Sorption And Desorption Of Ammonium Nitrogen On Sediments Of Different Grain Sizes In Western Liao River

In order to provide the basis for the nitrogen cycling in Liao River, sorption and desorption characteristics of ammonium nitrogen on sediments with different grain sizes in the Western Liao River were investigated by batch experiments of equilibrium sorption-desorption. The results indicated that sorption and desorption of sediments with different grain sizes conformed to the Langmuir and Freundlich isotherms. The sorption capacities of clay and silt were 3643.82 and 2693.71 mg ammonium nitrogen per kilogram sediments, respectively, which were 8.04 and 5.94 times higher than those of the coarse sand. Furthermore, the sorption capacities of clay and silt accounted for as saturated adsorption rates were:17.90% clay and silt 17.06%. The desorption ratios of clay or silt were low, reaching 30.66% and 42.04%. Furthermore, the sorption state ammonium nitrogen carried by clay and silt was a vital part of the sediment nitrogen cycling. Sediments of ammonia nitrogen the specific surface area of standardized adsorption distribution coefficient and loosely combined humus correlation is the largest, respectively, the specific surface area of standardized sorption capacities and stability combined humus correlation is the largest and followed by tight combined humus. The humus content in clay or silt was much higher than that in the coarse sand, because there was a micro-hole filling sorption mechanism in the aggregate structure. The higher the clay or silt sediment sorption capacity, the lower the desorption ratio.