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1.
Waste Manag Res ; : 734242X241237092, 2024 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-38576307

RESUMO

The generation of industrial waste is mainly dependent on several factors, including the type of industry, production capacity, technology use and raw materials involved in the manufacturing processes. The present study is a cross-sectional study that was conducted with 580 industries under six industrial sectors in Sri Lanka in 2022. The main objective of this research was to investigate solid waste generation and estimate the recyclable fraction in the waste. Furthermore, this study calculated the prevailing recycling rate of each industrial sector and the waste generation per person employed in the sector. Industrial processes, the types and quantities of waste, waste disposal methods and management activities in terms of recycling and disposal were evaluated through a structured questionnaire and random field observations. The study identified that the composition of selected recyclable items was 16.7% of the total waste generated in the industrial sector. The prevailing rate of recycling in different sectors was as follows: manufacturing of food products (36.6%), manufacturing of beverages (82.3%), manufacturing of textiles (68.6%), manufacturing of chemical and chemical products (28.5%), manufacturing of rubber and plastic (46.5%) and manufacturing of metallic mineral products (17.8%) from the total generated recyclable material. The study further estimated the waste intensity (waste generation per unit of product output) of the industrial sectors as follows: 0.38 (manufacturing of food products), 0.36 (manufacturing of beverages), 0.27 (manufacturing of textiles), 0.26 (manufacturing of chemical and chemical products), 0.17 (manufacturing of rubber and plastic) and 0.16 (manufacturing of non-metallic mineral products).

2.
Chempluschem ; 89(6): e202300694, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38355904

RESUMO

Polymer waste is a pressing issue that requires innovative solutions from the scientific community. As a beacon of hope in addressing this challenge, the concept of sustainable supramolecular polymers (SSPs) emerges. This article discusses challenges and efforts in fabricating SSPs. Addressing the trade-offs between mechanical performance and sustainability, the ultra-tough and multi-recyclable supramolecular polymers are fabricated via tailoring mismatched supramolecular interactions. Additionally, the healing of kinetically inert polymer materials is realized through transient regulation of the interfacial reactivity. Furthermore, a possible development trajectory for SSPs is proposed, and the transient materials can be regarded as the next generation in this field. The evolution of SSPs promises to be a pivotal stride towards a regenerative economy, sparking further exploration and innovation in the realm of sustainable materials.

3.
Heliyon ; 10(4): e26353, 2024 Feb 29.
Artigo em Inglês | MEDLINE | ID: mdl-38404851

RESUMO

Biological and mechanical biological treatment plants combine mechanical and biological treatments to recover the greatest possible amount of materials from municipal solid waste (MSW) and biostabilize the organic fraction to be landfilled or applied in land. These plants handle a high percentage of the MSW generated in Europe. This work presents an exhaustive analysis of the existing plants in Spain which evaluates their typology as well as their performance. In Spain, 137 plants, which receive 13 Mt/year of waste, provide the country with total coverage. Twenty-two types of plants have been identified and grouped into six categories. There are four categories that receive mixed MSW: 1) sorting plants; 2) recovery and composting plants; 3) biodrying and recovery plants; and 4) recovery, biomethanation and composting plants and two that receive separately collected biowaste: 5) composting plants, and 6) biomethanation and composting plants. In plants that receive mixed waste, around 5% of the total input is recovered as recyclable materials (662,182 t/year), of which 29% corresponds to plastics, 27% to metals, and 27% to paper and cardboard. In addition, biostabilized material and/or biogas, and rejects (45-77% of the input) are obtained. In the biowaste plants, high-quality compost (more than 105,000 t/year), a higher biogas yield (43.60 Nm3/t·year) and a lower proportion of rejects (around 29%) are obtained.

