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1.
Ecotoxicol Environ Saf ; 194: 110443, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-32155479

RESUMEN

Anthropogenic activities mediated antibiotic resistance genes (ARGs) in the pristine aquatic bodies (lakes) is raising concern worldwide. Long read shotgun sequencing was used to assess taxonomic diversity, distribution of ARGs and metal resistance genes (MRGs) and mobile genetic elements (MGEs) in six sites within hypersaline Lonar soda lake (India) prone to various anthropogenic activities. Proteobacteria and Euryarchaeota were dominant phyla under domain Bacteria and Archaea respectively. Higher abundance of Bacteroidetes was pragmatic at sites 18LN5 and 18LN6. Functional analysis indicated 26 broad-spectrum ARGs types, not reported earlier in this ecosystem. Abundant ARG types identified were multidrug efflux, glycopepetide, bacitracin, tetracycline and aminogylcoside resistance. Sites 18LN1 and 18LN5 depicted 167 and 160 different ARGs subtypes respectively and rpoB2, bcrA, tetA(48), mupA, ompR, patA, vanR and multidrug ABC transporter genes were present in all samples. The rpoB2 gene was dominant in 18LN1, whereas bcrA gene in 18LN2-18LN6 sites. Around 24 MRGs types were detected with higher abundance of arsenic in 18LN1 and copper in 18LN2-18LN6, signifying metal contamination linked to MRGs. The bacterial taxa Pseudomonas, Thioalkalivibrio, Burkholderia, Clostridium, Paenibacillus, Bacillus and Streptomyces were significantly associated with ARGs. This study highlights the resistomic hotspots in the lake for deploying policies for conservation efforts.


Asunto(s)
Farmacorresistencia Microbiana/genética , Monitoreo del Ambiente/métodos , Lagos/microbiología , Metagenoma , Archaea/efectos de los fármacos , Bacterias/efectos de los fármacos , Ecosistema , Genes Bacterianos/efectos de los fármacos , India , Metales , Proteobacteria/genética
2.
Indian J Microbiol ; 57(2): 241-249, 2017 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-28611503

RESUMEN

Phosphate depletion is one of the favorable ways to enhance the sewage water treatment with the algae, however, detailed information is essential with respect to internal phosphate concentration and physiology of the algae. The growth rate of the phosphate-starved Scenedesmus cells was reduced drastically after 48 h. Indicating cells entered in the stationary phase of the growth cycle. Fourier Transform Infrared analysis of phosphate-starved Scenedesmus cells showed the reduction in internal phosphate concentration and an increase in carbohydrate/phosphate and carbohydrate/lipid ratio. The phosphate-starved Scenedesmus cells, with an initial cell density of, 1 × 106 cells mL-1 shows 87% phosphate and 100 % nitrogen removal in 24 h. The normal Scenedesmus cells need approximately 48 h to trim down the nutrients from wastewater up to this extent. Other microalgae, Ankistrodesmus, growth pattern was not affected due to phosphate starvation. The cells of Ankistrodesmus was able to reduce 71% phosphate and 73% nitrogen within 24 h, with an initial cell density of, 1 × 106 cells mL-1.

3.
Org Biomol Chem ; 14(11): 3027-30, 2016 Mar 21.
Artículo en Inglés | MEDLINE | ID: mdl-26911555

RESUMEN

An unprecedented synthesis of novel 3-azido indoles has been developed using I2 and NaN3 in high yields and excellent regioselectivity. The reaction proceeds under metal-free conditions at room temperature. Essentially, an umpolung in reactivity at the C-3 position of indole has been achieved by the activation of indoles with I2.

