Banana peel: a green and economical sorbent for Cr (III) removal

Anal. Environ. Chem 01/2008; 9(1):20-25.


Banana peel, a common fruit waste has been investigated to remove and preconcentrate Cr(III) from industrial wastewater. It was characterized by FT-IR spectroscopy. The parameters pH, contact time, initial metal ion concentration and temperature were investigated and the maximum sorption was found to be 95%. The binding of metal ions was found to be pH dependent with the optimal sorption occurring at pH 4. The retained species were eluted using 5mL of 2 M HNO 3 . The mechanism for the binding of Cr(III) on the banana peel surface was also studied in detail. The Langmuir and Dubinin-Radushkevich (D-R) isotherms were used to describe the partitioning behavior for the system at different temperatures. Kinetic and thermodynamic measurements of the banana peel for chromium ions were also studied. The method was applied for the removal and preconcentration of Cr(III) from industrial wastewater. Chromium is the common contaminant in wastewater from electroplating, leather tanning and metal-finishing plants. The physiological effects of chromium on the biological system depend upon its oxidation state i.e. Cr(III) and Cr(VI). Cr(III) may be considered as an essential trace element for the proper functioning of living organisms (mammals) e.g. for the maintenance of "glucose tolerance factor"; it is thought to be a cofactor for the insulin action and to have a role in the peripheral activity of this hormone. The toxicity of metal ions comes to play when their concentration values exceed than the threshold value. Chromium is toxic, corrosive and irritant. The maximum allowable limit for total chromium in drinking water as recommended by the World Health Organization (WHO) is 0.05 mg L -1 [1]. The conventional chromium treatment method consists of following three steps.

Download full-text


Available from: Saima Memon
Show more