Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 32
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Sci Rep ; 14(1): 8318, 2024 04 09.
Artigo em Inglês | MEDLINE | ID: mdl-38594356

RESUMO

The Danube is a significant transboundary river on a global scale, with several tributaries. The effluents from industrial operations and wastewater treatment plants have an impact on the river's aquatic ecosystem. These discharges provide a significant threat to aquatic life by deteriorating the quality of water and sediment. Hence, a total of 16 Polycyclic Aromatic Hydrocarbons (PAHs) compounds were analyzed at six locations along the river, covering a period of 12 months. The objective was to explore the temporal and spatial fluctuations of these chemicals in both water and sediment. The study revealed a significant fluctuation in the concentration of PAHs in water throughout the year, with levels ranging from 224.8 ng/L during the summer to 365.8 ng/L during the winter. Similarly, the concentration of PAHs in sediment samples varied from 316.7 ng/g in dry weight during the summer to 422.9 ng/g in dry weight during the winter. According to the Europe Drinking Water Directive, the levels of PAHs exceeded the permitted limit of 100 ng/L, resulting in a 124.8% rise in summer and a 265.8% increase in winter. The results suggest that the potential human-caused sources of PAHs were mostly derived from pyrolytic and pyrogenic processes, with pyrogenic sources being more dominant. Assessment of sediment quality standards (SQGs) showed that the levels of PAHs in sediments were below the Effect Range Low (ERL), except for acenaphthylene (Acy) and fluorene (Fl) concentrations. This suggests that there could be occasional biological consequences. The cumulative Individual Lifetime Cancer Risk (ILCR) exceeds 1/104 for both adults and children in all sites.


Assuntos
Hidrocarbonetos Policíclicos Aromáticos , Poluentes Químicos da Água , Criança , Humanos , China , Ecossistema , Monitoramento Ambiental/métodos , Sedimentos Geológicos/química , Hungria , Hidrocarbonetos Policíclicos Aromáticos/análise , Medição de Risco , Rios/química , Água , Poluentes Químicos da Água/análise , Adulto
2.
Mar Pollut Bull ; 202: 116333, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38579446

RESUMO

The temporal and spatial variations of 16 Polycyclic Aromatic Hydrocarbons (PAHs) were examined at multiple sites around Lake Balaton from February 2023 to January 2024. The results indicated that the concentrations of PAHs in sediment were high during the winter months, 448.35 to 619.77 ng/g dry weight, and low during the summer months, 257.21 to 465.49 ng/g dry weight. The concentration of high molecular weight PAHs (HMWPAHs), consisting of 5-6 rings, was greater than that of low molecular weight PAHs (LMWPAHs), which had 2-3 rings. The total incremental lifetime cancer risk (ILCR) for both dermal and ingestion pathways was high for both adults and children during the four seasons, with the highest records as the following: winter > spring > summer > autumn. The ecological effects of the 16 PAHs were negligible except for acenaphthylene (Acy) and fluorene (Fl), which displayed slightly higher concentrations during the autumn and spring, respectively.


Assuntos
Monitoramento Ambiental , Sedimentos Geológicos , Lagos , Hidrocarbonetos Policíclicos Aromáticos , Estações do Ano , Poluentes Químicos da Água , Hidrocarbonetos Policíclicos Aromáticos/análise , Lagos/química , Poluentes Químicos da Água/análise , Sedimentos Geológicos/química , Peso Molecular , Humanos
3.
Materials (Basel) ; 17(5)2024 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-38473504

