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1.
Molecules ; 26(3)2021 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-33525610

RESUMO

Precious metals, in particular Pd, have a wide range of applications in industry. Due to their scarcity, precious metals have to be recycled, preferably with green and energy-saving recycling processes. In this article, palladium extraction from an aluminosilicate-supported catalyst, containing about 2 wt% (weight%) of Pd (100% PdO), with supercritical CO2 (scCO2) assisted by complexing polymers is described. Two polymers, p(FDA)SH homopolymer and p(FDA-co-DPPS) copolymer (FDA: 1,1,2,2-tetrahydroperfluorodecyl acrylate; DPPS: 4-(diphenylphosphino)styrene), were tested with regards to their ability to extract palladium. Both polymers showed relatively low extraction conversions of approximately 18% and 30%, respectively. However, the addition of piperidine as activator for p(FDA-co-DPPS) allowed for an increase in the extraction conversion of up to 60%.


Assuntos
Silicatos de Alumínio/química , Dióxido de Carbono/química , Paládio/química , Piperidinas/química , Polímeros/química , Acrilatos/química , Catálise , Reciclagem/métodos , Estireno/química
2.
Int J Biol Macromol ; 170: 793-809, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33387544

RESUMO

Paper industry uses cationic polymers for imparting strong bonds with pulp furnish to enhance strength properties. Due to environmental reasons, emphasis is on utilization of biobased polymers in place of synthetic. Sugarcane bagasse, an agro-industrial waste, was processed for extraction of alpha cellulose and preparation of cationic derivative. Reaction conditions were optimized to achieve highly substituted cationic derivative with insertion of 2-hydroxy-3-(trimethylammonium) propyl group. Artificial neural network (ANN) was applied to analyze the experimental data for cationization modeling. Maximum degree of substitution 0.66, was achieved at 5.0 M NaOH/anhydro glucose unit (AGU), 20 °C alkalization temperature, 8 min alkalization time, 3.5 M/AGU etherification agent concentration, 45 min time and 60 °C etherification reaction temperature. The experimental results showed that mean square error values for input parameters were significantly low. The ANN based regression values of the output, and computed values of target were close to unity. ANN based fitting indicates better performance level to predict the degree of substitution. The synthesized cationic cellulose was characterized through FTIR, XRD, NMR, FESEM and TGA. The activity of cationized cellulose as wet-end additive was tested for bagasse, wheat straw and recycled pulps due to their shorten fiber and feeble pulp characters than wood pulp.


Assuntos
Celulose/química , Saccharum/química , Cátions/química , Resíduos Industriais , Polímeros/química , Reciclagem/métodos , Temperatura
3.
Molecules ; 26(1)2020 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-33374496

RESUMO

The development of low-cost electrode devices from conductive materials has recently attracted considerable attention as a sustainable means to replace the existing commercially available electrodes. In this study, two different electrode surfaces (surfaces 1 and 2, denoted as S1 and S2) were fabricated from chocolate wrapping aluminum foils. Energy dispersive X-Ray (EDX) and field emission scanning electron microscopy (FESEM) were used to investigate the elemental composition and surface morphology of the prepared electrodes. Meanwhile, cyclic voltammetry (CV), chronoamperometry, electrochemical impedance spectroscopy (EIS), and differential pulse voltammetry (DPV) were used to assess the electrical conductivities and the electrochemical activities of the prepared electrodes. It was found that the fabricated electrode strips, particularly the S1 electrode, showed good electrochemical responses and conductivity properties in phosphate buffer (PB) solutions. Interestingly, both of the electrodes can respond to the ruthenium hexamine (Ruhex) redox species. The fundamental results presented from this study indicate that this electrode material can be an inexpensive alternative for the electrode substrate. Overall, our findings indicate that electrodes made from chocolate wrapping materials have promise as electrochemical sensors and can be utilized in various applications.


