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1.
Environ Res ; 241: 117627, 2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-37967700

RESUMO

Arsenic is the hazardous species and still is the global challenge in water treatment. Apatite soil is highly rich in arsenic species, and its mining presents various environmental issues. In this study, novel magnetic microbeads as adsorbent were developed for the elimination of hazardous arsenic ions from apatite soil's aqueous leachate before discharging into environment. The microbeads were fabricated with metformin polyether sulfone after being doped with zero-valent iron (Met-PES/ZVI). The microbeads were characterized using various techniques, including FTIR, XRD, SEM-EDX, VSM, and zeta potential analysis. The developed adsorbent demonstrated a significant elimination in arsenic in aqueous leachate, achieving 82.39% removal after 30 min of contact time, which further increased to 90% after 180 min of shaking. The kinetic analysis revealed that the pseudo-second-order model best represented the adsorption process. The intra-particle diffusion model indicated that the adsorption occurred in two steps. The Langmuir model (R2 = 0.991), with a maximum adsorption capacity of 188.679 mg g-1, was discovered to be the best fit for the experimental data as compared Freundlich model (R2 = 0.981). According to the thermodynamic outcome (ΔG < -20 kJ/mol), the adsorption process was spontaneous and involved physisorption. These findings demonstrate the potential of magnetic Met-PES/ZVI microbeads as an efficient adsorbent for the removal of arsenic from apatite soil aqueous leachate.


Assuntos
Arsênio , Poluentes Químicos da Água , Purificação da Água , Arsênio/análise , Solo , Cinética , Microesferas , Termodinâmica , Adsorção , Fenômenos Magnéticos , Poluentes Químicos da Água/análise , Concentração de Íons de Hidrogênio , Purificação da Água/métodos
2.
Environ Res ; 246: 118027, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38159670

RESUMO

The study explores co-gasification of palm oil decanter cake and alum sludge, investigating the correlation between input variables and syngas production. Operating variables, including temperature (700-900 °C), air flow rate (10-30 mL/min), and particle size (0.25-2 mm), were optimized to maximize syngas production using air as the gasification agent in a fixed bed horizontal tube furnace reactor. Response Surface Methodology with the Box-Behnken design was used employed for optimization. Fourier Transformed Infra-Red (FTIR) and Field Emission Scanning Electron Microscopic (FESEM) analyses were used to analyze the char residue. The results showed that temperature and particle size have positive effects, while air flow rate has a negative effect on the syngas yield. The optimal CO + H2 composition of 39.48 vol% was achieved at 900 °C, 10 mL/min air flow rate, and 2 mm particle size. FTIR analysis confirmed the absence of C─Cl bonds and the emergence of Si─O bonds in the optimized char residue, distinguishing it from the raw sample. FESEM analysis revealed a rich porous structure in the optimized char residue, with the presence of calcium carbonate (CaCO3) and aluminosilicates. These findings provide valuable insights for sustainable energy production from biomass wastes.


Assuntos
Compostos de Alúmen , Gases , Esgotos , Gases/química , Óleo de Palmeira , Temperatura , Biomassa
3.
Environ Res ; 229: 115915, 2023 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-37076030

RESUMO

Pharmaceutical compounds are among the environmental contaminants that cause pollution of water resources and thereby threaten ecosystem services and the environmental health of the past decades. Antibiotics are categorized as emerging pollutants due to their persistence in the environment that are difficult to remove by conventional wastewater treatment. Ceftriaxone is one of the multiple antibiotics whose removal from wastewater has not been fully investigated. In this study, TiO2/MgO (5% MgO) the efficiency of photocatalyst nanoparticles in removing ceftriaxone was analyzed by XRD, FTIR, UV-Vis, BET, EDS, and FESEM. The results were compared with UVC, TiO2/UVC, and H2O2/UVC photolysis processes to evaluate the effectiveness of the selected methods. Based on these results, the highest removal efficiency of ceftriaxone from synthetic wastewater was 93.7% at the concentration of 400 mg/L using TiO2/MgO nano photocatalyst with an HRT of 120 min. This study confirmed that TiO2/MgO photocatalyst nanoparticles efficiently removed ceftriaxone from wastewater. Future studies should focus on the optimization of reactor conditions and improvements of the reactor design to obtain higher removal of ceftriaxone from wastewater.


