• Carbon letters
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• v.9 no.2
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• pp.97-104
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• 2008

In the present study Sisal fiber obtained from the leaves of Agave sisalana has been chosen to validate its viability as an adsorbent for the removal of Nickel from aqueous solutions. The material was also surface modified and its effect on adsorption of Nickel was also studied. Agave sisalana fiber was found to be a cheap and effective adsorbent doing away with the need to activate the material therby reducing processing cost. The equilibrium studies indicated that the adsorption capacity of raw fiber and the surface modified fiber was 8.66 and 9.77 mg/g respectively with the Langmuir isotherm describing the adsorption phenomena better than the Freundlich and Temkin isotherm. The adsorption was found to be exothermic from the thermodynamic studies and the kinetics showed that the adsorption phenomena were second order.

• Journal of Environmental Health Sciences
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• v.29 no.3
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• pp.50-58
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• 2003

Removal of heavy metal ions (Cd$^{2+}$, Cr$^{3+}$, Cu$^{2+}$, Pb$^{2+}$) by several chitosans was studied and the molecular weight of chitosan was investigated in order to examine the effect of autoclaving. Chitosan were divided into 3 groups (A type, controlled chitosan; B type, autoclaved for 15 min; C type, autoclaved for 60 min). The heavy metal removal capacity and rate of B type chitosan were higher than those of A type and B type chitosan. The molecular weight of chitosan was decreased by the increase of autoclaving time. Therefore, the heavy metal capacity was not well correlated to the molecular weight. Freundlich and Langmuir isotherm was determined from the experimental results of equilibrium adsorption for individual heavy metal ions on chitosan. Langmuir isotherm was well fitted to this experimental data. The heavy metal removal capacity of B type chitosan was in the order of Pb$^{2+}$ > Cu$^{2+}$ > Cd$^{2+}$> Cr$^{3+}$.3+/.$.3+/.

• Archives of Pharmacal Research
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• v.14 no.3
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• pp.249-254
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• 1991

Activated carbons from rice-straw can be used as an adsorbents for the purification of water were prepared and evaluated. The adsorptive capacities of activated carbons were measured by iodine, potassium permangante, phenol and metals. It was observed by electron microscope (SEM) and IR spectrum that organic components in the rice-straw and its carbonization product were disappeared. Slit-shaped and porousstructures were formed by activation. There was no relationship between temperature and adsorption of iodine but adsorption of potassium permanganate increased as temperature rose. The adsorption of the phenol was greater than 99%. The adsorption data of phenol at $25^\circ{C}$ obeyed the Freundlich's isotherm. Various metals except sodium were not removed by activated carbon.

• Journal of Environmental Science International
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• v.4 no.5
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• pp.141-141
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• 1995

The waste biomass of Sacchromyces uvarum, used in fermentation industries to produce ethanol, were studied for their ability to absorb various heavy metal ions. Heavy metal ions studied in this research were Cd, Co, Cr, Cu, Ni and Pb. The order of the sorption capacity was Pb>Cu>Co=Cr=Cd>Ni. The living Sacchromyces uvarum exhibited higher metal-uptake capacity than the dead Sacchromyces uvarum. After we compare the uptake capacity of the Sacchromyces uvarum for individual metal ions with for a mixture of them, the following was observed: in the mixed heavy metal solution the uptake capacity was decreased than the one heavy metal solution. The selective uptake was observed when all . the heavy metal ions were dissolved in a mixed solution. The adsorption isotherm modelling was decribed with the Langmuir and Freundlich model. The results were in good agreement with the Langmuir model.

• Journal of Environmental Science International
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• v.4 no.5
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• pp.527-534
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• 1995

The waste biomass of Sacchromyces uvarum, used in fermentation industries to produce ethanol, were studied for their ability to absorb various heavy metal ions. Heavy metal ions studied in this research were Cd, Co, Cr, Cu, Ni and Pb. The order of the sorption capacity was Pb>Cu>Co=Cr=Cd>Ni. The living Sacchromyces uvarum exhibited higher metal-uptake capacity than the dead Sacchromyces uvarum. After we compare the uptake capacity of the Sacchromyces uvarum for individual metal ions with for a mixture of them, the following was observed: in the mixed heavy metal solution the uptake capacity was decreased than the one heavy metal solution. The selective uptake was observed when all . the heavy metal ions were dissolved in a mixed solution. The adsorption isotherm modelling was decribed with the Langmuir and Freundlich model. The results were in good agreement with the Langmuir model.

