Al and Fe were highest in soil samples of P. vittata, with a good correlation. Results show that the metal content determined in plants is relatively high, particularly in P. vittata. Data also suggest that P. vittata colonies were able to tolerate and accumulate high levels of metal elements, which evidences their suitability for use as bioindicatord of soil metal contamination caused by mining activities.


Assuntos
Óxido de Alumínio , Biomarcadores Ambientais , Monitoramento Ambiental , Metais , Poluentes do Solo , Óxido de Alumínio/análise , Biodegradação Ambiental , China , Metais/análise , Solo , Poluentes do Solo/análise
11.
Sci Total Environ ; 698: 134344, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31783438

RESUMO

Around 3 billion tonnes of bauxite residue (BR), the by-product of alumina extraction, have been produced and stockpiled worldwide, representing a potential risk for the environment due to the high alkalinity and the presence of relatively high concentrations of trace elements. Phytoremediation (or simply revegetation) is regarded as the most promising in situ remediation option to mitigate the environmental risk that might arise from the land-disposal of BR. Rehabilitation strategies (including the incorporation of amendments such as gypsum and organic matter) have been employed to address the main limitations to plant establishment and growth on BR, typically the high alkalinity, salinity and sodicity. However, the potential for trace element uptake and phytotoxicity have been largely unreported in revegetated BRs. In order to assess the ecotoxicological risk, samples of previously revegetated BR were collected from the field, characterized in the laboratory, and used to conduct ex-situ plant bioassays (Phytotoxkit™ and the RHIZOtest). Without rehabilitation, fresh BR severely inhibits seed germinationand root/shoot development in test species Lepidium sativum, Sinapis alba and Sorghum saccharatum. Plant uptake for Al, As, Cr, V was assessed with RHIZOtest bioassay trials with Lolium perenne and demonstrated that plants exposed to fresh BR take up and translocated trace elements to their shoots at concentrations (As = 4.13 mg/kg dm; Cr = 3.29 mg/kg dm; V = 85.66 mg/kg dm) exceeding phytotoxic levels (vanadium) or maximum levels specified for animal feed (arsenic), showing visible stress symptoms in the seedlings. Conversely, revegetated BR show improved chemical properties, allow seed germination, and permits seedling growth with no evidence of trace element phytotoxicity. However, Na can be taken up at concentrations that could elicit phytotoxicity and impair the success of revegetation. For future rehabilitation programmes, direct revegetation on BR after the incorporation of amendments such as gypsum and organic matter is recommended.


Assuntos
Óxido de Alumínio/análise , Recuperação e Remediação Ambiental , Poluentes do Solo/análise , Óxido de Alumínio/toxicidade , Biodegradação Ambiental , Ecotoxicologia , Medição de Risco , Salinidade , Sinapis , Solo/química , Microbiologia do Solo , Poluentes do Solo/toxicidade , Sorghum
12.
Kathmandu Univ Med J (KUMJ) ; 18(72): 414-419, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-34165102

RESUMO

Bauxite is an ore from which Aluminium is produced. Malaysia, once the leading producer of bauxite has reduced production as mining activity has caused community outrage. Due to concerns about health concerns, rising pollution and environmental hazards, the government has revoked the licenses of bauxite miners. We therefore did a meta-analysis to assess the relationship between exposure to Bauxite and Alumina with incidence of various types of cancers. Bauxite mines and alumina refineries. Individuals of all ages exposed to Bauxite and Alumina. Exposure to bauxite and alumina. Incidence due to overall cancers and specific types of cancers. Exposure to bauxite and alumina did not cause variations in incidence of overall cancer and specific types of cancer such as cancer of lip, cancer of the oral cavity and pharynx, cancer of digestive organs and others. We conclude that there is no evidence that bauxite or alumina exposure cause increase incidence of cancer but due to the small number of studies included in this review, we recommend more cohort studies to be done in future.