RESUMO

Due to the growing concerns about pharmaceutical contamination and its devastating impact on the economy and the health of humans and the environment, developing efficient approaches for removing such contaminants has become essential. Adsorption is a cost-effective technique for removing pollutants. Thus, in this work, banana peels as agro-industrial waste were utilized for synthesizing activated carbon for removing pharmaceuticals, namely amoxicillin and carbamazepine from different water matrices. The chemically activated carbon by phosphoric acid (H3PO4) was carbonized at temperatures 350 °C, 450 °C and 550 °C. The material was characterized by several techniques such as scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), Boehm titration, point of zero charge (pHPZC), BET surface area (SBET), the proximate and ultimate analyses, X-ray powder diffraction (XRD), and thermos-gravimetric analysis (TGA). The SEM of banana peel activated carbon (BPAC) depicted a semi-regular and heterogeneous morphology, characterized by an abundance of pores with diverse forms and sizes. Boehm titration revealed an increase in the amounts of acidic groups by 0.711 mmol/g due to activation by H3PO4. FTIR recorded different peaks suggesting significant modifications in the spectroscopic characteristics of the BPAC surface due to the successful activation and adsorption of the pollutant molecules. The pHpzc of BPAC was calculated to be 5.005. The SBET surface area dramatically increased to 911.59 m2/g after the activation. The optimum conditions were 25 °C, a materials dosage of 1.2 g/L, a saturation time of 120 min, a pollutants mixture of 25 mg/L, and a pH of 5. Langmuir exhibits a slightly better fit than Freundlich with a low value of the residual sum of squares (SSE) and the data were better fitted to the pseudo-second-order kinetic. Furthermore, the efficacy of BPAC in eliminating pharmaceuticals from Milli Q water, lake water, and wastewater was successfully investigated over the seven cycles. The results of the present work highlighted a potential usage of agro-industrial waste in eliminating organic micropollutants while exhibiting sustainable management of this waste.

4.
Environ Res ; 251(Pt 1): 118565, 2024 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-38431073

RESUMO

This study endeavors to develop cost-effective environmentally friendly technology for removing harmful residual pharmaceuticals from water and wastewater by utilizing the effective adsorption of pistachio shell (PS) biochar and the degradation potency of laccase immobilized on the biochar (L@PSAC). The carbonatization and activation of the shells were optimized regarding temperature, time, and NH4NO3/PS ratio. This step yielded an optimum PS biochar (PSAC) with the highest porosity and surface area treated at 700 °C for 3 h using an NH4NO3/PS ratio of 3% wt. The immobilization of laccase onto PSAC (L@PSAC) was at its best level at pH 5, 60 U/g, and 30 °C. The optimum L@PSAC maintained a high level of enzyme activity over two months. Almost a complete removal (>99%) of diclofenac, carbamazepine, and ciprofloxacin in Milli-Q (MQ) water and wastewater was achieved. Adsorption was responsible for >80% of the removal and the rest was facilitated by laccase degradation. L@PSAC maintained effective removal of pharmaceuticals of ≥60% for up to six treatment cycles underscoring the promising application of this material for wastewater treatment. These results indicate that activated carbon derived from the pistachio shell could potentially be utilized as a carrier and adsorbent to efficiently remove pharmaceutical compounds. This enzymatic physical elimination approach has the potential to be used on a large-scale.


Assuntos
Carvão Vegetal , Lacase , Poluentes Químicos da Água , Purificação da Água , Poluentes Químicos da Água/química , Carvão Vegetal/química , Lacase/química , Purificação da Água/métodos , Adsorção , Pistacia/química , Preparações Farmacêuticas/química , Enzimas Imobilizadas/química , Águas Residuárias/química , Eliminação de Resíduos Líquidos/métodos , Diclofenaco/química , Diclofenaco/isolamento & purificação , Carbamazepina/química , Carbamazepina/isolamento & purificação
5.
Chemosphere ; 351: 141189, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38211782