4.
J Environ Chem Eng ; 11(3): 109673, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-36937242

RESUMEN

Presence of SARS-CoV-2 in wastewater is a major concern as the wastewater meets rivers and other water bodies and is used by the population for various purposes. Hence it is very important to treat sewage water in an efficient manner in order to reduce the public health risk. In the present work, various advanced oxidation processes (AOPs) have been evaluated for disinfection of SARS-CoV-2 from sewage water collected from STP inlet of academic institutional residential. The sewage water was subjected to ten AOPs, which include Ozone (O3), Hydrodynamic cavitation (HC), Ultraviolet radiation (UV), and their hybrid combinations like HC/O3, HC/O3/H2O2, HC/H2O2, O3/UV, UV/H2O2, UV/H2O2/O3, and O3/H2O2 to reduce SARS-CoV-2 viral load. Further, AOP treated sewage water was subjected to total nucleic acid isolation followed by RT-qPCR for viral load estimation. The sewage water treatment techniques were evaluated based on their viral concentration-reducing efficiency. It was found that ozone and ozone-coupled hybrid AOPs showed the most promising result with more than 98 % SARS-CoV-2 viral load reducing efficiency from sewage water. Interestingly, the best six AOPs used in this study significantly reduced both the SARS-CoV-2 and PMMoV (faecal indicator) viral load and improved water quality in terms of increasing DO and decreasing TOC.

5.
Environ Sci Pollut Res Int ; 30(56): 118976-118988, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37922087

RESUMEN

The COVID-19 pandemic has emphasized the urgency for rapid public health surveillance methods to detect and monitor the transmission of infectious diseases. The wastewater-based epidemiology (WBE) has emerged as a promising tool for proactive analysis and quantification of infectious pathogens within a population before clinical cases emerge. In the present study, we aimed to assess the trend and dynamics of SARS-CoV-2 variants using a longitudinal approach. Our objective included early detection and monitoring of these variants to enhance our understanding of their prevalence and potential impact. To achieve our goals, we conducted real-time quantitative polymerase chain reaction (RT-qPCR) and Illumina sequencing on 442 wastewater (WW) samples collected from 10 sewage treatment plants (STPs) in Pune city, India, spanning from November 2021 to April 2022. Our comprehensive analysis identified 426 distinct lineages representing 17 highly transmissible variants of SARS-CoV-2. Notably, fragments of Omicron variant were detected in WW samples prior to its first clinical detection in Botswana. Furthermore, we observed highly contagious sub-lineages of the Omicron variant, including BA.1 (~28%), BA.1.X (1.0-72%), BA.2 (1.0-18%), BA.2.X (1.0-97.4%) BA.2.12 (0.8-0.25%), BA.2.38 (0.8-1.0%), BA.2.75 (0.01-0.02%), BA.3 (0.09-6.3%), BA.4 (0.24-0.29%), and XBB (0.01-21.83%), with varying prevalence rates. Overall, the present study demonstrated the practicality of WBE in the early detection of SARS-CoV-2 variants, which could help track future outbreaks of SARS-CoV-2. Such approaches could be implicated in monitoring infectious agents before they appear in clinical cases.


Asunto(s)
COVID-19 , SARS-CoV-2 , Humanos , SARS-CoV-2/genética , Pandemias , COVID-19/epidemiología , India , Genómica , Aguas Residuales
6.
Sci Total Environ ; 807(Pt 3): 151038, 2022 Feb 10.
Artículo en Inglés | MEDLINE | ID: mdl-34688738

RESUMEN

Given a large number of SARS-CoV-2 infected individuals, clinical detection has proved challenging. The wastewater-based epidemiological paradigm would cover the clinically escaped asymptomatic individuals owing to the faecal shedding of the virus. We hypothesised using wastewater as a valuable resource for analysing SARS-CoV-2 mutations circulating in the wastewater of Pune region (Maharashtra; India), one of the most affected during the covid-19 pandemic. We conducted study in open wastewater drains from December 2020-March 2021 to assess the presence of SARS-CoV-2 nucleic acid and further detect mutations using ARTIC protocol of MinION sequencing. The analysis revealed 108 mutations across six samples categorised into 39 types of mutations. We report the occurrence of mutations associated with Delta variant lineage in March-2021 samples, simultaneously also reported as a Variant of Concern (VoC) responsible for the rapid increase in infections. The study also revealed four mutations; S:N801, S:C480R, NSP14:C279F and NSP3:L550del not currently reported from wastewater or clinical data in India but reported worldwide. Further, a novel mutation NSP13:G206F mapping to NSP13 region was observed from wastewater. Notably, S:P1140del mutation was detected in December 2020 samples while it was reported in February 2021 from clinical data, indicating the instrumentality of wastewater data in early detection. This is the first study in India to demonstrate utility of sequencing in wastewater-based epidemiology to identify mutations associated with SARS-CoV-2 virus fragments from wastewater as an early warning indicator system.


