**2.5. Modification of the dried algae**

The algae were modified by anchoring tetramethylethylenediamine onto its chemical structure to improve its chelating property [15]. The modification procedure involved chlorination of the biomaterial first and then condensing the resultant with the amino compound. A sample of the algae (30 g) was chlorinated using thionyl chloride (SOCl2) 100 ml, and the mixture heated under reflux at a temperature of 80°C for 4 h with continuous stirring. The chlorinated biomaterial was then washed with 100 ml of distilled water. The solution was filtered using Whatman No. 1 filter paper and dried in an oven set at 60°C. The dry chlorinated sample was then treated with 25.0 ml of tetramethylethylenediamine and refluxed for 3 h to anchor the tetramethylethylenediamine structure into the algal biomass.