• Journal of the Korean Society of Safety
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• v.15 no.2
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• pp.84-91
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• 2000

The adsorption characteristics of a respirator cartridge is affected by the kind of adsorbent, concentration of organic vapor, humidity and packing density of cartridge. In this study, activated carbon fiber(ACF) instead of activated carbon is used as a adsorbent of cartridges for the removement of organic vapor and the adsorption characteristics were examined. ACF made of cellulose showes high efficiency for the removal of carbon tetrachloride and the adsorption capacity was 0.569g/g ACF at 450 ppm. The relative humidity dose not affected to the adsorbed amount and Langmuir Isotherm was more adequate than Freundlich Isotherm for this adsorption phenomena.

• Journal of environmental and Sanitary engineering
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• v.13 no.1
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• pp.112-122
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• 1998

In recent years the accumulation of heavy metals in microorganisms, the biosorption has received much attention because of various environmental application. We have been to research the biosorption characteristics using algae, Spirulina, for the removal of heavy metal ions in industrial and polluted waters. In the adsorption of single heavy metal ions, the adsorption equilibrium was reached within 10min., and optimum pH and reaction temperature were 4.5-5 and 30-35$\circ $C, respectively. Under the above conditions, the maximum amounts of Pb, Cu, and Cd adsorbed to the unit weight of Spirulina were 107.6mg/g, 78.0mg/g, and 65.6mg/g, and three values were 1.45, 1.56, and 1.26 times higher than those adsorbed to the unit weight of activated carbon under same conditions. The adsorption kinetics of Pb, Cu, and Cd were fitted very well to the Freundlich isotherm and BET isotherm. Biosorption experiments in single ion solutions and binary ions solutions showed higher removal efficiency in the single ion solutions than in binary ions solutions.

• Journal of the Korean Society of Clothing and Textiles
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• v.22 no.5
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• pp.557-564
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• 1998

Dyeing properties of silk fabric with black tea colorants were investigated in terms of dye uptakes at various dyeing conditions and the effect of mordants on color change and colorfastness. Black tea colorants showed high affinity to silk and produced brown color. Two types of adsorption isotherm were obtained; Langmuir and Freundlich equilibrium at 360 nm and 460 nm, respectively. Thus, it is considered that both of ionic and hydrogen bondings are involved in silk dyeing with black tea colorants. Dye uptake increased continuously as concentration of colorants increased. Brown color was not changed with mordant type except that Fe mordant produced dark brown color. Mordanting did not influence colorfastness of dyed silk significantly. Therefore, mordanting was not necessary in dyeing silk with black tea colorants.

• Bulletin of the Korean Chemical Society
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• v.34 no.11
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• pp.3391-3398
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• 2013

The carboxylated multiwall carbon nanotubes (MWCNT-COOH) and functionalized with isatin derivative (MWCNT-isatin) have been used as efficient adsorbents for the removal of lead (Pb) from aqueous solutions. The influence of variables including pH, concentration of the lead, amount of adsorbents and contact time was investigated by the batch method. The adsorption of the lead ions from aqueous solution by modified MWCNTs was studied kinetically using different kinetic models. The kinetic data were fitted with pseudo-first-order, pseudo-second-order, and intra-particle diffusion models. The sorption process with MWCNT-COOH and MWCNT-isatin was well described by pseudo-second-order and pseudo-first-order kinetics, respectively which it was agreed well with the experimental data. Also, it involved the particle-diffusion mechanism. The values of regression coefficient of various adsorption isotherm models like Langmuir, Freundlich and Tempkin to obtain the characteristic parameters of each model have been carried out. The Langmuir isotherm was found to best represent the measured sorption data for both adsorbent.

• Journal of Environmental Health Sciences
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• v.23 no.4
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• pp.21-25
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• 1997

A study on the removal of mercury by Saccharomyces cerevisiae and Aureobasidium pullulans was done, in which the model of adsorption isotherm and adsorption rate was proposed. The adsorption isotherm of mercury by S. cerevisiae was accorded with Langmuir model but A. pullulans was followed to Freundlich model. The amount of mercury removed by A. pullulans was higher than that of S. cerevisiae, but the adsorption rate of mercury by A. pullulans was slower than that of S. cerevisiae. In a rapid adsorption process, therefore, it is more useful to use S. cerevisiae as a biosobent.