Natural zeolites are crystalline hydrated alkali metal and alkaline earth metal aluminosilicates with unique ion-exchange and sorption properties. The exceptional structure of pores gives natural zeolites several application possibilities, especially for water treatment and construction. For a wider use of natural zeolites, such as catalysis, properties—especially chemical, textural, and mechanical—need to be modified. In this study, the basic natural zeolite foam was synthesized by alkali activation of natural zeolite with an activator (KOH + Na₂SiO₃) and foamed by hydrogen peroxide solution. Other foams were prepared by a partial replacement of the natural zeolite with CaO, MgO, and metakaolin (MK) and alkali activated and foamed in the same manner as the basic natural zeolite foam. Other properties of the foams were modified by acid leaching. The aim of the study was to compare the basic alkali activated zeolite foam with the CaO, MgO, and MK modified zeolite foams and determine the effect of the CaO, MgO, and MK modification and the subsequent leaching of the alkali activated zeolite foams on the textural, mechanical, and chemical properties. Properties of alkali activated zeolite foams were determined by Hg porosimetry, N₂ physisorption, NH₃-TPD, XRF, XRD, and strength analyses. From the data, it is apparent that all modified samples have an increase of pore volume in the mesoporous region and the partial replacement by MgO or CaO significantly increased surface area up to 288.2 m²/g while increasing the strength several times. The obtained data showed an improvement in properties and extension of the potential applicability of modified zeolite foams in the chemical industry, especially for catalytic and sorption applications.

中文翻译：

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具有改善的结构和力学性能的改性碱活化沸石泡沫

天然沸石是具有独特离子交换和吸附特性的结晶水合碱金属和碱土金属铝硅酸盐。孔的特殊结构为天然沸石提供了多种应用可能性，尤其是在水处理和建筑领域。为了更广泛地使用天然沸石，例如催化，需要修改其性能，尤其是化学，结构和机械性能。在这项研究中，基本的天然沸石泡沫是通过使用活化剂（KOH + Na ₂ SiO ₃）并用过氧化氢溶液发泡。其他泡沫是通过用CaO，MgO和偏高岭土（MK）代替天然沸石部分制备的，并以与碱性天然沸石泡沫相同的方式进行碱活化和发泡。泡沫的其他性能通过酸浸改性。该研究的目的是将碱性碱活化沸石泡沫与CaO，MgO和MK改性沸石泡沫进行比较，并确定CaO，MgO和MK改性的影响以及碱活化沸石泡沫随后在树脂上的浸出。质地，机械和化学性质。通过汞孔隙率法，N ₂物理吸附，NH ₃来测定碱活化沸石泡沫的性能-TPD，XRF，XRD和强度分析。从数据可以明显看出，所有改性样品在中孔区域的孔体积都有所增加，用MgO或CaO的部分替代可以显着增加表面积，最高可达288.2 m ² / g，同时可以使强度提高数倍。所获得的数据显示出改性的沸石泡沫在化学工业中的性质的改善和潜在适用性的扩展，特别是对于催化和吸附应用。