硅改性花生壳生物炭对水中磷的吸附特性

为实现花生壳资源化利用，通过硅酸钠溶液对花生壳进行浸渍改性，再热解制备成硅改性花生壳生物炭（Si-PSBs），探究Si-PSBs对水中磷的吸附特性.结果表明，相比于未改性花生壳生物炭（PSB），Si-PSBs对磷的吸附量明显增大，8%硅酸钠溶液改性的生物炭（8% Si-PSB）对磷的吸附量是改性前的3.9倍.SEM、FTIR和XRD等结果表明8% Si-PSB上有二氧化硅生成，二氧化硅影响吸附过程中源于生物炭的碳酸钙形态，提高了生物炭自身所含金属离子Ca²⁺的反应活性.强酸强碱环境中，8% Si-PSB对磷均具有良好的吸附效果.反应平衡后，8% Si-PSB和PSB对磷的吸附量分别在2.79 mg ·g^-1和0.71 mg ·g^-1上下浮动，对磷的吸附均更符合准二级动力学模型，说明反应以化学吸附为主.等温吸附实验数据采用Langmuir模型拟合度更高，说明8% Si-PSB和PSB对磷的吸附均以单层吸附为主.溶液中腐殖酸（HA）的存在抑制8% Si-PSB和PSB对磷的吸附.8% Si-PSB是一种低成本的新型除磷材料，可提高花生壳自身金属钙离子的利用程度.

Characteristics of Phosphorus Adsorption in Aqueous Solution by Si-modified Peanut Shell Biochar

In this work, a novel sodium silicate-modified peanut shell biochar(Si-PSB) was synthesized and used as phosphorus adsorbents. Compared with unmodified biochar(PSB), the adsorption capacity of Si-PSBs increased significantly. The adsorption capacity of 8% sodium silicate solution modified biochar(8%Si-PSB) was 3.9 times higher than that of PSB. The biochar was characterized using scanning electron microscopy(SEM), Fourier transformed infrared(FTIR), and X-ray diffraction(XRD), which confirmed that silica was present on the surface of 8%Si-PSB. The introduction of silica improved the reaction activity of biochar''s own metal ions by affecting the morphology of calcium carbonate. The 8%Si-PSB had a good adsorption effect on phosphorus in both acid and alkali environments. Phosphorus adsorption by 8%Si-PSB and PSB was described well by the pseudo-second-order model, and the adsorption capacity after equilibrium fluctuated between 2.79 mg·g^-1 and 0.71 mg·g^-1, respectively. Further, the isothermal adsorption experimental data fitted well to the Langmuir model. The presence of humic acid in the solution inhibited the adsorption of phosphorus by the 8%Si-PSB and PSB. The 8%Si-PSB, as a new low-cost phosphorus removal material, can improve the utilization of metal ions in peanut shell itself.