Assuntos
Neoplasias , Exposição Ocupacional , Óxido de Alumínio/efeitos adversos , Óxido de Alumínio/análise , Humanos , Incidência , Malásia , Neoplasias/epidemiologia , Neoplasias/etiologia
13.
Environ Pollut ; 255(Pt 1): 113131, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31521992

RESUMO

Low-cost particulate matter (PM) air quality sensors are becoming widely available and are being increasingly deployed in ambient and home/workplace environments due to their low cost, compactness, and ability to provide more highly resolved spatiotemporal PM concentrations. However, the PM data from these sensors are often of questionable quality, and the sensors need to be characterized individually for the environmental conditions under which they will be making measurements. In this study, we designed and assessed a cost-effective (∼$700) calibration chamber capable of continuously providing a uniform PM concentration simultaneously to multiple low-cost PM sensors and robust calibration relationships that are independent of sensor position. The chamber was designed and evaluated with a Computational Fluid Dynamics (CFD) model and a rigorous experimental protocol. We then used this new chamber to calibrate 242 Plantower PMS 3003 sensors from two production lots (Batches I and II) with two aerosol types: ammonium nitrate (for Batches I and II) and alumina oxide (for Batch I). Our CFD models and experiments demonstrated that the chamber is capable of providing uniform PM concentration to 8 PM sensors at once within 6% error and with excellent reliability (intraclass correlation coefficient > 0.771). The study identified two malfunctioning sensors and showed that the remaining sensors had high linear correlations with a DustTrak monitor that was calibrated for each aerosol type (R2 > 0.978). Finally, the results revealed statistically significant differences between the responses of Batches I and II sensors to the same aerosol (P-value<0.001) and the Batch I sensors to the two different aerosol types (P-value<0.001). This chamber design and evaluation protocol can provide a useful tool for those interested in systematic laboratory characterization of low-cost PM sensors.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/análise , Monitoramento Ambiental/instrumentação , Monitoramento Ambiental/métodos , Material Particulado/análise , Aerossóis/análise , Óxido de Alumínio/análise , Calibragem , Hidrodinâmica , Nitratos/análise , Tamanho da Partícula , Reprodutibilidade dos Testes
14.
Ecotoxicol Environ Saf ; 185: 109708, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31563748

RESUMO

In this study, the effluent from the Bayer process of transforming bauxite into alumina, followed by dissolved air flotation (DAF) treatment, was evaluated to identify the best experimental conditions that generate less toxic or nontoxic effluent for discharge. Two freshwater organisms, the Chlorophyceae microalga Raphidocelis subcapitata (96-h algal growth inhibition test), and the microcrustacean Daphnia similis (48-h acute immobility test), were used to analyze the efficiency of effluent treatment by detecting and comparing the toxicity of the treated effluent. Experimental factorial planning used different concentrations of the coagulant ferric chloride and the flocculant Nalco® N-99-005B, and different recycle ratios. The highest recycle ratio (30%) and highest flocculant concentration (150 mg/L) had the best solids removal efficiency, above 90%. Probably the higher concentration of flocculant led to the formation of a more stable froth, promoting an increase in the hydrophobic characteristics of the flocs. Two operating conditions were satisfactory according to acute and chronic bioassays, with removal efficiencies of total suspended solids and turbidity higher than 98%, for both variables. Producers, R. subcapitata microalga, were more sensitive than the primary consumers, D. similis microcrustaceans, indicating the importance of performing tests with different bioindicators.


Assuntos
Ar/análise , Óxido de Alumínio/toxicidade , Material Particulado/toxicidade , Poluentes Químicos da Água/toxicidade , Purificação da Água/métodos , Óxido de Alumínio/análise , Animais , Daphnia/efeitos dos fármacos , Ecotoxicologia , Floculação , Microalgas/efeitos dos fármacos , Modelos Teóricos , Tamanho da Partícula , Material Particulado/análise , Poluentes Químicos da Água/análise
15.
J Environ Radioact ; 205-206: 72-78, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31121423

