制备方法对生物质炭外源磷吸附解吸的影响

Influences of Preparation Method on the Characteristics of Phosphorus Adsorption-desorption on Biochars

探讨了制备温度、洗涤处理及颗粒粒径大小对芦苇秸秆生物质炭的外源磷吸附和解吸性能的影响。结果表明:600℃和350℃制备的生物质炭对磷的等温吸附曲线分别与Langmir和Fredulich方程有更高的拟合度,600℃制备的生物质炭对磷最大吸附量(1040.3~2194.6 mg kg-1)显著高于350℃制备的生物质炭(424.4~945.4 mg kg-1),但磷的解吸率(0.41~4.95%)显著低于350℃制备的生物质炭(6.66~13.89%);洗涤处理降低了生物质炭吸附磷的性能,且600℃制备的生物质炭降低幅度更大,但均提高生物质炭磷的平均解吸率;随着颗粒粒径减小,生物质炭吸附磷的性能有增强趋势。研究发现制备温度为600℃、未洗涤处理且颗粒粒径大于60目的生物质炭对磷吸附性能最好。

In the present study, the effect of pyrolysis temperature, washing treatment and particle size on the sorption-desorption of phosphorus on reed straw biochars was investigated. Batch experiment results showed that the adsorption isothermal curves of phosphorus on biochars pyrolysised at 600 ℃ and 350 ℃ were better fitted with Langmir equation and Fredulich equation, respectively. The pyrolysis temperature significantly affected the phosphorus sorption capacity on biochars. The maximum adsorption capacity of phosphorus on biochars pyrolysised at 600 ℃(1040.3-2194.6 mg kg-1) was significantly higher than that on the biochars pyrolysised at 350 ℃(424.4-945.4 mg kg-1), while the phosphorus desorption rate(0.41-4.95%) from biochars pyrolysized at 600 ℃ was significantly lower than that(6.66-13.89%) from biochars pyrolysised at 350 ℃. Washing treatment reduced phosphorus adsorption capacity on biochars, while this performance was more significant on biochars pyrolysised at 600 ℃. Moreover, washing treatment significantly increased phosphorus desorption rate from biochars pyrolysised at two different temperatures. With the decrease of particle size, the phosphorus adsorption capacity on biochar with different treatments tended to increase.On the whole, biochars pyrolysised at 600 ℃, with no washing treatment and particle size greater than 60 meshes,owned the highest adsorption capacity of phosphorus.