Asunto(s)
COVID-19 , SARS-CoV-2 , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , India , Pandemias , Aguas Residuales
7.
Diabetes Metab Syndr ; 16(8): 102528, 2022 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-35863268

RESUMEN

BACKGROUND AND AIMS: The rapid increase in burden of type 2 diabetes mellitus (T2DM), poses a huge medico-economic challenge, especially when the cost of care is funded by out-of-pocket expenses. The aim of this review is to highlight various issues associated with rising cost of insulin, prevalence of cost-related insulin underuse, insulin related cost-saving behaviors, and viable solutions for the benefit of patients with T2DM receiving insulin. METHODS: Electronic databases (PubMed and Google Scholar) from 2000 to 2020 were searched using the key terms uncontrolled diabetes mellitus, insulin therapy, glycemic control, direct cost, indirect cost, out-of-pocket expenses, cost-related insulin underuse, cost-saving behaviors, and biosimilar insulin in developed countries and India. RESULTS: In majority of the patients with T2DM on monotherapy, addition of another oral antidiabetic agent is required. Despite these measures, the target glycemic goals are not achieved in majority of the patients resulting in various complications. These complications can be prevented and target glycemic goals can be achieved with early initiation of insulin therapy. However, rising cost is a major deterrent to the lifelong use of insulin. This results in non-compliance and further deterioration of glycemic control. Recently, biosimilar insulins have revolutionized the management of T2DM and look promising from the economic point of view. CONCLUSIONS: Biosimilar insulins are likely to further enhance the compliance of patients and should be used whenever feasible in patients with DM. However, the patient, along with prescriber should be allowed to make shared, informed decisions regarding the insulin they wish to use.


Asunto(s)
Biosimilares Farmacéuticos , Diabetes Mellitus Tipo 2 , Insulinas , Glucemia , Humanos , Hipoglucemiantes , Insulina
8.
Environ Sci Pollut Res Int ; 28(14): 17532-17545, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33400106

RESUMEN

The degradation of nitroaromatics/toxic energetic compounds contaminated water is a major cause of concern. W-doped TiO2 nanoparticles (NPs) were synthesized in ionic liquid, ethyl methyl imidazolium dicyanamide (EMIM-DCA) by a solvothermal method. The developed NPs were sintered at 500 °C and characterized by UV-Vis-DRS, FT-IR, FE-SEM, XRD, XPS, and BET techniques. The 30-40-nm-sized NPs were subjected to photocatalytic degradation of the toxic energetic compound, tetryl (2,4,6-trinitrophenylmethylnitramine) under UV-Vis light. Various operating parameters such as the effect of concentration of catalyst, pH of feed phase, oxidizing agents, and recycling of catalyst were studied in detail. For the first time, the degradation-mechanism pathway and kinetics of tetryl were evaluated. The degradation products were precisely analyzed by using HPLC, GC-MS, and TOC techniques. The USEPA has prescribed a drinking water limit of 0.02 mg L-1, and it was found that 0.5 g of 4% W-TiO2 could totally degrade tetryl (50 mg L-1) within 8 h. The kinetic rate constant of 4% W-TiO2 was 0.356 h-1, whereas pure TiO2 showed 0.207 h-1.


