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1.
Environ Prog Sustain Energy ; : e13937, 2022 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-35942312

RESUMO

Presently, the coronavirus (COVID-19) epidemic presents a major threat to global communal fitness also socio-financial development. Ignoring worldwide isolation as well as shutdown attempts, the occurrence of COVID-19 infected patients continues to be extremely large. Nonetheless, COVID-19's final course, combined with the prevalence of emerging contaminants (antibiotics, pharmaceuticals, nanoplastics, pesticides, and so forth) in wastewater treatment plants (WWTPs), presents a major problem in wastewater situations. The research, therefore, intends near examine an interdisciplinary as well as technical greet to succor COVID-19 with subsequent COVID cycles of an epidemic as a framework for wastewater treatment settings. This research investigated the potential for wastewater-based epidemiology to detect SARS-CoV-2 also the enzymes happening in wastewater conditions. In addition, a chance for the incorporation into the WWTPs of emerging and robust technologies such as mesmeric nanobiotechnology, electrochemical oxidation, microscopy, and membrane processes to enhance the overall likelihood of environmental consequences of COVID-19 also strengthen such quality of water is resolved.

2.
J Pharm Anal ; 11(1): 48-56, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33717611

RESUMO

A simple and reliable strategy was proposed to engineer the glutathione grafted graphene oxide/ZnO nanocomposite (glutathione-GO/ZnO) as electrode material for the high-performance piroxicam sensor. The prepared glutathione-GO/ZnO nanocomposite was well characterized by X-ray diffraction (XRD), Fourier transform infrared spectrum (FTIR), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV). The novel nanocomposite modified electrode showed the highest electrocatalytic activity towards piroxicam (oxidation potential is 0.52 V). Under controlled experimental parameters, the proposed sensor exhibited good linear responses to piroxicam concentrations ranging from 0.1 to 500 µM. The detection limit and sensitivity were calculated as 1.8 nM and 0.2 µA/µM·cm2, respectively. Moreover, it offered excellent selectivity, reproducibility, and long-term stability and can effectively ignore the interfering candidates commonly existing in the pharmaceutical tablets and human fluids even at a higher concentration. Finally, the reported sensor was successfully employed to the direct determination of piroxicam in practical samples.

3.
Sci Total Environ ; 756: 144073, 2021 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-33279200

RESUMO

In the present-day context, micro-plastic particles in a marine environment are increasingly ubiquitous and of considerable persistence. In line with the micro-plastic pollution, the present contribution is devoted to the investigation of micro-plastic particles (MPs) along the urban sandy beach called Marina, the renowned longest beach in India. Along the sea coast of about 5 km, the quantification of micro-plastic particles using optical microscope evidenced the granular, filamentous, filmy and tubular fragments in a total of 72 marine samples including those filtered in the marine water column (WAT; 24 samples), those found in wet sediment (WET; 24 samples) and those found in dry sand (DSS; 24 samples). The filamentous-typed plastics of 79%, 57% and 52%, respectively in WET, WAT and DSS dominated over the other granular and tubular types. The micro-plastic particles were in the range of 60-820 items per m3, 60-1620 items per kg and 20-1540 items per kg for WAT, WET and DSS, respectively. The standard deviation for the microplastics abundance were 193.1, 396.6 and 364.6 for WAT, WET and DSS respectively. Upon visual inspection, the micro particles were observed in eight different colors and most of the samples were found to contain two different fragment types. Apart from the optical microscopic examination, the micro-plastics particles were studied by scanning electron microscope (SEM) coupled with elemental analysis by energy dispersive spectroscopy (EDS). The energy spectral graphs displayed that the micro-filaments and micro-tubular particles contained polyesters and fluoro-polymers. The presence of few micro-filaments of polypropylene and polyethylene was also evidenced from their atomic percentage values of carbon of about 88% and 93%, respectively. The presence of fluoro-polymers and polyesters was also confirmed by Fourier Transform Infra-Red (FTIR). Excepting the fluoro-polymers, the micro-plastics particles contained elements arising from sea water (Na, Cl, S, Mg, Ca, K). Heavy metals such as Cu, Mn, Mo, Ru and Rh were observed in micro-tubular fragments. Fe and Ti elements were detected with the highest atomic percentage of 17.19 and 19.84 in micro-tubular fragments. All the observations and analyses give a photography of the nature and the spatial distribution of MPs along this Indian beach.