RESUMO

Kinetics analyses of sorption and desorption provide important insight into reaction mechanisms occurring at the mineral-water interface. They are also needed to determine when equilibrium is achieved, identify intermediate chemical species, and inform models describing neptunium mobility. Neptunium sorption to and desorption from four different aluminum (hydr)oxides - bayerite (α-Al(OH)3), gibbsite (γ-Al(OH)3), corundum (α-Al2O3), and γ-alumina (γ-Al2O3) - were investigated as a function of mineral concentration (5 - 170 m2 L-1), neptunium concentration (10-9 - 10-7 M), and pH (5.5 - 10.5). Neptunium sorption was characterized by a two-step reaction with an initial fast sorption step occurring within minutes followed by a slower equilibrium process, which was attributed to initial sorption of neptunium to a small number of strong sorption sites followed by sorption of neptunium to a larger number of weak sorption sites. The kinetics data were modeled using the linear and non-linear forms of the pseudo-first and pseudo-second order rate equations and the goodness of fit parameters were compared. Non-linear pseudo-second order rate constants described neptunium sorption to aluminum (hydr)oxides most accurately and were used to determine the reaction orders with respect to mineral concentration and [H+]. Neptunium desorption experiments demonstrated that the desorption mechanism changed as a function of pH and that the forward and reverse reactions were not equivalent. At pH ≥ 7.5, desorption reached steady-state within an hour and was accurately described by the non-linear pseudo-second order rate equations. A desorption plateau was observed at pH 5.5 that could not be described by either pseudo-first or -second order kinetics, suggesting the possibility of a multi-step desorption reaction. The comparatively slow desorption kinetics observed here suggests that sorbed neptunium could be slowly released back into the aqueous phase and act as a continuous source of contamination to the environment.


Assuntos
Hidróxido de Alumínio/análise , Óxido de Alumínio/análise , Minerais/análise , Netúnio/química , Adsorção , Concentração de Íons de Hidrogênio , Cinética
16.
Astrobiology ; 19(7): 867-884, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-30994366

RESUMO

Carbon-enriched rocky exoplanets have been proposed to occur around dwarf stars as well as binary stars, white dwarfs, and pulsars. However, the mineralogical make up of such planets is poorly constrained. We performed high-pressure high-temperature laboratory experiments (P = 1-2 GPa, T = 1523-1823 K) on chemical mixtures representative of C-enriched rocky exoplanets based on calculations of protoplanetary disk compositions. These P-T conditions correspond to the deep interiors of Pluto- to Mars-sized planets and the upper mantles of larger planets. Our results show that these exoplanets, when fully differentiated, comprise a metallic core, a silicate mantle, and a graphite layer on top of the silicate mantle. Graphite is the dominant carbon-bearing phase at the conditions of our experiments with no traces of silicon carbide or carbonates. The silicate mineralogy comprises olivine, orthopyroxene, clinopyroxene, and spinel, which is similar to the mineralogy of the mantles of carbon-poor planets such as the Earth and largely unaffected by the amount of carbon. Metals are either two immiscible iron-rich alloys (S-rich and S-poor) or a single iron-rich alloy in the Fe-C-S system with immiscibility depending on the S/Fe ratio and core pressure. We show that, for our C-enriched compositions, the minimum carbon abundance needed for C-saturation is 0.05-0.7 wt% (molar C/O ∼0.002-0.03). Fully differentiated rocky exoplanets with C/O ratios more than that needed for C-saturation would contain graphite as an additional layer on top of the silicate mantle. For a thick enough graphite layer, diamonds would form at the bottom of this layer due to high pressures. We model the interior structure of Kepler-37b and show that a mere 10 wt% graphite layer would decrease its derived mass by 7%, which suggests that future space missions that determine both radius and mass of rocky exoplanets with insignificant gaseous envelopes could provide quantitative limits on their carbon content. Future observations of rocky exoplanets with graphite-rich surfaces would show low albedos due to the low reflectance of graphite. The absence of life-bearing elements other than carbon on the surface likely makes them uninhabitable.