4.
Small Methods ; 8(1): e2300452, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37817378

RESUMO

Li-O2 batteries (LOB) performance degradation ultimately occurs through the accumulation of discharge products and irreversible clogging of the porous electrode during the cycling. Electrode binder degradation in the presence of reduced oxygen species can result in additional coating of the conductive surface, exacerbating capacity fading. Herein, a facile method to fabricate free-standing is established, binder-free electrodes for LOBs in which multi-wall carbon nanotubes form cross-linked networks exhibiting high porosity, conductivity, and flexibility. These electrodes demonstrate high reproducibility upon cycling in LOBs. After cell death, efficient and inexpensive methods to wash away the accumulated discharge products are demonstrated, as reconditioning method. The second life usage of these electrodes is validated, without noticeable loss of performance. These findings aim to assist in the development of greener high energy density batteries while reducing manufacturing and recycling costs.

5.
Adv Mater ; 35(42): e2303632, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37435992

RESUMO

With the development of various gel-based flexible sensors, novel gels with multiple integrated and efficient properties, particularly recyclability, have been developed. Herein, a starch-based ADM (amylopectin (AP)-poly(3-[dimethyl-[2-(2-methylprop-2- enoyloxy)ethyl]azaniumyl]propane-1-sulfonate) (PDMAPS)-MXene) gel is prepared by a facile "cooking" strategy accompanying the gelatinization of AP and polymerization reaction of zwitterionic monomers. Reversible crosslinking in the gel occurs through hydrogen bonding and electrostatic interactions. The ADM gel exhibits high stretchability (≈2700%, after one month), swift self-healing performance, self-adhesive properties, favorable freezing resistance, and satisfactory moisturizing properties (≥30 days). Interestingly, the ADM gel can be recycled and reused by a "kneading" method and "dissolution-dialysis" process, respectively. Furthermore, the ADM gel can be assembled as a strain sensor with a broad working strain range (≈800%) and quick response time (response time 211 ms and recovery time 253 ms, under 10% strain) to detect various macro- and micro-human-motions, even under harsh conditions such as pronunciation and handwriting. The ADM gel can also be used as a humidity sensor to investigate humidity and human respiratory status, suggesting its practical application in personal health management. This study provides a novel strategy for the preparation of high-performance recycled gels and flexible sensors.

6.
Angew Chem Int Ed Engl ; 62(29): e202301762, 2023 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-37208825

RESUMO

Supramolecular interactions facilitate the development of tough multifunctional thermoplastic elastomers. However, the fundamental principles that govern supramolecular toughening are barely understood, and the rational design to achieve the desired high toughness remains daunting. Herein, we report a simple and robust method for toughening thermoplastic elastomers by rationally tailoring hard-soft phase separation structures containing rigid and flexible supramolecular segments. The introduced functional segments with distinct structural rigidities provide mismatched supramolecular interactions to efficiently tune the energy dissipation and bear an external load. The optimal supramolecular elastomer containing aromatic amide and acylsemicarbazide moieties demonstrates a record toughness (1.2 GJ m-3 ), extraordinary crack tolerance (fracture energy 282.5 kJ m-2 ), an ultrahigh true stress at break (2.3 GPa), good elasticity, healing ability, recyclability, and impact resistance. The toughening mechanism is validated by testing various elastomers, confirming the potential for designing and developing super-tough supramolecular materials with promising applications in aerospace and electronics.

7.
Adv Mater ; 35(22): e2300487, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37002908

RESUMO

Polymer hydrogels mimic biological tissues and are suitable for future lifelike machines. However, their actuation is isotropic, so they must be crosslinked or placed in a turgor membrane to achieve high actuation pressures, severely impeding their performance. Here, it is shown that organizing cellulose nanofibrils (CNFs) in anisotropic hydrogel sheets leads to mechanical in-plane reinforcement that generates a uniaxial, out-of-plane strain with performance far surpassing polymer hydrogels. These fibrillar hydrogel actuators expand uniaxially by 250 times with an initial rate of 100-130% s-1 , compared to <10 times and <1% s-1 in directional strain rate for isotropic hydrogels, respectively. The blocking pressure reaches 0.9 MPa, similar to turgor actuators, while the time to reach 90% of the maximum pressure is 1-2 min, compared to 10 min to hours for polymer hydrogel actuators. Uniaxial actuators that lift objects 120 000 times their weight and soft grippers are showcased. In addition, the hydrogels can be recycled without a loss in performance. The uniaxial swelling allows adding channels through the gel for local solvent delivery, further increasing the actuation rate and cyclability. Thus, fibrillar networks can overcome the major drawbacks of hydrogel actuators and is a significant advancement towards hydrogel-based lifelike machines.

