Removal Efficiency of Hexavalent Chromium from Laboratory Wastewater Treated by Combined Precipitation using NaOH and Ca(OH)2 with Adsorption by Granular Activated Carbon
Fadli Mulyadi, Yulianti Pratama, Lina Apriyanti
National Institute of Technology, Bandung
Abstract
Liquid laboratory waste generated from water quality examination activities especially from the COD (Chemical Oxygen Demand) analysis. The COD wastewater contains Cr VI which potentially pollute the environment due to its carcinogenic effect. The research aimed to determine the efficiency of removal of Cr VI treated by a combination between precipitation and adsorption methods. In this research, the variations of precipitate and height of adsorbent were made. Two types of hydroxide precipitate between NaOH and Ca(OH)2 were used in this research at concentrations of 50%. The pH levels were adjusted between 8; 9; 10; 11 while the heights of adsorbent were varied of 7,5 cm, 15 cm, and 22,5 cm, respectively. Results showed that the highest Cr VI removal of 60,98% was obtained by precipitation process using Ca(OH)2 50% with the pH adjusted at 9,06. Whereas the significant adsorption efficiency was achieved 88.13% by the height of granular activated carbon of 22.5 cm with the addition of acidification process.
Keywords: COD contained wastewater, Hexavalent Chromium, Precipitation, Adsorption, Granular Activated Carbon.
Topic: Environmental Technology