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为了解土壤保持氟的能力和可溶性氟化物在土中的迁移、变化,选用三种母质(石灰岩、玄武岩、砂岩)上发育的红壤进行等温吸附-解吸实验和土柱淋溶实验。研究结果指出,文献报道的土壤保持氟的能力往往偏高,是因为用吸附量(或最大吸附量)作标准之故。衡量土壤氟保持容量用净吸附量为宜,它受土壤母质、质地和矿物组成等因素的影响。石灰岩、玄武岩、砂岩发育的红壤实测最大净吸附量分别为740,464和244μg F~-/g土,表明这三种红壤保持氟的潜力不同,即使母质相同,而因土壤其它性质差异,从全氟量接近的污染土壤中测出的水溶性氟、交换性氟、1%C_6H_8O_7·H_2O和0.5N HCl提取的氟均不相同。证明土壤吸附氟的解吸特征极为重要,其能力大小影响土壤氟环境容量。无论从那个角度看,土壤对氟具有很大的保持能力,即使在比现代工业高得多的氟化物沉降条件下,一般也不会造成地下水的污染。
In order to understand the ability of soil to maintain fluoride and the migration and variation of soluble fluoride in soil, isothermal adsorption-desorption experiments and soil column leaching experiments were conducted using red soil developed on three parent materials (limestone, basalt and sandstone). The results indicate that the soil reported in the literature tends to retain high levels of fluoride because of the use of adsorption (or maximum adsorption) as a criterion. The net capacity of soil to measure fluoride retention capacity is appropriate, it is affected by soil parent material, texture and mineral composition and other factors. The maximum net adsorption capacity of red soil with developed limestone, basalt and sandstone was 740, 464 and 244 μg F ~ - / g, respectively, indicating that the three red soils have different potential for maintaining fluoride. However, due to the difference of other soil properties, Measured in the amount of contaminated soil water soluble fluorine, fluorine exchange, 1% C_6H_8O_7 · H_2O and 0.5N HCl extracted fluorine are not the same. It is extremely important to prove the desorption characteristics of fluoride adsorbed on soils. The capacity of soil depends on its capacity of fluorine environment. In any case, the soil has a great ability to retain fluoride and generally does not cause groundwater pollution even under much higher fluoride settling conditions than in modern industry.