Assuntos
Águas Residuárias , Poluentes Químicos da Água , Raios Ultravioleta , Óxido de Magnésio , Ceftriaxona , Peróxido de Hidrogênio , Ecossistema , Titânio , Antibacterianos , Catálise
4.
Environ Res ; 216(Pt 1): 114416, 2023 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-36181897

RESUMO

In this study, an adsorbent made of alginate (Alg) caged magnesium sulfide nanoparticles (MgS) microbeads were used to treat lead ions (Pb2+ ions). The MgS nanoparticles were synthesized at low temperatures, and Alg@MgS hydrogel microbeads were made by the ion exchange process of the composite materials. The newly fabricated Alg@MgS was characterized by XRD, SEM, and FT-IR. The adsorption conditions were optimized for the maximum removal of Pb2+ ions by adjusting several physicochemical parameters, including pH, initial concentration of lead ions, Alg/MgS dosage, reaction temperature, equilibration time, and the presence of co-ions. This is accomplished by removing the maximum amount of Pb2+ ions. Moreover, the adsorbent utilized more than six times with a substantial amount (not less than 60%) of Pb2+ ions was eliminated. Considering the ability of sodium alginate (SA) for excellent metal chelation and controlled nanosized pore structure, the adsorption equilibrium of Alg@MgS can be reached in 60 min, and the highest adsorption capacity for Pb2+ was 84.7 mg/g. The sorption mechanism was explored by employing several isotherms. It was found that the Freundlich model fits the adsorption process quite accurately. The pseudo-second-order model adequately described the adsorption kinetics.


Assuntos
Nanopartículas , Poluentes Químicos da Água , Purificação da Água , Alginatos/química , Águas Residuárias , Magnésio , Microesferas , Chumbo , Poluentes Químicos da Água/análise , Espectroscopia de Infravermelho com Transformada de Fourier , Adsorção , Cinética , Sulfetos , Concentração de Íons de Hidrogênio
5.
Environ Res ; 204(Pt A): 111959, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34474032

RESUMO

In this study, the new lanthanum sulfide nanoparticle (La2S3) was synthesized and incorporated onto magnetic graphene oxide (MGO) sheets surface to produce potential adsorbent (MGO@LaS) for efficient removal of lead ions (Pb2+) from wastewater. The synthesized MGO@LaS adsorbent was characterized using Fourier transform infrared spectroscopy, field emission scanning electron microscopy and energy-dispersive X-ray spectroscopy. The effective parameters on the adsorption process including solution pH (~5), adsorbent dosage (20 mg), contact time (40 min), initial Pb2+ concentration and temperature were studied. The removal efficiency was obtained >95% for lead ions at pH 5 with 20 mg adsorbent. To validate the adsorption rate and mechanism, the kinetic and thermodynamic models were studied based on experimental data. The Langmuir isotherm model was best fitted to initial equilibrium concentration with a maximum adsorption capacity of 123.46 mg/g. This indicated a monolayer adsorption pattern for Pb2+ ions over MGO@LaS. The pseudo-second-order as the kinetic model was best fitted to describe the adsorption rate due to high R2 > 0.999 as compared first-order. A thermodynamic model suggested a chemisorption and physisorption adsorption mechanism for Pb2+ ions uptake into MGO@LaS at different temperatures; ΔG° < -5.99 kJ mol-1 at 20 °C and ΔG° -18.2 kJ mol-1 at 45 °C. The obtained results showed that the novel nanocomposite (MGO@LaS) can be used as an alternative adsorbent in wastewater treatment.


