Efficiency of modified attapulgite in controlling phosphorus release from sediment
改性凹凸棒土覆盖抑制底泥磷释放的影响和效果

The characteristics of adsorption of phosphate on modified attapulgite were investigated through isothermal adsorptive and kinetic experiments. The efficiency of controlling TP release from sediments was studied under the conditions of non-barrier, sand barrier and modified attapulgite barrier. The factors affecting release, including barrier thickness, temperature and grain size, were analysed. The results show that Freundlich isotherm can match the isothermal adsorptive characteristic of phosphate on modified attapulgite with a correlation coefficient of more than 0.98. The reaction between modified attapulgite and phosphate is fast and reaction may reach equilibrium within 30 minutes. Compared to the no-barrier case, both sand and modified attapulgite barriers are able to control the TP release from the sediment, and the former is better than the latter. The barrier thickness is a major factor for the control of phosphorus release. More phosphorus is released with the increase of thickness and temperature. A small grain size of modified attapulgite is beneficial to the control of phosphorus release from the sediment.