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为揭示氮、磷在农业沟渠中的迁移转化机制,研究沟渠沉积物的吸附特性。通过吸附实验,研究氨氮和磷酸盐的吸附动力学及吸附等温线特征。结果表明,沉积物对氨氮和磷酸盐的吸附是一个复合动力学过程,主要吸附过程发生在0~5 h之内,氨氮、磷酸盐最大吸附速率分别为160 mg/(kg·h)和300 mg/(kg·h);在实验浓度范围内,氨氮和磷酸盐的吸附等温线均呈良好线性变化;与同流域内湖泊河流相比,氮、磷在农田沟渠中并未大量累积;当pH在5~9之间变化时,pH值升高有利于沟渠沉积物对氨氮的吸附,而磷酸盐的吸附能力随pH值的降低而增强。
In order to reveal the migration and transformation mechanism of nitrogen and phosphorus in agricultural ditches, the adsorption characteristics of ditches and sediments were studied. Adsorption experiments were carried out to study the adsorption kinetics and adsorption isotherms of ammonia nitrogen and phosphate. The results show that the adsorption of ammonia nitrogen and phosphate is a complex kinetic process. The main adsorption process takes place within 0-5 h. The maximum adsorption rates of ammonia nitrogen and phosphate are 160 mg / (kg · h) and 300 mg / (kg · h). In the experimental concentration range, the adsorption isotherms of ammonia nitrogen and phosphate showed a good linear change. Compared with the lakes and rivers in the same basin, nitrogen and phosphorus did not accumulate much in farmland ditches. When the pH varied from 5 to 9, the increase of pH value was favorable to the adsorption of ammonia nitrogen by ditch sediments, while the adsorption capacity of phosphate increased with the decrease of pH value.