## 4 Mechanism of Action in Cyclodextrin  
Cyclodext (CDs) are spherical oligosaccharides produced from starch grains during enzymatic degradation. They are characterized by their molecular compatibility cavities, which accommodate many guest fractions. Due to their macrocyclic architecture, these supramolecular entities provide an internal hydrophobic cavity and a surface conducive to adsorption through electrostatic interactions, hydrogen bonding, and weak van der Waals forces of attraction [30]. This suggests that within metal complexes, the cavity of cyclodextrin functions as a binding site that works in conjunction with the metal centre to facilitate the transformation of non-coordinating substrates (artificial metalloenzymes) and to discriminate chiral guests (molecular receptors) [31]. The binding affinity between M-\(\gamma\)-CD and heavy metals is enhanced by the presence of hydrogen bonds, which play a crucial role in encapsulating metal ions within the hydrophobic cavity [27; 32]. The formation of hydrogen bonds may influence the conformational dynamics of M-\(\gamma\)-CD, potentially enhancing its ability to adapt to various metal ions. When a heavy-metal ion is sequestered within this cavity, hydrogen bonding helps orient and stabilize the ion within the cyclodextrin framework, thus preventing its re-entry into the solution. This encapsulation is essential for achieving high removal rates, particularly in complex mixtures where competition for binding sites may occur [27; 30]. This adaptability could improve its overall performance across a range of heavy metals, facilitating effective removal under diverse environmental conditions [32; 33]. The increased affinity results in improved removal efficiencies for various heavy metals, as the metal ions are effectively trapped within the cyclodextrin cavity through hydrophobic interactions combined with hydrogen bonding [27; 32]. Although countless authors have conducted numerous studies on CDs, the scientific literature regarding the application of M-\(\gamma\)-CD in soil remediation remains limited. Nonetheless, research debates continue. For instance, the functional groups of \(\beta\)-cyclodextrinntrin possess the ability to form crystallized mononuclear \(\beta\)-cyclodextrinntrin complexes with Sn (IV), Pb (IV), Mg (IV), and Ge (IV) by providing a mono-nucleating binding site for high-valent metal centres. In such cases, multiple CDs create a diagonal or octahedral geometry wherein \begin{table}
\begin{tabular}{l l} \hline
**Heavy Metal** & **Removal Efficiency (\%)** \\ \hline Copper (Cu) & \(>\)99\% [27] \\ \hline Cadmium (Cd) & \(>\)99\% [27] \\ \hline Nickel (Ni) & \(\sim\)99\% [27] \\ \hline Zinc (Zn) & \(\sim\)99\% [27; 28] \\ \hline \end{tabular}
\end{table} 
Table 1: The effectiveness (in %) of methylated gamma-cyclodextrinntrin (M-\(\gamma\)-CD) in removing heavy metals. the tetravalent metals are situated at the centre, coordinated by four deprotonated hydroxyl (OH) groups. For trivalent ions, the secondary hydroxyl groups of CDs participate in coordination with Cu (II) ions, demonstrating that modified CDs serve as highly effective agents for the amputation of both noxious elements (Cu) and organic contaminants from effluents [23]. Additionally, polynuclear inclusion complexes can be synthesized with Pb (II) ions using multi-deprotonated \(\gamma\)-CDs. Furthermore, CDs exhibit a heightened sensitivity towards Cd (II) ions in alkaline solutions, augmented by the formation of hydroxide gels at elevated pH levels. Modified CDs outperform their native counterparts in the remediation of lethal element ions from water-based mediums [23].