Efficiency of EDTA and TWEEN 80 for the Removal of Chromium using Soil Washing Technologies

The study on the efficiency of chelate and surfactant for the removal of chromium using soil washing technology of which the chelate is EDTA and surfactant is TWEEN 80 at concentrations of 8, 16 and 32 millimoles was separately conducted. The experiment soil was synthetic soil with chromium contamination for 2 years. In this study, 20 g of contaminated soil would be washed with 200 milliliters of EDTA and TWEEN 80 with pH values of 2, 4, 6, 8 and 10 before being shaken at speeds of 90, 120 and 150 rpm for 15, 30, 60, 90, 120 and 180 min and at every 3 h until it reached its equilibrium point at room temperature. After that it was filtered with filter paper before digestion with acid whereupon the obtained solution would be further analyzed. The study result revealed that EDTA could remove chromium best at a concentration of 32 millimoles with pH of 10 and shaking speed of 120 rpm and it could eliminate chromium at the level of 38.54%. In the meantime, TWEEN 80 could remove chromium best at a concentration of 32 millimoles with pH of 10 and shaking speed of 150 rpm and it could eliminate chromium at the level of 9.86%. Therefore, when comparing efficiency between EDTA and TWEEN 80, the researcher concluded that EDTA had higher efficiency in removing chromium from soil than TWEEN 80.