Research and development of efficient, economical and resource-based flue gas desulfurization technology has always been a hot spot in the field of air pollution control. Molecular sieve materials have been paid atten...Research and development of efficient, economical and resource-based flue gas desulfurization technology has always been a hot spot in the field of air pollution control. Molecular sieve materials have been paid attention to by SO<sub>2</sub> adsorbent researchers due to their huge specific surface area. In this paper, 13X zeolite was modified with Cu(NO<sub>3</sub>) <sub>2</sub>·3H<sub>2</sub>O to obtain 13x-Xwt %CuO (calculated by the amount of CuO loaded). The adsorption time and capacity of SO<sub>2</sub> penetration sorbent and the isothermal curve of N<sub>2</sub> adsorption-desorption were studied. The results are as follows: 13X-3wt%CuO has the best adsorption effect, the penetration adsorption time is 110 min, the penetration adsorption capacity is 43.41 mg·g<sup>-1</sup>, the saturation adsorption capacity is 49.27 mg·g<sup>-1</sup>;The amount of CuO loading has a great influence on the adsorption effect of modified 13X molecular sieve on SO<sub>2</sub>. SEM and BET characterization showed that CuO modification did not change the external morphology of 13X molecular sieve, changed the pore size, but did not block the original channel of the molecular sieve, before and after modification belong to the type I adsorption isothermal curve. The pore size distribution and type of molecular sieve, as well as the content and type of alkali metal cations jointly control the adsorption process of SO<sub>2</sub> by 13X-xwt %CuO. XPS characterization showed that Cu(NO<sub>3</sub>) <sub>2</sub> decomposed into CuO and Cu<sub>2</sub>O during roasting at 450°C, CuO/Cu<sub>2</sub>O ≈ 1.5. The R<sup>2</sup> values of the quasi-second-order kinetic models obtained from the 13X-Xwt %CuO particle diffusion kinetic models were all above 0.99, indicating that the quasi-second-order kinetic equations were more relevant. Particle diffusion dynamics model in fitting results show that the adsorption process can be divided into two stages, the first phase of surface adsorption and diffusion rate in the granules common control process, more accurate dynamics model of the secondary in the second phase particle diffusion rate control stage, mainly for the micropore adsorption or chemical adsorption, quasi level 2 dynamic model conformity of variation;C is a constant not equal to 0, indicating that the adsorption of SO<sub>2</sub> is not completely through the form of intra-particle diffusion, and a small amount of chemisorption exists. And it is the compound effect of multiple adsorption mechanisms.展开更多
建立了13X分子筛微柱离子交换分离预富集-流动注射火焰原子吸收光谱法检测水中痕量铜的新分析方法。铜以自由离子的形式而非螯合的形式滞留在13X分子筛微柱上,然后用0.5 mL 10%(V/V)HNO3洗脱,通过原子吸收光谱法进行检测。并对流动注射...建立了13X分子筛微柱离子交换分离预富集-流动注射火焰原子吸收光谱法检测水中痕量铜的新分析方法。铜以自由离子的形式而非螯合的形式滞留在13X分子筛微柱上,然后用0.5 mL 10%(V/V)HNO3洗脱,通过原子吸收光谱法进行检测。并对流动注射的一些主要参数和各种干扰离子进行了研究。在最优条件下,富集2 min即进样体积为18 mL,测得的线性范围为0.002～0.150μg/mL,检出限为0.5μg/L(3σ,n=11),相对标准偏差(RSD)为1.1%(0.05μg/mL,n=11),富集系数为23.3,采样频率为30次/h。可以通过增加进样体积到36 mL,得到更低的检出限为0.28μg/L。将该方法用于各种水样中铜的分析,加标回收率符合分析要求。展开更多
文摘Research and development of efficient, economical and resource-based flue gas desulfurization technology has always been a hot spot in the field of air pollution control. Molecular sieve materials have been paid attention to by SO<sub>2</sub> adsorbent researchers due to their huge specific surface area. In this paper, 13X zeolite was modified with Cu(NO<sub>3</sub>) <sub>2</sub>·3H<sub>2</sub>O to obtain 13x-Xwt %CuO (calculated by the amount of CuO loaded). The adsorption time and capacity of SO<sub>2</sub> penetration sorbent and the isothermal curve of N<sub>2</sub> adsorption-desorption were studied. The results are as follows: 13X-3wt%CuO has the best adsorption effect, the penetration adsorption time is 110 min, the penetration adsorption capacity is 43.41 mg·g<sup>-1</sup>, the saturation adsorption capacity is 49.27 mg·g<sup>-1</sup>;The amount of CuO loading has a great influence on the adsorption effect of modified 13X molecular sieve on SO<sub>2</sub>. SEM and BET characterization showed that CuO modification did not change the external morphology of 13X molecular sieve, changed the pore size, but did not block the original channel of the molecular sieve, before and after modification belong to the type I adsorption isothermal curve. The pore size distribution and type of molecular sieve, as well as the content and type of alkali metal cations jointly control the adsorption process of SO<sub>2</sub> by 13X-xwt %CuO. XPS characterization showed that Cu(NO<sub>3</sub>) <sub>2</sub> decomposed into CuO and Cu<sub>2</sub>O during roasting at 450°C, CuO/Cu<sub>2</sub>O ≈ 1.5. The R<sup>2</sup> values of the quasi-second-order kinetic models obtained from the 13X-Xwt %CuO particle diffusion kinetic models were all above 0.99, indicating that the quasi-second-order kinetic equations were more relevant. Particle diffusion dynamics model in fitting results show that the adsorption process can be divided into two stages, the first phase of surface adsorption and diffusion rate in the granules common control process, more accurate dynamics model of the secondary in the second phase particle diffusion rate control stage, mainly for the micropore adsorption or chemical adsorption, quasi level 2 dynamic model conformity of variation;C is a constant not equal to 0, indicating that the adsorption of SO<sub>2</sub> is not completely through the form of intra-particle diffusion, and a small amount of chemisorption exists. And it is the compound effect of multiple adsorption mechanisms.
