Cu(I)Y分子筛表面酸性对其吸附脱硫性能的影响

Effects of Surface Acidity on the Adsorption Desulfurization of Cu(I)Y Zeolites

用固相离子交换(SSIE)和液相离子交换(LPIE)法制备了不同离子交换度的Cu(I)Y分子筛,采用吡啶吸附红外光谱(Py-IR)表征了分子筛的表面酸性,并用固定床吸附穿透实验评价了分子筛的吸附脱硫性能.结果表明,不同的离子交换法改性后,Cu(I)Y分子筛仍然保持了完整的Y型分子筛结构.Cu+的交换量和表面酸性的分布显著地影响分子筛的吸附脱硫性能,固相离子交换后随离子交换度的增加,分子筛表面Brnsted(B)酸逐渐转化为Lewis(L)酸,吸附性能增强.对不同离子交换法制备的Cu(I)Y分子筛吸附脱硫性能与表面酸性关联后,发现分子筛表面B酸量减少,提高了分子筛的吸附脱硫活性.

Cu（I）Y zeolites with different degrees of ion exchange were prepared by solid state ion exchange （SSIE） and liquid phase ion exchange （LPIE）. The surface acidity of the Cu（I）Y zeolite was characterized by adsorbed pyridine infrared spectroscopy （Py-IR） and the adsorbents desulfurization capabilities were evaluated by a fixed-bed adsorption experiment. We observed that after modification using different ion exchange methods the Cu（I）Y zeolites retained the structure of the Y zeolite completely. The amount of exchanged Cu＋ and the surface acidity including the [Bronsted] （B） acid content and the Lewis （L） acid content greatly affected the adsorption desulfurization process. After SSIE and with an increased degree of ion exchange the B acid gradually transformed to the L acid as a result of an improvement in the adsorption capacity. The results revealed that decreasing B acid content might be the essiential reason for the evidently improved adsorption desulfurization activity for the Cu（I）Y zeolites prepared by different ion exchange methods.