4.
RSC Adv ; 11(20): 12361-12373, 2021 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-35423732

RESUMO

In this paper, we propose a fluorescent biosensor for the sequential detection of Pb2+ ions and the cancer drug epirubicin (Epn) using the interactions between label-free guanine-rich ssDNA (LFGr-ssDNA), acridine orange (AO), and a metal-phenolic nanomaterial (i.e., nano-monoclinic copper-tannic acid (NMc-CuTA)). An exploration of the sensing mechanism shows that LFGr-ssDNA and AO strongly adsorb on NMc-CuTA through π-π stacking and electrostatic interactions, and this results in the fluorescence quenching of AO. In order to sense the target Pb2+, initially, LFGr-ssDNA specifically binds with Pb2+ ions to form a G4 complex (G-Pb2+-G base pair), which was released from the surface of NMc-CuTA with strong AO fluorescence enhancement (Turn-ON). The subsequent addition of a biothiol, like cysteine (Cys), to the G4 complex decreases the fluorescence, as the Pb2+ ions released from the G4 complex have a higher interaction affinity with the sulfur atoms of Cys; this further induces the unwinding of the G4 complex to form LFGr-ssDNA. Finally, Epn was added to this, which intercalates with LFGr-ssDNA to form a G4 complex via G-Epn-G, resulting in fluorescence recovery (Turn-ON). Accordingly, the Turn-ON fluorescent probe had subsequent limits of detection of 1.5 and 5.6 nM for Pb2+ and Epn, respectively. Hence, the reported NMc-CuTA-based sensing platform has potential applications for the detection of Pb2+ and Epn in real samples with good sensitivity and selectivity.

5.
Artigo em Chinês | WPRIM (Pacífico Ocidental) | ID: wpr-883498

RESUMO

A simple and reliable strategy was proposed to engineer the glutathione grafted graphene oxide/ZnO nanocomposite(glutathione-GO/ZnO)as electrode material for the high-performance piroxicam sensor.The prepared glutathione-GO/ZnO nanocomposite was well characterized by X-ray diffraction(XRD),Fourier transform infrared spectrum(FTIR),X-ray photoelectron spectroscopy(XPS),field emission scanning electron microscopy(FE-SEM),cyclic voltammetry(CV),electrochemical impedance spectros-copy(EIS)and differential pulse voltammetry(DPV).The novel nanocomposite modified electrode showed the highest electrocatalytic activity towards piroxicam(oxidation potential is 0.52 V).Under controlled experimental parameters,the proposed sensor exhibited good linear responses to piroxicam concentrations ranging from 0.1 to 500 μM.The detection limit and sensitivity were calculated as 1.8 nM and 0.2 μA/μM·cm2,respectively.Moreover,it offered excellent selectivity,reproducibility,and long-term stability and can effectively ignore the interfering candidates commonly existing in the pharmaceutical tablets and human fluids even at a higher concentration.Finally,the reported sensor was successfully employed to the direct determination of piroxicam in practical samples.

6.
RSC Adv ; 9(8): 4268-4276, 2019 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-35520178

RESUMO

A novel colorimetric sensing platform using the peroxidase mimicking activity of ternary MoS2-loaded ZnO-g-C3N4 nanocomposites (ZnO-g-C3N4/MoS2) has been developed for the determination of Hg(ii) ions over co-existing metal ions. The nanocomposite was prepared using an exfoliation process, and the product was further characterized using SEM, TEM, XRD and FTIR analysis. The ZnO-g-C3N4/MoS2 possesses excellent intrinsic catalytic activity to induce the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) in aqueous solution in the presence of H2O2 to generate deep blue coloured cation radicals (TMB+) which can be viewed with the naked eye and produce absorbance at a wavelength of 652 nm. The addition of a well known bioradical scavenger, glutathione (GSH), to the solution hinders the generation of cation radicals and turns the solution colourless. The introduction of Hg(ii) to this solution brings the blue colour back into it, due to the strong affinity of the thiol in the GSH. Based on this mechanism, we have developed a simple and rapid colorimetric sensor for the highly sensitive and selective detection of Hg(ii) ions in aqueous solution with a low detection limit of 1.9 nM. Furthermore, the prepared colorimetric sensor was effectively applied for the quantification analysis of real water samples.