Assuntos
Alumínio/química , Chocolate , Técnicas Eletroquímicas/métodos , Eletrodos , Grafite/química , Metais/química , Reciclagem/métodos , Oxirredução , Propriedades de Superfície
4.
PLoS One ; 15(8): e0231933, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32818952

RESUMO

Financing municipal solid waste (MSW) services is one of the key challenges faced by cities in developing countries. This study used plastic waste, a constituent of MSW, to explore the possibility of generating revenue for financing MSW management in the municipalities of Nepal. The results of this study suggest that plastic material recovery could generate revenue, which is equivalent to 1.38 times of the plastic-waste-related management cost when collection efficiency reaches 66.7%. An increase in 1% of recovery rate and collection efficiency could cover an additional 4.64% and 2.06% of the costs of managing plastic waste, respectively. In addition, an increase in tax on imported plastic materials could also motivate recovery of plastic waste for recycle and reuse. An additional 1% tax on plastic imports would be sufficient to cover plastic-related waste management when plastic waste recovery and collection efficiency rates are low. This plastic recovery- revenue exercise could be expanded to other materials such as paper and metal to fully understand the possibility of sustainable financing of MSW management and reducing environmental harm in developing countries like Nepal.


Assuntos
Reciclagem/métodos , Resíduos Sólidos/economia , Gerenciamento de Resíduos/métodos , Cidades , Países em Desenvolvimento , Nepal , Plásticos/análise , Plásticos/química , Reciclagem/economia , Eliminação de Resíduos/economia , Eliminação de Resíduos/métodos , Resíduos Sólidos/análise , Gerenciamento de Resíduos/economia
5.
Chemosphere ; 259: 127402, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32593819

RESUMO

Plastic waste has caused severe environmental problems. Some additives in plastics, like organophosphates, enter the environment with plastic waste, causing significant harm to plants and creatures. However, the primary method of recycling phosphorus-containing plastic, especially polycarbonate and acrylonitrile-butadiene-styrene copolymer (PC/ABS), is a mechanical method, which not only does not effectively separate plastics and organophosphates but also tends to cause polymer degradation during recycling. In order to overcome these problems, we proposed an efficient and sustainable approach to recycle of phosphorus-containing plastic. In this method, N, N-dimethylcyclohexylamine (DMCHA), a switchable hydrophilicity solvent (SHS), was used to react with and extract organophosphates in plastic, achieving the goal of complete separation of plastic and organophosphates. PC/ABS can be recovered by precipitation. Dissolved organophosphates can also be easily recovered due to the switching characteristics of SHS. Both of recovered materials were of high purity and were close to virgin materials. This technique is an easy and efficient approach to separate plastic and organophosphates, which has excellent application prospects in recycling phosphorus-containing plastic.


Assuntos
Fósforo/química , Plásticos/química , Reciclagem/métodos , Acrilonitrila , Butadienos , Interações Hidrofóbicas e Hidrofílicas , Cimento de Policarboxilato , Polímeros , Poliestirenos , Solventes
6.
Can J Surg ; 63(3): E278-E283, 2020 05 21.
Artigo em Inglês | MEDLINE | ID: mdl-32437094

