Impact Of Different Adsorbents On The Sorption/desorption Behavior Of Herbicidesin Soil

China is a great agricultural country, and crop pests occur seriously and frequently, thereby large amount and various agricultural chemicals are needed. A large number of organic pesticides are entered into environment and ecological system through various channels, which causes a series of pollution problems, specially produces much harm with the pollution to the soil, Not only can cause soil acidification, nutrient of soil reduced; Having a negative impact on soil fauna, microbes, crops at the same time. Only in China, half of the land area exists various degree of pollution. Nowadays, the problem has become a difficulty all over the world. In response to the question, We hope to establish a simple, economical method of soil clean-up through the study, To provide criterion for the comprehensive control of the pesticides pollution.In my thesis, three adsorbing substances which are pulverized coal, zeolite and chitose are appended in the soil, Conducted research in four areas with batch constant temperature oscillating method and GC-MS , HPLC. (1) Impact of different types of soil on the sorption/desorption behavior; (2) Impact of different adsorbents on the sorption/desorption behavior of herbicides in soil;(3) Impact of environmental conditions on the sorption/desorption behavior of herbicides in soil;(4) Impact of sorption/desorption behavior on the leaching of herbicides in soil.1. Impact of different types of soil on the sorption/desorption behavior: the adsorption of herbicides in the soil is divided into rapid allocated phase and slow gap filling phase, and the adsorption capacity and strength of the soil on the herbicides increase with the increasing of the organic content in the soil and decrease with the increasing of the soil pH. That the soil has the desorption hysteresis on the herbicides is relevant with the organic content in the soil.2. Impact of pulverized coal, zeolite and chitose on the sorption/desorption behavior of herbicides in soil. When the three appended materials have the same quantities, the pulverized coal has the strongest adsorption capacity, the zeolite follows the pulverized coal, and the weakest comes to the chitose. When the three appended materials have diverse quantities, and that the artificial adsorbents have the adsorption capacity and strength and the desorption hysteresis on the herbicides all increase gradually with the increase of adsorbing substance content is found. Besides, that the various artificial adsorbents have effects on the adsorption and desorption isotherm non-linearity is investigated, and the result shows that increasing the content of the adsorbing substance can turn the sorption/desorption behavior isotherm from linearity to non-linearity, and also turn the leading adsorption mechanism from dispensing effect to surface adsorption.3. Impact of different environmental conditions on the sorption/desorption behavior of herbicides in soil: when the temperature rises, the adsorption capacity and strength of the artificial adsorbents on the fomesafen is reduced. When pH is increased, similar varying tendency is also appeared. Besides, the organic content of the soil is a substantial factor which affects the adsorption capacity and strength, wherein the higher the organic content is, the greater the ability of the artificial adsorbents to adsorb the fomesafen has.4. Impact of leaching of fomesafen in Soil amended with pulverized coal: the sorption/desorption behavior of pesticides in soil can influence the leaching in Soil amended with pulverized coal directly. The soil column leaching test is applied to simulate practical environment condition. The resulit shows, the leaching of the fomesafen in soil is improved after appending the adsorbing substances in the soil, and the leaching depth of the fomesafen reduces distinctively.