## 4 Conclusions  
Amine immobilized GMA-\(g\)-NWF were successfully produced via pre-radiation grafting technique which followed by functionalization process with several aliphatic amines. The aliphatic amine concentration had imposed a significant effect on the AD yield during the functionalization process. However, the AD reduces as the aliphatic amine chain grows more extended, from EDA to TETA. The addition molecular weight and bulky structure further attribute steric hindrance which obstructs the corporation of amine group onto GMA. The similar trend observed in all other experimental condition which had been investigated. The AD increases linearly as the concentration of amine increases. The differences in amine immobilized GMA-\(g\)-NWF and IRP samples were extinguished by using various characterization tools. The structural coordination of GMA-\(g\)-NWF and IRP samples were analyzed with XPS and EXAFS spectroscopy. The complexation of the Cu ion with the prepared adsorbent takes place by the binding of Cu-O. The structural coordination of IRP samples remains the same even after the crosslinking process. The adsorptive capacity and selectively of both amine immobilized GMA-\(g\)-NWF and IRP samples were compared at similar experimental conditions. The IRP samples had exhibited superior adsorptive capacity and selectivity in comparison to amine immobilized GMA-\(g\)-NWF. The selectivity of amine immobilized GMA-\(g\)-NWF was greatly enhanced by associating \begin{table}
\begin{tabular}{c c c c c c} \hline
**Sample** & **Shell** & **N** & **R (Å)** & \(\sigma^{2}\) (Å\({}^{2}\)) & **E\({}_{0}\) (eV)** \\ \hline \multirow{3}{*}{**EDA-IRP**} & Cu–O & 4.000 & 4.061 & 0.029 & 7.622 \\ \cline{2-6}  & Cu–N & 6.000 & 2.014 & 0.008 & 3.501 \\ \hline \multirow{3}{*}{**DETA-IRP**} & Cu–O & 4.000 & 4.085 & 0.004 & 7.100 \\ \cline{2-6}  & Cu–N & 6.000 & 2.038 & 0.012 & 3.749 \\ \hline \multirow{3}{*}{**TETA-IRP**} & Cu–O & 4.000 & 4.001 & 0.020 & 7.600 \\ \cline{2-6}  & Cu–N & 6.000 & 2.014 & 0.010 & 2.652 \\ \hline \multirow{3}{*}{**TETA-IRP**} & Cu–O & 4.000 & 3.999 & 0.025 & 7.501 \\ \cline{2-6}  & Cu–N & 6.000 & 2.038 & 0.014 & 4.709 \\ \hline \multirow{3}{*}{**EDA-GMA-g-NWF**} & Cu–O & 4.000 & 4.205 & 0.004 & 4.045 \\ \cline{2-6}  & Cu–N & 4.000 & 1.999 & 0.003 & 4.058 \\ \hline \multirow{3}{*}{**DETA-GMA-g-NWF**} & Cu–O & 4.000 & 4.218 & 0.004 & 4.124 \\ \cline{2-6}  & Cu–N & 4.000 & 1.993 & 0.003 & 3.882 \\ \hline \multirow{3}{*}{**TETA-GMA-g-NWF**} & Cu–O & 4.000 & 4.253 & 0.004 & 4.253 \\ \cline{2-6}  & Cu–N & 4.000 & 1.973 & 0.005 & 1.657 \\ \hline \multirow{3}{*}{**TETA-GMA-g-NWF**} & Cu–O & 4.000 & 4.240 & 0.007 & 4.240 \\ \cline{2-6}  & Cu–N & 4.000 & 1.968 & 0.004 & 0.197 \\ \hline \end{tabular}
\end{table} 
Table 5: Structural parameters of both amines immobilized GMA-\(g\)-NWF and IRP complexes from EXAFS spectra. ion reorganization technique. However, the selectivity of IRP samples reduces slightly as the aliphatic amines change form EDA to longer molecules chain of TEPA. This study particularly proves the correlation between aliphatic amine chain length with selectivity towards dedicate metal ion. The aliphatic amine with short chain gives higher selectivity in comparison to those aliphatic amines that have a long chain. In the future, the adsorption capacity and selectivity of IRP samples should be tested in multiple metal systems to evaluate the adsorptive properties comprehensively. The following are available online at [[http://www.mdpi.com/2073-4360/11/12/1994/s1](http://www.mdpi.com/2073-4360/11/12/1994/s1)]([http://www.mdpi.com/2073-4360/11/12/1994/s1](http://www.mdpi.com/2073-4360/11/12/1994/s1)). Conceptualization, N.A.F.O. ; Formal analysis, N.A.F.O., [PERSON] and [PERSON]; Funding acquisition, N.S. ; Investigation, N.A.F.O. ; Methodology, N.A.F.O. ; Resources, H.H. ; Supervision, N.S. ; Validation, [PERSON]; Writing--original draft, N.A.F.O. and [PERSON]; Writing--review and editing, T.A.T.A. and N.S.