RESUMO

Background: It is estimated that one-quarter to half of all hospital waste is produced in the operating room. Recycling of surgical waste in the perioperative setting is uncommon, even though there are many recyclable materials. The objective of this study was to determine the amount of waste produced in the preoperative and operative periods for several orthopedic subspecialties and to assess how much of this waste was recycled. Methods: Surgical cases at 1 adult and 1 pediatric tertiary care hospital in Calgary, Alberta, were prospectively chosen from 6 orthopedic subspecialties over a 1-month period. Waste was collected, weighed and divided into recyclable and nonrecyclable categories in the preoperative period and into recyclable, nonrecyclable, linen and biological categories in the intraoperative period. Waste bags were weighed using a portable hand-held scale. The primary outcome was the amount of recyclable waste produced per case. Secondary outcomes included the amount of nonrecyclable, biological and total waste produced. An analysis of variance was performed to test for statistically significant differences among subspecialties. Results: This study included 55 procedures. A total of 341.0 kg of waste was collected, with a mean mass of 6.2 kg per case. Arthroplasty produced a greater amount of recyclable waste per case in the preoperative (2017.1 g) and intraoperative (938.6 g) periods as well as total recyclable waste per case, resulting in a greater ratio of waste recycling per case then nearly all other subspecialties in the preoperative (86%) and intraoperative (14%) periods. Arthroplasty similarly produced a greater amount of nonrecyclable waste per case (5823.6 g) than the other subspecialties, most of which was produced during the intraoperative period (5512.9 g). Overall an average of 27% of waste was recycled per case. Conclusion: Among orthopedic subspecialties, arthroplasty is one of the largest waste producers and it has the highest potential for recycling of materials. Effective recycling programs in the operating room can reduce our ecological footprint by diverting waste from landfills, as our study revealed that nearly three-quarters of this waste is recyclable.


Assuntos
Procedimentos Ortopédicos/instrumentação , Ortopedia/métodos , Reciclagem/métodos , Gerenciamento de Resíduos/métodos , Humanos , Salas Cirúrgicas , Estudos Prospectivos
7.
Int J Food Microbiol ; 327: 108652, 2020 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-32442778

RESUMO

Food-grade waste and side streams should be strictly kept in food use in order to achieve sustainable food systems. At present, the baking industry creates food-grade waste as excess and deformed products that are mainly utilized for non-food uses, such as bioethanol production. The purpose of this study was therefore to explore the potential of waste wheat bread recycling for fresh wheat bread production. Waste bread recycling was assessed without further processing or after tailored fermentation with lactic acid bacteria producing either dextran or ß-glucan exopolysaccharides. When non-treated waste bread slurry was added to new bread dough, bread quality (specific volume and softness) decreased with increasing content of waste bread addition. In situ EPS-production (dextran and microbial ß-glucan) significantly increased waste bread slurry viscosity and yielded residual fructose or glucose that could effectively replace the sugar added for yeast leavening. Furthermore, fermentation acidified waste bread matrix, thus improving the hygienic safety of the process. Bread containing dextran synthesized in situ by Weissella confusa A16 showed good technological quality. The produced dextran compensated the adverse effect of recycled bread on new bread quality attributes by 12% increase in bread specific volume and 37% decrease in crumb hardness. In this study, a positive technological outcome of the bread containing microbial ß-glucan was not detected. The waste bread fermented by W. confusa A16 containing dextran appears to enable safe bread recycling with low acidity and minimal quality loss.


Assuntos
Pão/microbiologia , Pão/normas , Fermentação , Indústria Alimentícia , Resíduos Industriais , Reciclagem/métodos , Triticum/microbiologia , Dextranos/metabolismo , Ácido Láctico/metabolismo , Weissella/metabolismo , Leveduras/metabolismo , beta-Glucanas/metabolismo
8.
Am J Nurs ; 120(6): 48-55, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32443125

RESUMO

Nurses have the capacity and opportunity to alter their organization's environmental footprint. This article addresses how they can strengthen efficiency and environmental sustainability initiatives in their facilities by engaging in, monitoring, and supporting environmentally friendly clinical practices and programs at the point of care. Included are practical tips and examples of projects in which nurses identified sources of waste-the relaundering of unused linens; disposal of unused products; and improper sorting of pharmaceutical waste, recycling, and regulated medical waste-and realized significant cost savings as well as improved efficiency and environmental sustainability.


