Kinetic characteristics of phosphorus adsorption on surface coatings in natural water

Surface coatings have a strong adsorption to phosphorus in natural water environment.The kinetic characteristics of phosphorus adsorption on natural surface coatings were discussed in this paper.Surface coatings were collected from several typical natural waters and were then broken,oscillated and weighed in the laboratory.On the condition of constant temperature,250 mL orthophosphate solution with concentration varying from 0.6 to 2.0 mg·L-1 was adsorbed by surface coatings with wet weight of 2 g.The phosphorus was determined by the ammonium molybdate spectrophotometric method at different time of absorption.The phosphorus adsorption amount by surface coatings was calculated and the kinetic characteristics of adsorption process were determined.The impact of environmental factors on the adsorption process was also analyzed.The results showed that nature surface coatings had a strong adsorption to phosphorus.The adsorption quantity varied from 100 to 2000 mg·kg-1.The adsorption was consistent with pseudo-second and pseudo-first order kinetic model.Adsorption rate and equilibrium adsorption capacity were affected by temperature.The best adsorption temperature was 25 ～ 30 ℃,and pH of solution did not affect the adsorption significantly.