7.
J Fluoresc ; 27(6): 2101-2109, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28819702

RESUMO

A label -free DNAzyme amplified biosensor is found to be highly selective and sensitive towards fluorescent detection of Pb2+ ions in aqueous media. The DNAzyme complex has designed by the hybridization of the enzyme and substrate strand. In the presence of Pb2+, the DNAzyme activated and cleaved the substrate strand of RNA site (rA) into two oligonucleotide fragments. Further, the free fragment was hybridized with a complementary strand on the surface of MBs. After magnetic separation, SYBER Green I was added and readily intercalate with the dsDNA to gives a bright fluorescence signal with intensity directly proportional to the concentration of Pb2+ions. A detection limit of 5 nM in Pb2+ the detection range 0 to 500 nM was obtained. This label- free fluorescent biosensor has been successfully applied to the determination of environmental water samples. Then results open up the possibility for real-time quantitative detection of Pb2+ with convenient potential applications in the biological and environmental field. Graphical Abstract.


Assuntos
Técnicas Biossensoriais/métodos , DNA Catalítico/química , Fluorescência , Chumbo/análise , Água/química , Limite de Detecção
8.
Water Environ Res ; 88(9): 838-846, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27654082

RESUMO

The textile dyeing industry consumes a significant amount of high-quality water for processing, which stresses water resources. In recent decades, technologies have been developed to recover water from wastewater. This study describes the high recovery (greater than 92%) of reusable water from an industrial-scale hosiery dye-water recovery facility, consisting of three stages of reverse osmosis and ultrafiltration. The effluent was pre-treated before the membrane process was performed to prevent biofouling. The process performance results in the generation of a consistent water quality that is required for dyeing operations. An average feed flux of 15 l/m2h was maintained in the reverse osmosis membrane by regular chemical dosing and cleaning. The integrated membrane process achieved a permeate with a pH of 6.5 and total dissolved solids (TDS) of 160 mg/l, with no other contaminants, which is of sufficient quality for reuse in the cotton hosiery dyeing process.


Assuntos
Corantes/análise , Resíduos Industriais/análise , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/análise , Monitoramento Ambiental , Filtração , Membranas Artificiais , Indústria Têxtil , Ultrafiltração
9.
J Nanosci Nanotechnol ; 14(4): 2937-46, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24734714

RESUMO

Mn2O3 doped Poly Aniline (MPANI) nanocomposite was prepared by chemical oxidative polymerization. Characterization of the MPANI nanocomposite was carried out using Fourier transfer infrared spectroscopy (FT-IR), Powder X-ray diffraction (XRD), Thermogravimetric analysis (TGA), Scanning electron microscopy (SEM) and Energy dispersive analysis of X-rays (EDAX). SEM image showed that the MPANI nanocomposite shows agglomerated sponge of 200-500 nm in length. XRD data revealed that the doping of Mn2O3 onto polymer surface which was confirmed due to the decrease in crystalline nature. The MPANI nanocomposite was used as an efficient adsorbent for removal Pb(II), Ni(II), and Cd(II) ions in aqueous media. Batch experiments show maximum adsorption capacity for MPANI nanocomposite on Pb(II) (437 mg/g), Ni(II) (494 mg/g), and Cd(II) (480 mg/g). The metal ions adsorption on MPANI nanocomposite is a fast process and the kinetics followed a pseudo second order rate equation (R2 approximately 0.99).

10.
Bioresour Technol ; 119: 28-34, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22728178

RESUMO

The production of porous cross-linked enzyme aggregates (p-CLEAs) is a simple and effective methodology for laccase immobilization. A three-phase partitioning technique was applied to co-precipitate laccase and starch, followed by cross-linking with glutaraldehyde and removal of starch by α-amylase to create pores in the CLEAs. Scanning electron microscopy revealed a very smooth spherical structure with numerous large pores. The half-life of free laccase at 55°C was calculated to be 1.3h, while p-CLEAs did not lose any activity even after 14 h. p-CLEAs also exhibited improved storage stability, catalytic efficiency and could be recycled 15 times with 60% loss of activity. The catalysts decolorized triphenylmethane and reactive dyes by 60-70% at initial dye concentrations of 2 and 0.5 g L(-1), respectively, without any mediators. These results suggest the potential of CLEA technology in waste-water treatment.


