**6.2. Supportive to health and growth**

The use of calcium montmorillonite (Nova Sil clay type) in human diet can diminish healthharming effects of aflatoxin-contaminated food. The study was based on a clinical trial of selected volunteers in the age range of 20–45 years. It included 23 males and 27 females. The volunteers received calcium montmorillonite low dose (1.5 g/day) and high dose (3 g/day) for weeks. The compliance to study trial by the volunteers was indicated as 99.1%.

Laboratory analysis of blood and urine samples was performed prior and after trial. Hematology, liver and kidney function, electrolytes, vitamins A and E, and minerals were not significantly changed in any study group. The study indicated the protection of participant from adverse effects of aflatoxins [33].

Montmorillonite can be the source of mineral for bacterial nutrition and found to maintain the pH levels required for a sustained growth [34]. Several bacterial species differing in morphology, motility, and Gram reaction were assisted in respiration by montmorillonite. The research results obtained show the relationship between clay minerals (montmorillonite and kaolinite), and population growth and ecology of microorganism in natural habitat.

#### **6.3. Resistance to tooth decay**

Another important obtainable effect is the resistance to tooth decay. Tooth decay can be resisted by filling micro-pore using a fluid resin which polymerizes *in situ* and creates a micromechanical interlock in the tooth structure. This bonding process is a selective substitution for tooth minerals. The use of montmorillonite as a reinforcing filler for dental adhesives (typically methacrylate monomers with solvent and a photo initiator) may be possible.

Results obtained for flexural strength, elasticity modulus, tensile strength, and thermal resistance on the applied dental adhesive, using montmorillonite as an additive, were encouraging. Adhesive produced with dimethacrylate copolymer and montmorillonite (0.2% concentration) showed significant performance as a dental adhesive. Improved performance obtained using 0.2% concentration of montmorillonite, indicated by X-ray diffraction (XRD) test results, was attributed to its exfoliated morphology. The resulting dental adhesive reduces the weakening of tooth structure. However, the highest concentration of 1.5% produced agglomerated clay and no significant performance enhancement [35].

**6.6. Adsorption of toxic heavy metals**

Zn were reviewed [39].

methylphosphonium-, N<sup>−</sup>

constant was evaluated [40].

montmorillonite.

morillonite loading.

applied to potato starch.

**6.7. Montmorillonite in biopolymer**

An important application of adsorption properties of montmorillonite is seen in the removal of toxic heavy metals from aqueous solution. The adsorption studies using montmorillonite and kaolinite for the removal of toxic metals including As, Cd, Cr, Co, Cu, Fe, Pb, Mn, Ni, and

Montmorillonite and its modified forms exhibited a significantly increased metal adsorption capacity relative to kaolinite and modified kaolinite. The modified clay mineral form was produced by pillaring montmorillonite or kaolinite by using polyoxy cations including Zn4+, Al3+, Si4+, Ti4+, Fe3+, Cr3+, or Ga3+. The modified form can also be produced using quaternary ammonium cations including tetramethylammonium-, tetramethylphosphonium-, and tri-

Montmorillonite modified using sodium dodecylsulfate (SDS) can remove Cu2+ and Zn2+ by sorption from aqueous solutions. The study was conducted as a function of solution pH, sol-

for Cu2+ and Zn2+ sorption on modified montmorillonite were evaluated. The study finds out that the kinetics for the sorption of Cu2+ and Zn2+ was assessed and the pseudo-first-order rate

Biopolymer modification using montmorillonite as nanofiller is found to improve the thermomechanical properties. Biopolymer produced from chitosan/montmorillonite nanocomposite through diluted acetic acid used as solvent for dissolving and dispersing chitosan and

Pure chitosan was compared with chitosan-montmorillonite nanocomposite with and without acetic acid in terms of morphological structure and selected properties. Results obtained in XRD and TEM indicated an intercalated and exfoliated nanostructure at a reduced montmorillonite loading and an intercalated and flocculated nanostructure at an increased mont-

Thermal stability and mechanical properties were determined using TGA and nanoindentation. Thermal stability, hardness, and elastic modulus of nanocomposite matrix improve with the increasing loading of nano-dispersed montmorillonite. Crystallinity, thermal stability, and mechanical properties may be influenced by acetic acid residue in chitosan matrix [41]. The study of montmorillonite in potato starch showed the improvement in thermal and Young modulus properties. Nanocomposite films of glycerol-plasticized starch/ montmorillonite were produced. Three different loadings of montmorillonite aqueous suspension were

Dispersion of montmorillonite in starch was studied using X-ray diffraction (XRD). Results indicated that the nanomontmorillonite formed an intercalated structure and complete exfoliation was not observed under the experimental conditions used. Thermogravimetric analysis indicated the enhancement in the thermal resistance with the increased loading of montmorillonite; however, the water absorption by the starch-montmorillonite nanocomposite, at 75%

ute concentration, and temperature (25–55°C). The thermodynamic parameters (Δ*H*<sup>o</sup>


Montmorillonite: An Introduction to Properties and Utilization

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

and Δ*S*<sup>o</sup>

)

15


The use of montmorillonite as a filler may be possible in any of the following morphologies:


#### **6.4. Drug delivery system**

Adsorption and swelling characteristics of montmorillonite are useful in drug delivery systems. An increased adsorption capacity provides improved drug entrapment and sustained release of pharmaceutical drugs. Solubility, dissolution rate, adsorption, and bioavailability of hydrophobic drugs are enhanced by montmorillonite. The effects of montmorillonite in improving the drug delivery system were reviewed [36].

#### **6.5. Adsorption of dyestuff**

Effluent loading, from dyeing industries and textile-processing units, to natural environment is a serious concern. Technological solution is required to remove residual dye content from the used water. The application of montmorillonite as an adsorbent for cationic dye is an important effect. The removal of cationic dye, methylene blue, from water is achievable through adsorption process. Montmorillonite concentration used for the removal of cationic dye depends upon the initial dye concentration, contact time, solution pH, and temperature. Results obtained on dye adsorption demonstrated the equilibrium data follow the Langmuir isotherm equation [37].

Thermodynamic study of methylene blue adsorption on montmorillonite indicates that the process is endothermic revealed by the determination of enthalpy, entropy, and Gibb's free energy. Importantly, the results support the possibility of using montmorillonite as low-cost adsorbent for wastewater treatment containing cationic dyestuff. There is a large number of textile dyeing industries, in India, Pakistan, and China, that release used dye bath water containing cationic dyestuff. Adsorption system developed using montmorillonite can be useful for water recycling in dyeing industries.

Possibly, montmorillonite can be used to influence the optical, chemical, and spectral characteristics of cationic dyes. The layer charge of montmorillonite can affect the cationic dye molecular aggregation. The subject was reviewed through the research literature discussing dye reaction with clay minerals [38].
