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International Journal of Environment Science and Technology
Center for Environment and Energy Research and Studies (CEERS)
ISSN: 1735-1472
EISSN: 1735-2630
Vol. 10, No. 6, 2013, pp. 1255-1264
Bioline Code: st13122
Full paper language: English
Document type: Research Article
Document available free of charge

International Journal of Environment Science and Technology, Vol. 10, No. 6, 2013, pp. 1255-1264

 en Sorption of lead by chemically modified rice bran
Fatima, T.; Nadeem, R.; Masood, A.; Saeed, R. & Ashraf, M.

Abstract

In this work, the effectiveness of native and chemically modified rice bran to remove heavy metal Pb(II) ions from aqueous solution was examined. Chemical modifications with some simple and low-cost chemicals resulted in enhancement of the adsorption capacities and had faster kinetics than native rice bran. Experiments were conducted in shake flasks to monitor the upshot of parameters over a range of pH, initial Pb(II) concentrations and contact times using a batch model study. The sorption capacities q (mg g -1 ) increased in the following order: NaOH (147.78), Ca(OH) 2 (139.08), Al(OH) 3 (127.24), esterification (124.28), NaHCO 3 (118.08), methylation (118.88), Na 2 CO 3 (117.12) and native (80.24). The utmost uptake capacity q (mg g -1 ) was shown by NaOH-pretreated rice bran. The results showed that, using NaOH-modified rice bran, the chief removal of Pb(II) was 74.54 % at pH 5, primary Pb(II) concentration 100 mg L -1 and contact time 240 min. Equilibrium isotherms for the Pb(II) adsorption were analyzed by Langmuir and Freundlich isotherm models. The Langmuir isotherm model, showing Pb(II) sorption as accessible through the high value of the correlation coefficient ( R 2 = 0.993), showed a q max value of 416.61 mg g -1 . The kinetic model illustrated adsorption ates well, depicted by a second order, which gives an indication concerning the rate-limiting step. Thermodynamic evaluation of the metal ion δ G ° was carried out and led to the observation that the adsorption reaction is spontaneous and endothermic in nature. NaOH chemically modified rice bran was a superb biosorbent for exclusion of Pb(II) and proved to be excellent for industrial applications.

Keywords
Equilibrium isotherm; Gibbs free energy; Industrial wastewater; Pretreatments

 
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