8.
Waste Manag Res ; 40(12): 1766-1776, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35723614

RESUMO

The numerous amount of electronic waste (e-waste) has not been managed effectively resulting informal dismantling sites are being expanded in Thailand. The government attempts to improve the efficiency of an integrated e-waste management system, but baseline data of e-waste stream in informal sectors are insufficient. This research aimed to investigate the inflow and outflow of the materials throughout the informal e-waste dismantling processes at the well-known second-largest community in Buriram province during 2017-2018. To describe the quantities of dismantled materials, a material flow analysis was performed. The overall amount of e-waste taken to the community was estimated to be in the range of 1593-12,943 tonnes year-1. Valuable materials could be recovered at more than 90% (by mass) from fans, refrigerators, washing machines, microwaves and air conditioners. The amount of e-waste residue that the local administrative organization had to handle was up to 1144 tonnes year-1. The quantitative data retrieved from this study could provide a satisfactory equation for estimating the amount of separated valuable and non-valuable materials. Recyclable materials from dismantling have an economic incentive, e-waste dismantlers in a small and large household group that can earn approximately 798 and 1262 USD month-1 income, respectively. The notable e-waste characterization and quantification of recovered materials would be useful for improving the potential circular flow of e-waste in Thailand.


Assuntos
Resíduo Eletrônico , Utensílios Domésticos , Gerenciamento de Resíduos , Resíduo Eletrônico/análise , Tailândia , Reciclagem
9.
Waste Manag ; 136: 195-203, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34695726

RESUMO

Mechanical sorting plays a pivotal role in current municipal solid waste management systems for resource recovery. However, material recovery facilities, generally face several challenges in meeting quality standards for multiple waste fractions. Improving these facilities requires a better understanding of municipal solid waste physical characteristics, since they are directly targeted by mechanical sorting unit operations. Three waste physical properties (bulk density, particle size and shape factor) were characterized for several recyclable materials. Narrow ranges of densities were observed for similar waste materials, while the particle size distributions were found to vary widely. Statistical parameters were determined for these two properties. A novel approach, based on the void fraction of a waste item, is proposed to quantify the shape factor. Potential applications of the characterization results for improving mechanical sorting are demonstrated through the analysis of the recovery of corrugated cardboards and multilayer cardboards in a material recovery facility.


Assuntos
Eliminação de Resíduos , Gerenciamento de Resíduos , Fenômenos Físicos , Reciclagem , Resíduos Sólidos
10.
Materials (Basel) ; 14(16)2021 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-34443280

RESUMO

The objective of this investigation is to study the printing parameter requirements for sustainable 3D printable geopolymer materials. Side streams of the paper, mining, and construction industries were applied as geopolymer raw materials. The effect of printing parameters in terms of buildability, mixability, extrudability, curing, Al-to-Si ratio, and waste materials utilisation on the fresh and hardened state of the materials was studied. The material performance of a fresh geopolymer was measured using setting time and shape stability tests. Standardised test techniques were applied in the testing of the hardened material properties of compressive and flexural strength. The majority of developed suitable 3D printable geopolymers comprised 56-58% recycled material. Heating was used to improve the buildability and setting of the material significantly. A reactive recyclable material content of greater than 20% caused the strength and material workability to decrease. A curing time of 7-28 days increased the compressive strength but decreased the flexural strength. The layers in the test samples exhibited decreased and increased strength, respectively, in compressive and flexural strength tests. Geopolymer development was found to be a compromise between different strength values and recyclable material contents. By focusing on specialised and complex-shape products, 3D printing of geopolymers can compete with traditional manufacturing in limited markets.

