## 3 Environmental Applications of Organoclays
### Water Pollution
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Clay** & **Modifier** & **Methodology** & **Application** & **Efficiency** & **Reference** \\ \hline Montmorillonite & Sodium benzyl dodecyl sulphate & & & & \\ (Pakistan) & Activated carbon & Cation exchange & Dye Removal & 1429 mg g\({}^{-1}\) & [115] \\ \hline Montmorillonite & Al-intercalated and & Magnetic stirred & & & \\ (China) & Al-pilared & & & & \\ (China) & Al-pilared & & & & \\ \hline Montmorillonite & Acetic acid & & & & \\ and & Sodium dodecyl sulfonate & Magnetic stirred & Heavy metal & 52.381 mg g\({}^{-1}\) & \\ Cellulose & Chitosan & Cation exchange & Removal & 60.272 mg g\({}^{-1}\) & \\   acetate (China) & & & & (Cu) & \\ \hline Montmorillonite & Fe\({}_{3}\)O\({}_{4}\) particles and & & & & \\ (Russia) & dodecyldimethylbenzylammonium & Cation exchange & Heavy metal & 38.8 mg g\({}^{-1}\) (Cr) & [118] \\ Chloride & & & & \\ \hline Ca- & & & & \\ Montmorillonite & Humic Acid & Cation exchange & Heavy metal & 70.34\% (Cr) & [119] \\ (China) & & & & \\ \hline Montmorillonite & MoS\({}_{2}\) & hydrothermal & Heavy metal & 97.09 mg g\({}^{-1}\) (Pb) & [120] \\ (China) & NaF & Cation exchange & Removal & & \\ \hline  & & 2023 & & & \\ \hline Na- & Gemini quaternary ammonium & & & \\ Montmorillonite (China) & surfactants & Cation exchange & Phenol & 115.11 mg g\({}^{-1}\) & [121] \\ \hline Bentonite & Hexadecyltrimethylammonium & & & \\ (China) & chloride and & Cation exchange & Phenol & 14.75 mg g\({}^{-1}\) & [122] \\  & Carboxymethylcellulose & & & \\ \hline  & dodecyldimethyl betaine & & & \\ Bentonite & ethylene bis and & & & \\ (China) & (tetradacyl dimethyl ammonium & & & \\ \multicolumn{2}{c}{chloride)} & & & \\ \hline Montmorillonite & Sodium dodecyl benzene sulfonate & Cation exchange & Heavy metal & 61.53 mg g\({}^{-1}\) & [124] \\ (China) & chlorophyll vinyl ethyloxysilane & grafting & Heavy metal & 63.49 mg g\({}^{-1}\) & [125] \\ \hline Kaolinite & Ethyl 2-((3-(triethoxysil))pro & & & 99.66\% (Pb) & \\ Fe\({}_{3}\)O\({}_{4}\)@MCM41 & pylamino(phenyl)methyl)-3- & Cation exchange & Heavy metal & 93.18\% (Cd) & [126] \\ (Iran) & oxobutanoate & & Removal & 99.88\% (Pb) & \\ \hline Montmorillonite & & & & \\ (China) & @MgAl-CO\({}_{3}\) LDH & Cation exchange & Dye Removal & 815.998 mg g\({}^{-1}\) & [127] \\ \hline Na- & \multicolumn{2}{c}{Polyvinylidene fluoride} & & \\ \multicolumn{2}{c}{1-Hexadecyl-3-methylimidazolium} & Cation exchange & & & \\ Montmorillonite & chloride & Magnetic stirred & Dye Removal & 90\% & \\ (China) & Polyvinylpyrrolidone & Megntic stirred & Digassed & 99\% & \\ \multicolumn{2}{c}{dimethylacetamideamide} & & & & \\ \hline Na- & Polyvinylidene fluoride & & & \\ Montmorillonite & different chain lengths & Cation exchange & Dye & 99.67\% & [129] \\ (China) & ionic liquids & & & \\ \hline Bentonite & & & & \\ (Iran) & Ag NPs & Cation exchange & Cl-1 Removal & 90\% & [130] \\ \hline \hline \end{tabular}
\end{table} 
Table 3: _Cont._[PERSON] et al. [53], [PERSON] et al. [54], [PERSON] et al. [55], [PERSON] et al. [56], [PERSON] et al. [57], and [PERSON] [58] have published work on modifying montmorillonite/bentonite with quaternary ammonium modifier to remove dye and phenol molecules and found that long-chain modifiers, such as hexadecyltrimethylammonium bromide, have a higher removal tendency compared to short-chain quaternary ammonium modifiers. Although modified clay comes from different sources and has different CEC values and surface areas, the removal rate trend is higher in long-chain modifiers due to the hydrophobic behavior of clay. Similar work was conducted in 2014 by [PERSON] et al. [59], where they used clay to remove heavy metals and phenol. In 2015 the applicability of various organic modifiers, such as Arquad 2 HT-75 and palmitic acid from [PERSON] and [PERSON] [61], was investigated. Specifically, bis-N,N,N-hexadecyldimethyl-p-phenylenediammonium dibromide by [PERSON] et al. [62], bis-imidazol salts by [PERSON] et al. [64], and aminopropyltriethoxysilane by [PERSON] et al.