Transport behaviors of humic acid, kaolin and kaolin–humic acid compound colloids on naphthalene in floating islands with biofilmed fillers

Abstract As one of the persistent organic pollutants, the investigations of naphthalene transports with humic acid, kaolin and kaolin–humic acid compound colloids by passing through the floating islands with biofilmed filler matrix pores were checked out. Naphthalene was easily captured onto the biofilmed fillers while it was passing through the floating islands with the filling percentages of 0.0 to 60.0 by absorbing bigger contaminated colloids, reflecting that the naphthalene concentrations in influents were, respectively, decreased from 200 to 57 μg L −1 for the humic acid colloids, to 32 μg L −1 for the kaolin colloids and to 13 μg L −1 for the kaolin–humic acid compound colloids. With the filling percentages of 60.0 to 80.0, the naphthalene concentrations in effluents were maintained at 57 ± 2 μg L −1 for the humic acid colloids, at 32 ± 3 μg L −1 for the kaolin colloids and at 13 ± 3 μg L −1 for the kaolin–humic acid compound colloids, respectively. The naphthalene distribution amounts on the biofilmed fillers were, respectively, from 213 to 96 ng m −1 for the humic acid colloids, from 274 to 96 ng m −1 for the kaolin colloids and from 340 to 83 ng m −1 for the kaolin–humic acid compound colloids. Thus, the biofilmed fillers in the floating islands could decrease the naphthalene concentrations by the captures of the humic acid, kaolin and kaolin–humic acid compound colloids to make the contaminated colloid concentrations reduced and promote the water qualities.