Chromium (III) Removal and Recovery from Tannery Wastewater by Precipitation Process
Abass Esmaeili, Alireza Mesdaghi nia and Reza Vazirinejad
DOI : 10.3844/ajassp.2005.1471.1473
American Journal of Applied Sciences
Volume 2, Issue 10
Chromium (III) salts are the most widely used chemicals for tanning processes, but 60-70% of total chromium salts reacts with the hides. In the other word, about 30-40% of the chromium amount remains in the solids and liquid wastes (especially spent tanning solutions). Therefore, the removal and recovery of the chromium content of these wastewaters are necessary for environmental protection and economic reasons. Removal and recovery of chromium were carried out by using precipitation process. For this purpose, three precipitating agents calcium hydroxide, sodium hydroxide and magnesium oxide were used. The effects of pH, stirring time, settling rate and sludge volume were studied in batch experiments. Results show that the optimum pH is 8-9 and the good sludge with high settling rate and lower volume obtain by the MgO precipitating agent. Hence the MgO is a good precipitating agent for removal and recovery of chromium from tanning wastewater.
© 2005 Abass Esmaeili, Alireza Mesdaghi nia and Reza Vazirinejad. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.