[Phosphate adsorption characteristics onto surface sediments from aquaculture area in Sungo bay]

Phosphate adsorption characteristics onto surface sediments from aquaculture area in Sungo bay were studied in laboratory simulating condition, and phosphate adsorption-desorption equilibrium mass concentration was also analyzed. The results showed that the process of phosphate adsorption onto sediments mainly occurred within 0.5 h, and attended to dynamic equilibrium after 6 h. Adsorption kinetics were fitted to modified Elovich model which can be expressed by Q = 85.536 + 35.512 lnt (R2 = 0.9602). Under low initial phosphate concentration condition, the adsorption isotherm curves were fitted to linear equation Q = 265.04c(e) - 7.46 (R2 = 0.965), while under high initial phosphate concentration condition, the adsorption isotherm curves were fitted to Langmuir equation (R2 = 0.989). The native adsorbed phosphorus was 7.46 microg/g and the maximum adsorption capacity was 769.23 microg/g. The phosphate adsorption-desorption equilibrium mass concentration was 0.028 mg/L, which indicated that the sediments played the source role in most time in this area based on the phosphate concentration in water body.