Assuntos
Basidiomycota/enzimologia , Cor , Corantes/química , Lacase/síntese química , Compostos de Terfenil/química , Compostos de Tritil/química , Corantes/isolamento & purificação , Reagentes de Ligações Cruzadas/química , Enzimas Imobilizadas/síntese química , Porosidade , Compostos de Terfenil/isolamento & purificação , Compostos de Tritil/isolamento & purificação
12.
J Am Acad Dermatol ; 61(5): 793-8, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19766350

RESUMO

BACKGROUND: Psoralen plus ultraviolet A (PUVA) for the treatment of psoriasis has never been evaluated using the Psoriasis Area Severity Index (PASI) in a randomized, double-blind, placebo-controlled trial. The lack of such data limits our capacity to estimate PUVA's efficacy relative to other treatment options that are available today. OBJECTIVES: The purpose of this study was to evaluate the efficacy of PUVA therapy for patients with plaque-type psoriasis. METHODS: This study involved 40 patients with psoriasis; 30 received PUVA and 10 received UVA with placebo. PASI scores were assessed at baseline and every 4 weeks thereafter for 12 weeks. RESULTS: By nonresponder imputation, 60% (18 of 30) in the PUVA group achieved 75% or more improvement in PASI score after 12 weeks of treatment compared with 0% (0 of 10) in the UVA plus placebo group (P < .0001). Using intent to treat with last observation carried forward analysis, 63% (19 of 30) in the PUVA group achieved 75% or more improvement in PASI score compared with 0% (0 of 10) in the UVA plus placebo group (P < .0001). By per protocol analysis, 86% (18 of 21) in the PUVA group as compared with 0% (0 of 7) in the UVA plus placebo group reached 75% or more improvement in PASI score after 12 weeks (P < .0001). LIMITATIONS: The study was relatively small with only 40 patients enrolled and 28 patients who completed the protocol. Further studies that involve head-to-head comparison of PUVA with other treatment modalities are needed. Nonresponder imputation, last observation carried forward with intent to treat, and per protocol analyses each have separate advantages and limitations when determining clinical significance. CONCLUSIONS: This study supports the observation that PUVA is a highly efficacious treatment for chronic plaque psoriasis.


Assuntos
Ficusina/administração & dosagem , Terapia PUVA , Fármacos Fotossensibilizantes/administração & dosagem , Psoríase/tratamento farmacológico , Administração Oral , Adulto , Idoso , Método Duplo-Cego , Feminino , Ficusina/efeitos adversos , Humanos , Masculino , Pessoa de Meia-Idade , Fármacos Fotossensibilizantes/efeitos adversos , Placebos , Psoríase/patologia , Índice de Gravidade de Doença , Pele/patologia , Resultado do Tratamento , Adulto Jovem
13.
J Hazard Mater ; 159(2-3): 427-34, 2008 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-18384949

RESUMO

Large pore HY zeolite was modified with phosphoric acid by wet method. The modified zeolite was converted to Na(+) form using aqueous NaHCO(3) solution(.) The Na(+) form of modified zeolite, represented as PNa(2)Y, was characterized by XRD, BET surface area, SEM, and AAS techniques. The XRD analysis showed diffraction patterns same as that of parent HY zeolite, as a result there has been no structural degradation during modification. It was then tested for sorption of Cu(2+) ions from aqueous solution. The Cu(2+) content of the solution was analyzed by AAS. PNa(2)-Y shows higher sorption capacity ( approximately 40%) than the parent Na-Y ( approximately 23%) zeolite, which is attributed to the double of amount Na(+) content in PNa(2)-Y compared to the Na-Y zeolite. Equilibrium modeling data were found to fit more to the linear Langmuir model than the Freundlich model. The thermodynamic parameters such as change in free energy (DeltaG degrees ), enthalpy (DeltaH degrees ), and entropy (DeltaS degrees ), were also calculated. These parameters confirmed that the sorption of Cu(2+) is feasible, spontaneous and endothermic.