Asunto(s)
Doping en los Deportes , Líquidos Iónicos , Catálisis , Cinética , Oxidantes , Espectroscopía Infrarroja por Transformada de Fourier , Titanio , Tungsteno
9.
Chemosphere ; 264(Pt 2): 128574, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33059288

RESUMEN

Lonar Lake, India; a hypersaline and hyperalkaline extremophilic ecosystem having a unique microbial population has been rarely explored for bioremediation aspects. MinION-based shotgun sequencing was used to comprehensively compare the microbial diversity and functional potential of xenobiotic degradation pathways with seasonal changes. Proteobacteria and Firmicutes were prevalent bacterial phyla in the pre-monsoon and post-monsoon samples. Functional analysis from SEED-subsystem and KEGG database revealed 28 subsystems and 18 metabolic pathways for the metabolism of aromatic compounds and xenobiotic biodegradation respectively. Occurrence of N-phenyl alkanoic, benzoate, biphenyl, chloroaromatic, naphthalene, and phenol degradation genes depicted varied abundance in the pre-monsoon and post-monsoon samples. Further, KEGG analysis indicated nitrotoluene degradation pathway (ko00633) abundant in post-monsoon samples, and the benzoate degradation pathway (ko00362) predominant in 19LN4S (pre-monsoon) than 18LN7S (post-monsoon) samples. The abundant genes for benzoate degradation were pcaI: 3-oxoadipate CoA-transferase, alpha subunit, pcaH: protocatechuate 3,4-dioxygenase, beta subunit, and pcaB: 3-carboxy-cis, cis-muconate cycloisomerase, and 4-oxalocrotonate tautomerase. This metagenomic study provides a unique blueprint of hitherto unexplored xenobiotic biodegradation genes/pathways in terms of seasonal variations in the Lonar Lake, and warrants active exploitation of microbes for bioremediation purposes.


Asunto(s)
Lagos , Microbiota , Biodegradación Ambiental , India , Metagenoma , Microbiota/genética
10.
Chem Biol Drug Des ; 98(2): 258-269, 2021 08.
Artículo en Inglés | MEDLINE | ID: mdl-34013630

RESUMEN

For quantitative structure-activity relationship (QSAR) modeling in ligand-based drug discovery programs, pseudo-molecular field (PMF) descriptors using intrinsic atomic properties, namely, electronegativity and electron affinity are studied. In combination with partial least squares analysis and Procrustes transformation, these PMF descriptors were employed successfully to develop correlations that predict the activities of target protein inhibitors involved in various diseases (cancer, neurodegenerative disorders, HIV, and malaria). The results show that the present QSAR approach is competitive to existing QSAR models. In order to demonstrate the use of this algorithm, we present results of screening naturally occurring molecules with unknown bioactivities. The pIC50 predictions can screen molecules that have desirable activity before assessment by docking studies.


Asunto(s)
Descubrimiento de Drogas/métodos , Ligandos , Relación Estructura-Actividad Cuantitativa , Algoritmos , Electrones , Análisis de los Mínimos Cuadrados
11.
Chemosphere ; 250: 126298, 2020 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-32234622

RESUMEN

Chlorophenol (CP) is considered as environmentally hazardous material due to its acute toxicity, persistent nature and strong bioaccumulation. The dechlorination of 4-CP was investigated by using various catalysts such as bimetallic (Fe0/Cu0, Al0/Fe0), Pd/C, Raney Ni and Fe0 at room temperature. Among the catalysts studied, Raney Ni proved to be very economical and efficient catalyst that worked without the use of an external reducing agent. The dechlorination of 4-CP by Raney Ni was therefore further explored. Complete dechlorination of 4-CP (30 mg L-1) was achieved in 6 h at an optimum Raney Ni catalyst loading of 3 g L-1. The effect of triethylamine (TEA) and tripropylamine (TPA) was also investigated and it was observed that 100% dechlorination is possible in presence of 45 mg L-1 of TEA. The kinetics of dechlorination of 4-CP was investigated and found to be first order with a rate constant of 0.017 min-1 at 50 οC, and it enhances to 0.109 min-1 with addition of TEA. In the absence of a reducing agent, acidic to neutral pH favors dechlorination of 4-CP. The final product of dechlorination was estimated to be phenol by performing HPLC, LCMS and NMR analysis. Based on the results, a probable dechlorination mechanism of 4-CP is also proposed. It can be concluded that the catalytic hydrodechlorination is an effective and economical technique for dechlorination of 4-CP and it has a potential for the dechlorination of other toxic derivatives of chlorinated aromatics.


