Determination of Fe(III) in manganese processing’s waste water using digital image methods with Terminalia catappa L. leaves extract as a complexing agent

Generally, chemical analysis-including metal ions analysis-involves the use of complexing agents that react with analytes to produce color change which can be used to identify the analytes both qualitatively and quantitatively. The disadvantages of using of those complexing agents can be viewed from the economical and environmental perspective. The use of a reagent categorized as green reagent can overcome the limitation of the conventional complexing agents. In this work, ethanol extract of Terminalia catappa L. leaves was used as complexing agent to determinate Fe(III) in waste water of manganese processing employing digital image method. The calibration curve with correlation coefficient approaching 1 indicated that this method was compatible for determination of Fe(III). By comparing this method with a standard method of Fe(III) determination using spectrophotometry UV-Vis with KSCN as complexing agent, we found that the two methods for determining of Fe(III) did not differ significantly in terms of precision but differed significantly for accuracy. The concentration of Fe(III) in waste water of manganese processing determinated using digital image method and spectrophotometry method were 0.005 ppm and 0.008 ppm respectively. It is recommended to purify the extract before it will be applied for this purpose.