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1.
Cureus ; 10(8): e3157, 2018 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-30349764

RESUMO

Introduction The objective of this study was to assess the effect of heparin irrigation in the management of superficial first and second degree burns with special reference to pain relief and wound healing. Materials and methods This pilot study was carried out over a period of 12 months in a tertiary care centre in South India. The study patients were divided into two groups: the heparin group and the saline control group. In the control group, the burn wound was irrigated with 100 mL of normal saline before the conventional dressing with silver sulfadiazine. In the heparin irrigation group, the wound was irrigated with heparin solution before the conventional dressing. Wound healing was assessed in terms of necrotic tissue score and granulation tissue score. Patient satisfaction in terms of patient satisfaction score, visual analogue scale (VAS) score, and length of hospitalization were compared between the two groups. Results A total of 40 patients were analysed in the study, 20 patients in each group. Both the groups were comparable with respect to age, gender, co-morbidities, body mass index (BMI), and degree of burns. Wound healing parameters like necrotic tissue score of six [40% vs. 50%; p = 0.024] and granulation tissue score of four [85% vs. 65%; p= 0.06] were significant in the heparin group compared to the control group. However, the difference was not statistically significant. The mean length of hospitalization between the two groups [10.5 days vs. 12.6 days; p = 0.74] were not statistically significant. Similarly, there was no statistically significant difference between the two groups with respect to the VAS pain score on the seventh dressing day [6.9 vs. 7.3; p= 0.321]. Conclusion In comparison to saline irrigation, heparin irrigation would result in better wound healing in superficial first and second-degree burns. The length of hospital stay in days and VAS pain score on the seventh dressing day were not statistically significant between the two groups.

2.
J Environ Biol ; 34(5): 831-5, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24558794

RESUMO

The uptake and recovery of Pb (II) ions were investigated by using sodium alginate beads. Biosorption experiments are carried out in batch mode. The experimental results showed that the beads were effective in removing Pb (II) ions from solution. Biosorption equilibrium was approached within 16hrs. Pseudo first order was applicable to all the sorption data over the entire time range. The sorption data conformed well for the Langmuir isotherm model. The maximum adsorption capacity (qmax) onto alginate beads was 62.5 mg g-1 for Pb (II) ions. The maximum uptake of metal ions was obtained at pH 7. At temperature 35 degreeC, the biosorption of metal ions was found to be highest, with increase or decrease in temperature resulted in a decrease in the metal ions uptake capacity. The maximum removal efficiency of 94.02% was obtained at 100 mg I' of metal concentration with 200 numbers of immobilized beads. The results suggested that alginate beads can be used as a biosorbent for an efficient removal of Pb (II) ions from aqueous solution.


Assuntos
Kluyveromyces/metabolismo , Chumbo/metabolismo , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/metabolismo , Adsorção , Alginatos/metabolismo , Reatores Biológicos/microbiologia , Ácido Glucurônico/metabolismo , Ácidos Hexurônicos/metabolismo , Concentração de Íons de Hidrogênio , Íons , Temperatura
3.
Environ Sci Pollut Res Int ; 19(5): 1828-40, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22207236

RESUMO

UNLABELLED: BACKGROUND, AIM, SCOPE: Treatment of wastewater has become significant with the declining water resources. The presence of recalcitrant organics is the major issue in meeting the pollution control board norms in India. The theme of the present investigation was on partial or complete removal of pollutants or their transformation into less toxic and more biodegradable products by heterogeneous Fenton oxidation process using mesoporous activated carbon (MAC) as the catalyst. MATERIALS AND METHODS: Ferrous sulfate (FeSO(4)·7H(2)O), sulfuric acid (36 N, specific gravity 1.81, 98% purity), hydrogen peroxide (50% v/v) and all other chemicals used in this study were of analytical grade (Merck). Two reactors, each of height 50 cm and diameter 6 cm, were fabricated with PVC while one reactor was packed with MAC of mass 150 g and other without MAC served as control. RESULTS AND DISCUSSION: The oxidation process was presented with kinetic and thermodynamic constants for the removal of COD, BOD, and TOC from the wastewater. The activation energy (Ea) for homogeneous and heterogeneous Fenton oxidation processes were 44.79 and 25.89 kJ/mol, respectively. The thermodynamic parameters ΔG, ΔH, and ΔS were calculated for the oxidation processes using Van't Hoff equation. Furthermore, the degradation of organics was confirmed through FTIR and UV-visible spectroscopy, and cyclic voltammetry. CONCLUSIONS: The heterocatalytic Fenton oxidation process efficiently increased the biodegradability index (BOD/COD) of the tannery effluent. The optimized conditions for the heterocatalytic Fenton oxidation of organics in tannery effluent were pH 3.5, reaction time-4 h, and H(2)O(2)/FeSO(4)·7H(2)O in the molar ratio of 2:1.