Assuntos
Meio Ambiente Extraterreno/química , Grafite/análise , Modelos Químicos , Planetas , Óxido de Alumínio/análise , Óxido de Alumínio/química , Exobiologia/métodos , Gases/química , Compostos de Ferro/análise , Compostos de Ferro/química , Compostos de Magnésio/análise , Compostos de Magnésio/química , Óxido de Magnésio/análise , Óxido de Magnésio/química , Minerais/análise , Minerais/química , Silicatos/análise , Silicatos/química , Astros Celestes , Água/química
17.
J Hazard Mater ; 373: 250-257, 2019 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-30921576

RESUMO

Biochar system technology has been proved as a sustainable remediation method for metal contaminated soils. However, little attention has been paid to the interaction between biochar and oxide minerals and their influence on metal immobilization in soils. In this study, batch-type Zn sorption experiments were conducted using the mixture of γ-Al2O3 and rice straw biochar as a model binary geosorbent systems. In addition, advanced spectroscopic technics such as EXAFS, FTIR and XRD were performed to reveal the mechanism. EXAFS spectroscopy revealed that 62% of Zn existed as Zn-Al layered double hydroxide (LDH) on γ-Al2O3 at pH 7.5 (for 2 mM Zn loading) within 24 h, which was 19% in the mixture. The Zn in biochar samples mainly existed as Zn-OM (53%-76%) and Zn2SiO4 (21%-47%), while the proportion of Zn2SiO4 (0-6%) was negligible compared with Zn-Al silicate (26-48%) in the mixtures. The overall findings confirmed that Al released from γ-Al2O3 was sorbed in parallel with Zn on biochar to form Zn-Al silicate, rather than Zn-Al LDH on the γ-Al2O3 surface. These results unveiled the dynamic interactions between amended biochar and soil oxide minerals which can significantly affect the immobilization pathways of metals in contaminated soils.


Assuntos
Óxido de Alumínio/química , Carvão Vegetal/química , Zinco/isolamento & purificação , Adsorção , Óxido de Alumínio/análise , Carvão Vegetal/análise , Microscopia Eletrônica de Varredura , Oryza
18.
PDA J Pharm Sci Technol ; 73(3): 235-246, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30651335

RESUMO

Sensitivity of drugs to one or more elements of the primary packaging is a serious concern for the pharmaceutical industry. Biologics in particular are highly sensitive, leading to a higher risk of incompatibility and stability test failure as worst-case scenario.This potential incompatibility-and the consequent formulation instability due to the interactions between the drug and the primary container surface-may have multiple causes: the intrinsic nature of the container surface, leachables coming from the materials used, substances coming from the production process, or silicone oil droplets or other particles.The Alba primary packaging platform was designed to have the same interface between the drug and the glass container surface on the different primary packaging containers in order to minimize the emergence of instabilities at later stages of formulation development. Alba containers are internally treated with an innovative cross-linked coating based on silicone oil lubricant, and the additional rubber components have been selected to minimize the possible differences between the container typologies.This paper shows in great detail the reduction of the inorganic extractables released and the comparability of the performances of the different containers obtained using Alba technology.The improvement has been demonstrated by stressing the containers with different extract solutions; Alba-coated containers show a strong reduction of inorganic extractables and of corrosion degree compared to spray-on siliconized and bulk products. The containers included in the Alba platform present comparable results, and this represents a strong advantage during the drug formulation development by facilitating the transition from one container to another.LAY ABSTRACT: The sensitivity of drugs to one or more elements of the primary packaging is a serious concern for the pharmaceutical industry. Biologics in particular are highly sensitive, leading to a higher risk of incompatibility and stability test failure worst-case scenario.This potential incompatibility-and the consequent formulation instability due to the interactions between the drug and the primary container surface-may have multiple causes: the intrinsic nature of the container surface, leachables coming from the materials used, substances coming from the production process, or silicone oil droplets or other particles.The Alba primary packaging platform was designed to minimize these problems associated with the interaction between the drug and its primary packaging. This paper shows in great detail and with robust data the inorganic extractables release reduction and the delamination risk mitigation obtained using the Alba technology.