RESUMO

The olive stone is a large waste product of the olive oil extraction industry. The present study investigates developing activated carbon from olive stone waste (OSAC) to remove pharmaceuticals from water. Different temperatures and olive stone: KOH ratios were studied. The OSAC produced at 750 °C and 1:3 ratio was found to have the highest porosity and surface area and was tested in the adsorption process. Diclofenac and ciprofloxacin were selected as model contaminants. The adsorption process was optimized with regards to OSAC dosage, pH, temperature, and initial concentration of adsorbate. The OSAC was found to be effective for a wide pH range (2-11) with an optimum dosage of 1 g/L at 25 °C. The pharmaceuticals were almost completely removed in 75 min. The adsorption was endothermic and followed first-order kinetics with physical mechanisms such as electrostatic possibly being the main driver. The optimum conditions were applied to test the removal of diclofenac and ciprofloxacin in synthetic water, lake water (Lake Balaton, Hungary) and secondary wastewater for seven cycles. There was little difference between the removal of the tested water matrices highlighting the potency of OSAC as an adsorbent for pharmaceutical removal in industrial applications. The removal dropped from >99% for the first cycle to 20-30% for the seventh cycle.


Assuntos
Olea , Poluentes Químicos da Água , Água , Diclofenaco , Poluentes Químicos da Água/análise , Concentração de Íons de Hidrogênio , Ciprofloxacina , Adsorção , Carvão Vegetal , Cinética , Preparações Farmacêuticas
6.
Environ Res ; 246: 118097, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38176629

RESUMO

This study examined the use of modified multiwall carbon nanotubes (M-MWCNTs) with immobilized laccase (L@M-MWCNTs) for removing ciprofloxacin (Cip), carbamazepine (Cbz), diclofenac (Dcf), benzo[a]pyrene (Bap), and anthracene (Ant) from different water samples. The synthesized materials were characterized using an array of advanced analytical techniques. The physical immobilization of laccase onto M-MWCNTs was confirmed through Scanning electron microscope (SEM)-dispersive X-ray spectroscopy (EDS) analysis and Brunner-Emmet-Teller (BET) surface area measurements. The specific surface area of M-MWCNTs decreased by 65% upon laccase immobilization. There was also an increase in nitrogen content seen by EDS analysis asserting successful immobilization. The results of Boehm titration and Fourier transform infrared (FTIR) exhibited an increase in acidic functional groups after laccase immobilization. L@M-MWCNTs storage for two months maintained 77.8%, 61.6%, and 57.6% of its initial activity for 4 °C, 25 °C, and 35 °C, respectively. In contrast, the free laccase exhibited 55.3%, 37.5%, and 23.5% of its initial activity at 4 °C, 25 °C, and 35 °C, respectively. MWCNTs improved storability and widened the working temperature range of laccase. The optimum removal conditions of studied pollutants were pH 5, 25 °C, and 1.6 g/L of M-MWCNTs. These parameters led to >90% removal of the targeted pollutants for four treatment cycles of both synthetic water and spiked lake water. L@M-MWCNTs demonstrated consistent removal of >90% for up to five cycles even with spiked wastewater. The adsorption was endothermic and followed Langmuir isotherm. Oxidation, dehydrogenation, hydroxylation, and ring cleavage seem to be the dominant degradation mechanisms.


Assuntos
Poluentes Ambientais , Nanotubos de Carbono , Poluentes Químicos da Água , Águas Residuárias , Nanotubos de Carbono/química , Água , Lacase/química , Lacase/metabolismo , Lagos , Poluentes Ambientais/análise , Poluentes Químicos da Água/análise , Cinética , Adsorção
7.
Heliyon ; 9(11): e21799, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-38034807