Assuntos
Resinas de Troca Iônica/química , Ácidos Fosfóricos/química , Zeolitas/química , Adsorção , Difusão , Concentração de Íons de Hidrogênio , Troca Iônica , Cinética , Microscopia Eletrônica de Varredura , Prótons , Sódio/química , Bicarbonato de Sódio , Termodinâmica
14.
J Hazard Mater ; 158(1): 142-50, 2008 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-18313841

RESUMO

The use of low-cost and ecofriendly adsorbents has been investigated as an ideal alternative to the current expensive methods of removing dyes from wastewater. This paper deals with the removal of Acid Red 114 (AR 114) from aqueous solutions using activated carbons prepared from agricultural waste materials such as gingelly (sesame) (Sp), cotton (Cp) and pongam (Pp) seed shells. Optimum conditions for AR 114 removal were found to be pH 3, adsorbent dosage=3g/L of solution and equilibrium time=4h. Higher removal percentages were observed at lower concentrations of AR 114. The adsorption isotherm data were fitted to Langmuir and Freundlich equation, and the adsorption capacity of the studied adsorbents was in the order Sp>Cp>Pp. Kinetic studies showed that the adsorption followed both pseudo-second-order and Elovich equation. The thermodynamics parameters such as DeltaG degrees, DeltaH degrees, DeltaS degrees were also evaluated. The activated carbons prepared were characterized by FT-IR, SEM and BET analysis.


Assuntos
Compostos Azo/isolamento & purificação , Carvão Vegetal/química , Naftalenossulfonatos/isolamento & purificação , Sementes/química , Eliminação de Resíduos Líquidos/métodos , Adsorção , Gossypium/química , Concentração de Íons de Hidrogênio , Resíduos Industriais/análise , Cinética , Pongamia/química , Sesamum/química , Indústria Têxtil , Termodinâmica
15.
J Hazard Mater ; 155(1-2): 39-44, 2008 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-18162299

RESUMO

The adsorption of rhodamine B dye was carried out using sodium montmorillonite clay. The effect of parameters such as pH, adsorbent dosage and initial dye concentration was studied. The Langmuir and Freundlich isotherm models were applied and the Langmuir model was found to best fit the equilibrium isotherm data. Langmuir adsorption capacity was found to be 42.19 mg/g. Kinetic data followed pseudo-second-order kinetics. Maximum color removal was observed at pH 7.0. The DeltaG degrees value was found to be negative, the adsorption process was feasible. The results indicate that sodium montmorillonite clay can be used for the removal of basic dyes from aqueous solutions.


Assuntos
Bentonita/química , Corantes/química , Rodaminas/química , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/química , Purificação da Água/métodos , Adsorção , Concentração de Íons de Hidrogênio , Cinética , Soluções , Temperatura
16.
J Hazard Mater ; 151(2-3): 316-22, 2008 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-17689864

RESUMO

The adsorption of Acid Violet 17 (AV17) was carried out using various activated carbons prepared from sunflower seed hull (SSH), an agricultural solid waste by-product. The effect of parameters such as agitation time, initial dye concentration, adsorbent dosage, pH and temperature were studied. The Langmuir and Freundlich isotherm models were applied and the Langmuir model was found to best report the equilibrium isotherm data. Langmuir adsorption capacity was found to be 116.27 mg/g. Kinetic data followed pseudo-second-order kinetics. Maximum colour removal was observed at pH 2.0. It was observed that the rate of adsorption improves with increasing temperature and the process is endothermic. The adsorbent surface was analysed with a scanning electron microscope. The results indicate that activated sunflower seed hull could be an attractive option for colour removal from dilute industrial effluents.


Assuntos
Carbono/química , Corantes de Rosanilina/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/instrumentação , Purificação da Água/métodos , Água/química , Adsorção , Carvão Vegetal/química , Helianthus , Concentração de Íons de Hidrogênio , Cinética , Modelos Químicos , Extratos Vegetais , Corantes de Rosanilina/análise , Corantes de Rosanilina/química , Sementes/metabolismo , Termodinâmica , Eliminação de Resíduos Líquidos , Poluentes Químicos da Água/análise
17.
J Hazard Mater ; 141(1): 301-4, 2007 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-16914265