Assuntos
Contaminação de Medicamentos/prevenção & controle , Embalagem de Medicamentos/normas , Preparações Farmacêuticas/normas , Óxido de Alumínio/análise , Compostos de Boro/análise , Vidro/química , Vidro/normas , Infusões Parenterais , Óxidos/análise , Preparações Farmacêuticas/administração & dosagem , Plásticos/química , Plásticos/normas , Dióxido de Silício/análise , Compostos de Sódio/análise , Propriedades de Superfície , Seringas
19.
Bull Environ Contam Toxicol ; 102(1): 98-104, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30374583

RESUMO

The behavior of nanoparticles released to the soil has been extensively studied in recent years; however, the effects of nanoparticles on the distribution of soil elements and on sowing are still unknown. To this end, to examine the distribution of selected elements in soil, soil samples were treated weekly with 1.0 mg and 20.0 mg of Al2O3 nanoparticles for 3 weeks. Additionally, different types of plants (including taproot, fibrous root and ornamental bulbous plants) were sowed in the soil samples. After each treatment, surface soil samples were collected and digested with acid digestion. The concentrations of selected elements (Ca, Mg, Fe, Al, Cu, Co, Ni) were determined using a microwave plasma atomic emission spectrometer. Al2O3 treatment for 3 weeks, both low and high doses, had no effect on the Al content in soil samples when compared to the controls. Additionally, Al2O3 showed desorption properties on the analyte elements.


Assuntos
Óxido de Alumínio/análise , Nanopartículas/análise , Solo/química , Alumínio/análise , Cálcio , Cobalto/análise , Cobre/análise , Ferro/análise , Magnésio/análise , Níquel/análise , Raízes de Plantas/química
20.
Environ Monit Assess ; 190(10): 617, 2018 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-30267160

RESUMO

This work proposes the quantification of Cr (VI) ions in natural waters in trace level, using activated alumina (Al2O3) as preconcentration support, controlled in-line dissolution of the solidified chromophore diphenylcarbazide after heat treatment and spectrophotometric detection. The manifold ensures high sensitivity of analytical response, good repeatability, and stability. In this work, optimization of experimental conditions of a flow injection system was chosen as the parameters for greater sensitivity and better selectivity. The selected optimized conditions were 0.30 mol L-1 for H2SO4 concentration, system flow rate as 0.40 mL min-1, sample injection volume of 192.50 µL, 2 min for preconcentration time, and 0.10 mol L-1 for eluent concentration. The analytical curves obtained for real sample analysis show linear range from 0.192 to 0.961 µM, linear correlation coefficient R = 0.9997 and LOD = 0.024 µM. The preconcentration factor of about four times was obtained through the passage of 800 µL of a standard solution containing 0.961 µM of Cr (VI) through mini-column of preconcentration followed by elution at 192.5 µL of NH4OH 0.1 mol L-1 solution. The solid chromogenic reagent presented high durability (weeks in daily use with mass of 0.0993 g) and good reproducibility in analytical signal. The reactivation of the mini-column of alumina should be executed after ten injections of eluent, using 800 µL of HCl 0.02 mol L-1 solution in flow through the same. Each cycle of injection and elution of the sample takes about 5 min on the proposed terms. Despite the length of each cycle still be high, low concentrations can be detected using a technique of relatively low cost. This is due in part, the association dissolution of the chromogenic reagent directly in the line and the preconcentration step. Another important factor is the economy of reagent chromogenic, low generation of reject contributing to better quality of the environment, and the high potential for applications to work in field.


Assuntos
Cromo/análise , Difenilcarbazida/química , Monitoramento Ambiental/métodos , Espectrofotometria/métodos , Óxido de Alumínio/análise , Temperatura Alta , Íons/análise , Reprodutibilidade dos Testes , Solubilidade
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