Assuntos
Resíduos Industriais , Eliminação de Resíduos Líquidos/métodos , Análise da Demanda Biológica de Oxigênio , Catálise , Peróxido de Hidrogênio/química , Concentração de Íons de Hidrogênio , Cinética , Oxirredução , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier , Termodinâmica , Fatores de Tempo
4.
J Hazard Mater ; 176(1-3): 154-64, 2010 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-19962826

RESUMO

Conventional wastewater treatment techniques are inefficient to manage large quantities of refractory organics discharged by specialty chemical industries. It is aimed in the present investigation to compare overall performance of the basic electrochemical reactor configurations such as batch, batch recirculation and continuous recycle reactors, in removing the organic part of wastewater from a medium-scale, specialty chemical industry. The effects of current density, supporting electrolyte concentration, electrolysis duration and fluid flow rate on the pollutant removal and energy consumption performances were critically evaluated. Continuous recycle reactor is found to be the better configuration, because of its flexibility of operation. Circulation flow rate and withdrawal flow rate enable control on transfer coefficients and treatment duration respectively. The ability of artificial neural network (ANN) in predicting the performance of the batch electrochemical treatment has also been demonstrated.


Assuntos
Técnicas Eletroquímicas , Resíduos Industriais/prevenção & controle , Purificação da Água/métodos , Indústria Química , Compostos Orgânicos/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação
5.
J Environ Sci Eng ; 50(1): 23-8, 2008 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19192923

RESUMO

Batch and packed bed continuous biosorption studies were conducted to investigate the kinetics and isotherms of Cu(II) ions on the biomass of blue green alga Azolla rongpong. It is observed that the biosorption capacity of algae depends on initial pH and dosage. The biosorption capacity increases with increasing concentration and follows Freundlich isotherm model well with k and n values 0.06223 and 0.949 respectively. The optimum pH of 3.5 with an algae dosage of 1 g/L was observed. The results indicate that with the advantage of high metal biosorption capacity and recovery of Cu(II) ions, A. rongpong can be used as an efficient and economic biosorbent for the removal and recovery of toxic heavy metals from aqueous wastes even at higher concentration.


Assuntos
Adsorção , Biotecnologia/métodos , Cobre/análise , Cobre/química , Íons , Metais/química , Biomassa , Eucariotos , Gleiquênias , Concentração de Íons de Hidrogênio , Cinética , Fatores de Tempo , Água/química , Purificação da Água/métodos
6.
J Environ Sci Eng ; 50(4): 249-54, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19697758

RESUMO

Sorption capacity of different parts of Eichhornia crassipes, such as rhizome, root, lamina and petiole on basic aurophine-o was studied in a batch system. The equilibrium uptake capacity was observed as 13.65 mg/g (using root), 13.5 mg/g (using lamina), 12.9 mg/g (using rhizome) and 12.75 mg/g (using petiole). It was observed that the equilibrium dye uptake capacity using root was found to be more when compared to all other E. crassipes parts used in the present investigation. The shortcut equations developed are accurate and can be used in the place of experimental data. The shortcut equations form the basis for further research. The intra particle diffusion coefficient (K(i)) and effective diffusion coefficient (D(i)) were evaluated for the removal of dye using root, which were found to be more when compared to all other parts of E. crassipes studied such as, lamina, rhizome and petiole.