RESUMO

Efficient thermal insulation materials considerably lower power consumption for heating and cooling of buildings, which in turn minimises CO2 emissions and improves indoor comfort conditions. However, the selection of suitable insulation materials is governed by several factors, such as the environmental impact, health impact, cost and durability. Additionally, the disposal of used insulation materials is a major factor that affects the selection of materials because some materials could be very toxic for humans and the environment, such as asbestos-containing materials. Therefore, there is a continuous research effort, in both industry and academia, to develop sustainable and affordable insulation materials. In this context, this work aims at utilising the packing industry wastes (cardboard) to develop an eco-friendly insulation layer, which is a biodegradable material that can be disposed of safely after use. Experimentally, wasted cardboard was collected, cleaned, and soaked in water for 24 h. Then, the wet cardboard was minced and converted into past papers, then cast in square moulds and left in a ventilated oven at 75 °C to dry before de-moulding them. The produced layers were subjected to a wide range of tests, including thermal conductivity, acoustic insulation, infrared imaging and bending resistance. The obtained results showed the developed material has a good thermal and acoustic insulation performance. Thermally, the developed material had the lowest thermal conductivity (λ) (0.039 W/m.K) compared to the studied traditional materials. Additionally, it successfully decreased the noise level from 80 to about 58 dB, which was better than the efficiency of the commercial polyisocyanurate layer. However, the bending strength of the developed material was a major drawback because the material did not resist more than 0.6 MPa compared to 2.0 MPa for the commercial polyisocyanurate and 70.0 MPa for the wood boards. Therefore, it is recommended to investigate the possibility of strengthening the new material by adding fibres or cementitious materials.

8.
Sci Rep ; 13(1): 15852, 2023 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-37740043

RESUMO

A synergistic combination of electrocoagulation-electrooxidation (EC-EO) process was used in the current study to treat domestic greywater. The EC process consisted of an aluminium (Al) anode and an iron (Fe) cathode, and the EO process consisted of titanium with platinum coating mesh (Ti/Pt) as an anode and stainless steel as a cathode. The effect of operative variables, namely current density, pH, EC time and EO time, on the removal of chemical oxygen demand (COD), colour, turbidity, and total organic carbon (TOC) was studied and optimised using Response Surface Methodology (RSM). The results showed that although the pH affected the removal of all studied pollutants, it had more effect on turbidity removal with a contribution of 88.44%, while the current density had the main dominant effect on colour removal with a contribution of 73.59%. It was also found that at optimal operation conditions for a current density of 2.6 A, an initial pH of 4.67, an EC time of 31.67 min, and an EO time of 93.28 min led to a COD, colour, turbidity, and TOC removal rates of 96.1%, 97.5%, 90.9%, and 98%, respectively, which were close to the predicted results. The average operating cost and energy consumption for the removal of COD, colour, turbidity, and TOC were 0.014 $/m3 and 0.01 kWh/kg, 0.083 $/m3 and 0.008 kWh/kg, 0.075 $/m3 and 0.062 kWh/kg, and 0.105 $/m3 and 0.079 kWh/kg, respectively.

9.
Sci Rep ; 13(1): 13148, 2023 08 12.
Artigo em Inglês | MEDLINE | ID: mdl-37573363

RESUMO

A new green reactive adsorbent (calcium ferric oxide silica sand (CFO-SS)) made from wastepaper sludge ash and ferric ions was synthesised and shown to remove tetracycline antibiotics (TC) from contaminated water effectively. The synthesised sand was dried at 95 °C, and a series of batch and fixed bed experiments were performed to determine the optimum operating conditions. Results showed that the adsorption capacity of the CFO-SS increases with the concentration gradient between the solid and liquid phases. 0.3 g of the new adsorbent was proven sufficient to remove more than 90% of the TC at a pollutant dose of 50 mg/L in 50 mL of simulated groundwater with an agitation speed of 200 rpm for 3 h. The adsorption isotherm followed the Langmuir isotherm model, with a loading capacity of 21.96 mg/g at pH 7, while the Pseudo second-order model best described the absorption kinetics. The adsorption mechanisms proposed included electrostatic interaction, intraparticle diffusion, hydrogen bonding, and cation-π interactions. Characterisation investigations revealed that the newly precipitated oxides on silica sand play an essential role in TC adsorption support. In fixed-bed experiments, it was discovered that reducing the flow rate and inflow concentration of TC and increasing the sorbent mass significantly extended the lifetime of the produced sorbent in the packed column. The measured breakthrough curves were best fit with the Adams-Bohart and the Clark models, as they provided the highest square root number (R2) values. Finally, considering the efficacy of CFO-SS in TC adsorption performance, it can be noted that the novel synthesised reactive material is an efficient and environmentally friendly material for TC removal, and it presents a potential solution to resolving the challenge of TC-rich groundwater.