Assuntos
Gerenciamento de Resíduos/métodos , Roupas de Cama, Mesa e Banho/efeitos adversos , Roupas de Cama, Mesa e Banho/normas , Recuperação e Remediação Ambiental/métodos , Recuperação e Remediação Ambiental/tendências , Recursos em Saúde/tendências , Humanos , Reciclagem/métodos , Reciclagem/tendências
9.
Artigo em Inglês | MEDLINE | ID: mdl-32325760

RESUMO

The recycling of e-waste by the informal sector has brought countries in the Global South raw materials (e.g. metals and plastics), second-hand electronic equipment and components, and economic opportunities in conjunction with appalling environmental pollutions and health problems. Despite the longstanding international and national legislation regulating transnational trade and domestic recycling, informal e-waste economies are still clustering in many Global South countries. This study offers historically and geographically specific explanations of this conundrum, by interrogating the multi-scalar regulatory frameworks in which the informal e-waste economies and their pollutions are embedded, by drawing on China, particularly the former global e-waste hub-Guiyu town, as the case study. We argue that the contested and problematic application of current international and national legislation in regulating e-waste is in part pertaining to the slippery definition of what counts as "e-waste" and its paradoxical nature as both resources and pollutants. At the global scale, trajectories of global e-waste flows are shaped by the multitude of loopholes, contradictions and ambiguous articles left by the Basel Convention and by different countries' disparate attitudes towards the e-waste trade. At the national scale, the ambiguities and contradictions in the Basel Convention have been passed on to and shaped China's national e-waste regulatory frameworks. China's equivocal legislation, paradoxical attitude, and formal enterprises' weak competence contribute to the rise of informal e-waste recycling in Guiyu. Yet, China's e-waste regime has been greatly restructured within the past decade, with formal recycling enterprises playing an increasingly significant role.


Assuntos
Resíduo Eletrônico , Poluentes Ambientais , Reciclagem/métodos , Gerenciamento de Resíduos/métodos , China , Análise por Conglomerados , Humanos , Gestão da Segurança/métodos
10.
PLoS One ; 15(4): e0230996, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32243461

RESUMO

The use of compost in urban agriculture offers an opportunity to increase nutrient recycling in urban ecosystems, but recent studies have shown that compost application often results in phosphorus (P) being applied far in excess of crop nutrient demand, creating the potential for P loss through leachate and runoff. Management goals such as maximizing crop yields or maximizing the mass of nutrients recycled from compost may inadvertently result in P loss, creating a potential ecosystem disservice. Here, we report the results from the first two years of an experimental study in which four different crops grown in raised-bed garden plots with high background P and organic matter received one of two types of compost (municipal compost made from urban organics waste, or manure-based compost) at two different levels (applied based on crop N or P demand), while additional treatments received synthetic N and P fertilizer or no soil amendments. Because of the low N:P ratio of compost relative to crop nutrient uptake, compost application based on crop N demand resulted in overapplication of P. Crop yield did not differ among treatments receiving compost inputs, and the mass of P recovered in crops relative to P inputs decreased for treatments with higher compost application rates. Treatments receiving compost targeted to crop N demand had P leachate rates approximately twice as high as other treatments. These results highlight tradeoffs inherent in recycling nutrients through UA, but they also show that targeted compost application rates have the capacity to maintain crop yields while minimizing nutrient loss. UA has the potential to help close the urban nutrient loop, but if UA is to be scaled up in order to maximize potential social, economic, and environmental benefits, it is especially important to carefully manage nutrients to avoid ecosystem disservices from nutrient pollution.


Assuntos
Agricultura/métodos , Compostagem , Produtos Agrícolas/crescimento & desenvolvimento , Jardins , Biomassa , Ecossistema , Poluição Ambiental/análise , Poluição Ambiental/prevenção & controle , Fertilizantes/análise , Esterco/análise , Minnesota , Nitrogênio/análise , Nutrientes/análise , Fósforo/análise , Reciclagem/métodos , Solo/química , Poluentes do Solo/análise , Urbanização
11.
Cardiovasc Intervent Radiol ; 43(6): 910-915, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32034434

