Sorption experiments of heavy metals using the Aspergillus niger fungus for cadmium removal were carried out to study the factors influencing the biosorption of heavy metals. By studying the isotherm in series, the effects of pH, time, amount of biomass, and initial concentration of the heavy metal on the rate of metallic biosorption were examined. An experimental planning was also carried out with view to determine the values of the studied variables that provided greater biosorption efficiency. This research work proved that the biosorption process with fungus could successfully be used for heavy metal removal from oil field water in the oil industry.
Bacteria, fungus and seaweed could be used to remove heavy metals and radioactive compounds from aqueous solutions1. Biosorption carried out by fungus is an optional form of treatment of effluents charged with toxic metallic ions2.
The objective of the present research was to study the effect of pH, concentration of cadmium, amount of biomass and time on biosorption of cadmium using Aspergillus niger biomass.
Methods Biosorption Experiments Biosorption experiments in series were carried out separately in order to study the pH effect, time, biomass quantity and initial concentration of the heavy metal in the removal process of the metallic cadmium. Concentrations of the heavy metal were determined using a spectrophotometer for atomic absorption.
Experimental Planning Modeling of the biosorption process studied at laboratory was carried out according to an experimental planning. In this study the programs MODREG and STATISTIC for Windows, Release 5.5, consisting of an experimental planning with a central point were used.
Results and Effect of pH on Biosorption Discussions The effect of the pH on the biosorption of cadmium by the Aspergillus niger biomass could be seen in Figure 1.
BLOCK 1 - - FORUM 6 567
Sorption capacity Sorption capacity Equilibrium concentration Equilibrium concentration 77 10 10 66 88 55 4 6 4 6 33 44 (mg/L)(mg/L) 22 22 11 Equilibrium concentration Equilibrium concentration Sorption capacity (mg/g BM)Sorption capacity (mg/g BM) 00 00 22 33 44 55 66 77 pH pH Figure 1: Biosorption of cadmium by Aspergillus Niger dependent on pH value.
For the Aspergillus niger, the optimum biosorption (mg of Cd / g of biomass) and low equilibrium concentration (mg of Cd / L) were obtained with a pH ranging between 4.0 and 5.5.This range was selected for the experimental planning.
Analysis of the Kinetics of the Cadmium Biosorption by Aspegillus niger.
The cadmium biosorption i
