Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 69
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Arch Gynecol Obstet ; 309(1): 183-193, 2024 01.
Artigo em Inglês | MEDLINE | ID: mdl-36708424

RESUMO

PURPOSE: Dietary micronutrient intakes of iron, folate and vitamin B12 are known to influence hemoglobin. Low maternal hemoglobin (maternal anemia) has been linked to low birthweight and other adverse health outcomes in the fetus and infant. Our primary aim was to explore relationships between maternal dietary micronutrient intakes, maternal full blood count (FBC) parameters and fetal abdominal circumference (AC) and estimated fetal weight (EFW) growth trajectories. Secondarily, we aimed to assess relationships between maternal dietary micronutrient intakes, maternal hemoglobin values and placental weight and birthweight. METHODS: Mother-child pairs (n = 759) recruited for the ROLO study were included in this analysis. Maternal dietary micronutrient intakes were calculated from food diaries completed during each trimester of pregnancy. FBC samples were collected at 13- and 28-weeks' gestation. Fetal ultrasound measurements were recorded at 20- and 34-weeks' gestation. Growth trajectories for AC and EFW were estimated using latent class trajectory mixture models. RESULTS: Dietary intakes of iron and folate were deficient for all trimesters. Mean maternal hemoglobin levels were replete at 13- and 28-weeks' gestation. Dietary iron, folate and vitamin B12 intakes showed no associations with fetal growth trajectories, placental weight or birthweight. Lower maternal hemoglobin concentrations at 28 weeks' gestation were associated with faster rates of fetal growth and larger placental weights and birthweights. CONCLUSION: The negative association between maternal hemoglobin at 28 weeks' gestation and accelerated fetal and placental growth may be due to greater consumption of maternal iron and hemoglobin by fetuses' on faster growth trajectories in addition to placental biochemical responses to lower oxygen states.


Assuntos
Ácido Fólico , Ferro , Gravidez , Feminino , Humanos , Peso ao Nascer , Estudos de Coortes , Vitamina B 12 , Placenta , Desenvolvimento Fetal , Idade Gestacional , Hemoglobinas , Ingestão de Alimentos
2.
J Environ Manage ; 345: 118449, 2023 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-37390731

RESUMO

Mechanical separation of anaerobic digestate has been identified as a method to reduce pollution risk to waterways by partitioning phosphorus in the solid fraction and reducing its application to land. Separators have adjustable parameters which affect separation efficiency, and hence the degree of phosphorous partitioning, but information on how these parameters affect separation performance is limited in the literature. Two well known technologies were investigated, decanter centrifuge and screw press, to determine the most efficient method of separation. Counterweight load and the use of an oscillator were adjusted for the screw press, while bowl speed, auger differential speed, feed rate and polymer addition were modified for the decanter centrifuge. Separation efficiency was determined for total solids, phosphorus, nitrogen, potassium, and carbon, and the total solids content of resulting fractions was measured. The decanter centrifuge had higher separation efficiency for phosphorus in all cases, ranging from 51% to 71.5%, while the screw press had a phosphorus separation efficiency ranging from 8.5% to 10.9% for digestate of ∼5% solids (slurry/grass silage mix). Separation by decanter centrifuge partitioned up to 56% of nitrogen in the solid fraction leaving a reduced nitrogen content in the liquid fraction available for land spreading; this nitrogen would most likely need to be replaced by chemical fertiliser which would add to the cost of the system. The decanter centrifuge is better suited to cases where phosphorus recovery is the most important factor, while the screw press could be advantageous in cases where cost is a limiting factor.


