红壤对磷的吸附特性及其影响因素研究

以红壤为吸附剂,研究了固/液吸附体系中红壤对磷的吸附特性,探讨了温度和pH对红壤吸附磷的影响.结果表明,红壤对磷的等温吸附数据与Langmuir和Freundlich方程的拟合优度较高,当温度为30℃时,红壤对磷的饱和吸附量高达1.61 mg/g,说明红壤是一种优良的磷素吸附材料;红壤对磷的吸附量在吸附初期随吸附时间急剧上升而后期趋于稳定,当磷的初始浓度为25～100 mg/L时,12 h时的吸附量均可达到平衡吸附量的90%以上;当磷的初始浓度<50 mg/L时,温度对红壤吸附磷基本无影响,但随着磷初始浓度的升高,温度对红壤吸附磷的影响渐趋明显;在所检测的试验体系中,pH值为4～8时对红壤吸附磷无明显影响.

Phosphorus Adsorption Characteristics of Red Soil and Its Influencing Factors

The phosphorus adsorption characteristics of red soil in solid-liquid adsorption system were studied, and the influence of temperature and pH on the phosphorus adsorption was discussed. The results indicate that the isothermal adsorption data fit well with the Langmuir and Freundlich models. The saturated adsorption capacity of phosphorus can reach 1.61 mg/g when the temperature is 30 ℃, indicating that the red soil is a good adsorbent material for removing phosphorus. The phosphorus adsorption quantity increases rapidly with time in the initial period and then approaches to a constant level in the later period. When the initial phosphorus concentration is 25 to 100 mg/L, the phosphorus adsorption quantity can reach over 90% of the equilibrium adsorption quantity within 12 h. The influence of temperature on phosphorus adsorption is negligible when the initial phosphorus concentration is less than 50 mg/L.The influence of pH of 4 to 8 on phosphorus adsorption is not significant in the test sample system.