Assuntos
Corantes/química , Corantes/metabolismo , Eichhornia/química , Eichhornia/metabolismo , Poluentes Químicos da Água/química , Poluentes Químicos da Água/metabolismo , Purificação da Água/métodos , Adsorção , Biodegradação Ambiental , Corantes/isolamento & purificação , Simulação por Computador , Resíduos Industriais/prevenção & controle , Cinética , Taxa de Depuração Metabólica , Modelos Biológicos , Modelos Químicos , Indústria Têxtil/métodos
7.
J Hazard Mater ; 136(3): 922-9, 2006 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-16510239

RESUMO

Activated carbon was produced from a biowaste product, rubberwood sawdust (RWSD) using steam in a high temperature fluidized bed reactor. Experiments were carried out to investigate the influence of various process parameters such as activation time, activation temperature, particle size and fluidising velocity on the quality of the activated carbon. The activated carbon was characterized based on its iodine number, methylene blue number, Brauner Emmet Teller (BET) surface area and surface area obtained using the ethylene glycol mono ethyl ether (EGME) retention method. The best quality activated carbon was obtained at an activation time and temperature of 1h and 750 degrees C for an average particle size of 0.46 mm. The adsorption kinetics shows that pseudo-second-order rate fitted the adsorption kinetics better than pseudo-first-order rate equation. The adsorption capacity of carbon produced from RWSD was found to be 1250 mg g(-1) for the Bismark Brown dye. The rate constant and diffusion coefficient for intraparticle transport were determined for steam activated carbon. The characteristic of the prepared activated carbon was found comparable to the commercial activated carbon.


Assuntos
Carbono/química , Hevea/química , Adsorção , Algoritmos , Compostos Azo/química , Corantes/química , Difusão , Poeira , Indicadores e Reagentes , Resíduos Industriais , Cinética , Microscopia Eletrônica de Varredura , Tamanho da Partícula , Vapor , Temperatura
8.
J Hazard Mater ; 136(3): 791-9, 2006 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-16487654

RESUMO

Eleven different species of marine macroalgae were screened at different pH conditions on the basis of zinc(II) biosorption potential. Among the seaweeds, a green alga, Ulva reticulata, exhibited a highest uptake of 36.1 mg/g at pH 5.5 and 100 mg/l initial zinc(II) concentration. Further experiments were conducted to evaluate the zinc(II) biosorption potential of U. reticulata. Sorption isotherm data obtained at different pH (5-6) and temperature (25-35 degrees C) conditions were fitted well with Sips model followed by Freundlich, Redlich-Peterson and Langmuir models. A maximum zinc(II) biosorption capacity of 135.5 mg/g was observed at optimum conditions of 5.5 (pH) and 30 degrees C (temperature), according to the Langmuir model. It was observed from the kinetic data that the zinc(II) biosorption process using U. reticulata follows pseudo-second-order kinetics. Various thermodynamic parameters, such as DeltaG degrees , DeltaH degrees and DeltaS degrees were calculated and they indicated that the present system was a spontaneous and an endothermic process. The influence of the co-ions (Na(+), K(+), Ca(2+) and Mg(2+)) along with zinc(II) present in the wastewater was also studied. Desorption of zinc(II) ions from the zinc(II)-loaded biomass were examined using 0.1 M CaCl(2) at different pH conditions in three sorption-desorption cycles. A fixed-bed column (2 cm i.d. and 35 cm height) was employed to evaluate the continuous biosorption performance of U. reticulata. The column experiments at different bed heights and flow rates revealed that the maximum zinc(II) uptake was obtained at the highest bed height (25 cm) and the lowest flow rate (5 ml/min). Column data were fitted well with Thomas, Yoon-Nelson and modified dose-response models. The column regeneration studies were carried out for three sorption-desorption cycles. A loss of sorption performance was observed during regeneration cycles indicated by a shortened breakthrough time and a decreased zinc(II) uptake.


Assuntos
Clorófitas/química , Recuperação e Remediação Ambiental , Alga Marinha/química , Eliminação de Resíduos Líquidos , Zinco/química , Adsorção , Algoritmos , Biomassa , Concentração de Íons de Hidrogênio , Modelos Estatísticos , Phaeophyceae/química , Termodinâmica
9.
Bioresour Technol ; 97(12): 1411-9, 2006 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16112568