Assuntos
Nanopartículas , Poluentes Químicos da Água , Adsorção , Grafite , Concentração de Íons de Hidrogênio , Cinética , Lantânio , Chumbo , Fenômenos Magnéticos , Espectroscopia de Infravermelho com Transformada de Fourier , Sulfetos , Termodinâmica , Águas Residuárias , Poluentes Químicos da Água/análise
6.
Environ Res ; 214(Pt 2): 113831, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-35841973

RESUMO

The current study presents a viable and straightforward method for synthesizing titanium lanthanum three oxide nanoparticles (TiLa) and their decoration onto the ferrous graphene oxide sheets to produce FeGO-TiLa as efficient magnetic adsorbent. Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and vibration sample magnetometer (VSM) were used to evaluate the physical and chemical properties of the produced nanocomposites. The FeGO-TiLa was used to enhance the removal of lead ions from aqueous solution. The FeGO-TiLa nanocomposite exhibited a much higher removal efficiency (93%) for lead ions than pure TiLa nanoparticles (81%) and magnetic graphene oxide (74%). The influence of FeGO-TiLa dosage, contact time, solution pH, solution temperature, and starting quantity on the lead ions was evaluated and adjusted. The investigations demonstrated that a pH 6 with 40 mg adsorbent resulted in >91% removal of lead ions at ambient temperature after 120 min. Isotherm models were used to analyze experimental results, and Langmuir model fitted the data well as compared Freundlich model with a maximum adsorption capacity of 109.89 mg g-1. Kinetic and studies are performed the lead adsorption over FeGO-TiLa follow pseudo-second-order rate. Langmuir and Free energy suggested the lead ions uptake with FeGO-TiLa was monolayer and physical adsorption mechnaism, respectively. Finally, the FeGO-TiLa nanocompoiste can be used as an alternative adsorbent for water remediation.


Assuntos
Nanocompostos , Poluentes Químicos da Água , Adsorção , Grafite , Concentração de Íons de Hidrogênio , Íons , Cinética , Lantânio , Chumbo , Fenômenos Magnéticos , Nanocompostos/química , Óxidos , Espectroscopia de Infravermelho com Transformada de Fourier , Titânio , Água , Poluentes Químicos da Água/análise
7.
Environ Res ; 212(Pt B): 113164, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35398078

RESUMO

Metal-organic frameworks (MOFs) are a promising class of porous nanomaterials in the field of environmental remediation. Ni-MOF and Fe-MOF were chosen for their advantages such as structural robustness and ease of synthesis route. The structure of prepared MOFs was characterized using FE-SEM, XRD, FTIR, and N2 adsorption-desorption. The efficiency of MOFs to remove organic model contaminants (anionic Alizarin Red S (ARS) and cationic malachite green (MG) and inorganic fluoride was studied. Fe-MOF and Ni-MOF adsorbed 67, 88, 6% and 32, 5, and 9% of fluoride, ARS, and MG, respectively. Further study on ARS adsorption by Fe-MOF showed that the removal efficiency was high in a wide range of pH from 3 to 9. Moreover, dye removal was directly increased by adsorbent mass (0.1-0.75 g/L) and decreased by ARS concentration (25-100 mg/L). The pseudo-first-order kinetic model and Langmuir isotherm model with a qmax of 176.68 mg/g described the experimental data well. The separation factor, KL, was in the range of 0-1, which means the adsorption process was favorable. In conclusion, Fe-MOF showed remarkable adsorption of organic and inorganic model contaminants.


Assuntos
Estruturas Metalorgânicas , Poluentes Químicos da Água , Adsorção , Fluoretos , Ferro/química , Níquel , Poluentes Químicos da Água/química
8.
Environ Res ; 207: 112209, 2022 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-34653412