Asunto(s)
Clorofenoles/química , Modelos Químicos , Níquel/química , Catálisis , Halogenación , Concentración de Iones de Hidrógeno , Cinética , Sustancias Reductoras
12.
J Indian Soc Pedod Prev Dent ; 38(3): 247-252, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33004722

RESUMEN

BACKGROUND: We aimed to determine the fluoride release and fluoride-recharging ability of a sealant containing surface pre-reacted glass (S-PRG) ionomer filler particles (BeautiSealant) with a fluoride-releasing resin sealant (Helioseal F), and a glass-ionomer sealant (Fuji VII). METHODOLOGY: Forty-eight disc-shaped specimens of each material were immersed in deionized water to determine the fluoride release utilizing a fluoride ion-selective electrode. After 21 days, 8 specimens were soaked in 0.22% Sodium Fluoride solution for 2 min; 8 specimens were coated with 1.23% Acidulated Phosphate Fluoride (APF) gel for 4 min, and the fluoride-recharging ability was evaluated for 40 days. Data were analyzed using one way-ANOVA and Bonferroni post hoc tests. RESULTS: Total fluoride release over the 21-day period was: Fuji VII > BeautiSealant > Helioseal F, (P = 0.000). After refluoridation of the specimens with 0.22% Sodium Fluoride solution, the cumulative fluoride release during the 40-day period for each material was: BeautiSealant > Fuji VII > Helioseal (P = 0.000). After exposure to 1.23% APF gel, the cumulative fluoride release during the 40-day period for each material was: BeautiSealant > Fuji VII > Helioseal F (P = 0.000). CONCLUSION: Glass ionomer-based sealants (Fuji VII) exhibited higher initial fluoride release whilst the surface pre-reacted glass-ionomer filler containing sealant (BeautiSealant) demonstrated superior fluoride recharging properties.


Asunto(s)
Materiales Dentales , Fluoruros , Fluoruro de Fosfato Acidulado , Electrodos de Iones Selectos
13.
J Hazard Mater ; 160(2-3): 414-21, 2008 Dec 30.
Artículo en Inglés | MEDLINE | ID: mdl-18524474

RESUMEN

Water pollution by toxic organic compounds is of concern and the demand for effective adsorbents for the removal of toxic compounds is increasing. Present work deals with the adsorption of phenol (PhOH) and o-chlorophenol (o-CP) on mesoporous MCM-41 material. The effect of surfactant template in MCM-41 on the removal of PhOH and o-CP was investigated. The comparison of adsorption of PhOH and o-CP on uncalcined MCM-41 (noted as MCM-41) and calcined MCM-41 (noted as C-MCM-41) was investigated. It was found that MCM-41 shows significant adsorption for PhOH and o-CP as compared to C-MCM-41, this may be because of the hydrophobicity created by surfactant template in the MCM-41. Batch adsorption studies were carried out to study the effect of various parameters like adsorbent dose, pH, initial concentration and the presence of co-existing ions. It was found that adsorption of PhOH and o-CP depends upon the solution pH as well as co-existing ions present in the aqueous solution. The equilibrium adsorption data for PhOH and o-CP was analyzed by using Freundlich adsorption isotherm model. From the sorption studies it was observed that the uptake of o-CP was higher than PhOH.