Assuntos
Poluição Ambiental , Nitrogênio , Anaerobiose , Nitrogênio/análise , Esterco , Fósforo/química
3.
Environ Chem Lett ; 21(1): 97-152, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36245550

RESUMO

The development and recycling of biomass production can partly solve issues of energy, climate change, population growth, food and feed shortages, and environmental pollution. For instance, the use of seaweeds as feedstocks can reduce our reliance on fossil fuel resources, ensure the synthesis of cost-effective and eco-friendly products and biofuels, and develop sustainable biorefinery processes. Nonetheless, seaweeds use in several biorefineries is still in the infancy stage compared to terrestrial plants-based lignocellulosic biomass. Therefore, here we review seaweed biorefineries with focus on seaweed production, economical benefits, and seaweed use as feedstock for anaerobic digestion, biochar, bioplastics, crop health, food, livestock feed, pharmaceuticals and cosmetics. Globally, seaweeds could sequester between 61 and 268 megatonnes of carbon per year, with an average of 173 megatonnes. Nearly 90% of carbon is sequestered by exporting biomass to deep water, while the remaining 10% is buried in coastal sediments. 500 gigatonnes of seaweeds could replace nearly 40% of the current soy protein production. Seaweeds contain valuable bioactive molecules that could be applied as antimicrobial, antioxidant, antiviral, antifungal, anticancer, contraceptive, anti-inflammatory, anti-coagulants, and in other cosmetics and skincare products.

4.
Environ Chem Lett ; : 1-37, 2023 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-37362011

RESUMO

New technologies, systems, societal organization and policies for energy saving are urgently needed in the context of accelerated climate change, the Ukraine conflict and the past coronavirus disease 2019 pandemic. For instance, concerns about market and policy responses that could lead to new lock-ins, such as investing in liquefied natural gas infrastructure and using all available fossil fuels to compensate for Russian gas supply cuts, may hinder decarbonization efforts. Here we review energy-saving solutions with a focus on the actual energy crisis, green alternatives to fossil fuel heating, energy saving in buildings and transportation, artificial intelligence for sustainable energy, and implications for the environment and society. Green alternatives include biomass boilers and stoves, hybrid heat pumps, geothermal heating, solar thermal systems, solar photovoltaics systems into electric boilers, compressed natural gas and hydrogen. We also detail case studies in Germany which is planning a 100% renewable energy switch by 2050 and developing the storage of compressed air in China, with emphasis on technical and economic aspects. The global energy consumption in 2020 was 30.01% for the industry, 26.18% for transport, and 22.08% for residential sectors. 10-40% of energy consumption can be reduced using renewable energy sources, passive design strategies, smart grid analytics, energy-efficient building systems, and intelligent energy monitoring. Electric vehicles offer the highest cost-per-kilometer reduction of 75% and the lowest energy loss of 33%, yet battery-related issues, cost, and weight are challenging. 5-30% of energy can be saved using automated and networked vehicles. Artificial intelligence shows a huge potential in energy saving by improving weather forecasting and machine maintenance and enabling connectivity across homes, workplaces, and transportation. For instance, 18.97-42.60% of energy consumption can be reduced in buildings through deep neural networking. In the electricity sector, artificial intelligence can automate power generation, distribution, and transmission operations, balance the grid without human intervention, enable lightning-speed trading and arbitrage decisions at scale, and eliminate the need for manual adjustments by end-users.

5.
Environ Chem Lett ; : 1-31, 2023 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-37362015

RESUMO

The rising amount of waste generated worldwide is inducing issues of pollution, waste management, and recycling, calling for new strategies to improve the waste ecosystem, such as the use of artificial intelligence. Here, we review the application of artificial intelligence in waste-to-energy, smart bins, waste-sorting robots, waste generation models, waste monitoring and tracking, plastic pyrolysis, distinguishing fossil and modern materials, logistics, disposal, illegal dumping, resource recovery, smart cities, process efficiency, cost savings, and improving public health. Using artificial intelligence in waste logistics can reduce transportation distance by up to 36.8%, cost savings by up to 13.35%, and time savings by up to 28.22%. Artificial intelligence allows for identifying and sorting waste with an accuracy ranging from 72.8 to 99.95%. Artificial intelligence combined with chemical analysis improves waste pyrolysis, carbon emission estimation, and energy conversion. We also explain how efficiency can be increased and costs can be reduced by artificial intelligence in waste management systems for smart cities.