RESUMO

The present study reports the successful functionalization/magnetization of bio-polymer to produce chitosan-magnetic graphene oxide grafted polyaniline doped with cobalt oxide (ChMGOP-Co3O4). Analytical techniques furrier transform infra-red (FT-IR), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS) were used to confirm the formation of ChMGOP-Co3O4. The effects of several experimental factors (solution pH, adsorbent dosage and coexisting ions) on the uptake of As(V) ions using ChMGOP-Co3O4 were examined through batch experiments. As(V) removal process was validated by experimentally and theoretically investigating the adsorption capacity, rate, and thermal effects. Thermodynamic parameters such as free energy (ΔG°), entropy (ΔS°) and enthalpy (ΔH°) were also calculated and were used to explain the mechanism of adsorption. Based on the results, the sorbent showed a high adsorption capacities (90.91 mg/g) at favorable neutral pH and superior removal efficiencies as high as 89% within 50 min. In addition, the adsorption isotherm followed the Langmuir isotherm in compare to the Freundlich, due to its higher R2 value (0.992 < 0.941). Meanwhile, the kinetic data revealed that the of As(V) adsorption was controlled by pseudo-second-order. Overall, the adsorption mechanism studies revealed a spontaneous endothermic nature with predominance of physisorption over chemisorption. This study indicated that ChMGOP-Co3O4 is an exceptional novel adsorbent material for the efficient isolation of As(V) from aqueous media.


Assuntos
Arsênio , Quitosana , Grafite , Poluentes Químicos da Água , Purificação da Água , Adsorção , Compostos de Anilina , Arsênio/química , Quitosana/química , Cobalto , Grafite/química , Concentração de Íons de Hidrogênio , Cinética , Fenômenos Magnéticos , Óxidos , Espectroscopia de Infravermelho com Transformada de Fourier , Termodinâmica , Água/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos
9.
Environ Res ; 214(Pt 3): 114026, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-35977588

RESUMO

Azithromycin (AZM), an antibacterial considered one of the most consumed drugs, especially during the period against the Covid 19 pandemic, and it is one of the persistent contaminants that can be released into aquatic ecosystems. The purpose of this study is to determine the efficacy of a Fenton-like process (chlorine/iron) for the degradation of AZM in an aqueous medium by determining the impact of several factors (the initial concentration of (FeSO4, NaClO, pollutant), and the initial pH) on the degradation rate. The Response Surface Methodology (RSM) based on the Box-Wilson design as well as the Artificial Neural Network (ANN) modeling combined with a genetic algorithm (GA) approaches were used to determine the optimal levels of the selected variables and the optimal rate of degradation. The quadratic model of multi-linear regression developed indicated that the optimal conditions were a concentration of chlorine of 600 µM, the concentration of AZM is 32.8 mg/L, the mass of the catalyst FeSO4 is 3.5 mg and a pH of 2.5, these optimal values gave a predicted and experimental yield of 64.05% and 70% respectively, the lack of fit test in RSM modeling (F0 = 3.31 which is inferior to Fcritic (0.05, 10.4) = 5.96) indicates that the true regression function is not linear therefore, the ANN-GA modeling as non-linear regression indicated that the optimal conditions were a concentration of chlorine of 256 µM, the concentration of AZM is 5 mg/L, the mass of the catalyst FeSO4 is 9.5 mg and a pH of 2.8, these optimal values gave a predicted and experimental yield of 79.69% and close to 80% respectively, Furthermore, biotoxicity tests were conducted to confirm the performance of our process using bio-indicators called daphnia (Daphnia magna), which demonstrated the efficacy of the like-Fenton process after 4 h of degradation.


Assuntos
Tratamento Farmacológico da COVID-19 , Daphnia , Animais , Azitromicina/toxicidade , Cloro/toxicidade , Ecossistema , Redes Neurais de Computação , Água
10.
J Environ Manage ; 320: 115772, 2022 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-35944317

RESUMO

Palm oil mill waste has a complex cellulosic structure, is rich in nutrients, and provides a habitat for diverse microbial communities. Current research focuses on how the microbiota and organic components interact during the degradation of this type of waste. Some recent studies have described the microbial communities present in different biodegradation processes of palm oil mill waste, identifying the dominant bacteria/fungi responsible for breaking down the cellulosic components. However, understanding the degradation process's mechanisms is vital to eliminating the need for further pretreatment of lignocellulosic compounds in the waste mixture and facilitating the commercialization of palm oil mill waste treatment technology. Thus, the present work aims to review microbial community dynamics via three biological treatment systems comprehensively: composting, vermicomposting, and dark fermentation, to understand how inspiration from nature can further enhance existing degradation processes. The information presented could be used as an umbrella to current research on biological treatment processes and specific research on the bioaugmentation of indigenous microbial consortia isolated during the biological degradation of palm oil mill waste.


