Effects of sediment particle morphology on adsorption of phosphorus elements

Sediment particle surface morphology affects phosphorus adsorption. This paper studied the phosphorus adsorption on sediment particle by using a Scanning Electron Microscope (SEM) and an Energy Dispersive X-ray Spectroscopy (EDS). Sediment samples from the Yangtze, Yellow and Yongding rivers in China were chosen to measure the particle surface morphology, surface gray scale and element distribution maps. These samples were firstly cleaned and put into phosphate solution for adsorption. Both the Langmuir equation and Freundlich equation were used for descriptions of adsorption-desorption isotherms for sediments. Particles were then dried and scanned. The results show that the adsorption of phosphorus depends on the surface morphology of particles. Phosphorus exists mostly in the ridges and channels, while a few exist in the slopes, and casually in the peaks, passes and pits.