11.
Adv Mater ; 32(50): e2005759, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33175420

RESUMO

There is a huge requirement of elastomers for use in tires, seals, and shock absorbers every year worldwide. In view of a sustainable society, the next generation of elastomers is expected to combine outstanding healing, recycling, and damage-tolerant capacities with high strength, elasticity, and toughness. However, it remains challenging to fabricate such elastomers because the mechanisms for the properties mentioned above are mutually exclusive. Herein, the fabrication of healable, recyclable, and mechanically tough polyurethane (PU) elastomers with outstanding damage tolerance by coordination of multiblock polymers of poly(dimethylsiloxane) (PDMS)/polycaprolactone (PCL) containing hydrogen and coordination bonding motifs with Zn2+ ions is reported. The organization of bipyridine groups coordinated with Zn2+ ions, carbamate groups cross-linked with hydrogen bonds, and crystallized PCL segments generates phase-separated dynamic hierarchical domains. Serving as rigid nanofillers capable of deformation and disintegration under an external force, the dynamic hierarchical domains can strengthen the elastomers and significantly enhance their toughness and fracture energy. As a result, the elastomers exhibit a tensile strength of ≈52.4 MPa, a toughness of ≈363.8 MJ m-3 , and an exceptional fracture energy of ≈192.9 kJ m-2 . Furthermore, the elastomers can be conveniently healed and recycled to regain their original mechanical properties and integrity under heating.

12.
Adv Mater ; 32(39): e2002008, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32844527

RESUMO

The host-guest interaction as noncovalent bonds can make polymeric materials tough and flexible based on the reversibility property, which is a promising approach to extend the lifetime of polymeric materials. Supramolecular materials with cyclodextrin and adamantane are prepared by mixing host polymers and guest polymers by planetary ball milling. The toughness of the supramolecular materials prepared by ball milling is approximately 2 to 5 times higher than that of supramolecular materials prepared by casting, which is the conventional method. The materials maintain their mechanical properties during repeated ball milling treatments. They are also applicable as self-healable bulk materials and coatings, and they retain the transparency of the substrate. Moreover, fractured pieces of the materials can be re-adhered within 10 min. Dynamic mechanical analysis, thermal property measurements, small-angle X-ray scattering, and microscopy observations reveal these behaviors in detail. Scars formed on the coating disappear within a few seconds at 60 °C. At the same time, the coating shows scratch resistance due to its good mechanical properties. The ball milling method mixes the host polymer and guest polymer at the nano level to achieve the self-healing and recycling properties.

13.
Adv Mater ; 32(36): e2000096, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32705730

RESUMO

Covalent thermosets generally exhibit robust mechanical properties, while they are fragile and lack the ability to be reprocessed or recycled. Herein, a new strategy of incorporating noncovalent bonds into main-chains is developed to construct tough and multi-recyclable cross-linked supramolecular polyureas (CSPU), which are prepared via the copolymerization of diisocyanate monomers, noncovalently bonded diamine monomers linked by quadruple hydrogen bonds, and covalent diamine/triamine monomers. The CSPU exhibit remarkable solvent resistance and outstanding mechanical properties owing to the covalent cross-linking via triamine monomer. Through the incorporation of 9.7% and 14.6% quadruple hydrogen bonded diamine monomer, the transparent CSPU films are endowed with superior toughness of 74.17 and 124.17 MJ m-3 , respectively. Impressively, even after five generations of recycling processes, the mechanical properties of reprocessed CSPU can recover more than 95% of their original properties, displaying excellent multiple recyclablity. As a result, the superior toughness, remarkable solvent resistance, high transparency, and excellent multiple recyclability are well-combined in the CSPU. It is highly anticipated that this line of research will provide a facile and general method to construct various cross-linked polymer materials with superior recyclability and mechanical properties.