RESUMO

PURPOSE: With a shift to single-use products in interventional radiology (IR) centres for sterility and cost reasons, it is prudent to consider the burden of packaging and employ efforts to assess and reduce waste, as well as promote recycling wherever possible. This study aimed to quantify the amount of waste in IR packaging and what proportion is recyclable. MATERIALS AND METHODS: A range of IR products were weighed using mass scales. Products were assessed for total weight, overall waste, and potentially recyclable waste. Waste was defined as any packaging which was not considered vital to the product to perform its duty and thus was for packaging or shipping purposes. Products were pooled into one of the following categories: catheters and sheaths, wires, needles, devices, coils, and packs/ancillary. RESULTS: Seventy-two different products were collected from 26 manufacturers to represent a range of items. The weight of all products was 12,466 g (median 51, range 2-1600), and weight of waste was 6830.7 g (median 34, range 1.1-732). The weight of recyclable waste was 5202.2 g (median 11.5, range 0-701). There were median 2 waste packages per item (range 1-5). The proportion of waste of the overall weight was 54.8% and of this, 76% of all waste was potentially recyclable. CONCLUSION: There is a significant burden of waste in manufactured IR products, and while a high proportion is recyclable, we encourage manufacturers of IR products and devices to consider alternative means of transport and packaging of products which will reduce the overall waste burden. LEVEL OF EVIDENCE: Level 3.


Assuntos
Equipamentos Descartáveis/estatística & dados numéricos , Embalagem de Produtos/instrumentação , Radiologia Intervencionista/instrumentação , Reciclagem/métodos , Reciclagem/estatística & dados numéricos , Humanos
12.
Chemosphere ; 246: 125725, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31927362

RESUMO

Contaminated air in battery recycling halls threatens the health of factory workers. In this work, a new 3D hydrogel was designed in a simulated salon with an innovative rotary module. The Pb(II), Fe(III) and SO42- was adsorbed from air. Solar energy was transferred by wind to the factory hall and absorbed moisture was evaporated. The hydrophilicity, stability in water and storage of Pb(II) and Fe(III) in the hydrogel were optimized. Brunauer-Emmett-Teller (BET) theory, Field emission scanning electron microscope (FE-SEM), X-ray diffraction (XRD) analysis and Fourier transform infrared spectroscopy (FT-IR) were employed to characterize and analyze the 3D hydrogel. The collector was able to quickly raise the wind temperature to 44 °C. In each cycle, in average 60% of air moisture was absorbed on the 3D hydrogel. The evaporation rate was more than 1.4 kg m-2 h-1. The efficiency of ions removal in each cycle was 82%. In the 0.68 m3 min-1 of wind flow the temperature was 43.3 °C and evaporation was done in a shorter time.


Assuntos
Fontes de Energia Elétrica , Hidrogéis , Reciclagem/métodos , Energia Solar , Vento , Adsorção , Compostos Férricos , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura
13.
Sci Rep ; 10(1): 136, 2020 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-31924816

RESUMO

There is an increased interest in recycling valuable waste materials for usage in procedures with high added values. Silica microparticles are involved in the processes of catalysis, separation, immobilization of complexants, biologically active compounds, and different nanospecies, responding to restrictive requirements for selectivity of various chemical and biochemical processes. This paper presents the surface modification of accessible and dimensionally controlled recycled silica microfiber with titanium dioxide. Strong base species in organic solvents: methoxide, ethoxide, propoxide, and potassium butoxide in corresponding alcohol, activated the glass microfibres with 12-13 µm diameter. In the photo-oxidation process of a toxic micro-pollutant, cyclophosphamide, the new composite material successfully proved photocatalytic effectiveness. The present work fulfills simultaneously two specific objectives related to the efforts directed towards a sustainable environment and circular economy: recycling of optical glass microfibers resulted as waste from the industry, and their usage for the photo-oxidation of highly toxic emerging micro-pollutants.