RESUMO

Biosorption of each of the heavy metals, copper(II) and cobalt(II) by crab shell was investigated in this study. The biosorption capacities of crab shell for copper and cobalt were studied at different particle sizes (0.456-1.117 mm), biosorbent dosages (1-10 g/l), initial metal concentrations (500-2000 mg/l) and solution pH values (3.5-6) in batch mode. At optimum particle size (0.767 mm), biosorbent dosage (5 g/l) and initial solution pH (pH 6); crab shell recorded maximum copper and cobalt uptakes of 243.9 and 322.6 mg/g, respectively, according to Langmuir model. The kinetic data obtained at different initial metal concentrations indicated that biosorption rate was fast and most of the process was completed within 2h, followed by slow attainment of equilibrium. Pseudo-second order model fitted the data well with very high correlation coefficients (>0.998). The presence of light and heavy metal ions influenced the copper and cobalt uptake potential of crab shell. Among several eluting agents, EDTA (pH 3.5, in HCl) performed well and also caused low biosorbent damage. The biosorbent was successfully regenerated and reused for five cycles.


Assuntos
Biotecnologia/métodos , Cobalto/química , Cobre/química , Absorção , Animais , Concentração de Íons de Hidrogênio , Íons , Cinética , Frutos do Mar , Temperatura , Fatores de Tempo , Eliminação de Resíduos Líquidos , Poluentes da Água , Purificação da Água
10.
J Hazard Mater ; 133(1-3): 304-8, 2006 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-16297540

RESUMO

Biosorption of nickel(II) ions from aqueous solution onto Sargassum wightii has been studied and the equilibrium isotherms were determined. The experimental data obtained at different pH conditions (pH 3.0-4.5) have been analyzed using five two-parameter models (Langmuir, Freundlich, Temkin, Dubinin-Radushkevich and Flory-Huggins) and five three-parameter models (Redlich-Peterson, Sips, Khan, Radke-Prausnitz and Toth). In order to determine the best fit isotherm, three error analysis methods were used to evaluate the data: correlation coefficient, residual root mean square error and chi-square test. The error analysis demonstrated that the three-parameter models better described the nickel biosorption data compared to two-parameter models. In particular, Toth equation provided the best model for nickel biosorption data at all pH conditions examined.


Assuntos
Níquel/química , Níquel/metabolismo , Sargassum/metabolismo , Adsorção , Concentração de Íons de Hidrogênio , Íons/química , Modelos Biológicos , Modelos Químicos
11.
Bioresour Technol ; 97(16): 2189-93, 2006 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16293414

RESUMO

The effect of Acid Orange 7, Acid Red 18 and Reactive Black 5 on the growth and decolorization properties of Schizophyllum commune was studied with respect to the initial pH varying from 1 to 6 and initial dye concentration (10-100 mg/L). The optimum pH value was found to be 2 for both growth and color removal of these azo dyes. Increasing the concentration of azo dyes inhibited the growth of S. commune. It was observed that S. commune was capable of removing Acid Orange 7, Acid Red 18 and Reactive Black 5 with a maximum specific uptake capacity of 44.23, 127.53 and 180.17 (mg/g) respectively for an initial concentration of 100 mg/L of the dye. Higher decolorization was observed at lower concentrations for all the dyes. Finally it was found that the percentage decolorization was more in the case of Reactive Black 5 dye compared to the other two dyes used in the present investigation.


Assuntos
Compostos Azo/metabolismo , Naftalenossulfonatos/metabolismo , Rodaminas/metabolismo , Schizophyllum/metabolismo , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/metabolismo , Purificação da Água/métodos , Análise de Variância , Compostos Azo/farmacocinética , Benzenossulfonatos , Concentração de Íons de Hidrogênio , Naftalenossulfonatos/farmacocinética , Rodaminas/farmacocinética , Schizophyllum/crescimento & desenvolvimento
12.
J Hazard Mater ; 126(1-3): 63-70, 2005 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-16040190

RESUMO

Hevea brasiliensis or rubberwood tree, as it is commonly known finds limited use once the latex has been tapped. The sawdust of this tree is chosen to ascertain it viability as a precursor for activation. The carbons thus obtained were characterized in terms of iodine, methylene blue number and surface area. The best carbon in each method was utilized to study the adsorption of Bismark Brown, a dye used in the leather industry. Adsorption equilibrium studies were carried out with the synthetic solutions of the dye, at room temperature (298 K). Equilibrium data are fitted with the Langmuir and the Freundlich isotherms models for the system. The effects of contact time, adsorbent dosage and initial dye concentrations on sorption capacity were carried out. Excellent adsorption capacities of 2000 and 1111 mg g(-1) were obtained for steam and chemical followed by steam-activated carbons, respectively. Pilot-plant experimental studies have been performed using packed-bed column with different feed concentrations, flow rates and bed heights, to evaluate sorption of Bismark Brown on steam-activated carbon. Bed depth service time (BDST) design model have been used to analyze the data.


