PhD research student Abhijit Chatterjee will exlpain his research on methods for treating metal-bearing wastewater at the March 9 WERC Friday Seminar.
Simultaneous removal of Cd (II) and Zn (II) ions by protonated citrus peels in batch and fixed-bed reactors
Conventional methods for treating metal-bearing wastewater, such as chemical precipitation, ion exchange and membrane filtration, often fail to meet stringent regulatory criteria or are too costly to operate for dilute wastewaters. Alternatively, biosorption is a low cost technique for removing metals from the wastewater based on the metal-sequestering capacity of certain natural organic materials. Those may be microbial biomass or agricultural residues which are particularly suitable for concentrating metals from a large volume of dilute discharge such as mining effluent.
This study focused primarily on the simultaneous biosorption of Cd (II) and Zn (II) ions by protonated citrus peels in batch and fixed-bed reactors. For experimental purposes, it is easier to utilize a batch reactor than a fixed bed reactor while the latter is more suitable from a commercial point of view as it can be operated at a continuously higher driving force. A fixed-bed column made of clear extruded polyacrylic with a length of 30 cm and a diameter of ž inch was used for the dynamic study, whereas equilibrium isotherms were derived from batch experiments. The equilibrium uptake of Cd (II) and Zn (II) ions was found to be 0.68 and 1.02 meq/g respectively, according to single metal isotherms at pH 5.0. When both metals were biosorbed simultaneously, equilibrium uptake capacities were decreased due to competitive behavior. It was observed that biosorption of Zn (II) ions was more influenced by the presence of Cd (II) ions than vice-versa. In the fixed bed reactor, 19 L of feed solution containing 0.1 meq/L of Cd (II) ions were treated in the column at a flow rate of 9 ml/min until breakthrough occurred. Compared to that, the breakthrough volume was only 16 L for a feed solution containing 0.1 meq/L Zn (II) ions. When both metals were present simultaneously, individual breakthrough volumes were decreased compared to the mono-component systems. Citrus peels were found to remove Cd (II) and Zn (II) ions from a sample of mining effluent which was collected from Greens Creek Mine, Juneau. Breakthrough curves were modeled considering a finite mass transfer rate.
Courtesy Abhijit Chatterjee
Abhijit Chatterjee is conducting a batch experiment using Metrohm auto-titrator to determine the efficiency of citrus peels in removing toxic metal ions from aqueous sample.
Friday Seminar Series
- What:Simultaneous removal of Cd (II) and Zn (II) ions by protonated citrus peels in batch and fixed-bed reactors
- Who: Presenter Abhijit Chatterjee
- When: 3:30-4:30 p.m. Friday, March 9
- Where: 531 Duckering
Seminar schedule in PDF