This chapter is focused on the treatment of waters and wastewaters with zeolites or with metal-ceramic nanocomposites obtained from zeolites. In particular, in a first introductory paragraph, the properties of cation exchange and adsorption from the liquid phase, which allow the use of zeolites in this field, are recalled. The second paragraph of this chapter intends to supply the reader with a simple, overall view of the two operational modes of cation exchange and adsorption from the liquid phase: the columnar plants, treated in a first sub-paragraph, and the batch reactor systems, treated in a second sub-paragraph. To fulfil this goal, the features of the plants needed to perform cation exchange or adsorption from the liquid phase operations, for both columnar plants and batch reactor systems, are presented. Moreover, the basic theory underlying these operations, in the two different operational modes, is explained in a simple and talkative manner, which appears decidedly proper for the new-comers in these fields. However, if the reader wishes to gain further insight into this topic, he is provided with the proper references, wherein he will find more in depth, mathematical considerations. Moreover, within this paragraph devoted to the two different modes of operating cation exchange and adsorption from the liquid phase, particular care is taken in evidencing the strong and the weak points of both columnar plants and batch reactor systems, as well as in evidencing the problems that may occur at an industrial level in the two different operational modes. Finally, this paragraph supplies the reader with useful indications concerning the final fate of the polluting entity originally present in the water that was treated. Such final fate may vary depending on the nature of the polluting entity itself and the type of operational mode, wherein cation exchange and adsorption from the liquid phase operations were performed. The following paragraphs, composing this chapter, are concerned about some example of depuration of waters or wastewaters using zeolites or metal-ceramic nanocomposites obtained from zeolites. In particular, the third paragraph reports the very interesting data obtained in operating large mole columnar plants, which perform the removal of ammonium from real municipal wastewaters. It appears noteworthy that all these large mole columnar plants, some of them being at the industrial level, are loaded with very cheap, natural zeolites. The fourth paragraph of this chapter concerns the removal of heavy metals from water by cation exchange using very cheap, natural zeolites in small, laboratory level, columnar plants and batch reactor systems. This paragraph encompasses three sub-paragraphs concerning the removal of three different heavy metal cations, such as Pb2+, Cr3+, Cd2+, from distilled water or simulated industrial wastewaters. These cations were chosen, on the one hand, as their removal from water represents a very important environmental issue. On the other, the features of the cation exchange reactions that they undergo on zeolites, are strongly different from each other. This fact allows the authors to supply the readers with different useful indications, which apply to the three different cation removals from water. The fifth paragraph of this chapter of this book concerns the removal of the agrochemical simazine, from both distilled water and a natural water (properly characterized), by adsorption on zeolites or on materials derived from zeolites, in batch reactor systems. As far as the first part of this fifth paragraph, centered on zeolites, is concerned, zeolite H-Y was chosen. After describing its preparation, the extent to which the pH of the water affects simazine adsorption on it is presented. These data were used to formulate a mechanism, which properly explains it. Such mechanism confirmed that simazine adsorption on zeolite H-Y is not affected by the type of water, wherein adsorption occurs. Finally, an iterative process, which brings simazine concentration from the level, whereat it is found in natural waters, to below the Italian law limit, is presented. The second part of this fifth paragraph is devoted to the removal of simazine from water by adsorption on magnetic metal-ceramic nanocomposites, in a batch reactor system. The preparation of two different samples of such materials, which are formed by a dispersion of magnetic metallic iron or magnetite nanoparticles into a ceramic matrix composed mainly by amorphous silica and alumina, is accurately described. The adsorption of simazine on these two magnetic adsorbents was found to depend on pH in decidedly different ways. This item was interpreted in the light of their phase composition, which allowed to propose decidedly different mechanisms of adsorption. Then, two different iterative process of removal of simazine from water were presented. Both of them proved to be able to bring simazine concentration from the level, whereat it is present in natural water bodies, to below the Italian law limit. Finally, thermal regeneration for the exhausted, simazine bearing magnetic metal-ceramic nanocomposites was envisaged. A final sixth paragraph accounts the reader for the future trend of the research in this field. It strongly suggests the use of magnetic metal-ceramic nanocomposites or magnetic zeolites in batch reactor systems as a proper way to face with problems of depuration of waters from various polluting entities.