6.
Environ Chem Lett ; 21(1): 447-477, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36161092

RESUMO

Metal-organic frameworks are porous polymeric materials formed by linking metal ions with organic bridging ligands. Metal-organic frameworks are used as sensors, catalysts for organic transformations, biomass conversion, photovoltaics, electrochemical applications, gas storage and separation, and photocatalysis. Nonetheless, many actual metal-organic frameworks present limitations such as toxicity of preparation reagents and components, which make frameworks unusable for food and pharmaceutical applications. Here, we review the structure, synthesis and properties of cyclodextrin-based metal-organic frameworks that could be used in bioapplications. Synthetic methods include vapor diffusion, microwave-assisted, hydro/solvothermal, and ultrasound techniques. The vapor diffusion method can produce cyclodextrin-based metal-organic framework crystals with particle sizes ranging from 200 nm to 400 µm. Applications comprise food packaging, drug delivery, sensors, adsorbents, gas separation, and membranes. Cyclodextrin-based metal-organic frameworks showed loading efficacy of the bioactive compounds ranging from 3.29 to 97.80%.

7.
BMC Ophthalmol ; 22(1): 397, 2022 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-36199054

RESUMO

INTRODUCTION: Glaucoma is the leading cause of irreversible blindness worldwide and is often undetected in resource-limited settings. Early screening and treatment of elevated intraocular pressure (IOP) reduces both the development and progression of visual field defects. IOP screening in developing countries is limited by access to ophthalmic equipment, trained ophthalmic staff, and follow up. High-volume cataract surgery outreaches in resource-limited countries provide ample opportunity for glaucoma screening, intervention and follow up. METHODS: This prospective cross-sectional study took place during a cataract outreach campaign sponsored by the Himalayan Cataract Project (HCP) in partnership with Felege Hiwot Hospital in Bahir Dar, Ethiopia, during April 5th - April 10th 2021. IOP was measured on the surgical eye of patients before undergoing small incision cataract surgery (SICS) using rebound tonometry with an iCare tonometer model IC100. RESULTS: Intraocular pressure (IOP) was measured in 604 eyes of 595 patients who received SICS. Mean IOP was 12.1 mmHg (SD = 5.0 mmHg). A total of 29 patients had an IOP greater than 21 mmHg representing 4.8% of total IOP measurements. A total of 17 patients received oral acetazolamide prior to surgery to acutely lower IOP. Six of these patients had their surgery delayed due to elevated IOP and 9 patients received excisional goniotomy at the time of SICS. A temporal approach during SCIS was taken for all patients with elevated IOP to allow for possible trabeculectomy at a future date. DISCUSSION: IOP screening during high-volume cataract outreach campaigns can be performed safely, accurately and on a large scale with minimal resources and supplemental training. Pre-operative IOP measurement can improve surgical care at the time of cataract surgery as well as help establish long-term follow up for patients with glaucoma.


Assuntos
Catarata , Glaucoma , Trabeculectomia , Acetazolamida , Estudos Transversais , Etiópia , Glaucoma/diagnóstico , Glaucoma/cirurgia , Humanos , Pressão Intraocular , Estudos Prospectivos
8.
J Environ Manage ; 304: 114319, 2022 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-35021592