RESUMO

In this study, experiments were conducted to investigate the production of biogas from municipal solid waste (MSW) and domestic sewage by using anaerobic digestion process. The batch type of reactor was operated at room temperature varying from 26 to 36 degrees C with a fixed hydraulic retention time (HRT) of 25 days. The digester was operated at different organic feeding rates of 0.5, 1.0, 2.3, 2.9, 3.5 and 4.3kg of volatile solids (VS)/m(3) of digester slurry per day. Biogas generation was enhanced by the addition of domestic sewage to MSW. The maximum biogas production of 0.36m(3)/kg of VS added per day occurred at the optimum organic feeding rate of 2.9kg of VS/m(3)/day. The maximum reduction of total solids (TS) (87.6%), VS (88.1%) and chemical oxygen demand (COD) (89.3%) occurred at the optimum organic loading rate of 2.9kg of VS/m(3)/day. The quality of biogas produced during anaerobic digestion process was 68-72%.


Assuntos
Reatores Biológicos , Fontes Geradoras de Energia , Gerenciamento de Resíduos/métodos
18.
J Hazard Mater ; 137(3): 1554-9, 2006 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-16757111

RESUMO

The present study was carried out to gain knowledge of current surface ozone concentrations and the effects of meteorological parameters in the highly populated urban area of Chennai, in South India. We have reported measurement results of surface ozone (O(3)) and meteorological parameters from 17th March to 10th October 2005. A photometric ozone analyzer continuously recorded the ozone concentrations at this site. The present study deals with the statistical characteristics of daily and monthly mean ozone levels under different meteorological conditions. The highest ozone concentrations were recorded in ESE-SE sectors. The monthly mean concentrations were higher in May (23+/-14 ppb) and lower in April at this site (10+/-8 ppb). The maximum hourly ozone concentration reached 69 ppb on 21st April.


Assuntos
Ozônio/química , Cidades , Índia , Luz , Oceanos e Mares , Fatores de Tempo
19.
J Hazard Mater ; 136(3): 989-92, 2006 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-16513258

RESUMO

The adsorption of Acid dye, C.I. Acid Red 151 from aqueous solution onto modified hectorite at different concentrations and pH has been studied. Hectorite clay has been modified using two cationic surfactants, cetyldimethylbenzylammonium chloride and cetylpyridinium chloride. Present experimental study shows that acidic pH favours enhanced adsorption. The adsorption isotherms are described by means of Langmuir and Freundlich isotherms. The adsorption capacity has been found to be 208.33 and 169.49 mg g(-1) for the modified cetyldimethylbenzylammonium chloride-hectorite (CDBA-hect) and cetylpyridinium chloride (CP-hect), respectively.


Assuntos
Compostos Azo/química , Corantes/química , Naftalenos/química , Silicatos/química , Adsorção , Fenômenos Químicos , Físico-Química , Concentração de Íons de Hidrogênio , Termodinâmica , Difração de Raios X
20.
J Hazard Mater ; 136(3): 721-6, 2006 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-16488537

RESUMO

Pseudo second order kinetic expressions of Ho, Sobkowsk and Czerwinski, Blanachard et al. and Ritchie were fitted to the experimental kinetic data of malachite green onto activated carbon by non-linear and linear method. Non-linear method was found to be a better way of obtaining the parameters involved in the second order rate kinetic expressions. Both linear and non-linear regression showed that the Sobkowsk and Czerwinski and Ritchie's pseudo second order model were the same. Non-linear regression analysis showed that both Blanachard et al. and Ho have similar ideas on the pseudo second order model but with different assumptions. The best fit of experimental data in Ho's pseudo second order expression by linear and non-linear regression method showed that Ho pseudo second order model was a better kinetic expression when compared to other pseudo second order kinetic expressions. The amount of dye adsorbed at equilibrium, q(e), was predicted from Ho pseudo second order expression and were fitted to the Langmuir, Freundlich and Redlich Peterson expressions by both linear and non-linear method to obtain the pseudo isotherms. The best fitting pseudo isotherm was found to be the Langmuir and Redlich Peterson isotherm. Redlich Peterson is a special case of Langmuir when the constant g equals unity.


Assuntos
Carvão Vegetal/química , Corantes de Rosanilina/química , Adsorção , Algoritmos , Cinética , Modelos Lineares , Dinâmica não Linear , Análise de Regressão , Termodinâmica
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