不同碳化时间对园林废弃物生物炭氮磷吸附解吸研究

Study on the Adsorption and Desorption of Nitrogen and Phosphorus by Biochar Prepared from Garden Waste Branches and Leaves in Different Carbonization Time

为探索碳化时间对生物炭氮磷吸附解吸的影响,以园林废弃树枝和树叶为原料,在碳化时间为2、3、4、5 h下制备的生物炭为吸附剂对不同浓度梯度的氮磷溶液进行吸附试验,结果表明:(1)随着碳化时间的延长树枝生物炭对磷的吸附量基本保持在0.4 mg·g^-1左右,但随着磷浓度的升高,各生物炭对磷的吸附能力均有所增强,其中碳化时间为3 h和4 h的树枝生物炭对磷的吸附能力增长更为明显;树叶生物炭对磷的吸附能力随碳化时间的延长而增大,且随着磷浓度的升高;而增强当碳化时间为5 h时,树枝生物炭和树叶生物炭对铵态氮的吸附效果最佳;树叶生物炭对氮磷的吸附能力高于树枝生物炭。(2)随着碳化时间的延长,树枝生物炭对磷的解吸率基本保持在46%~66%之间;树叶生物炭则随着碳化时间的延长对磷的解吸能力而降低,而碳化时间则对生物炭的铵态氮解吸效果无显著影响;树枝生物炭和树叶生物炭对铵态氮的解吸率分别在31.58%~56.68%和12.77%~28.29%之间。

In order to explored the effection of carbonization time for biochars,we usd garden waste branches and leaves as raw materials,and the biochars which prepared at 2 h,3 h,4 h,and 5 h as the adsorbent to adsorbed and desorbed NH4+and PO4^3- in waste water at different concentration.The result indicated that the adsorption capacity of branch biochar for PO4^3- was about 0.4 mg·g^-1.However,the adsorption efficiency of efficiency of branch biochar for PO4^3- increased with the rising of the initial concentration.And the adsorption capacity of branch biochar with carbonization time of 3 h and 4 h for PO4^3- increased significantly.Besides,the adsorption efficiency of leaf biochar for PO43-increased with the rising of carbonization time,and it aslo increased with the initial concentration.All of the biochars which carbonization time was 5 h had the strongest adsorption efficiency of NH4+.Furthermore,the adsorption efficiency of leaf biochar for PO4^3- and NH4^+ was higher than that of the branch biochar.With the extension of carbonization time,the desorption rate of PO43-was between 46%~66%.The desorption efficiency of leaf biochar for PO4^3- decreased with the rising of carbonization time.It was no significant effect on the desorption capacity of biochar for NH4^+ with the rising of carbonization time.And the desorption rate of PO4^3- for branch and leaf biochars were between 31.58%~56.68%and12.77%~28.29%respectively.