Effect of Solution pH to Indigosol Blue Adsorption on Humic Acid Isolated from Kalimantan Peat Oil

Abstract

There has been study on the isolated of humic acid and its interaction with indigosol blue. The objectives of study were to isolate humic acid from Kalimantan peat soil and to study pH optimation indigosol blue on humic acid. Isolated of humic acid using alkali extraction method with NaOH as solvent and precipitated with HCl. Humic acid was characterized using FTIR spectroscopy to determine functional group. Based on the result FTIR characterization, adsorption of humic acid was found in the wave number 3140,15 cm-1 which show the vibration of -OH, 2924,09 cm-1 show vibration of aliphatic -CH, 1705 cm-1 show vibration -C = O of COOH, 1627,92 cm-1 show vibration of C=C aromatic and 1226,73 cm-1 indicate of -OH and CO from -COOH. Based on the result of study, pH optimation of indigosol blue at pH 5.