Assuntos
Compostagem , Bactérias/metabolismo , Biodegradação Ambiental , Resíduos Industriais/análise , Consórcios Microbianos , Óleo de Palmeira/metabolismo
11.
Molecules ; 27(24)2022 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-36557973

RESUMO

In this study, a novel biomass adsorbent based on activated carbon incorporated with sulfur-based binary metal oxides layered nanoparticles (SML-AC), including sulfur (S2), manganese (Mn), and tin (Sn) oxide synthesized via the solvothermal method. The newly synthesized SML-AC was studied using FTIR, FESEM, EDX, and BET to determine its functional groups, surface morphology, and elemental composition. Hence, the BET was performed with an appropriate specific surface area for raw AC (356 m2·g−1) and modified AC-SML (195 m2·g−1). To prepare water samples for ICP-OES analysis, the suggested nanocomposite was used as an efficient adsorbent to remove lead (Pb2+), cadmium (Cd2+), chromium (Cr3+), and vanadium (V5+) from oil-rich regions. As the chemical structure of metal ions is influenced by solution pH, this parameter was considered experimentally, and pH 4, dosage 50 mg, and time 120 min were found to be the best with high capacity for all adsorbates. At different experimental conditions, the AC-SML provided a satisfactory adsorption capacity of 37.03−90.09 mg·g−1 for Cd2+, Pb2+, Cr3+, and V5+ ions. The adsorption experiment was explored, and the method was fitted with the Langmuir model (R2 = 0.99) as compared to the Freundlich model (R2 = 0.91). The kinetic models and free energy (<0.45 KJ·mol−1) parameters demonstrated that the adsorption rate is limited with pseudo-second order (R2 = 0.99) under the physical adsorption mechanism, respectively. Finally, the study demonstrated that the AC-SML nanocomposite is recyclable at least five times in the continuous adsorption−desorption of metal ions.


Assuntos
Metais Pesados , Punica granatum , Poluentes Químicos da Água , Cádmio/análise , Carvão Vegetal/química , Óxidos de Enxofre , Chumbo , Metais Pesados/análise , Óxidos , Adsorção , Cinética , Poluentes Químicos da Água/química , Íons , Concentração de Íons de Hidrogênio
12.
Environ Res ; 201: 111588, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34175289

RESUMO

In this study, magnetic sporopollenin supported cyanocalixarene (MSP-CyCalix) nanocomposite was synthesized and introduced as an adsorbent material for the removal of pesticides from aqueous media. MSP-CyCalix was characterized by different analytical techniques FTIR, SEM, EDX, BET, VSMand TEM. Chlorpyrifos and hexaconazole pesticides were chosen as model analytes solutions for testing the adsorption efficiency of MSP-CyCalix adsorbent. The adsorption results showed that the incorporated cyano functional groups significantly increased the chemical reactivity and adsorption capacity for pesticides. To obtain the highest possible performance, experimental parameters such as pH, salt, dosage and time were optimized. Adsorption kinetics and isotherms models showed that pesticide adsorption process was well fitted with the pseudo-second-order and Langmuir models with a maximum adsorption capacity of 13.88 mg g-1 and 12.34 mg g-1 and a removal efficiency of >90% for both pesticides. Lastly, MSP-CyCalix maintained a removal efficiency of >80% for ten cycles and 60% after the eleventh cycles of usage. The results proved that MSP-CyCalix nanocomposite can be used as an efficient adsorbent for the removal of pesticide residues from water.


