GAC adsorption treated pulp and paper mill effluents using ozone as a pre-treatment

Abstract

This research examined the impact of ozonation on lignin-derived and aliphatic compounds ratio (L/A ratio) in secondary pulp and paper mill effluents. Afterwards, adsorption process was employed to investigate the adsorption behavior of ozonized compounds on granular activated carbon (GAC). Phenol and isopentanoic acid (IPA) were practically used as substitute of lignin-derived and aliphatic compounds, respectively. The paper presents the results obtained at laboratory scale with ozone and GAC adsorption as a mean to obtain effluents suitable as reclamation for pulp and paper industry, which requires very stringent limitation in terms of DOC and color removal. The conversion of recalcitrant nature of pulp and paper mill wastewater had been moderate in term of L/A ratio after time interval of ozonation. After ozonation pre-treatment, the adsorption experimental was performed to investigate the adsorption behaviors of phenol and IPA from aqueous solutions onto GAC compared with the decolorization behaviors in real effluents. The best isotherm models fitted to phenol and IPA adsorption on PPHO were determined in the order of Ridlich-Peterson isotherm > Langmuir isotherm > Freundlich isotherm. The IPA was adsorbed strongly on GAC as compared with phenol due to its properties. The maximum adsorption capacity of phenol and IPA on GAC were 0.32 g.g-1 and 0.65 g.g-1, respectively. As result in real effluents, the adsorption capacity of color from the ozonized effluents on GAC was 132.93 ADMI unit.L/mg which was much higher than those of non-ozonized effluents (78.78 ADMI unit.L/mg) and synthetic lignin solutions (55.97 ADMI unit.L/mg).