Asunto(s)
Clorofenoles/aislamiento & purificación , Fenoles/aislamiento & purificación , Dióxido de Silicio/química , Adsorción , Aniones/química , Cetrimonio , Compuestos de Cetrimonio/química , Concentración de Iones de Hidrógeno , Indicadores y Reactivos , Cinética , Porosidad , Espectroscopía Infrarroja por Transformada de Fourier , Tensoactivos/análisis , Termodinámica , Contaminantes Químicos del Agua/análisis , Difracción de Rayos X
14.
J Hazard Mater ; 140(1-2): 149-54, 2007 Feb 09.
Artículo en Inglés | MEDLINE | ID: mdl-16860467

RESUMEN

In this work, the photocatalytic degradation (PCD) of p-toluenesulfonic acid (p-TSA) in batch reactor using concentrated solar radiation was investigated. The effect of the various operating parameters such as initial concentration of substrate, catalyst loading, solution pH and types of ions on photocatalytic degradation has been studied in a batch reactor to derive the optimum conditions. The rate of photocatalytic degradation was found to be maximum at the self pH (pH 3.34) of p-TSA. It was also observed that in the presence of anions and cations, the rate of PCD decreases drastically. The kinetics of photocatalytic degradation of p-TSA was studied. The PCD of p-TSA was also carried at these optimized conditions in a bench scale slurry bubble column reactor using concentrated solar radiation.


Asunto(s)
Bencenosulfonatos/química , Bencenosulfonatos/efectos de la radiación , Fotoquímica , Energía Solar , Catálisis , Concentración de Iones de Hidrógeno , Cinética , Radiación
15.
Korean J Pain ; 30(3): 183-191, 2017 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-28757918

RESUMEN

BACKGROUND: Current therapy for the treatment of neuropathic pain is often unsatisfactory. Considerable variation in treatment pattern still exists in spite of availability of sufficient literature from various guidelines. Recent Indian market data suggested that the utilization (sale) of drugs such as amitriptyline, pregabalin, and gabapentin was more for low-dose unit packs than that of the high-dose unit packs, raising the belief that these drugs are prescribed at a lower dose than is actually recommended in the guidelines. To test this hypothesis, a survey was conducted across speciality throughout the country to observe the prescription pattern of these drugs amongst the health care providers in India. METHODS: Three hundred fifty survey forms were distributed of which 281 forms were included for analysis. RESULTS: It was observed that the commonly used initiation and maintenance dose for amitriptyline, pregabalin, and gabapentin was 5-10 mg/day, 50-75 mg/day, and 100-300 mg/day, respectively. The reason to select the lower dosages was to have a balancing effect to achieve good efficacy with minimum side effects. Care-givers reported no side effects/not many side effects as a reason in 22.2%, 16.88%, and 23.86% patients with amitriptyline, pregabalin, and gabapentin, respectively. Sedation and giddiness were commonly reported with all three drugs. CONCLUSIONS: Commonly prescribed drugs for management of neuropathic pain, such as amitriptyline, pregabalin, and gabapentin are preferred at lower doses in Indian clinical settings. Acceptable efficacy and low tolerance to the standard dosage is believed to be the reason behind the prescribed dose.

