沱江流域磷石膏的磷形态组成及潜在释放特征

Phosphorus forms and potential release characteristics of phosphogypsum in Tuojiang River basin

  • 摘要: 对沱江流域磷石膏中磷形态组成及浓度、磷释放动力学特征、环境因子对磷释放的影响进行了研究。结果表明:沱江流域磷石膏总磷(TP)浓度为3.70 mg/g,磷石膏中磷释放主要来自弱吸附态磷(Ex-P)、可提取态有机磷(Org-P)和铁磷(Fe-P),且Ex-P、Fe-P释放所占比例较大;磷石膏与水的水土比为500 ∶1时,磷释放量达到最大值,磷的释放过程主要发生在前8 h,最大释放速率(Vmax)为3.52 mg/(g·h),一级动力学方程可较好地拟合磷释放动力学过程,其平衡浓度(Qmax)拟合值为2.30 mg/g;水体pH对磷石膏中磷释放影响显著,酸性或碱性条件均有利于磷的释放,水体盐度和温度越高,越有利于磷释放,水体温度从10 ℃升至25 ℃时,磷总释放量逐渐提高,25 ℃时磷的总释放量最大。

     

    Abstract: The phosphorus form and content, release kinetics characteristics of phosphorus and the influence of environmental factors on phosphorus release were investigated from phosphogypsum samples collected in Tuojiang River basin. The results showed that the TP content of phosphogypsum was 3.70 mg/g, and the release of phosphorus was mainly carried out by Ex-P, Org-P and Fe-P. Among them, Ex-P and Fe-P accounted for a large proportion. When the ratio of water to phosphogypsum was 500 ∶1, the phosphorus release reached the maximum value, and the phosphorus release mainly occurred in the first 8 hours. The maximum release rate of phosphorus from phosphogypsum was 3.52 mg/(g ·h). The first order kinetic equation can fit the phosphorus release kinetic process well with the maximum release Qmax of 2.30 mg/g under the experimental condition. The pH had significant effect on phosphorus release from phosphogypsum, and either acidic or alkaline water environment was conducive to release of phosphate. Higher salinity and temperature were favorable to the release of phosphorus, and total phosphorus release increased the most as temperature increasing from 10 to 25 ℃ with the maximum at 25 ℃.

     

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