Book of Abstracts - Ruhr-Universität Bochum

P-65
ISBOMC `10 5.7 – 9.7. 2010 Ruhr-Universität Bochum
Study of Heavy Metals Biosorption from Aqueous Solutions
by Using Biological Wastes
Mohammad Ali Zazouli, *a and Mayram Bagheri a
a Department of Environmental Health Engineering, Faculty of Health, Mazandaran University of
Medical Sciences, Sari, Iran, E-mail: Zazoli49@yahoo.com
Heavy metal pollution is posing significant threats to the environment and public health because of its
toxicity, non-biodegradability and bioaccumulation. 1 The increasing environmental concern for these
contaminants, there has been serious interest in removal of heavy metals from contaminated
wastewater & water. A number of technologies such as precipitations, ion exchange, membrane
processes and adsorption on activated carbon, have been used over the years to remove toxic metals
from water but these techniques are often ineffective and/or very expensive in the reduction of heavy
metals from water at very low concentration. 2 The search for alternative and innovate treatment
techniques has focused attention on the use of biological materials for heavy metal removal. The
objective of this study is to investigate of heavy metals (Cadmium, Chromium and lead) biosorption
from aqueous solutions by using orange mesocarp and rice husk.
The selected biomass were first cut into small size, washed with water to remove impurity and soluble
components and oven-dried at 100 o C for 24h until constant weight was reached. The washed and
dried materials were crushed and sieved using 1.00 mm mesh size sieve. Then pretreated separately
with soaking in NaOH(0.4N) and HNO3(0.4N) for 24h. After that washed with distilled water until it
had no color in the filtrate. Biosorption studies were carried out batch method. After the desired
contact time, the biosorbent was removed by filtration. The metal concentrations were measured by
using atomic absorption spectrophotometer. All experiments were conducted in duplicate. Finally,
Adsorption isotherms of metal on adsorbents were determined.
Results show that metal sorption initially increases with increasing in metal concentration in the
solution, and then becoming saturated after a certain concentration of metal. The maximum sorption
capacities with orange waste were for Cr and with rice husk was Pb. The results showed that the
percentage removal of metals as a function of equilibrium pH. The effect of pH on metals sorption was
very different for all metals and for two biosorbents. Biosorption was very fast for the first 30 min but
slowed markedly after 1 h. Biosorption continued to increase after which it became constant reaching
equilibrium. The adsorption data fit well with the Langmuir and Freundlich isotherm model for orange
waste and rice husk, respectively.
This study indicates that both biomass residues have the capacity to remove metal ions from aqueous
solution, and the amount of the heavy metal ions bound by cellulosic substrate depends on the metal
ion type, biosorbent type and dosage, pH and contact time. Thus, orange waste and rice husk could be
potentially used for the removal of heavy metals from aqueous solution as erials stand out as very
good and lowest biosorbents.
Keywords: Biosorption, Heavy metals, Orange wastes, Rice husk, Biological wastes
References
1. E.-S. Z. El-Ashtoukhy, N.K. Amin, O. Abdelwahab, Desalination. 2008, 223, 162-173.
2. A.B. Pérez-Marín, A. Ballester, F. González, M.L. Blázquez, J.A. Muñoz, J. Sáez, V. Meseguer
Zapata, Bioresour. Technol. 2008, 99, 8101-8106.
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