Assuntos
Poluentes Químicos da Água , Purificação da Água , Dióxido de Silício , Areia , Antibacterianos , Adsorção , Água , Tetraciclinas , Cinética , Tetraciclina , Concentração de Íons de Hidrogênio , Purificação da Água/métodos
10.
Sci Rep ; 13(1): 11933, 2023 07 24.
Artigo em Inglês | MEDLINE | ID: mdl-37488185

RESUMO

In this study, pomegranate peels (PPs) as an abundant fruit processing waste was used to produce cost-effective, eco-friendly, and high-quality activated carbon. The produced carbon (fossil free activated carbon) was used for immobilizing laccase to remove a range of emerging pollutants namely diclofenac, amoxicillin, carbamazepine, and ciprofloxacin from water and wastewater. The loaded activated carbon by laccase (LMPPs) and the unloaded one (MPPs) were characterized using advanced surface chemistry analysis techniques. MPPs was found to have a porous structure with a large surface area and an abundance of acidic functional groups. Laccase immobilization reduced surface area but added active degradation sites. The optimal immobilization parameters were determined as pH 4, 35 °C, and a laccase concentration of 2.5 mg/mL resulting in a 69.8% immobilization yield. The adsorption of the emerging pollutant onto MPPs is best characterized as a spontaneous endothermic process that adheres to the Langmuir isotherm and first-order kinetics. Using synergistic adsorption and enzymatic degradation, the target pollutants (50 mg/L) were eliminated in 2 h. In both water types, LMPPs outperformed MPPs. This study shows that pomegranate peels can effectively be harnessed as an enzyme carrier and adsorbent for the removal of emerging pollutants even from a complex sample matrix. The removal of contaminants from wastewater lasted five cycles, whereas it continued up to six cycles for water.


Assuntos
Punica granatum , Punica granatum/química , Resíduos Industriais , Poluentes Químicos da Água/química , Lactase/química , Lactase/metabolismo , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Carvão Vegetal/química , Águas Residuárias/química , Cinética , Estabilidade Enzimática
11.
RSC Adv ; 13(24): 16196-16205, 2023 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-37260710

RESUMO

This study investigates the effectiveness of using Iraqi clay as a low-permeability layer to prevent the migration of lead and nickel ions in groundwater-aquifers. Tests of batch operation have been conducted to determine the optimal conditions for removing Pb2+ ions, which were found to be 120 minutes of contact time, a pH of 5, 0.12 g of clay per 100 mL of solution, and an agitation of 250 rpm. These conditions resulted in a 90% removal efficiency for a 50 mg L-1 initial concentration of lead ions. To remove nickel ions with an efficiency of 80%, the optimal conditions were 60 minutes of contact time, a pH of 6, 12 g of clay per 100 mL of solution, and an agitation of 250 rpm. Several sorption models were evaluated, and the Langmuir formula was found to be the most effective. The highest sorption capacities were 1.75 and 137 mg g-1 for nickel and lead ions, respectively. The spread of metal ions was simulated using finite element analysis in the COMSOL multiphysics simulation software, taking into account the presence of a clay barrier. The results showed that the barrier creates low-discharge zones along the down-gradient of the barrier, reducing the rate of pollutant migration to protect the water sources.

