# Kinetics and Thermodynamics of Efficient Phosphorus Removal by a Composite Fiber
## 3 Results and Discussion
### Adsorption Kinetics at Different Temperatures
#### 3.1.5 Performance of Phosphorus Removal Adsorbents  
The partition coefficient is often used in solid-liquid adsorption system representing the ratio of adsorbate concentration in the solid phase to the concentration in the liquid phase at equilibrium. It is an objective performance metric to assess sorbents, despite of differences in operating conditions [29]. Some phosphorus removal adsorbents are evaluated in Table 9. Among these adsorbents, ZSFB composite fiber had comparative performance with the partition coefficient of 1.49 mg/g/\(\mu\)M. Nanomaterials and their composites generally showed enhanced performance for the removal of phosphorous from an aqueous solution compared with others. Among these adsorbents, hollow magnetic Fe\({}_{3}\)O\({}_{4}\)@NH\({}_{2}\)-MIL-101(Fe) had the best performance in terms of partition coefficient (24.65 mg/g/\(\mu\)M). The reason behind these chemical interactions was the presence of partially positively-charged metal sites in the metal organic frameworks [30; 31]. These positively charged metal sites can interact with negatively charged sites through electrostatic interactions, leading to the adsorption of phosphate ions [32].  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Adsorption (mg P)** & **Desorption (mg P)** & **Desorption Rate (\%)** \\ \hline
0.421 & 0.0007 & 0.166 \\
0.798 & 0.0016 & 0.201 \\
1.986 & 0.0083 & 0.418 \\
2.980 & 0.0215 & 0.721 \\
3.434 & 0.0331 & 0.964 \\
3.658 & 0.0376 & 1.028 \\
3.740 & 0.0379 & 1.013 \\ \hline \hline \end{tabular}
\end{table}
Table 7: Desorption of ZSFB composite fiber in hot water.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Sulfuric Acid** & & & \\
**Concentration (mol/L)** & **Adsorption (mg P)** & **Desorption (mg P)** & **Desorption Rate (\%)** \\ \hline
0.01 & 0.425 & 0.145 & 34.118 \\
0.05 & 0.411 & 0.355 & 86.375 \\
0.1 & 0.416 & 0.398 & 95.673 \\
0.5 & 0.409 & 0.406 & 99.267 \\
1.0 & 0.416 & 0.413 & 99.279 \\ \hline \hline \end{tabular}
\end{table}
Table 8: Desorption of ZSFB composite fiber in sulfuric acid solution.  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline  & \multicolumn{2}{c}{**Optimum**} & \multicolumn{2}{c}{**Residual**} & \multicolumn{2}{c}{**Maximum**} & \multicolumn{2}{c}{**Residual**} & \multicolumn{2}{c}{**Maximum**} & \multicolumn{2}{c}{**Partition**} \\
**adsorbent** & **Condition** & **Initial Phosphorus** & **Concentration (\(\mu\)M)** & **Removal** & **Phosphorus** & **adsorption** & **Coefficient** \\  & **(Temperature (’C), pH)** & & **Efficiency (\%)** & **Concentration (\(\mu\)M)** & **Capacity (mg P/g)** & **(mg/g/uM)** & **References** \\ \hline Iron-zirconium & & & & & & & \\ modified activated & 25, 4 & 315.89 & 22.5 & 244.81 & 26.3 & 0.11 & [33] \\ carbon nanofiber & & & & & & \\ \hline Aluminum hydroxide & & & & & & & \\ palygorside modified & 45, 5 & 10,529.64 & – & – & 16.86 & – & [34] \\ nanocomposite & & & & & & & \\ \hline Zirconium ions & 15, 4 & 210.59 & 61.27 & 81.56 & 61.7 & 0.76 & [35] \\ modified chitosan beads & & & & & & & \\ \hline Fe-Cu binary oxides & 25, 7 & 52.65 & – & – & 35.2 & – & [36] \\ \hline Hollow magnetic & 20, - & 6.32 & 92.33 & 0.48 & 11.95 & 24.65 & [31] \\ Fe\({}_{3}\)O\#NH\({}_{2}\)-MIL101(Fe) & & & & & & & \\ \hline Dipolar grafted & 50, 5 & 1263.56 & 99.45 & 6.99 & 46.94 & 6.72 & [37] \\ hydroxyethyl cellulose & & & & & & \\ \hline Ferrihydrite-coated and lanthanum-decorated & 25, 6.28 & 1052.96 & 74.4 & 269.56 & 44.8 & 0.17 & [38] \\ magnetite & & & & & & & \\ \hline MIL-100(Fe) & 25, 4 & 84.24 & 93.05 & 5.85 & 93.55 & 15.98 & [32] \\ \hline ZSFB composite fiber & 35, 4 & 322.89 & 99.13 & 2.81 & 4.18 & 1.49 & This work \\ \hline \hline \end{tabular}
\end{table}
Table 9: Performance of different adsorbents for adsorptive removal of phosphorus from aqueous solution.