Assuntos
Citostáticos/química , Poluentes Ambientais/química , Vidro/química , Processos Fotoquímicos , Reciclagem/métodos , Dióxido de Silício/química , Resíduos , Catálise , Citostáticos/toxicidade , Poluentes Ambientais/toxicidade , Microesferas , Oxirredução , Propriedades de Superfície , Titânio/química
14.
Environ Sci Pollut Res Int ; 27(8): 8507-8525, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31907809

RESUMO

The extensive waste produced in construction and demolition activities affects the ecological environment, impeding green development in countries worldwide, including China. China has paid increasing attention to managing construction and demolition waste (CDW). However, most of the existing research only qualitatively studies the factors affecting the recycling of CDW and does not reveal the critical factors. Therefore, based on stakeholder theory and the grey-DEMATEL method, this paper aims to identify and quantitatively analyze the critical factors in CDW recycling from the perspective of China. This paper drew the following conclusions: (1) Stakeholders in China's CDW recycling mainly include the government, CDW production units, and CDW recycling units. (2) Public policy, government subsidies, media promotion, human resources, cost, environmental awareness, technological innovation, and supply chain management are the eight dimensions with 13 factors that constitute CDW recycling in China. (3) For the total relations between factors affecting the recycling of CDW in China, the most influential factor is specific legislation and regulations. The factor with the highest degree of prominence is environmental awareness. The factor with the largest net cause value is the rationality of disposal and landfill charges. The factor with the largest net effect value is experienced construction workers. (4) The critical factors in China's CDW recycling include specific legislation and regulations, mandatory degree of normative standards, environmental awareness, the supply of raw materials for CDW recycling units, and the sale of remanufactured products. Finally, this paper identifies the following management implications: (1) the government should prioritize the task of improving specific legislation and regulations, with a focus on a mandatory degree of normative standards. (2) CDW production units should put the task of improving environmental awareness high on their agenda, with a focus on the supply of raw materials for recycling units. (3) CDW recycling units should prioritize the issue of the sale of remanufactured products. This paper also provides a theoretical basis for revealing the critical factors of CDW recycling in other countries or regions.


Assuntos
Indústria da Construção , Materiais de Construção/análise , Reciclagem/métodos , Gerenciamento de Resíduos , China , Indústria da Construção/economia , Materiais de Construção/economia , Humanos , Resíduos Industriais , Gerenciamento de Resíduos/métodos
15.
Chemosphere ; 242: 125291, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31896181

RESUMO

The huge usage of rechargeable batteries in electronics has added to a recurrent problem worldwide in generating tonnage of spent lithium-ion batteries (LIBs). The inadequacy of the resources of the depleting critical metals has also been described in vogue. The environmental assessment of the life cycle of the LIBs has been elucidated vis-a-vis the effects of raw material supply, transportation, and recycling. Based on the available work for recycling technologies, this review also attempts to elicit the various methods practiced in discharging/dismantling, classification, and separation of components followed by metal recovery. The authors have reviewed the major developments in the area of recycling of cathode material by using various acids for extraction of metals from spent LIBs, compared the merits and demerits of acids used and presented a comprehensive outlook to the processes formulated vis-à-vis imperative need for using green techniques. The necessity for benign recycling methods is stressed upon to alleviate the need for high temperature and oxidative acid leaching conditions. The various green lixiviants (organic acids) attempted to extract metals from spent LIBs have been discussed in detail with respect to the mechanism, efficacies as well as the various factors (selectivity, cost, etc.) that govern the use of organic acids in battery recycling. It was ascertained that the GHG emissions to extract Co using organic acids stand 1/8 of that using an inorganic acid leaching process. Efforts need to be envisaged in separating the leached metals from these lixiviants ensuring economics and environmental benefits.