12.
Environ Res ; 227: 115791, 2023 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-36997042

RESUMO

Recent Iraqi battles against ISIS in 2014 and 2015 resulted in the destruction or severe damage to several refineries' infrastructure. This, along with other factors, has led to the release and accumulation of a wide range of hazardous chemicals into the environment, for instance, polycyclic aromatic hydrocarbons (PAH). Thus, for the first time, a comprehensive 16 PAHs measurements campaign over the course of six months near the oil refineries along the Tigris River and its estuaries was investigated. The 16 PAHs concentrations in surface water and the sediments for the following oil refineries: Baiji, Kirkuk, Al-Siniyah, Qayyarah, Al-Kasak, Daura, South Refineries Company, and Maysan were examined. The overall findings indicated that the 16 PAHs concentrations ranged from 567.8 to 3750.7 ng/L for water and 5619.2-12795.0 ng/g for sediment. Water samples in South Refineries Company recorded the highest PAH concentrations while Baiji oil refinery registered the highest PAH concentrations in the sediment samples. The percentages of high molecular weight PAH (5-6 rings) in water and sediment samples were the highest, ranging from 49.41% to 81.67% and from 39.06% to 89.39% of total PAH for water and sediment, respectively. The majority of 16 PAHs measured in water and sediment samples of the Tigris River were derived from pyrogenic sources. Based on sediment quality guidelines (SQGs), most sites showed a possible effect range with occasional biological effects of most of the PAH concentrations in all sediments' samples. The calculated incremental lifetime cancer risk (ILCR) value was high risk with adverse health effects, including cancer.


Assuntos
Neoplasias , Hidrocarbonetos Policíclicos Aromáticos , Poluentes Químicos da Água , Humanos , Hidrocarbonetos Policíclicos Aromáticos/análise , Iraque , Rios/química , Poluentes Químicos da Água/análise , Sedimentos Geológicos , Monitoramento Ambiental/métodos , Medição de Risco , Água , Indústria de Petróleo e Gás , China
13.
Mar Pollut Bull ; 187: 114568, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36638718

RESUMO

This study presented for the first time a comprehensive measurement campaign of 16 PAHs along the Euphrates River for five months, in both water and sediment samples. Our study revealed that the PAHs contamination increased along the flow direction due to the increasing non-point pollution and the return flows of agriculture. The 5-6 rings PAHs were dominant in water and sediment samples with an average of 42 % and 50 %, respectively. The diagnostic ratios of PAHs suggest that the pollution of these compounds originated mainly from petroleum product combustions. The carcinogenic PAHs formed 46 % and 55 % of the total measured compounds in water and sediment samples, respectively, which highlights potential ecological and human health risks. Based on sediment quality guidelines (SQGs), most sites exhibit an effect range between low and medium. The calculated incremental lifetime cancer risk (ILCR) for adult and children were in the 10-2-10-3 range, which is 3-6-fold higher than what was reported in the literature. These observations call for urgent attention from environmental authorities of countries sharing this key water source in Western Asia.


Assuntos
Hidrocarbonetos Policíclicos Aromáticos , Poluentes Químicos da Água , Adulto , Criança , Humanos , Hidrocarbonetos Policíclicos Aromáticos/análise , Monitoramento Ambiental , Rios , Água , Poluentes Químicos da Água/análise , Sedimentos Geológicos , Medição de Risco , China
14.
Chemosphere ; 311(Pt 2): 137133, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36343736

RESUMO

In recent years, enzymatic remediation/biocatalysis has gained prominence for the bioremediation of recalcitrant chemicals. Laccase is one of the commonly investigated enzymes for bioremediation applications. There is a growing interest in immobilizing this enzyme onto adsorbents for achieving high pollutant removal through simultaneous adsorption and biodegradation. Due to the influence of the biomolecule-support interface on laccase activity and stability, it is crucial to functionalize the solid carrier prior to immobilization. Date stone (PDS), as an eco-friendly, low-cost, and effective natural adsorbent, was utilized as a carrier for laccase (fungus Trametes versicolor). After activating PDS through chemical treatments, the surface area increased by thirty-six-fold, and carbonyl groups became more prominent. Batch experiments were carried out for ketoprofen and aspirin biodegradation in aqueous solutions. After six cycles, the laccase maintained 54% of its original activity confirmed by oxidation tests of 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS). In addition, the storage, pH, and thermal stability of immobilized laccase on functionalized date stone (LFPDS) were found to be superior to that of free laccase, demonstrating its potential for ongoing applications. In the aqueous batch mode, this immobilized laccase system was used to degrade 25 mg L-1 of ketoprofen and aspirin, resulting in almost complete removal within 4 h of treatment. This study reveals that agricultural wastes such as date stone can successfully be valorized through simple activation techniques, and the final product can be used as an adsorbent and substrate for immobilization enzyme. The high efficiency of the LFPDS in removing ketoprofen and aspirin highlights the potential of this technology for removing pharmaceuticals and merits its continued development.