14.
Macromol Rapid Commun ; 41(24): e2000097, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32400939

RESUMO

Surlyn consists of ionomers of poly(ethylene-co-methacrylic acid) (PEMA) partially neutralized with metal ions. Considering its huge consumption every year, it is highly desirable to realize efficient healing and recycling of Surlyn through an easily available method. Herein, healable and recyclable Surlyn materials are fabricated by complexation of PEMA with Zn2+ ions followed by a hot-pressing process. The PEMA/Zn composites exhibit a tensile strength of ≈37 MPa, Young's modulus of ≈343 MPa, and toughness of ≈95 MJ m-3 . Structural analysis discloses that the PEMA/Zn composites are dynamically cross-linked with coordination interactions and reinforced with polyethylene nanocrystals, and have the typical structure of supramolecular thermosets. As supramolecular thermosets, the reversibility of coordination interactions endows the PEMA/Zn composites with good healing and recycling capacities. The PEMA/Zn composites can fully heal mechanical damage to restore their original mechanical strength when heated at 90 °C. Under a pressure of 3 MPa at 100 °C, the PEMA/Zn composites can be recycled multiple times to regain their structural integrity and mechanical properties.


Assuntos
Temperatura Alta , Reciclagem , Módulo de Elasticidade , Teste de Materiais , Resistência à Tração
15.
ACS Appl Mater Interfaces ; 12(20): 23484-23493, 2020 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-32343136

RESUMO

The synthesis of polymeric materials that simultaneously possess multiple excellent mechanical properties and high-efficient self-healability at room temperature is always a huge challenge. Here, we report the synthesis of a transparent polyurea material that can self-heal at room temperature with the aid of water and, meanwhile, has multiple remarkable mechanical performances, including super-high strength, excellent toughness, and large stretchability. Thanks to the synergistic enhancement of both dynamic imine bonds and hierarchical hydrogen bonds within the networks, the resulting polyureas have a world-record tensile strength of 41.2 MPa when compared with other polyurethanes that can self-heal at room temperature and, at the same time, a large breaking strain of 823.0% and a superior toughness of 127.2 MJ/m3. Besides the influence of imine bonds, the mechanical properties of the polyureas are also strongly related to the density and strength of the hierarchical hydrogen bonds within the polyurea networks, and these two factors could be finely controlled by adjusting the mass ratio of the soft segments with different chain lengths and the types of diisocyanates used for polyurea synthesis, respectively. More importantly, the highly dynamic characteristic of both imine bonds and hierarchical hydrogen bonds within the polyureas endows the materials with repeated water-enabled room-temperature self-healing capacity with a high healing efficiency of 92.2%. Moreover, the polyureas can also be recycled or remolded under mild conditions by the hot-pressing or dissolution/casting process. The synthesized polyureas also show great potential in damping applications with a loss factor larger than 0.3 over the temperature range from 12 to 75 °C. It is believed that polyureas with super-high and well-tunable mechanical properties and high-efficient room-temperature self-healing ability have great potential to substitute traditional irreparable polymers in diverse practical applications.

16.
ACS Appl Mater Interfaces ; 11(9): 9478-9486, 2019 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-30742407

RESUMO

The fabrication of mechanically robust polymeric materials capable of self-healing and recycling remains challenging because the mobility of polymer chains in such polymers is very limited. In this work, mechanically robust supramolecular thermosets capable of healing physical damages and recycling under mild conditions are fabricated by trimerization of bi-( ortho-aminomethyl-phenylboronic acid)- and tri-( ortho-aminomethyl-phenylboronic acid)-terminated poly(propylene glycol) oligomers (denoted as Bi-PBA-PPG and Tri-PBA-PPG, respectively). The resultant supramolecular thermosets are cross-linked by dynamic covalent bonds of nitrogen-coordinated boroxines. The mechanical properties of the supramolecular thermosets can be systematically tailored by varying the ratios between Tri-PBA-PPG and Bi-PBA-PPG, which changes the cross-linking density of nitrogen-coordinated boroxines and the topology of the supramolecular thermosets. The mechanically strongest supramolecular thermosets with a molar ratio of Tri-PBA-PPG to Bi-PBA-PPG being 1:2 have a glass transition temperature of ∼36 °C, a tensile strength of ∼31.96 MPa, and a Young's modulus of ∼298.5 MPa. The high reversibility of nitrogen-coordinated boroxines and the flexibility of poly(propylene glycol) chains enable the supramolecular thermosets with the strongest mechanical strength to be highly efficiently healed at 55 °C and recycled under a pressure of 4 MPa at 60 °C to regain their original mechanical strength and integrity.