16.
Chemosphere ; 159: 359-366, 2016 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-27318451

RESUMEN

The zero-valent copper (Cu(0)) nanoparticles were prepared by chemical reduction method. The morphology of nanoparticles was investigated by using X ray diffraction, scanning electron microscopy-energy dispersive X ray, UV-visible spectrophotometer and Brunauer-Emmett-Teller surface area analyser. The Cu(0) nanoparticles along with reducing agents, NaBH4/5% acidified alcohol were used for the dechlorination of chloroaromatics at room temperature. Chlorobenzene (Cl-B), chlorotoluene (Cl-T), chloropyridine (Cl-Py) and chlorobiphenyl (Cl-BPh) were selected as the contaminants. The effect of various operating parameters such as pH, concentration of the catalyst and reducing agent (NaBH4), and recycling of the catalyst on dechlorination were studied. Nearly complete dechlorination of all the chloroaromatics were achieved in the presence of Cu(0) nanoparticles (2.5 g L(-1)) and NaBH4 (1.0 g L(-1)) within 12 h. On the contrary, approximately 70% of dechlorination was observed in the presence of 5% acidified alcohol at similar experimental conditions. The dechlorination mechanism highlighted the importance of Cu(0) nanoparticles as a surface mediator. The kinetics of the dechlorination of chloroaromatics was investigated and compared with chloroaliphatics. The dechlorination rate differed from 0.23 h(-1) (Cl-B) to 0.15 h(-1) (Cl-BPh) in the presence of Cu(0) nanoparticles and NaBH4. The effectiveness of Cu(0) nanoparticles with NaBH4 (1 g L(-1)) and 5% acidified alcohol as electron donors were studied by oxidation-reduction potential and observed to be -1016 mV and -670 mV, respectively. Final products of the dechlorination were benzene, toluene, pyridine and biphenyl, as identified by gas chromatograph mass spectrometer and nuclear magnetic resonance spectroscopy.


Asunto(s)
Cobre/química , Nanopartículas/química , Sustancias Reductoras/química , Catálisis , Clorobencenos/química , Halogenación , Cinética , Difracción de Rayos X
17.
J Hazard Mater ; 237-238: 161-9, 2012 Oct 30.
Artículo en Inglés | MEDLINE | ID: mdl-22944591

RESUMEN

A new alumina supported carbon composite material called "Eggshell Composite" (EC) was synthesized from eggshell waste as calcium source for selective fluoride adsorption from water. The effect of various synthesis parameters like eggshell (ES): Eggshell membrane (ESM) ratio, aluminium loading, mixing time and calcinations temperature to optimize the synthesis conditions for selective fluoride removal has been studied. It was observed that the synthesis parameters have significant influence on development of EC and in turn on fluoride removal capacity. EC synthesized was characterized for elemental composition, morphology, functionality and textural properties. Results showed that EC obtained from eggshell modified with alumina precursor is more selective and efficient for fluoride removal. Langmuir and Freundlich isotherm were used to obtain ultimate fluoride removal capacity. The calcium and alumina species in EC shows synergistic effect in fluoride adsorption process. Fluoride sorption studies were carried out in synthetic, groundwater and wastewater. EC proved to be a potential, indigenous and economic adsorbent for fluoride removal.


Asunto(s)
Óxido de Aluminio/química , Carbono/química , Cáscara de Huevo/química , Fluoruros/química , Contaminantes Químicos del Agua/química , Adsorción , Animales , Reciclaje/métodos , Restaurantes , Residuos , Purificación del Agua/métodos
18.
J Colloid Interface Sci ; 332(2): 280-90, 2009 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-19181328

RESUMEN

In the present study, the metal-binding property of chitosan is used to incorporate titanium metal and applied as an adsorbent for fluoride adsorption. Titanium macrospheres (TM) were synthesized by a precipitation method and characterized by FTIR, SEM, and XRD. The Langmuir and Freundlich adsorption models were applied to describe the adsorption equilibrium and the adsorption capacities were calculated. Thermodynamic parameters of standard free energy change (DeltaG(o)), standard enthalpy change (DeltaH(o)), and standard entropy change (DeltaS(o)) were also calculated. The effects of various physico-chemical parameters such as pH, initial concentration, adsorbent dose, and the presence of coexisting anions were studied. The fluoride uptake was maximum at neutral pH 7 and decreased in acidic and alkaline pH. The presence of coexisting anions has a negative effect on fluoride adsorption. TM was found to have very fast kinetics in the first 30 min and then the rate slowed down as equilibrium was approached. A comparison of fluoride removal in simulated and field water shows a high adsorption capacity in simulated water.


Asunto(s)
Quitosano/química , Fluoruración , Purificación del Agua/métodos , Adsorción , Concentración de Iones de Hidrógeno , Cinética , Termodinámica , Titanio
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