Assuntos
Praguicidas , Biopolímeros , Carotenoides , Cinética , Fenômenos Magnéticos , Água
13.
J Environ Manage ; 285: 112174, 2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-33607566

RESUMO

Chromium (Cr) is a trace element critical to human health and well-being. In the last few decades, its contamination, especially hexavalent chromium [Cr(VI)] form in both terrestrial and aquatic ecosystems, has amplified as a result of various anthropogenic activities. Chromium pollution is a significant environmental threat, severely impacting our environment and natural resources, especially water and soil. Excessive exposure could lead to higher levels of accumulation in human and animal tissues, leading to toxic and detrimental health effects. Several studies have shown that chromium is a toxic element that negatively affects plant metabolic activities, hampering crop growth and yield and reducing vegetable and grain quality. Thus, it must be monitored in water, soil, and crop production system. Various useful and practical remediation technologies have been emerging in regulating chromium in water, soil, and other resources. A sustainable remediation approach must be adopted to balance the environment and nature.


Assuntos
Recuperação e Remediação Ambiental , Poluentes do Solo , Animais , Cromo/análise , Ecossistema , Saúde Ambiental , Humanos , Solo , Poluentes do Solo/análise
14.
Regul Toxicol Pharmacol ; 106: 68-80, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31028799

RESUMO

Fluoride (F-), a harmful compound if present in high concentration, is typically found in groundwater. It is important to investigate the F- concentrations in groundwaters of areas where individuals use groundwater for drinking purposes. The objectives of this study were: (a) to estimate the F- exposure, and (b) to assess the non-carcinogenic risk through consumption of groundwater among urban population (different age groups) of Agra city. A total of 28 groundwater samples were collected from Agra city in May 2016, which comprised 22 samples from hand pump and 6 samples from tube wells from shallow aquifers at different sites. The F- concentrations varied from 0.90 to 4.12 mg/L with an average value of 1.88 mg/L. The results obtained reveal that about 64% of the samples exceeded the F- permissible limit of 1.5 mg/L. Nevertheless, 32% of the samples were well within the WHO drinking water guidelines and 3.5% of the samples from the groundwater were below the 1.0 mg/L threshold. The maximum estimated exposure doses were 0.69, 0.31 and 0.12 mg/kg/day for infants, children and adults, respectively. A dental fluorosis becomes evident when the results obtained are compared with an oral reference dose of 0.06 mg/kg/day. The hazard quotient (HQ) was found to be more than 1 for infants and children in all the studied areas which indicates that young consumers are more vulnerable to non-carcinogenic risk due to exposure of F-. On the other hand, the adults at about 71% of the sampled sites may be victims of non-carcinogenic risk. From the results obtained in this study, it is recommended that there be implementation of the appropriate remediation for defluoridation of water to circumvent the population from the probable health risks of F-.


Assuntos
Monitoramento Ambiental , Fluoretos/análise , Água Subterrânea/química , Poluentes Químicos da Água/análise , Administração Oral , Criança , Pré-Escolar , Fluoretos/administração & dosagem , Fluoretos/efeitos adversos , Humanos , Índia , Lactente , Recém-Nascido , Medição de Risco , Poluentes Químicos da Água/administração & dosagem , Poluentes Químicos da Água/efeitos adversos
15.
Ecotoxicol Environ Saf ; 182: 109362, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31254856

RESUMO

In low concentration, fluoride is considered a necessary compound for human health. Exposure to high concentrations of fluoride is the reason for a serious disease called fluorosis. Fluorosis is categorized as Skeletal and Dental fluorosis. Several Asian countries, such as India, face contamination of water resources with fluoride. In this study, a comprehensive overview on fluoride contamination in Asian water resources has been presented. Since water contamination with fluoride in India is higher than other Asian countries, a separate section was dedicated to review published articles on fluoride contamination in this country. The status of health effects in Asian countries was another topic that was reviewed in this study. The effects of fluoride on human organs/systems such as urinary, renal, endocrine, gastrointestinal, cardiovascular, brain, and reproductive systems were another topic that was reviewed in this study. Different methods to remove fluoride from water such as reverse osmosis, electrocoagulation, nanofiltration, adsorption, ion-exchange and precipitation/coagulation were introduced in this study. Although several studies have been carried out on contamination of water resources with fluoride, the situation of water contamination with fluoride and newly developed technology to remove fluoride from water in Asian countries has not been reviewed. Therefore, this review is focused on these issues: 1) The status of fluoride contamination in Asian countries, 2) health effects of fluoride contamination in drinking water in Asia, and 3) the existing current technologies for defluoridation in Asia.


