载铁牡蛎壳粉对水中磷的吸附性能及机理

为解决生物絮凝养殖水体含磷物质积累，初步研究了载铁牡蛎壳粉吸附除磷性能及相关机理。结果表明，8 g·L⁻¹载铁牡蛎壳粉在初始TP浓度为20.00~50.00 mg·L⁻¹吸附效果最佳，TP去除率由(84.94±0.94)%增至(87.35±1.06)%，吸附量由(2.37±0.03) mg·g⁻¹增至(5.45±0.22) mg·g⁻¹；当pH为2.00~6.00时，TP去除率大于(80.13±3.27)%，吸附量大于(2.04±0.02) mg·g⁻¹；碳酸氢根的存在对载铁牡蛎壳粉吸附除磷有明显的抑制作用。X射线衍射结果表明，载铁牡蛎壳粉表面覆盖成分为Fe₂(PO)₅和Fe₄(PO₄)₂O。载铁牡蛎壳粉吸附过程符合Freundlich模型和准二级动力学模型，最大吸附量为9.81 mg·g⁻¹，吸附过程存在物理吸附和化学吸附，主要由化学吸附决定，膜扩散和颗粒内扩散为主要限速步骤，配位交换和静电吸附为主要吸附机理。以上研究结果可为实际养殖废水除磷方法提供参考。

Adsorption performance and mechanism of magnetic modified oyster shell powder on phosphorus in water

In order to solve the problem of phosphorus accumulation in bio-floc culture water, the performance and and mechanism of magnetic modified oyster shell powder on phosphorus removal were studied. The results showed that the best adsorption efficiency occurred for 8 g·L−1 magnetic modified oyster shell powder at the initial TP concentration of 20.00~50.00 mg·L−1, the TP removal rate increased from (84.94±0.94)% to (87.35±1.06)%, the adsorption amount (qe) increased from (2.37±0.03) mg·g−1 to (5.45±0.22) mg·g−1. When the pH was 2.00~6.00, the TP removal rate was higher than (80.13±3.27)%, and qe was higher than (2.04±0.02) mg·g−1. ${rm{HCO}}_3^ - $ had an obvious inhibitory effect on phosphorus adsorption by magnetic modified oyster shell powder. X-ray diffraction showed that the surface covering composition of the shell powder were Fe2(PO)5 and Fe4(PO4)2O. The adsorption process of magnetic modified oyster shell powder accorded with Freundlich model and pseudo-second kinetic model, the maximum adsorption capacity was 9.81 mg·g−1. Both physisorption and chemisorption contributed to the adsorption process, and the chemisorption played the main role. The film diffusion and intra-particle diffusion were the main speed limiting steps, ligand exchange and electrostatic interaction were the main phosphorus removal contributors. The above results can provide a reference for the actual phosphorus removal methods of aquaculture wastewater.