Dried Seaweed (Sargassum ilicifolium) as an Adsorbent for Phosphorous Removal from Aqueous Solutions

Aquaculture is a source of significant amounts of wastes, which generally leads to deterioration of water quality. Removal of phosphorous (P) from aquaculture wastewater is an important environmental challenge. In the present study, efficacy of dry sea weed (Sargassum ilicifolium) to remove water P was investigated under laboratory conditions. Several levels of medium pH (3.5-10), initial P concentration (0.015-0.45mgl-1), contact time (7-60min), particle size (0.5-5mm) and the sea weed particle concentration (10-40gl-1) have been monitored. The results showed a high efficiency of the sea weed to remove water P under different conditions (83.1-97.7% P removal). Among the tested pH, 3.5 had the lowest P removal. P removal linearly increased along with time progress. The lowest P removal was observed in the lowest initial P concentration (0.015mg/l), however, there was no significant difference among the groups with initial P concentration of 0.15-0.45 mg/l. P removal in 10g/l sea weed concentration was significantly lower than those of 20 and 40g/l. P removal significantly increased with decrease in sea weed particle size. Regression analysis showed that the weight of factors to remove P from the medium was as follow: particle size (β = -0.659)> particle concentration (β = 0.427)> time (β = 0.227)> initial P concentration (β = 0.190)> medium pH (β = 0.113). In conclusion, dry S. ilicifolium is capable to efficiently remove P from wastewater at aquaculture-relevant concentration. The P removal capability of the seaweed markedly increases by decrease in particle size and increase in particle concentration in medium.