Assuntos
Ácidos Carboxílicos/química , Fontes de Energia Elétrica , Resíduo Eletrônico/análise , Poluentes Ambientais/análise , Lítio/análise , Reciclagem/métodos , Eletrodos , Íons
16.
Mikrochim Acta ; 187(2): 114, 2020 01 09.
Artigo em Inglês | MEDLINE | ID: mdl-31919722

RESUMO

Amyloid-beta (Aß) oligomers causing neuron damage are regarded as potential therapeutic targets and diagnostic markers for Alzheimer's disease (AD). A homogeneous turn-on fluorometric aptasensor is described for Aß oligomers. It is highly selective and non-invasive and based on (a) the use of a luminescent metal-organic framework carrying aptamer-modified AuNPs (L-MOF/Apt-Au) as tracking agent, and (b) enzyme-assisted target recycling signal amplification. The tracking agent does not emit fluoresce by fluorescence resonance energy transfer (FRET) between the luminescent MOF as donor and Apt-Au as the acceptor under the excitation wavelength of 466 nm. When Aß oligomers are added to the tracking agent solution, the Apt-Au on tracking agent can preferentially bind with Aß oligomers and then be released. This turns the "off" signal of the luminescent MOF tracer to the "on" state. The enzyme (Rec Jf exonuclease) added into the supernatant further improves sensitivity due to enzyme-assisted target-recycling signal amplification. The assay has an excellent linear response to Aß oligomers from 1.0 pM to 10 nM, with a detection limit of 0.3 pM. This homogeneous turn-on fluorometric method is expected to have potential and applications in clinical diagnosis. Graphical abstractSchematic representation of fluorometric assay for amyloid-ß oligomers based on luminescence metal-organic framework nanocomposites as tracking agent with exonuclease-assisted target recycling.


Assuntos
Peptídeos beta-Amiloides/análise , Aptâmeros de Nucleotídeos , Fluorometria/métodos , Estruturas Metalorgânicas/química , Reciclagem/métodos , Doença de Alzheimer/diagnóstico , Técnicas Biossensoriais/métodos , Exonucleases , Ouro , Humanos , Limite de Detecção , Nanopartículas Metálicas/química
17.
Chemosphere ; 241: 124975, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31610460

RESUMO

A decline in the availability of fossil fuel resources coupled with deleterious environmental concerns has prompted further research into biofuels. Conventional bioethanol production via a first-generation approach may soon become superseded through integration with lignocellulosic feedstocks. However, the underlying concerns pertaining to the disposal of high-strength liquid waste (i.e. spentwash) remain both unchanged and constitute a substantial cost to bioethanol manufacturers. Therefore this review details current efforts in the literature to elucidate various approaches for spentwash treatment and investigate the potential for resource recovery. Insight into the composition of distillery wastewater is given in the lead-up to a thorough discussion encompassing the origin, transformation and characterisation of the highly problematic melanoidin compounds entrained within this effluent. Close examination of advanced organic characterisation methods used by researches yields further insight into the nature of spentwash dissolved organic matter (DOM). Employment of both biological and physio-chemical treatment schemes to alleviate the environmental footprint of such high-strength wastewater are also reviewed. Opportunities to dramatically improve the economic viability of biofuel production by exploiting the potential for resource recovery in the form of energy, organic/inorganic constituents and effluent reuse are discussed. Overall, the review culminates by highlighting recommendations for future work to accelerate the onset of an environmentally benign bio-refinery.


Assuntos
Biocombustíveis , Águas Residuárias/química , Etanol , Polímeros/isolamento & purificação , Reciclagem/métodos
18.
Chemosphere ; 241: 125020, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31614314

