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Materials Science in Additive Manufacturing Emerging 3D-printed zeolitic gas adsorbents

structures . Such structures can achieve the desired ● 3D printing further offers a convenient and
[9]
molecular sieving phenomena for gas separation straightforward fabrication of zeolitic composites for
[32]
technologies by selectively allowing the penetration of gas adsorption .
molecules under a specific size . Figure 1 illustrates the This review article focuses on the development of
[10]
forms and structures of zeolite A, a commonly used gas 3D-printed zeolite absorbents for gas adsorption purposes,
adsorbent, at different length scales. Silica-alumina ratio, where the current stage, fabrication strategies, and future
crystal structure, surface area, pore structure, and pore opportunities are outlined and discussed. After a brief
volume are important physio-chemical factors that affect introduction in Section 1, Section 2 provides a general
the adsorption efficiency of zeolite absorbent . description of zeolite and its conventional shaping and
[11]
Although multiple approaches have been developed structuring methods. The same section also discusses the
for the fabrication of zeolite materials and structures, basic concepts of different 3D printing processes to reveal
new scientific technologies are still expected to achieve their potential for zeolitic absorbents. Section 3 further
cost-effective production [14-16] . As a novel manufacturing gives a summary of the most recent developments in
technology, it is believed that three-dimensional (3D) 3D-printed zeolite absorbent, followed by an elaboration
printing can give rise to robust zeolite absorbent for gas on its different applications as gas adsorbent in Section 4.
separation [17,18] . 3D printing, also referred to as additive The article ends with conclusions and prospects in
manufacturing (AM), is a cutting-edge technology for Section 5.
manufacturing products with required customization, 2. Fabrication of zeolite absorbents
intricate geometry, and high flexibility [19-21] . Therefore, 3D
printing enables the fabrication of complex objects which The major benefit that 3D printing can bring for the
are generally challenging to be produced by conventional fabrication of zeolitic gas adsorbents is the high design
manufacturing methods [22,23] . The printing process typically flexibility, which allows the production of geometries
starts with creating a 3D model through digital design with more efficient adsorbent rate [33,34] . This section
or scanning, followed by generating sliced layers within illustrates the basic aspects of zeolite absorbents and their
special software. The fabrication of the targeted model conventional shaping and structuring methods, followed
is then accomplished by adding each individual two- by a brief description of 3D printing technologies.
dimensional (2D) layer over the prior one [24-26] . Due to this 2.1. Basic aspects of zeolites
unique building process, 3D printing has been proven to be
a promising method for producing natural materials and Together with good chemical and thermal stability, zeolite
synthetic materials in various fields, including aerospace, absorbents have demonstrated outstanding potential for
petrochemical, and environment industries [27-29] . For the gas adsorption. This section gives a general description of
fabrication of zeolite absorbents, 3D printing possesses zeolites and the influencing factors for the adsorption of
some distinct advantages when compared to traditional gases on zeolites.
manufacturing approaches:
● 3D printing enables customized configurations 2.1.1. Structure and type
of zeolitic absorbent to be effectively achieved by Zeolites are a class of aluminosilicate materials with a
freeform production . general chemical formula of M n+ [Al Si O ] wH O,
2+
[30]
x
y
•
2
2x+2y
x/n
● 3D printing also allows a complex zeolitic absorbent where M represents alkali or alkaline earth cation of
interior channel system with desired surface chemistry, valency n, w is the number of water molecules attached
shape, and porosity . with the zeolite unit. Subscripts x and y represent the
[31]

Figure 1. Forms and structures of zeolite A across different length scales. Adapted with permissions from Oheix et al. (crystalline structure and pore
[12]
structure) and Praipipat et al. (powder and crystal).
[13]
Volume 2 Issue 4 (2023) 2 https://doi.org/10.36922/msam.1880