Assuntos
Compostos Azo/isolamento & purificação , Carvão Vegetal/química , Corantes/isolamento & purificação , Hevea/química , Resíduos Industriais/prevenção & controle , Poluentes Químicos da Água/isolamento & purificação , Poluição Química da Água/prevenção & controle , Adsorção , Cinética , Modelos Químicos , Concentração Osmolar
13.
Chemosphere ; 60(3): 419-26, 2005 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-15924962

RESUMO

Biosorption of copper, cobalt and nickel by marine green alga Ulva reticulata were investigated in a packed bed up-flow column. The experiments were conducted to study the effect of important design parameters such as bed height and flow rate. At a bed height of 25 cm, the metal-uptake capacity of U. reticulata for copper, cobalt and nickel was found to be 56.3+/-0.24, 46.1+/-0.07 and 46.5+/-0.08 mgg(-1), respectively. The Bed Depth Service Time (BDST) model was used to analyze the experimental data. The computed sorption capacity per unit bed volume (N0) was 2580, 2245 and 1911 mgl(-1) for copper, cobalt and nickel, respectively. The rate constant (K(a)) was recorded as 0.063, 0.081 and 0.275 lmg(-1)h(-1) for copper, cobalt and nickel, respectively. In flow rate experiments, the results confirmed that the metal uptake capacity and the metal removal efficiency of U. reticulata decreased with increasing flow rate. The Thomas model was used to fit the column biosorption data at different flow rates and model constants were evaluated. The column regeneration studies were carried out for three sorption-desorption cycles. The elutant used for the regeneration of the biosorbent was 0.1 M CaCl2 at pH 3 adjusted using HCl. For all the metal ions, a decreased breakthrough time and an increased exhaustion time were observed as the regeneration cycles progressed, which also resulted in a broadened mass transfer zone. The pH variations during both sorption and desorption process have been reported.


Assuntos
Metais Pesados/análise , Ulva/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Adsorção , Biomassa , Cobalto/análise , Cobre/análise , Filtração , Cinética , Modelos Químicos , Níquel/análise
14.
J Hazard Mater ; 125(1-3): 121-9, 2005 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-15955624

RESUMO

The biosorption of Acid red 88 (AR88), Acid green 3 (AG3) and Acid orange 7 (AO7) by deactivated fresh water macro alga Azolla filiculoides was investigated in batch mode. Langmuir and Freundlich adsorption models were used for the mathematical description of the batch biosorption equilibrium data and model constants were evaluated. The adsorption capacity was pH dependent with a maximum value of 109.0 mg/g at pH 7 for AR88, 133.5 mg/g at pH 3 for AG3 and 109.6 mg/g at pH 3 for AO7, respectively, was obtained. The pseudo first and second order kinetic models were also applied to the experimental kinetic data and high correlation coefficients favor pseudo second order model for the present systems. The ability of A. filiculoides to biosorb AG3 in packed column was also investigated. The column experiments were conducted to study the effect of important design parameters such as initial dye concentration (50-100 mg/L), bed height (15-25 cm) and flow rate (5-15 mL/min) to the well-adsorbed dye. At optimum bed height (25 cm), flow rate (5 mL/min) and initial dye concentration (100 mg/L), A. filiculoides exhibited 28.1mg/g for AG3. The Bed Depth Service Time model and the Thomas model were used to analyze the experimental data and the model parameters were evaluated.


