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NISCAIR ONLINE PERIODICALS REPOSITORY (NOPR) >
NISCAIR PUBLICATIONS >
Research Journals >
Indian Journal of Natural Products and Resources (IJNPR)
[Formerly Natural Product Radiance (NPR)] >
NPR Vol.4 [2005] >
NPR Vol.4(5) [September-October 2005] >
| Title: | Dye |
| Issue Date: | Oct-2005 |
| Publisher: | CSIR |
| Abstract: | Low-cost
adsorbents have been investigated at the laboratory scale for the treatment of
coloured effluents with different degrees of success by researchers at
Department of Chemistry, Gauhati University, Guwahati, India. The dye, Methylene
Blue, was adsorbed on an adsorbent prepared from mature leaves of the Neem tree
(Azadirachta indica A. Juss.). A batch adsorption
study was carried out with variable adsorbate concentration, adsorbent amount,
pH and temperature. Ninety-three per
cent of the dye could be removed by 2g of the Neem leaf powder from 1 litre of
an aqueous solution containing 25mg of the dye at 300K. The adsorption followed
pseudo first order kinetics with a mean rate constant of
3.73×10−3/min and an intra-particle diffusion rate constant of
6.36×10−2mg/g/min−0.5. A possible mechanism of adsorption
was suggested on the basis of concurrently operating surface adsorption and pore
diffusion. The experimental data yielded excellent fits with Langmuir and
Freundlich isotherm equations. The Langmuir monolayer capacity had a mean value
of 8.76mg/g. The adsorption of the dye was endothermic in nature (ΔH:
4.62–16.74kJ/mol) and was accompanied by an increase in entropy (ΔS:
54.22–90.23J/mol/K) and a decrease in Gibbs energy (ΔG: −10.33 to
−13.62kJ/mol in the temperature range of 300–330K). The results indicated that
the dye, Methylene Blue, strongly interacts with a biomass-based adsorbent, the
Neem leaf powder. |
| Page(s): | 418 |
| ISSN: | 0975-1092 (Online); 0972-592X (Print) |
| Source: | NPR Vol.4(5) [September-October 2005]
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