Separation Science and Technology, Vol.41, No.5, 943-959, 2006
Adsorption of Fe+3 and Mn+2 from ground water onto maize cobs using batch adsorber and fixed bed column
The removal of iron and manganese from ground water is an important step for producing safe drinking water. A detailed investigation of the sorption of iron and manganese from ground water onto maize cobs is reported. This work deals with determination of adsorption equilibrium isotherms, kinetic, and fixed bed column studies. Results of Freundlich and Langmiur parameters revealed the favorability of maize cobs for adsorption of iron and manganese ions. Kinetic studies were carried out using from ground water samples (El-Mina Governorate, Egypt). From the kinetic studies, a model is proposed to determine the external mass transfer (Ks) which can be correlated by the following equation Ks =A (mass) B . where A and B are constants. During the fixed bed column studies, the effect of process variables such as bed height, flow rate, initial concentration, and percentage breakthrough has been investigated. A simplified design method, namely, the bed depth service time (BDST) model has been applied to the experimental data and the results of this analysis are presented. The mechanism of the metal ion sorption on maize cobs was also investigated. Both the calorific values and differential thermal analysis (DTA) data proved that the loaded maize cobs can be used as solid fuel. Pretences of iron and manganese salts catalyze the thermal decomposition reaction toward more flammable gases, which increase their calorific values. The loaded maize cobs are considered a new potential source for energy conversion.
Keywords:ground water;iron and manganese removal;maize cobs;adsorption equilibrium isotherms;kinetic studies;fired bed column studies