Exploiting the Zeolite Skills in Water and Wastewater Treatment

章节
发表日期：

2026年

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Michele Pansini,
Serena Esposito

摘要

This chapter is focused on the treatment of waters and wastewaters with zeolites or with metal-ceramic nanocomposites obtained from zeolites. In particular, in a first introductory paragraph, the properties of cation exchange and adsorption from the liquid phase, which allow the use of zeolites in this field, are recalled. The second paragraph of this chapter intends to supply the reader with a simple, overall view of the two operational modes of cation exchange and adsorption from the liquid phase: the columnar plants, treated in a first sub-paragraph, and the batch reactor systems, treated in a second sub-paragraph. To fulfil this goal, the features of the plants needed to perform cation exchange or adsorption from the liquid phase operations, for both columnar plants and batch reactor systems, are presented. Moreover, the basic theory underlying these operations, in the two different operational modes, is explained in a simple and talkative manner, which appears decidedly proper for the new-comers in these fields. However, if the reader wishes to gain further insight into this topic, he is provided with the proper references, wherein he will find more in depth, mathematical considerations. Moreover, within this paragraph devoted to the two different modes of operating cation exchange and adsorption from the liquid phase, particular care is taken in evidencing the strong and the weak points of both columnar plants and batch reactor systems, as well as in evidencing the problems that may occur at an industrial level in the two different operational modes. Finally, this paragraph supplies the reader with useful indications concerning the final fate of the polluting entity originally present in the water that was treated. Such final fate may vary depending on the nature of the polluting entity itself and the type of operational mode, wherein cation exchange and adsorption from the liquid phase operations were performed. The following paragraphs, composing this chapter, are concerned about some example of depuration of waters or wastewaters using zeolites or metal-ceramic nanocomposites obtained from zeolites. In particular, the third paragraph reports the very interesting data obtained in operating large mole columnar plants, which perform the removal of ammonium from real municipal wastewaters. It appears noteworthy that all these large mole columnar plants, some of them being at the industrial level, are loaded with very cheap, natural zeolites. The fourth paragraph of this chapter concerns the removal of heavy metals from water by cation exchange using very cheap, natural zeolites in small, laboratory level, columnar plants and batch reactor systems. This paragraph encompasses three sub-paragraphs concerning the removal of three different heavy metal cations, such as Pb2+, Cr3+, Cd2+, from distilled water or simulated industrial wastewaters. These cations were chosen, on the one hand, as their removal from water represents a very important environmental issue. On the other, the features of the cation exchange reactions that they undergo on zeolites, are strongly different from each other. This fact allows the authors to supply the readers with different useful indications, which apply to the three different cation removals from water. The fifth paragraph of this chapter of this book concerns the removal of the agrochemical simazine, from both distilled water and a natural water (properly characterized), by adsorption on zeolites or on materials derived from zeolites, in batch reactor systems. As far as the first part of this fifth paragraph, centered on zeolites, is concerned, zeolite H-Y was chosen. After describing its preparation, the extent to which the pH of the water affects simazine adsorption on it is presented. These data were used to formulate a mechanism, which properly explains it. Such mechanism confirmed that simazine adsorption on zeolite H-Y is not affected by the type of water, wherein adsorption occurs. Finally, an iterative process, which brings simazine concentration from the level, whereat it is found in natural waters, to below the Italian law limit, is presented. The second part of this fifth paragraph is devoted to the removal of simazine from water by adsorption on magnetic metal-ceramic nanocomposites, in a batch reactor system. The preparation of two different samples of such materials, which are formed by a dispersion of magnetic metallic iron or magnetite nanoparticles into a ceramic matrix composed mainly by amorphous silica and alumina, is accurately described. The adsorption of simazine on these two magnetic adsorbents was found to depend on pH in decidedly different ways. This item was interpreted in the light of their phase composition, which allowed to propose decidedly different mechanisms of adsorption. Then, two different iterative process of removal of simazine from water were presented. Both of them proved to be able to bring simazine concentration from the level, whereat it is present in natural water bodies, to below the Italian law limit. Finally, thermal regeneration for the exhausted, simazine bearing magnetic metal-ceramic nanocomposites was envisaged. A final sixth paragraph accounts the reader for the future trend of the research in this field. It strongly suggests the use of magnetic metal-ceramic nanocomposites or magnetic zeolites in batch reactor systems as a proper way to face with problems of depuration of waters from various polluting entities.