Adsorption of Nonylphenol onto Granular Activated Carbon

The applicability of granular activated carbon (GAC)filtration for the removal of the xeno-estrogenicmicropollutant nonylphenol (NP) is evaluated using batchadsorption data. From the obtained adsorption data, it wasapparent that with contact times of 4 d and 24 hr and GACdosages of 1 and 0.1 g L^-1 no saturationof the GAC could be obtained with NP total contaminantloadings up to 10 000 μg L^-1.Higher NP concentrations could not be applied due to its lowwater solubility (～5 mg L^-1). The influence of temperature(4 or 28 °C) on NP sorption onto GAC was negligible.The results showed that the sorption capacity of GAC for NPwas at least 100 mg g^-1 GAC. According to thesedata it can be concluded that a full-scale GACfilter unit will be sufficient to remove environmentallyrelevant NP concentrations of 10 μg L^-1.Consequently, the existing GAC treatment technology indrinking water treatment should protect the consumer from theintake of the xeno-estrogenic micropollutant NP via drinkingwater. The sorption capacity of dissolved humic acids (DHA)for NP is considerable at liquid NP concentrations of 10 μgL^-1 and the affinity of DHA for GAC is not significant.These observations suggest that interference on removal of NP onGAC, due to the presence of DHA, can be expected at microgramper liter concentrations of NP. They may warrant the removalof humic substances in treatment steps preceding GAC-filtration.