Assuntos
Fluoretos/análise , Água Subterrânea/química , Poluentes Químicos da Água/análise , Adsorção , Ásia/epidemiologia , Água Potável , Recuperação e Remediação Ambiental , Filtração , Fluorose Dentária/epidemiologia , Trato Gastrointestinal/química , Humanos , Índia , Desenvolvimento Industrial , Rim/química , Poluição da Água , Recursos Hídricos
16.
Mikrochim Acta ; 186(8): 578, 2019 07 26.
Artigo em Inglês | MEDLINE | ID: mdl-31350596

RESUMO

This review (with 168 refs) summarizes the progress that has been made on the field of microextraction of heavy metal ions using carbonaceous materials. Following an introduction into the features of such materials, we discuss the various kinds of sorption-based microextraction techniques (like solid phase extraction, micro solid phase extraction, solid phase microextraction, magnetic solid phase extraction, and dispersive solid phase extraction). The next section covers specific methods based on the use of carbon-based adsorbents (with subsections on uses of carbon nanotubes, graphene, fullerenes, activated carbon, carbon nanohorns, carbon nanofibers, graphitic carbon nitride, and their composites). The concluding section addresses current challenges, and gives an outlook on potential future trends. Graphical abstract Schematic of the variety of applications of carbonaceous sorbents in sorptive extraction methods including SPE, SPME, SBSE, DSPE, µSPE, D-µSPE, and MSPE for the extraction and enrichment of different heavy metals.

17.
J Environ Manage ; 228: 13-19, 2018 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-30212670

RESUMO

For decades, water treatment plants in Malaysia have widely employed aluminium-based coagulant for the removal of colloidal particles in surface water. This generates huge amount of by-product, known as sludge that is either reused for land applications or disposed to landfills. As sludge contains high concentration of aluminium, both can pose severe environmental issues. Therefore, this study explored the potential to recover aluminium from water treatment sludge using acid leaching process. The evaluation of aluminium recovery efficiency was conducted in two phases. The first phase used the one factor at a time (OFAT) approach to study the effects of acid concentration, solid to liquid ratio, temperature and heating time. Meanwhile, second phase emphasized on the optimization of aluminium recovery using Response Surface Methodology (RSM). OFAT results indicated that aluminium recovery increased with the rising temperature and heating time. Acid concentration and solid to liquid ratio, however, showed an initial increment followed by reduction of recovery with increasing concentration and ratio. Due to the solidification of sludge when acid concentration exceeded 4 M, this variable was fixed in the optimization study. RSM predicted that aluminium recovery can achieve 70.3% at optimal values of 4 M, 20.9%, 90 °C and 4.4 h of acid concentration, solid to liquid ratio, temperature and heating time, respectively. Experimental validation demonstrated a recovery of 68.8 ±â€¯0.3%. The small discrepancy of 2.2 ±â€¯0.4% between predicted and validated recovery suggests that RSM was a suitable tool in optimizing aluminium recovery conditions for water treatment sludge.


