**7. Environment concern**

Green chemistry is a demanding approach in organic synthesis, where the release of hazardous gases and liquids is undesired. Environment damage and ecological balance are required to be least affected. Montmorillonite is a solid acid used in organic synthesis. It has the potential to replace liquid acid catalyst with greener effects (**Figure 2**).

Natural and modified clays, including montmorillonite, received significant interest as catalyst (Section 7.8). The use of montmorillonite as a greener catalyst in organic synthesis is reviewed [49]. Several clay-based or montmorillonite-based catalysts are available in market including claycop TM, clayfen TM, clayzinc TM, envirocat TM, and so on.

can enter human body, reaching vital organs through blood circulation. The possibility is therefore indicated for tissue damage. Nanosized particles coming in contact with the tissue may introduce toxicity and health concerns; however, particles incorporated in the bulk

Montmorillonite: An Introduction to Properties and Utilization

http://dx.doi.org/10.5772/intechopen.77987

19

Therefore, there is clear partition line in risk assessment for two types of particle composition: ultrafine, and agglomerated and bulk material. The properties of nanosized particles are dif-

Beneficial effects of montmorillonite are known in the form of a voluminous product used effectively and discussed in Section 7. Calcium montmorillonite is also known as "living clay" being containing minerals capable to improve enzyme production in living organisms [51, 52].

It is important that there are several standards practiced, mainly in industrialized regions, addressing the health and safety risks at work places. Therefore, it is unlikely that the future

Clay minerals have long been benefiting the human and society. Montmorillonite, an important clay type, has received growing interest in utilization as an additive in polymer and products for enhanced effects. Bentonite is an important source of montmorillonite in nature.

The basic molecular structure comprises silica tetrahedron and aluminum octahedral. The cation Si+4 is fourfold and possesses tetrahedral coordination with oxygen, while the cation Al+3 occurs in sixfold or octahedral coordination. Chemical composition, ionic substitution, layer structure, and particle size of natural clay minerals are important to introduce the functional properties and effects in the application of montmorillonite. Sheet structure was used to

Important applications of montmorillonite include uses additive for food, health, and stamina, for antibacterial activity, improved polymer performance; as sorbent for nonionic, anionic,

classify the clay minerals, and chemical composition was used for nomenclature.

and cationic dyes; and as green chemistry catalyst in organic synthesis, and so on.

The author declares no conflict of interest in publishing this chapter.

Address all correspondence to: dfudfuca@yahoo.ca

Dadabhoy Institute of Higher Education, Karachi, Pakistan

materials or polymer products will not be exhibiting such effects.

ferent from the bulk material of the same composition.

would eliminate montmorillonite uses.

**8. Conclusion**

**Conflict of interest**

**Author details**

Faheem Uddin

**Figure 2.** Green chemistry effects in organic synthesis using montmorillonite as catalyst.

Good mining practices have shown bentonite as environmentally not hazardous provided dust abatement mask used. Bentonites demonstrate good performance as sealant and absorbent and used as barrier for landfill and toxic waste repository.

Environmental concern in the extraction, use, and application of clay can range over the environmental characteristics of clay type and its minerals (=minerals present in clay sample). Montmorillonite particles, depending upon the size range, may come in contact with living species. The health and safety concern related to montmorillonite particles received interest for study.

The nature and distribution of inorganic contaminants, such as metals and metalloids like arsenic, iron, and lead, in clay-bearing rocks, may introduce the environmental concerns. These environmental factors may influence the use of clays in natural and industrial applications [50].

Information obtained on environmental effects for industrial minerals, including various clay types, sand, gravel, and crushed stone may not be applicable to montmorillonite composition, and studies will be more useful that is clearly based on any montmorillonite structure.

Information on occupational exposure to bentonite dust in mines, processing plants, and user safety is limited [5]. Varying amount of silica is present in bentonite and kaolin clays; however, there are no reported cases of marked diffuse/nodular pulmonary tissue fibrotic reaction to montmorillonite containing no free silica. Bentonite comprising montmorillonite as major fraction, and kaoline have not shown local or systematic adverse effects in cosmetics. However, these were indicated to cause reduced toxicity toward aquatic organisms.

Particle size and the chemical structure of montmorillonite are two obviously different aspects. The increased concerns in the toxicity of airborne fine (0.1–2.5 μm) and ultrafine (<0.1 μm) particles received research interest. Epidemiological studies indicated an increase in morbidity, and mortality was associated with the rise in airborne particles, particularly in ultrafine size range. The decreasing potencies of quartz, kaolinite, and montmorillonite to introduce lung damage were related to their known relative active surface areas and surface chemistry. Therefore, handling of ultrafine particles requires more vigilant control to abate health effects.

Natural clay particles are smaller than 0.004 mm in diameter; however, manufactured nanoclay particles are in ultrafine size range and have shown toxic properties [1]. These nanoparticles can enter human body, reaching vital organs through blood circulation. The possibility is therefore indicated for tissue damage. Nanosized particles coming in contact with the tissue may introduce toxicity and health concerns; however, particles incorporated in the bulk materials or polymer products will not be exhibiting such effects.

Therefore, there is clear partition line in risk assessment for two types of particle composition: ultrafine, and agglomerated and bulk material. The properties of nanosized particles are different from the bulk material of the same composition.

Beneficial effects of montmorillonite are known in the form of a voluminous product used effectively and discussed in Section 7. Calcium montmorillonite is also known as "living clay" being containing minerals capable to improve enzyme production in living organisms [51, 52].

It is important that there are several standards practiced, mainly in industrialized regions, addressing the health and safety risks at work places. Therefore, it is unlikely that the future would eliminate montmorillonite uses.
