Study On The Stability Of OTAC Modified Lou Soil

Using cationic surface modification of the soil, the adsorption block is formed in the sub surface layer of the soil, to retain a fixed organic pollutants, can effectively block the organic pollutants in the soil of downward migration, and organic modified soil stability and organic pollutants being sucked attached fixation stability has a direct impact on the practical application of the technique. Therefore, the stability of organic modified soil and the adsorption stability of organic pollutants are of great significance for the protection of soil environment and ecological environment.This article is based on previous researches, selected Shaanxi Guanzhong area calcareous-Lou soil as the test soil sample, a abdication surfactant OTAC as organic modifier, phenol simulation as organic pollutants. 1) Study the characteristics of OTAC adsorption and desorption on Lou soilin different conditions. 2) The characteristics of adsorption and desorption of phenol on modified soil under different conditions were studied in order to verify the stability of adsorption. 3) To study the desorption of OTAC after adsorpting phenol and to clarify the stability of the modified soil after the adsorpting organic pollutants.The main study conclusions are as follows:1. The adsorption and desorption of OTAC on Lou Soil1) Lou soil of OTAC adsorption isotherm approximately L-shaped, Freundlich model fitting to conditions of Lou soil of OTAC adsorption isotherms under different temperature.The optimum adsorption conditions is 20℃, pH=7, ionic strength 0.001 mol/L.2) Different temperature, pH, effect of ionic strength on Lou soil adsorption OTAC:overall temperature increasing negative temperature effect; pH on Lou soil adsorption OTAC had no obvious effect; ionic strength in 0.001~0.05mol/L range. With the increase of the ionic strength of the solution and OTAC adsorption capacity significantly reduced.3) Lou soil easily adsorbed OTAC, and difficultly to desorption, adsorption capacity is far greater than the dsorption. When modified ratio is less than or equal to 100% CEC, the OTAC relative desorption rate maximum does not exceed 5% confirmed OTAC modified Lou soil with higher stability, but when modified ratio increased to 100% CEC, modified soil of bad stability.4) By ion exchange adsorption OTAC modifier molecules and not easy desorption, andOTAC through hydrophobic adsorption of modified agent molecules is easy desorption; Lou soil desorption OTAC was affected by temperature, pH and ionic strength conditions and the occurrence of changes and Lou soil adsorption of OTAC trend is consistent, the amount of Lou soil desorption OTAC decided on its adsorption capacity.2. Adsorption and desorption of phenol on modified soils1) The ability of the modified soil to adsorb phenol increased with the increase of the proportion of the modification, and the adsorption isotherm of phenol on the modified clay was Henry model.2) Phenol adsorption amount on OTAC modified soil increased with the increase of temperature and decrease, indicating phenol adsorption on OTAC modified Lou soil is an exothermic reaction, physical adsorption is the main adsorption mechanism; phenol adsorption amount on OTAC modified soil decreases with the increase of pH, with the increase of ionic strength increased.3) Desorption isotherms of phenol desorption from OTAC modified soil is linear,desorption process mainly consists of assigning role decided the desorption by adsorption effect larger;phenol desorption from OTAC modified soil increased with the increase of the proportion of modification, increased with temperature and increased first and then decreased,not affected by the pH, with the increase of ionic strength decreases.4)The desorption rate of OTAC modified soil was slightly decreased with the increase of the proportion of the modified phenol; the ratio of the modified OTAC modified soil was less than 24%,the fixed effect of organic matter in general.3 phenol adsorption for OTAC desorption1) Phenol had no significant effect to OTAC modified soil stability, the desorption of OTAC is through partition function, OTAC desorption temperature rise increases the overall,with decreasing ionic strength decreased is consistent with the same conditions under OTAC adsorption changes.2) For 25%CEC, 50%CEC that low proportion of modification OTAC modified soil,calcium chloride solution and phenol desorption effect close, OTAC desorption rate is very small, indicating that modified low proportion of OTAC modified soil under natural conditions and pollution has very good stability.3) For 100%CEC that modified high proportion of OTAC modified soil combination by hydrophobic, CaCl2 solution than phenol solution make it easier for OTAC desorption, OTAC desorption is mainly solution desorption by inorganic salt in the liquid, due to the synergistic effect of organic pollutants and high proportion of modification OTAC modified soil in polluted conditions than under natural conditions has better stability.4) Overall, the desorption rate of OTAC is no more than 7%, and the OTAC modified soil has good stability under different treatment conditions.