Assuntos
Compostos Azo/isolamento & purificação , Gleiquênias , Água Doce/química , Corantes Verde de Lissamina/isolamento & purificação , Rodaminas/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação , Poluição Química da Água/prevenção & controle , Adsorção , Compostos Azo/química , Benzenossulfonatos , Corantes/química , Corantes/isolamento & purificação , Concentração de Íons de Hidrogênio , Cinética , Corantes Verde de Lissamina/química , Modelos Químicos , Concentração Osmolar , Rodaminas/química
15.
Environ Technol ; 26(3): 267-76, 2005 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15881023

RESUMO

The ability of crab shell to remove copper and cobalt from aqueous solutions was examined in an up-flow packed column. The experiments were conducted to study the effect of important design parameters such as bed height and flow rate. At a bed height of 25 cm, metal uptake capacity of crab shell for copper and cobalt was 52.07 and 20.47 mg g(-1) respectively. In addition, the results obtained at different flow rates indicated that an increase in flow rate decreased the sorption performance of the crab shell. The Bed Depth Service Time model and the Thomas model were used to analyze the experimental data and the model parameters were evaluated for copper and cobalt sorption. The column regeneration studies were carried out for five sorption-desorption cycles. Loss of sorption performance was observed as the cycles progressed, indicated by a shortened breakthrough time and a broadened mass transfer zone. However, crab shell maintained a good metal sorption capacity for all the five cycles. The elutant used for the regeneration of the crab shell, 0.01 M EDTA at pH 3.5 adjusted using HCI, exhibited elution efficiencies greater than 98%.


Assuntos
Braquiúros/química , Cobalto/química , Cobalto/isolamento & purificação , Cobre/química , Cobre/isolamento & purificação , Modelos Teóricos , Poluentes da Água/isolamento & purificação , Purificação da Água/métodos , Absorção , Animais , Biodegradação Ambiental , Filtração , Tamanho da Partícula , Movimentos da Água
16.
J Hazard Mater ; 119(1-3): 251-4, 2005 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-15752873

RESUMO

This paper discusses the possible application of a biosorption system with acid-washed crab shells in a packed bed up-flow column for the removal of nickel from electroplating industrial effluents. Between two nickel-bearing effluents, effluent-1 is characterized by considerable amount of light metals along with trace amounts of lead and copper. Effluent-2 is characterized by relatively low conductivity, total dissolved solids and total hardness compared to effluent-1. Crab shells exhibited uptakes of 15.08 and 20.04 mg Ni/g from effluent-1 and effluent-2, respectively. The crab shell bed was regenerated using 0.01 M EDTA (pH 9.8, aq. NH3) and reused for seven sorption-desorption cycles. The EDTA elution provided elution efficiencies up to 99% in all the seven cycles. This, together with the data from regeneration efficiencies for seven cycles, provided evidence that the reusability of crab shell in the treatment of nickel-bearing electroplating industrial effluents is viable.


Assuntos
Bivalves/química , Galvanoplastia , Níquel/isolamento & purificação , Purificação da Água/métodos , Adsorção , Animais , Biodegradação Ambiental , Resíduos Industriais
17.
J Hazard Mater ; 113(1-3): 223-30, 2004 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-15363535

RESUMO

This paper investigates the ability of crab shell to remove nickel(II) ions from aqueous solution in a packed bed up-flow column with an internal diameter of 2 cm. The experiments were performed with different bed heights (15-25 cm) and using different flow rates (5-20 ml/min) in order to obtain experimental breakthrough curves. The bed depth service time (BDST) model was used to analyze the experimental data and the model parameters were evaluated. The column regeneration studies were carried out for seven sorption-desorption cycles. The elutant used for the regeneration of the sorbent was 0.01 M EDTA (disodium) solution at pH 9.8 adjusted using NH4OH. Due to continuous usage of crab shell, a performance loss was observed as the breakthrough curves become more flattened also indicated by the broadened mass transfer zone. The breakthrough time decreased uniformly from 28.1 to 9.5 h as the cycles progressed from one to seven, whereas nickel uptake remained approximately constant throughout the seven cycles. The life-factors for crab shell in terms of critical bed length and breakthrough time were found to be 1.1 cm/cycle and 0.17 per cycle, respectively. The elution efficiency was greater than 99.1% in all the seven cycles. The pH profiles during both sorption and desorption process were also reported. In sorption cycles, there was a sudden raise in pH in the early part of the process and then the pH decreased as the time progressed. In desorption cycles, pH decreased in initial stages and followed by gradual increase in pH, which eventually reached the pH of the inlet elutant.


Assuntos
Filtração/métodos , Níquel/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação , Água/química , Adsorção , Estruturas Animais , Animais , Biodegradação Ambiental , Braquiúros , Concentração de Íons de Hidrogênio , Íons/isolamento & purificação , Modelos Químicos , Soluções
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