RESUMO

Prunus Armeniaca seed (PAS) oil was utilised as a waste biomass feedstock for biodiesel production via a novel catalytic system (SrO-La2O3) based on different stoichiometric ratios. The catalysts have been characterised and followed by a parametric analysis to optimise catalyst results. The catalyst with a stoichiometric ratio of Sr: La-8 (Sr-La-C) using parametric analysis showed an optimum yield of methyl esters is 97.28% at 65 °C, reaction time 75 min, catalyst loading 3 wt% and methanol to oil molar ratio of 9. The optimum catalyst was tested using various oil feedstocks such as waste cooking oil, sunflower oil, PAS oil, date seed oil and animal fat. The life cycle assessment was performed to evaluate the environmental impacts of biodiesel production utilising waste PAS, considering 1000 kg of biodiesel produced as 1 functional unit. The recorded results showed the cumulative abiotic depletion of fossil resources over the entire biodiesel production process as 22,920 MJ, global warming potential as 1150 kg CO2 equivalent, acidification potential as 4.89 kg SO2 equivalent and eutrophication potential as 0.2 kg PO43- equivalent for 1 tonne (1000 kg) of biodiesel produced. Furthermore, the energy ratio (measured as output energy divided by input energy) for the entire production process was 1.97. These results demonstrated that biodiesel obtained from the valorisation of waste PAS provides a suitable alternative to fossil fuels.


Assuntos
Biocombustíveis , Prunus armeniaca , Animais , Catálise , Estágios do Ciclo de Vida , Óleos de Plantas
9.
Environ Chem Lett ; 20(4): 2277-2310, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35431715

RESUMO

The increasing global industrialization and over-exploitation of fossil fuels has induced the release of greenhouse gases, leading to an increase in global temperature and causing environmental issues. There is therefore an urgent necessity to reach net-zero carbon emissions. Only 4.5% of countries have achieved carbon neutrality, and most countries are still planning to do so by 2050-2070. Moreover, synergies between different countries have hampered synergies between adaptation and mitigation policies, as well as their co-benefits. Here, we present a strategy to reach a carbon neutral economy by examining the outcome goals of the 26th summit of the United Nations Climate Change Conference of the Parties (COP 26). Methods have been designed for mapping carbon emissions, such as input-output models, spatial systems, geographic information system maps, light detection and ranging techniques, and logarithmic mean divisia. We present decarbonization technologies and initiatives, and negative emissions technologies, and we discuss carbon trading and carbon tax. We propose plans for carbon neutrality such as shifting away from fossil fuels toward renewable energy, and the development of low-carbon technologies, low-carbon agriculture, changing dietary habits and increasing the value of food and agricultural waste. Developing resilient buildings and cities, introducing decentralized energy systems, and the electrification of the transportation sector is also necessary. We also review the life cycle analysis of carbon neutral systems.

10.
Environ Chem Lett ; 20(4): 2385-2485, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35571983

RESUMO

In the context of climate change and the circular economy, biochar has recently found many applications in various sectors as a versatile and recycled material. Here, we review application of biochar-based for carbon sink, covering agronomy, animal farming, anaerobic digestion, composting, environmental remediation, construction, and energy storage. The ultimate storage reservoirs for biochar are soils, civil infrastructure, and landfills. Biochar-based fertilisers, which combine traditional fertilisers with biochar as a nutrient carrier, are promising in agronomy. The use of biochar as a feed additive for animals shows benefits in terms of animal growth, gut microbiota, reduced enteric methane production, egg yield, and endo-toxicant mitigation. Biochar enhances anaerobic digestion operations, primarily for biogas generation and upgrading, performance and sustainability, and the mitigation of inhibitory impurities. In composts, biochar controls the release of greenhouse gases and enhances microbial activity. Co-composted biochar improves soil properties and enhances crop productivity. Pristine and engineered biochar can also be employed for water and soil remediation to remove pollutants. In construction, biochar can be added to cement or asphalt, thus conferring structural and functional advantages. Incorporating biochar in biocomposites improves insulation, electromagnetic radiation protection and moisture control. Finally, synthesising biochar-based materials for energy storage applications requires additional functionalisation.