Assuntos
Alumínio/isolamento & purificação , Esgotos/química , Água/química , Temperatura , Purificação da Água/métodos
18.
Int J Phytoremediation ; 19(5): 413-424, 2017 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-27748626

RESUMO

Artificial neural networks (ANNs) have been widely used to solve the problems because of their reliable, robust, and salient characteristics in capturing the nonlinear relationships between variables in complex systems. In this study, ANN was applied for modeling of Chemical Oxygen Demand (COD) and biodegradable organic matter (BOD) removal from palm oil mill secondary effluent (POMSE) by vetiver system. The independent variable, including POMSE concentration, vetiver slips density, and removal time, has been considered as input parameters to optimize the network, while the removal percentage of COD and BOD were selected as output. To determine the number of hidden layer nodes, the root mean squared error of testing set was minimized, and the topologies of the algorithms were compared by coefficient of determination and absolute average deviation. The comparison indicated that the quick propagation (QP) algorithm had minimum root mean squared error and absolute average deviation, and maximum coefficient of determination. The importance values of the variables was included vetiver slips density with 42.41%, time with 29.8%, and the POMSE concentration with 27.79%, which showed none of them, is negligible. Results show that the ANN has great potential ability in prediction of COD and BOD removal from POMSE with residual standard error (RSE) of less than 0.45%.


Assuntos
Vetiveria/metabolismo , Recuperação e Remediação Ambiental/métodos , Resíduos Industriais/análise , Redes Neurais de Computação , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/metabolismo , Biodegradação Ambiental , Análise da Demanda Biológica de Oxigênio , Recuperação e Remediação Ambiental/instrumentação , Malásia , Indústria Manufatureira , Óleo de Palmeira , Óleos de Plantas , Eliminação de Resíduos Líquidos/instrumentação
19.
Int J Phytoremediation ; 18(7): 679-85, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26684985

RESUMO

In this study, water hyacinth (Eichhornia crassipes) was used to treat domestic wastewater. Ten organic and inorganic parameters were monitored in three weeks for water purification. The six chemical, biological and physical parameters included Dissolved Oxygen (DO), Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Ammoniacal Nitrogen (NH3-N), Total Suspended Solids (TSS), and pH were compared with the Interim National Water Quality Standards, Malaysia River classification (INWQS) and Water Quality Index (WQI). Between 38% to 96% of reduction was observed and water quality has been improved from class III and IV to class II. Analyses for Electricity Conductivity (EC), Salinity, Total Dissolved Solids (TDS) and Ammonium (NH4) were also investigated. In all parameters, removal efficiency was in range of 13-17th day (optimum 14th day) which was higher than 3 weeks except DO. It reveals the optimum growth rate of water hyacinth has great effect on waste water purification efficiency in continuous system and nutrient removal was successfully achieved.


Assuntos
Eichhornia/metabolismo , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/análise , Poluentes Químicos da Água/metabolismo , Qualidade da Água , Biodegradação Ambiental , Malásia , Purificação da Água
20.
J Environ Manage ; 163: 125-33, 2015 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-26311085

RESUMO

The development of eco-friendly and efficient technologies for treating wastewater is one of the attractive research area. Phytoremediation is considered to be a possible method for the removal of pollutants present in wastewater and recognized as a better green remediation technology. Nowadays the focus is to look for a sustainable approach in developing wastewater treatment capability. Water hyacinth is one of the ancient technology that has been still used in the modern era. Although, many papers in relation to wastewater treatment using water hyacinth have been published, recently removal of organic, inorganic and heavy metal have not been reviewed extensively. The main objective of this paper is to review the possibility of using water hyacinth for the removal of pollutants present in different types of wastewater. Water hyacinth is although reported to be as one of the most problematic plants worldwide due to its uncontrollable growth in water bodies but its quest for nutrient absorption has provided way for its usage in phytoremediation, along with the combination of herbicidal control, integratated biological control and watershed management controlling nutrient supply to control its growth. Moreover as a part of solving wastewater treatment problems in urban or industrial areas using this plant, a large number of useful byproducts can be developed like animal and fish feed, power plant energy (briquette), ethanol, biogas, composting and fiber board making. In focus to the future aspects of phytoremediation, the utilization of invasive plants in pollution abatement phytotechnologies can certainly assist for their sustainable management in treating waste water.


Assuntos
Biodegradação Ambiental , Eichhornia/metabolismo , Metais Pesados/isolamento & purificação , Águas Residuárias/química , Poluentes Químicos da Água/isolamento & purificação , Solo
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