17.
Barbarói ; (54,n.esp): 112-132, 2019.
Artigo em Português | LILACS, BVSF | ID: biblio-1046670

RESUMO

A inclusão dos catadores na agenda de políticas de gestão de resíduos na cidade de Santa Cruz do Sul, que culminou com a celebração de contratos de prestação de serviços públicos, foi o resultado da ação coletiva realizada pelos catadores articulados no Movimento Nacional dos Catadores de Materiais Recicláveis (MNCR), com o apoio de demais organizações da sociedade e do Estado em nível local. Houve a ocorrência de um processo em que os catadores articulados junto ao MNCR passaram de excluídos a prestadores de serviço de destinação final e coleta seletiva de resíduos neste município. Neste artigo, realizamos a interpretação sociológica desse processo e de seus limites por meio de categorias como estigma, frames de ação coletiva e repertório de conflito presentes na literatura específica sobre relações excludentes e sobre movimentos sociais. Como forma de conferir rigor hermenêutico, será utilizado material empírico do MNCR, e também, referências de estudo da dissertação e da tese de um dos autores. (OLIVEIRA, 2010; 2016) Para descrever os limites da institucionalização no contexto local serão empregados estudos sobre esse conceito e sobre a estagnação da coleta seletiva feita pela Cooperativa dos Catadores de Santa Cruz do Sul (COOMCAT). Ao final, com base na descrição desse processo contencioso, elaboraremos algumas considerações sobre o conflito que se estabelece em torno da gestão de resíduos nesta localidade.(AU)


The inclusion of waste pickers in the waste management policy agenda in the city of Santa Cruz do Sul, which culminated in the conclusion of public service contracts, was the result of the collective action taken by the waste pickers articulated in the National Movement of Recyclable Materials Collectors (MNCR), with the support of local society and state organizations. There was a process in which the collectors articulated with the MNCR went from being excluded to service providers of final disposal and selective waste collection in this municipality. In this paper, we perform the sociological interpretation of this process and its limits through categories such as stigma, collective action frames and conflict repertoires of specific literature on exclusionary relations and social movements. For conferring hermeneutic rigor, empirical material from the MNCR will be used, as well as references from the dissertation and thesis of one of the authors. (OLIVEIRA, 2010; 2016) To describe the limits of institutionalization in the local context, studies on this concept and on the stagnation of selective collection performed by Recyclable Waste Collectors Cooperative of Santa Cruz do Sul (COOMCAT) will be deployed. In the end, based on the description of this contentious process, we will elaborate some considerations about the conflict around the waste management in this locality.(AU)


Assuntos
Humanos , Catadores , Gerenciamento de Resíduos , Reciclagem
18.
Waste Manag ; 80: 26-39, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30455007

RESUMO

There are approximately 15 million people engaged in waste collection or recycling activities in the world. Some of these dump sites are informal and people work in environments that are labor-intensive, unregulated, unregistered, low-paid, unrecorded, and environmentally hazardous. A systematic review was conducted to assess consequential health conditions and occupational risks that affect waste collectors in Brazil. The search was limited to Brazil because although the government closed dump sites, open-air dumping-the worst type of waste disposal-still occurs in about half of the country; moreover, Brazil is the only country to systematically collect data on the occupation, with an estimated 229,568 recyclable collectors of all types country-wide, which offers relevant and pertinent data on the topic. The results of the search indicated that nearly every region has individuals that work as recyclable collectors. As expected, the sites are full of occupational hazards to the workers that can include: long working hours; exposures to physical, chemical, mechanical, biological, ergonomic and social agents; and frequent work accidents. Exposure to these risks can result both in physical and psychological illnesses. In view of these findings, public policies could be strengthened by supporting and providing incentives to municipalities, schools, universities, health professionals, and all others who will contribute to the closure of open-air waste or poor waste disposal systems. Moreover, an improved awareness should be provided to the general population about environmental education and correct disposal of garbage. The goal of healthy waste disposal conditions ultimately decreases environmental and public health effects, while improving the working conditions, quality of life, and health outcomes for recyclable collectors.