RESUMO

A nanocomposite of graphene and titanium dioxide (G/TiO2) was prepared using the sol-gel method for use in an electrochemical adsorption/regeneration process. The effect of annealing temperature on electrochemical characteristics of the nanocomposites was investigated by cyclic voltammetry and constant current electrochemical regeneration, using methylene blue (MB) as the adsorbate. The G/TiO2 could be regenerated more rapidly and with less corrosion than the bare graphene. The G/TiO2 annealed at 400 °C had a higher proportion of anatase phase TiO2 (ca. 7% rutile TiO2) compared to that annealed at 500 °C (ca. 40% rutile TiO2). Cyclic voltammetry indicated that the G/TiO2 annealed at 400 °C had a higher activity for MB oxidation than the nanocomposite annealed at 500 °C. Similarly, the regeneration of MB loaded G/TiO2 annealed at 400 °C was much faster than for the nanocomposite annealed at 500 °C. Complete regeneration of the G/TiO2 annealed at 400 °C was obtained after an electrochemical charge of 21 C per mg of adsorbate. The G/TiO2 annealed at 400 °C was regenerated in half the time required for the bare graphene. TEM studies showed that the bare graphene was rapidly corroded, while corrosion was not observed for the G/TiO2 nanocomposites.


Assuntos
Corantes/química , Técnicas Eletroquímicas/métodos , Grafite , Nanocompostos/química , Reciclagem/métodos , Titânio , Adsorção , Corrosão , Eletrodos , Azul de Metileno/química
19.
Chemosphere ; 242: 125178, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31675587

RESUMO

The comprehensive recovery of iron and titanium resources from early tailings were systematically attempted from fundamental work to industrial application. Geochemical characterization of the tailings was first conducted, followed by the iron recovery and titanium recovery. Iron recovery was mainly achieved through a series of magnetic separation, and titanium recovery was on the combination of magnetic pre-concentration and flotation separation. Special for titanium recovery, different pretreatment methods including ultrasonic cleaning and attrition-scrubbing were studied to reduce the influence of serious surface pollution of early tailings on ilmenite floatability, and attrition-scrubbing proved to be the best one. Associated mechanisms of flocculants influence on ilmenite floatability and the attrition-scrubbing effects were explored using micro-flotation and XPS tests. After a series of fundamental studies, the industrial production of iron and ilmenite concentrate went into operation and the industrial debugging results were roughly satisfactory. At last, a brief economic analysis was given for the present work.


Assuntos
Ferro/provisão & distribução , Reciclagem/métodos , Titânio/provisão & distribução , Poluição Ambiental , Ferro/química , Reciclagem/economia , Titânio/química
20.
Chemosphere ; 238: 124652, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31473524

RESUMO

This research aimed to find the best phenotype of the brown algae Fucus vesiculosus (kelp) which has the greater potential to become a sorption byproduct for Zn removal from contaminated waters. Thus, the Zn uptake capacity and sorption mechanisms of the kelp collected from the Baltic Sea shore was, for the first time, investigated under various conditions, and compared to the phenotype habiting on the Irish Sea shore. Sorption studies were performed investigating the effect of algal dosage, Zn sources as well as algal harvesting time of the year on Zn uptake capacity. The results suggested that the Baltic algae is a better bio-sorbent for Zn uptake. Sorption mechanisms were studied by employing various indirect and direct approaches, more importantly, including high resolution synchrotron X-Ray Fluorescence and X-Ray Absorption Spectroscopy (XAS) and molecular modelling (MM). The results revealed that alginate and cellulose are among the main polysaccharide bonding Zn at algal surface, via coordination with O atoms from carboxyl and hydroxyl groups. XAS results giving direct measurements of Zn bonding environment on algal surface are supported by MM outputs and suggested that Zn is surrounded by ca. 5 O atoms at interatomic distances varying from 1.94 to 2.02 Å. The results contribute to understanding sorption mechanisms which can further lead to finding the best eluent for Zn desorption from the used biomass, bio sorbent reconditioning and reuse in multiple sorption desorption cycles as well as process optimization before industrial scaling up.


Assuntos
Biodegradação Ambiental , Fucus/metabolismo , Zinco/isolamento & purificação , Absorção Fisico-Química , Alginatos/metabolismo , Biomassa , Celulose/metabolismo , Fucus/química , Reciclagem/métodos , Zinco/farmacocinética
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