11.
J Chem Technol Biotechnol ; 92(12): 2952-2962, 2017 12.
Artigo em Inglês | MEDLINE | ID: mdl-29200585

RESUMO

BACKGROUND: Methanol to dimethyl ether (MTD) is considered one of the main routes for the production of clean bio-fuel. The effect of copper loading on the catalytic performance of different phases of alumina that formed by calcination at two different temperatures was examined for the dehydration of methanol to dimethyl ether (DME). RESULTS: A range of Cu loadings of (1, 2, 4, 6, 10 and 15% Cu wt/wt) on Al2O3 calcined at 350 and 550 °C were prepared and characterized by TGA, XRD, BET, NH3-TPD, TEM, H2-TPR, SEM, EDX, XPS and DRIFT-Pyridine techniques. The prepared catalysts were used in a fixed bed reactor under reaction conditions in which the temperature ranged from 180-300 °C with weight hourly space velocity (WHSV) = 12.1 h-1. It was observed that all catalysts calcined at 550 °C (γ-Al2O3 support phase) exhibited higher activity than those calcined at 350 °C (γ-AlOOH), and this is due to the phase support change. Furthermore, the optimum Cu loading was found to be 6% Cu/γ-Al2O3 with this catalyst also showing a high degree of stability under steady state conditions and this is attributed to the enhancement in surface acidity and hydrophobicity. CONCLUSION: The addition of copper to the support improved the catalyst properties and activity. For all the copper modified catalysts, the optimum catalyst with high degree of activity and stability was 6% copper loaded on gamma alumina. © 2017 The Authors. Journal of Chemical Technology & Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

12.
Eye Contact Lens ; 42(6): 339-346, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26825281

RESUMO

OBJECTIVES: Thermal pulsation (LipiFlow) has been advocated for meibomian gland dysfunction (MGD) treatment and was found useful. We aimed to evaluate the efficacy and safety of thermal pulsation in Asian patients with different grades of meibomian gland loss. METHODS: A hospital-based interventional study comparing thermal pulsation to warm compresses for MGD treatment. Fifty patients were recruited from the dry eye clinic of a Singapore tertiary eye hospital. The ocular surface and symptom were evaluated before treatment, and one and three months after treatment. Twenty-five patients underwent thermal pulsation (single session), whereas 25 patients underwent warm compresses (twice daily) for 3 months. Meibomian gland loss was graded using infrared meibography, whereas function was graded using the number of glands with liquid secretion. RESULTS: The mean age (SD) of participants was 56.4 (11.4) years in the warm compress group and 55.6 (12.7) years in the thermal pulsation group. Seventy-six percent of the participants were female. Irritation symptom significantly improved over 3 months in both groups (P<0.01), whereas tear breakup time (TBUT) was modestly improved at 1 month in only the thermal pulsation group (P=0.048), without significant difference between both groups over the 3 months (P=0.88). There was also no significant difference in irritation symptom, TBUT, Schirmer test, and gland secretion variables between patients with different grades of gland loss or function at follow-ups. CONCLUSIONS: A single session of thermal pulsation was similar in its efficacy and safety profile to 3 months of twice daily warm compresses in Asians. Treatment efficacy was not affected by pretreatment gland loss.


Assuntos
Síndromes do Olho Seco/terapia , Doenças Palpebrais/terapia , Hipertermia Induzida/métodos , Glândulas Tarsais , Adulto , Idoso , Síndromes do Olho Seco/etiologia , Síndromes do Olho Seco/patologia , Síndromes do Olho Seco/fisiopatologia , Dor Ocular/etiologia , Doenças Palpebrais/complicações , Feminino , Humanos , Modelos Lineares , Masculino , Glândulas Tarsais/metabolismo , Glândulas Tarsais/patologia , Glândulas Tarsais/fisiopatologia , Pessoa de Meia-Idade , Estudos Prospectivos , Lágrimas/metabolismo
13.
Ir J Med Sci ; 193(2): 921-925, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37733225