Assuntos
Resíduos de Alimentos , Saúde Ocupacional , Eliminação de Resíduos , Brasil , Humanos , Qualidade de Vida , Reciclagem
19.
Small ; : e1800762, 2018 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-30019826

RESUMO

CO2 conversion into value-added chemical fuels driven by solar energy is an intriguing approach to address the current and future demand of energy supply. Currently, most reported surface-sensitized heterogeneous photocatalysts present poor activity and selectivity under visible light irradiation. Here, photosensitized porous metallic and magnetic 1200 CoC composites (PMMCoCC-1200) are coupled with a [Ru(bpy)3 ]Cl2 photosensitizer to efficiently reduce CO2 under visible-light irradiation in a selective and sustainable way. As a result, the CO production reaches a high yield of 1258.30 µL with selectivity of 64.21% in 6 h, superior to most reported heterogeneous photocatalysts. Systematic investigation demonstrates that the central metal cobalt is the active site for activating the adsorbed CO2 molecules and the surficial graphite carbon coating on cobalt metal is crucial for transferring the electrons from the triplet metal-to-ligand charge transfer of the photosensitizer Ru(bpy)32+ , which gives rise to significant enhancement for CO2 reduction efficiency. The fast electron injection from the excited Ru(bpy)32+ to PMMCoCC-1200 and the slow backward charge recombination result in a long-lived, charge-separated state for CO2 reduction. More impressively, the long-time stability and easy magnetic recycling ability of this metallic photocatalyst offer more benefits to the photocatalytic field.

20.
Cad. psicol. soc. trab ; 21(1): 33-43, jan.-jun. 2018.
Artigo em Português | LILACS, Index Psicologia - Periódicos | ID: biblio-1055653

RESUMO

O artigo apresenta a trajetória de uma trabalhadora que encontrou na catação de material reciclável sua própria sobrevivência e a de seus familiares. Por meio de um estudo de caso baseado no Método Biográfico, conforme foi proposto por Louis Le Guillant (2006), buscou-se apreender o sentido que essa catadora atribui ao seu trabalho. Foram realizadas entrevistas em profundidade, além de uma pesquisa documental, visando conhecer a história da associação à qual ela está vinculada. Os resultados oferecem uma maior visibilidade ao catador e ao trabalho que realiza, concluindo que, apesar de ser pouco valorizado socialmente, para além da garantia da sobrevivência, esse trabalho pode ser fonte de reconhecimento e de identidade, permitindo a emergência de novas perspectivas de vida e a projeção de um futuro melhor. Os resultados apontam ainda que a atividade de catação, embora realizada sob condições adversas, não se reduz à luta contra o sofrimento, podendo ser percebida também como fonte permanente de recriação e de novas formas de viver.


This article presents the trajectory of a worker who found hers and her relatives' survival in the collection of recyclable material. Through a case study based on the Biographical Method, within the perspective proposed by Louis Le Guillant (2006), it was sought to apprehend the sense that this waste picker attributes to her work. Several in-depth interviews were carried out, in addition to a documentary research, aiming to know the history of the association. The results of the study offer a greater visibility to the waste picker and to the work she does, concluding that, despite being little valued socially, beyond guaranteeing survival, this work can be a source of recognition and identity, allowing the emergence of new perspectives of life and the projection of a better future. The results also pointed out that, although carried out under adverse conditions, the activity of waste picking is not limited to the struggle against suffering, and can also be perceived as a permanent source of recreation and new ways of living.


Assuntos
Humanos , Feminino , Idoso , Mulheres Trabalhadoras/psicologia , Catadores , Sobrevivência
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