# Nanofiber-Based Materials for Persistent Organic Pollutants in Water Remediation by Adsorption
## 2 Moderately Hydrophobic Pesticides
### Nanofibers for Pesticide Adsorption
#### 2.2.1 Impact of Adsorbent Specific and Contact Surface Area

Table 2: Nanofibrous adsorbent properties and adsorption conditions for the removal of Alachlor. BET: specific surface area. \begin{table}
\begin{tabular}{c c c c c c c c c c c c c c c} \hline \hline  & & \multicolumn{4}{c}{**Adaorbent Proposition**} & \multicolumn{4}{c}{**Adaorption Conditions**} & \multicolumn{4}{c}{**Adaorption Conditions**} & \multirow{2}{*}{**Removal (“sp)**} & **Filter** & **Component** & **Component** & **Fdg. Time (b)** & **Kindle Model** & **Isothermal Model** & **Is \begin{table}
\begin{tabular}{c c c c c c c c c c c c c c c} \hline \hline  & & \multicolumn{4}{c}{**Adaption Properties**} & \multicolumn{4}{c}{**Adaptiontion**} & \multicolumn{4}{c}{**Adaption**} & \multicolumn{4}{c}{**Adaption**} & \multicolumn{4}{c}{**Adaption**} \\ \cline{3-14} N & **Adaption** & **BET** & **Tail** & **Tail** & **Tail** & **Tail** & **Tail** & **Tail** & **Tail** & **Tail** & **Tail** & **Tail** & **Tail** & **Tail** \\  & & **BET** & **Tail** & **Tail** & **Tail** & **Tail** & **Tail** & **Tail** & **Tail** & **Tail** & **Tail** & **Tail** & **Tail** & **Tail** & **Tail** \\ \hline
1 & **Calibration** & 130 & 100 & 0.11 & 2.2 & 10.78 & 0.5 & 7 & 1 & & & 10.2 & [79] \\ \hline
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4 & **Additional** & **Tail** & **Tail** & **Tail** & **Tail** & **Tail** & **Tail** & **Tail** & **Tail** & **Tail** & **Tail** & **Tail** \\  & & **Tail** & **Tail** & **Tail** & **Tail** & **Tail** & **Tail** & **Tail** & **Tail** & **Tail** & **Tail** & **Tail** \\  & & & & & & & & & & & & & & & \\ \hline  
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\end{table} 
Table 4: Nanofibrous adsorbent properties and adsorption conditions for the removal of Atrazine. Concerning Atrazine removal, as represented in Figure 1E, the lower BET value reported at 110 m\({}^{2}\)/g for carbon nanofibers reached the least adsorption performance with a removal of 10.2% (Table 4, \(N1\)). Carbon nanotube-nanofiber composites and carbon nanotubes, however, reached a removal of 90.4% and 35% for a specific surface area of 310 m\({}^{2}\)/g and 300 m\({}^{2}\)/g, respectively (Table 4, \(N6\), \(N7\)). Higher specific surface areas of 2235 m\({}^{2}\)/g for activated carbons led to complete contaminant removal (Table 4, \(N13\)). As carbon-based materials are among the highest-performing adsorbents, this suggests that \(\pi\)-\(\pi\) electron interactions and electrostatic interactions are preferential adsorption mechanisms for the removal of Atrazine. Figure 1F shows the Atrazine adsorbents' composition and other carbon-based structures; biomass absorbance has been reported in this form or extracted from shells, kernels and leaves. For a similar range of specific surface area, kernel and shell adsorbents here showed better performance compared to their leaf counterparts, with over 99% and 89% highest removal percentages, respectively (Table 4, \(N20\), \(N25\)). This difference in performance suggests that the adsorbent structure can significantly influence the Atrazine adsorption. Furthermore, all biomass adsorbents fitted the Freundlich isotherm and pseudo-first-order kinetic models well (\(R^{2}>0.85\)), suggesting a heterogeneously distributed adsorption on the biosorbent surface and physisorption as the reaction rate-limiting step [30]. This may suggest that Atrazine could not diffuse as much nitrogen into the adsorbent surface pores or between fibers' interstitial spaces. The different trends of performance increase for Alachlor and Diazinon and decrease for Atrazine with increasing specific surface areas may be explained by the molecular geometry of the adsorbates and preferential adsorption mechanisms.