Assuntos
Cetoprofeno , Enzimas Imobilizadas/metabolismo , Lacase/metabolismo , Aspirina , Trametes
15.
Materials (Basel) ; 15(8)2022 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-35454648

RESUMO

The shortage of natural aggregates has compelled the developers to devote their efforts to finding alternative aggregates. On the other hand, demolition waste from old constructions creates huge land acquisition problems and environmental pollution. Both these problems can be solved by recycling waste materials. The current study aims to use recycled brick aggregates (RBA) to develop eco-friendly pervious concrete (PC) and investigate the new concrete's structural performance and pore structure distributions. Through laboratory testing and image processing techniques, the effects of replacement ratio (0%, 20%, 40%, 60%, 80%, and 100%) and particle size (4.75 mm, 9.5 mm, and 12.5 mm) on both structural performance and pore feature were analyzed. The obtained results showed that the smallest aggregate size (size = 4.75 mm) provides the best strength compared to the large sizes. The image analysis method has shown the average pore sizes of PC mixes made with smaller aggregates (size = 4.75 mm) as 1.8-2 mm, whereas the mixes prepared with an aggregate size of 9.5 mm and 12.5 mm can provide pore sizes of 2.9-3.1 mm and 3.7-4.2 mm, respectively. In summary, the results confirmed that 40-60% of the natural aggregates could be replaced with RBA without influencing both strength and pore features.

16.
Molecules ; 26(19)2021 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-34641456

RESUMO

The provision of safe water for people is a human right; historically, a major number of people depend on groundwater as a source of water for their needs, such as agricultural, industrial or human activities. Water resources have recently been affected by organic and/or inorganic contaminants as a result of population growth and increased anthropogenic activity, soil leaching and pollution. Water resource remediation has become a serious environmental concern, since it has a direct impact on many aspects of people's lives. For decades, the pump-and-treat method has been considered the predominant treatment process for the remediation of contaminated groundwater with organic and inorganic contaminants. On the other side, this technique missed sustainability and the new concept of using renewable energy. Permeable reactive barriers (PRBs) have been implemented as an alternative to conventional pump-and-treat systems for remediating polluted groundwater because of their effectiveness and ease of implementation. In this paper, a review of the importance of groundwater, contamination and biological, physical as well as chemical remediation techniques have been discussed. In this review, the principles of the permeable reactive barrier's use as a remediation technique have been introduced along with commonly used reactive materials and the recent applications of the permeable reactive barrier in the remediation of different contaminants, such as heavy metals, chlorinated solvents and pesticides. This paper also discusses the characteristics of reactive media and contaminants' uptake mechanisms. Finally, remediation isotherms, the breakthrough curves and kinetic sorption models are also being presented. It has been found that groundwater could be contaminated by different pollutants and must be remediated to fit human, agricultural and industrial needs. The PRB technique is an efficient treatment process that is an inexpensive alternative for the pump-and-treat procedure and represents a promising technique to treat groundwater pollution.