RESUMO

BACKGROUND: Seven per cent of general waste and 20% of healthcare risk waste produced in acute hospitals in Ireland comes from operating theatres. Surgical wrap comprises 11% of operating theatre waste. AIMS: The primary aim of this study was to pilot the implementation of a recycling initiative for surgical instrument set wrap in an operating theatre in Ireland. Secondary aims included quantification of the surgical wrap diverted from general waste to recycling streams over a 5-week period and estimation of the annual carbon emissions associated with gynaecology surgical wrap use in Cork. METHODS: The amount of polypropylene surgical wrap generated by a single gynaecology theatre at Cork University Maternity Hospital was prospectively quantified from 24/1/22 to 1/3/22. At the end of the study period, individual sheets of polypropylene wrap were counted and dimensions were measured to calculate the total surface area of surgical wrap saved for recycling. RESULTS: A total of 66 surgeries were performed over the 5-week study period. Two hundred twenty-one individual sheets of surgical wrap were collected, equating to 282.1 m2 of polypropylene wrap. An estimated 11,564 m2 of surgical wrap could be recycled annually from the gynaecology theatre service in Cork with an associated annual carbon emissions equivalent of at least 2.2 tonnes of CO2. CONCLUSION: Diversion of surgical wrap from general waste and clinical waste streams to the recycling stream is achievable in every operating theatre. Small changes to operating theatre waste disposal practices have the potential to yield significant reductions to theatre waste outputs and to hospital carbon emissions.


Assuntos
Polipropilenos , Reciclagem , Feminino , Gravidez , Humanos , Reciclagem/métodos , Salas Cirúrgicas , Hospitais Universitários , Carbono , Instrumentos Cirúrgicos
14.
Front Chem ; 12: 1404107, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38873404

RESUMO

This study explores the innovative application of iron filings solid waste, a byproduct from mechanical workshops, as a heterogeneous catalyst in the production of biodiesel from waste cooking oil. Focusing on sustainability and waste valorization, the research presents a dual-benefit approach: addressing the environmental issue of solid waste disposal while contributing to the renewable energy sector. Particle size distribution analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray fluorescence (XRF), Thermal analysis (TG-DTA), and FTIR analysis were used to characterize the iron filings. The response surface methodology (RSM) was used to guide a series of experiments that were conducted to identify the optimum transesterification settings. Important factors that greatly affect the production of biodiesel are identified by the study, including catalyst loading, reaction time, methanol-to-oil ratio, reaction temperature, and stirring rate. The catalyst proved to be successful as evidenced by the 96.4% biodiesel conversion efficiency attained under ideal conditions. The iron filings catalyst's reusability was evaluated, demonstrating its potential for numerous applications without noticeably decreasing activity. This work offers a road towards more environmentally friendly and sustainable chemical processes in energy production by making a strong argument for using industrial solid waste as a catalyst in the biodiesel manufacturing process.

15.
Environ Sci Pollut Res Int ; 31(38): 50493-50512, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-39096460

RESUMO

Leveraging date palm spikelets (DPS) as a precursor, this study developed a DPS-derived composite (ZnO@DPS-AC) for water treatment, focusing on methyl orange (MO) removal. The composite was synthesized through ZnCl2 activation and pyrolysis at 600 °C. Comprehensive characterization was conducted using TGA, FTIR, XRD, SEM/EDS, and pHPZC. Characterization revealed a highly carbonaceous material (> 74% carbon) with significant porosity and surface functional groups. ZnO@DPS-AC demonstrated rapid MO removal, achieving over 45% reduction within 10 min and up to 99% efficiency under optimized conditions. The Langmuir model-calculated maximum adsorption capacity reached 226.81 mg/g at 20 °C. Adsorption mechanisms involved hydrogen bonding, π-π interactions, and pore filling. The composite showed effectiveness in treating real wastewater and removing other pollutants. This study highlights the potential of agricultural waste valorization in developing efficient, sustainable adsorbents for water remediation, contributing to circular bioeconomy principles.


Assuntos
Compostos Azo , Carvão Vegetal , Phoeniceae , Termodinâmica , Águas Residuárias , Poluentes Químicos da Água , Purificação da Água , Adsorção , Cinética , Compostos Azo/química , Carvão Vegetal/química , Águas Residuárias/química , Purificação da Água/métodos , Poluentes Químicos da Água/química , Phoeniceae/química
16.
Environ Sci Pollut Res Int ; 31(31): 44254-44271, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38943002

RESUMO

Efficient catalysts play a pivotal role in advancing eco-friendly water treatment strategies, particularly in the removal of diverse organic contaminants found in water-petroleum sources. This study addresses the multifaceted challenges posed by contaminants, encompassing a spectrum of heavy metals such as As, Cd, Cr, Mn, Mo, Ni, Pb, Sb, Se, and Zn alongside pollutants like oily water (OIW), total suspended solids (TSS), chemical oxygen demand (COD), dyes, and pharmaceuticals, posing threats to both aquatic and terrestrial ecosystems. Herein, we present the synthesis of biogenically derived Mn@NiO nanocomposite (NC) photocatalysts, a sustainable methodology employing an aqueous Rosmarinus officinalis L. extract, yielding particles with a size of 36.7 nm. The catalyst demonstrates exceptional efficacy in removing heavy metals, achieving rates exceeding 99-100% within 30 min, alongside notable removal efficiencies for OIW (98%), TSS (87%), and COD (98%). Furthermore, our photodegradation experiments showed remarkable efficiencies, with 94% degradation for Rose Bengal (RB) and 96% for methylene blue (MB) within 120 min. The degradation kinetics adhere to pseudo-first-order behavior, with rate constants of 0.0227 min-1 for RB and 0.0370 min-1 for MB. Additionally, the NC exhibits significant antibiotic degradation rates of 97% for cephalexin (CEX) and 96% for amoxicillin (AMOX). The enhanced photocatalytic performance is attributed to the synergistic interplay between the Mn and NiO nanostructures, augmenting responsiveness to sunlight while mitigating electron-hole pair recombination. Notably, the catalyst demonstrates outstanding stability and reusability across multiple cycles, maintaining its stable nanostructure without compromise.


Assuntos
Petróleo , Poluentes Químicos da Água , Poluentes Químicos da Água/química , Nanoestruturas , Metais Pesados/química , Manganês/química , Níquel/química , Nanocompostos/química , Catálise , Purificação da Água/métodos
17.
ACS Omega ; 9(1): 1962-1976, 2024 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-38222655

RESUMO

This study focuses on upcycling cement kiln dust (CKD) as an industrial waste by utilizing the undissolved portion (UNP) as a multicomponent catalyst for bioethylene production from bioethanol, offering an environmentally sustainable solution. To maximize UNP utilization, CKD was dissolved in nitric acid, followed by calcination at 500 °C for 3 h in an oxygen atmosphere. Various characterization techniques confirmed that UNP comprises five different compounds with nanocrystalline particles exhibiting an average crystal size of 47.53 nm. The UNP catalyst exhibited a promising bioethylene yield (77.1%) and selectivity (92%) at 400 °C, showcasing its effectiveness in converting bioethanol to bioethylene with outstanding properties. This exceptional performance can be attributed to its distinctive structural characteristics, including a high surface area and multiple-strength acidic sites that facilitate the reaction mechanism. Moreover, the UNP catalyst displayed remarkable stability and durability, positioning it as a strong candidate for industrial applications in bioethylene production. This research underscores the importance of waste reduction in the cement industry and offers a sustainable path toward a greener future.

18.
Sci Total Environ ; 930: 172794, 2024 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-38677421

RESUMO

The rapid urbanization witnessed in developing countries in Asia and Africa has led to a substantial increase in municipal solid waste (MSW) generation. However, the corresponding disposal strategies, along with constraints in land resources and finances, compounded by unorganized public behaviour, have resulted in ineffective policy implementation and monitoring. This lack of systematic and targeted orientation, combined with blind mapping, has led to inefficient development in many areas. This review examines the key challenges of MSW management in developing countries in Asia and Africa from 2013 to 2023, drawing insights from 170 academic papers. Rather than solely focusing on recycling, the study proposes waste sorting at the source, optimization of landfill practices, thermal treatment measures, and strategies to capitalize on the value of waste as more pertinent solutions aligned with local realities. Barriers to optimizing management systems arise from socio-economic factors, infrastructural limitations, and cultural considerations. The review emphasizes the importance of integrating the study area into the circular economy framework, with a focus on enhancing citizen participation in solid waste reduction and promoting recycling initiatives, along with seeking economic assistance from international organizations.

19.
ACS Omega ; 9(5): 5100-5126, 2024 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-38343989

RESUMO

Mercury is a type of hazardous and toxic pollutant that can result in detrimental effects on the environment and human health. This review is aimed at discussing the state-of-the-art progress on the recent developments on the toxicity of mercury and its chemical compounds. More than 210 recent works of literature are covered in this review. It first delineates the types (covering elemental mercury, inorganic mercury compounds, organic mercury compounds), structures, and sources of mercury. It then discusses the pharmacokinetic profile of mercury, molecular mechanisms of mercury toxicity, and clinical manifestation of acute and chronic mercury toxicity to public health. It also elucidates the mercury toxicity to the environment and human health in detail, covering ecotoxicity, neurotoxicity diseases, neurological diseases, genotoxicity and gene regulation, immunogenicity, pregnancy and reproductive system damage, cancer promotion, cardiotoxicity, pulmonary diseases, and renal disease. In order to mitigate the adverse effects of mercury, strategies to overcome mercury toxicity are recommended. Finally, some future perspectives are provided in order to advance this field of research in the future.

20.
Environ Technol ; 34(21-24): 3005-16, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24617059

RESUMO

The urgent need for alternative renewable energies to supplement petroleum-based fuels and the reduction of landfill sites for disposal of solid wastes makes it increasingly attractive to produce inexpensive biofuels from the organic fraction of the municipal solid waste. Therefore, municipal waste in the form of newspaper was investigated as a potential feedstock for fermentable sugars production. Hydrolysis of newspaper by dilute phosphoric acid was carried out in autoclave Parr reactor, where reactor temperature and acid concentration were examined. Xylose concentration reached a maximum value of 14 g/100 g dry mass corresponding to a yield of 94% at the best identified conditions of 2.5 wt% H3PO4, 135 degrees C, 120 min reaction time, and at 2.5 wt% H3PO4, 150 degrees C, and 60 min reaction time. For glucose, an average yield of 26% was obtained at 2.5 wt% H3PO4, 200 degrees C, and 30 min. Furfural and 5-hydroxymethylfurfural (HMF) formation was clearly affected by reaction temperature, where the higher the temperature the higher the formation rate. The maximum furfural formed was an average of 3 g/100 g dry mass, corresponding to a yield of 28%. The kinetic study of the acid hydrolysis was also carried out using the Saeman and the two-fraction models. It was found for both models that the kinetic constants (K) depend on the acid concentration and temperature. The degradation of HMF to levulinic acid is faster than the degradation of furfural to formic acid. Also, the degradation rate is higher than the formation rate for both inhibitors when degradation is observed.


Assuntos
Glucose/química , Glucose/isolamento & purificação , Lignina/química , Jornais como Assunto , Papel , Ácidos Fosfóricos/química , Eliminação de Resíduos/métodos , Bactérias/metabolismo , Metabolismo dos Carboidratos/fisiologia , Catálise , Cidades , Etanol/metabolismo , Fermentação , Hidrólise
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA