有机酸对潮褐土和红壤吸附Cu(II)的影响及其机制

Effect of organic acids on Cu(II) sorption in meadow cinnamon soil and red soil

采用吸附平衡法,研究了有机酸(草酸、柠檬酸)对潮褐土和红壤吸附Cu2+的影响及机制。结果表明,潮褐土、红壤对Cu2+吸附明显有异,潮褐土对Cu2+吸附量是红壤对Cu2+吸附量的5倍多。潮褐土对Cu2+的竞争吸附率随有机酸浓度升高而降低,当草酸、柠檬酸浓度为10 mmolL-1时,Cu2+吸附率均分别比对照的降低40%和70%以上。在低浓度条件下,红壤对Cu2+的竞争吸附率随有机酸浓度的提高而增加,当草酸、柠檬酸浓度分别超过1 mmolL-1和0.05 mmolL-1时,又随有机酸浓度的升高而降低。两种土壤对Cu2+次级吸附率随有机酸浓度升高而变化的规律与竞争吸附的一致。在相同有机酸浓度下,土壤对Cu2+的次级吸附率均比竞争吸附率的高。

Effects of oxalate (OX) and citrate (CA) on Cu2+ sorption in meadow cinnamon soil (MCS) and red soil (RS) were studied by batch method. The results showed that maximum sorption of Cu2+ on MCS was 5 times of that on RS. The percentage of Cu2+ sorption decreased with the increment of organic acids,and at 10 mmolL-1 of oxalate and citrate, percentage of Cu2+ sorption decreased by over 40% and 70% than that of check. At lower concentration of oxalate or citrate, sorption of Cu2+of RS increased with the increment of organic acids .Sorption of Cu2+ began to decrease when the concentration of oxalate and citrate exceeded 1 mmolL-1 and 0.05 mmol稬-1. The percentage of Cu sequential sorption in two soils was similar to that of competive sorption. The percentage of Cu sequential sorption was higher than that of competive sorption.