17.
Environ Dev Sustain ; 23(9): 12738-12760, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33558801

RESUMO

The outbreak of COVID-19 has made a global catastrophic situation that caused 1,039,406 deaths out of 35,347,404 infections, and it will also cause significant socio-economic losses with poverty increasing from 17.1 to 25.9%. Although the spreading rate of COVID-19 is very high on October 6, 2020, the death rate is still less than 2.94%. Nonetheless, this review article shows that the lockdown has induced numerous positive impacts on the environment and on energy consumption. For instance, the lockdown has decreased the electricity demand by 30% in Italy, India, Germany, and the USA, and by 12-20% in France, Germany, Spain, India, and the UK. Additionally, the expenditure of the fuel supply has been decreased by 4% in 2020 as compared to the previous years (2012-2019). In particular, The global demand for coal fuel has been reduced by 8% in March and April 2020 as compared to the same time in 2019. In terms of harmful emissions, the lockdowns reduced the emissions of nitrous oxides by 20-30% in China, Italy, France, Spain, and by 77.3% in São Paulo, Brazil. Similarly, the particulate matter level has been reduced from 5-15% in Western Europe, to 200% in New Delhi, India, which in turn has enhanced the air quality in a never-seen manner in recent times. In some places, such as New York, USA, CO2 emission was also reduced by 5-10%. The water quality, in several polluted areas, has also been remarkably enhanced, for example, the dissolved oxygen content in the Ganga River, India, has increased by about 80%. Traffic congestion has also been reduced worldwide, and in some areas, it has been reduced by 50%, such as New York and Los Angeles, USA. Overall, while the COVID-19 pandemic has shrinked the global economy by 13-32%, the pandemic has also clearly benefited to other sectors, which must be considered as the spotlight for the permanent revival of the global ecosystem.

18.
Water Sci Technol ; 83(1): 77-89, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33460408

RESUMO

Phosphate in freshwater possesses significant effects on both quality of water and human health. Hence, many treatment methods have been used to remove phosphate from water/wastewaters, such as biological and electrochemical methods. Recent researches demonstrated that adsorption approaches are convenient solutions for water/wastewater remediation from phosphate. Thus, the present study employs industrial by-products (bottom ash (BA)), as a cost-effective and eco-friendly alternative, to remediate water from phosphate in the presence of competitor ions (humic acid). This study was initiated by characterising the chemical and physical properties of the BA, sample, then Central Composite Design (CCD) was utilised to design the required batch experiments and to model the influence of solution temperature (ST), humic acid concentration (HAC), pH of the solution (PoS) and doses of adsorbent (DoA) on the performance of the BA. The Langmuir model was utilised to assess the adsorption process. The outcomes of this study evidenced that the BA removed 83.8% of 5.0 mg/l of phosphates at ST, HAC, PoS and DoA 35 °C, 20 mg/L, 5 and 55 g/L, respectively. The isotherm study indicated a good affinity between BA and phosphate. Additionally, the developed model, using the CCD, reliably simulated the removal of phosphates using BA (R2 = 0.99).


Assuntos
Fosfatos , Poluentes Químicos da Água , Adsorção , Ânions , Cinza de Carvão , Humanos , Concentração de Íons de Hidrogênio , Cinética , Água , Poluentes Químicos da Água/análise
19.
Data Brief ; 31: 105961, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32671159

RESUMO

The development in the construction sector and population growth requires an increase in the consumption of construction materials, mainly concrete. Cement is the binder in concrete, so increasing cement production will increase the energy consumed, as well as in the emission of carbon dioxide. This harmful effect of the environment led to the search for alternative materials for cement, as the waste or by-products of other industries is a promising solution in this case. Among these common materials are ground granulated blast furnace slag (GGBS) and cement kiln dust (CKD). This dataset describes the compressive strength and ultrasonic pulse velocity of mortar consisted of high content of GGBS and CKD combinations as a partial substitute for cement (up to 80%) at the ages of 1, 2, 3, 7, 14, 21, 28, 56, 90 and 550 days. This dataset can help the researchers to understand the behaviour of GGBS and CKD in high replacement levels for cement during early (1 day) and later ages (550 days). According to this understanding, the authors believe that the data available here can be used to produce more environmentally friendly mortar or concrete mixtures by significantly reducing the amount of cement used by replacing it with waste or by-products of other industries.

20.
J Lipids ; 2020: 5704752, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32395348

RESUMO

[This corrects the article DOI: 10.1155/2019/5729498.].

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA