Title : " Reduction of Some Trace Metals in Industrial Effluents by Treated Onion and Shallot Skin”

Researcher : Saisunee Liawruangrath and Sawittree Rujitanapanich

Office of Researcher : CHEMISTRY


The use of some agricultural by-products, namely onion and shallot skin, for waste water treatment was investigated. The onion and shallot skin were tested as binding materials after appropriate treatments. Preliminary investigations have been carried out using the treated onion and shallot skins for binding some trace metal ions (Pb2+, Zn2+, Cu2+, Cd2+ and Mn2+) from spiked water samples by both string and passage through a column packed with the treated onion and/or shallot skin. The binding efficiencies of the meterials with various metal ions were determined by analyzing the metal ion content in the spiked water samples before the after treatment with each material atomic absorption spectrophotometrically. It was found that the binding efficiencies of the treat onion skin were slightly better than these of the treated shallot skin and the binding efficiencies was improved by using the packed column. For a mixture of metal ions in spiked water samples the competion among various heavy metal ions for onion and shallot skin was shown to be as follows. Pb2+>Cu2+>Cd2+>Zn2+>Mn2+.The reproducibilities (%RSD) obtainable using the packed column were 1.09% and 0.97%(n=7) for shallot and onion skin respectively. The recommended procedure has been successfully for the treatment of some heavy metals in industrial waste water.

Presented at : The 1st International Conference on Water Resources Management In Intermontane Basins, Chiang Mai, 2-6 February 1999.