聚天冬氨酸对土壤吸附、解吸汞的机制研究

为揭示土壤中添加聚天冬氨酸(PASP)后其对汞的吸附、解吸过程,探究了不同PASP用量对土壤吸附解吸汞的机制及有机质、pH、汞初始浓度等因素的影响.结果 表明,PASP可显著抑制土壤对汞的吸附,促进土壤对汞的解吸,在PASP用量为300 mg时,其吸附量、解吸量分别是未添加PASP时的0.68、27倍;有机质与PASP...

Mechanism of Adsorption and Desorption of Mercury on Soil by Polyaspartic Acid

In order to reveal the adsorption and desorption characteristics of mercury on soil with the presence of polyaspartic acid (PASP), the adsorption and desorption mechanisms of mercury on soil with various dosage of polyaspartic acid (PASP) were identified. Besides, the effects of soil organic matter, pH and initial concentration of mercury on the adsorption process were characterized. The results showed that PASP could inhibit the adsorption process and facilitate the desorption process of mercury on soil. When the dosage of PASP was 300 mg, the adsorption and desorption capacity were calculated to be 0.68 and 27 times greater than that of the treatment without PASP, respectively. Soil organic matter plays an antagonistic role in the adsorption process and a synergistic effect in the desorption process. Under a wide pH range (4.0-7.0) and different mercury concentrations (5-200 mg/L), PASP can inhibit the adsorption of mercury on soil in the whole adsorption process. The Langmuir, Freundlich, and pseudo-second-order kinetic equation can well describe the adsorption process. The presence of PASP made the fitting results deviated. The maximum adsorption capacity (q_m) of the raw soil and the organic matter removed soil were 2.1 and 2.0 mg/g respectively, which decreased by 65.47% and 12.94% compared with that without PASP. This study lays the foundation for the application of PASP in the remediation of mercury contaminated soil.