EFFECT OF ETHYLENEDIAMINETETRAACETIC ACID (EDTA) AND NITRILOTRIACETIC ACID (NTA) ON CADMIUM REMOVAL BY HYDROPONICS WITH MOFF DWARF NAPIER GRASS (Pennisetum purpureum cv. Mott)
Abstract:
The effects of ethylenediaminetetraacetic acid (EDTA) and nitrilotriacetic acid (NTA) on cadmium removal from the synthetic contaminated water by hydroponics with Moff dwarf napier grass (Pennisetum purpureum cv. Mott) were studied. The experimental sets can be divided into 5 groups including 1) uncontaminated water (deionized water without chelating agents), 2) contaminated water without addition of chelating agents, 3) contaminated water with EDTA addition with the Cd:EDTA ratio of 1:0.5 and 1:1 mole, 4) contaminated water with NTA addition with the Cd:NTA ratio of 1:0.5 and 1:1 mole, and 5) contaminated water with both EDTA and NTA addition with the ratio of 1:0.5 and 1:1 mole. Experimental sets 1 and 2 were considered as the control sets in this study. Plant and water samples were collected and analyzed for total Cd concentrations at 1, 15, 30, 45, 60, 75, 90 and 105 days. The accumulation of Cd in plant was determined in two parts of the plant which are shoot (stem and leaves) and root. The analytical results of all experimental sets showed highest Cd accumulation after 30 days of the experiment significant higher Cd accumulation in root than shoot were found. In addition, the accumulations of Cd in both shoots and roots of napier grass in all experimental sets with chelating agent were significant higher than those Cd accumulations in shoots and roots of napier grass in the control sets. When focusing at the molecular ratio of 1:1 of chelating addition, it was found that highest Cd concentrations of 256.97, 255.25 and 263.25 mg/kg dry weight were found in the shoots of napier grass collected from the experimental sets of EDTA, NTA and EDTA+NTA addition, respectively. While highest Cd accumulations in the roots of napier grass from these 3 experimental sets were 889.31, 638.98 and 596.59 mg/kg dry weight, respectively. In addition, it was found that higher amount of chelating agent addition could resulted in the higher Cd accumulation in both shoots and roots. About 3.46, 2.50 and 2.27 times of the ratio of Cd accumulation in roots and shoots were determined from the experimental sets with EDTA, NTA and EDTA+NTA addition, respectively. Therefore, it could be concluded that EDTA can enhance the translocation and accumulation of Cd in napier grass than the use of NTA and EDTA+NTA as the chelating agents.