天然沸石负载氧化镁对氮磷吸附解吸特性的影响

Study on the adsorption and desorption characteristics of zeolite loaded MgO on ammonia and phosphorus

采用平衡震荡法研究天然沸石负载氧化镁对溶液NH4+、H2PO4-的等温吸附-解吸行为,并运用Langmuir方程对其进行拟合分析,通过自由能的变化分析了吸附过程和吸附结合能。结果表明,天然沸石负载氧化镁与单一天然沸石相比,NH4+的最大吸附量降低了4.49 mg.g-1,H2PO4-提高了36倍;两种吸附材料对NH4+吸附机制主要以表面吸附为主,天然沸石负载氧化镁对H2PO4-的吸附机制主要以化学吸附(沉淀)为主,天然沸石主要以表面吸附和专性吸附为主;两种吸附材料对NH4+、H2PO4-的吸附均能自发进行,负载氧化镁后降低了天然沸石对NH4+的吸附能力,而显著提高了对H2PO4-的吸附能力。

The adsorption and desorption behaviors of zeolite loaded MgO on NH＋4 and H2PO-4 in solution were investigated using the batch equilibration method.The surface binding energy was analyzed by calculating the changes of free energy during the whole adsorption and desorption process.And the adsorption-desorption behavior of zeolite on NH＋4 and H2PO-4 could be described by langmuir model.The results showed that the maximum adsorptive capacity of the zeolite loaded MgO on NH＋4 reduced 4.49 mg·g-1 and on H2PO-4 increased by 36 times,compared with the single natural zeolite.The adsorptions of the two kinds of materials on NH＋4 were all produced mainly by surface adherence.The adsorption mechanism of zeolite loaded MgO on the H2PO-4 was mainly chemical adherence（precipitation） and the adsorption mechanism of natural zeolite on the H2PO-4 was mainly surface and specific adherence.The adsorption of two kinds of adsorbed materials on NH＋4 and H2PO-4was spontaneous process.Compared with that of zeolite loaded MgO,that of natural zeolite on NH＋4 decreased,but on H2PO-4 adsorptive capacity increased significantly.