## 3 Types of Adsorbents Made from Polyacrylonitrile
### Polyacrylonitrile in Hydrogels
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**S. No.**} & \multirow{2}{*}{**Adsorbent**} & \multicolumn{2}{c}{**Maximum Adsorption**} & \multicolumn{2}{c}{**Initial**} & \multirow{2}{*}{**Optimum pH**} & \multirow{2}{*}{**Reference**} \\  & & & **Capacity/Contact Time** & & & & \\ \hline \multicolumn{6}{c}{CHELATES} \\ \hline \multirow{2}{*}{1.} & Polyacrylonitrile-2- & \multirow{2}{*}{Hg2\({}^{+}\): 526.9 mg/g} & \multirow{2}{*}{-} & \multirow{2}{*}{6.5} & \multirow{2}{*}{[45]} \\  & amino-1,3,4- & & & & & \\  & thiadiazole & & & & \\ \hline \multirow{2}{*}{2.} & EDTA-functionalized & Ni2\({}^{+}\): 305.24 mg/g & \multirow{2}{*}{-} & \multirow{2}{*}{[43]} \\  & polyacrylamideonitrile & Co2\({}^{+}\): 88.35 mg/g & & 1.0 & \\ \hline \multirow{2}{*}{3.} & Ammonium & Co2\({}^{+}\): 9.424 mg/g & \multirow{2}{*}{10 mM} & \multirow{2}{*}{[49]} \\  & molybdenumate- & Sr2\({}^{+}\): 87.62 mg/g & & 7.0 & \\  & polyacrylamideonitrile & Cs\({}^{+}\): 81.069 mg/g & & 7.0 & \\ \hline \multirow{2}{*}{4.} & Polyacrylonitrile- & Ag\({}^{+}\): 108.14 mg/g/30 min & \multirow{2}{*}{110 ppm} & \multirow{2}{*}{[120]} \\  & TETA & Pb2\({}^{+}\): 99.01 mg/g/30 min & & & \\ \hline \multirow{2}{*}{5.} & Amidoximated & Hg2\({}^{+}\): 521.534 mg/g/600 min & \multirow{2}{*}{5 mM} & \multirow{2}{*}{[55]} \\  & AN/MA & Ca\({}^{+}\): 145.62 mg/g/600 min & & & \\  & AN/MA & Cu2\({}^{+}\): 127.727 mg/g/600 min & & & \\  & & Fe2\({}^{+}\): 41.325 mg/g/600 min & & & \\  & & Pb2\({}^{+}\): 12.42 mg/g/600 min & & & \\ \hline \multirow{2}{*}{6.} & Amidoximated & Cd2\({}^{+}\): 87 mg/g/40 min & \multirow{2}{*}{250 ppm} & \multirow{2}{*}{6.0} & \multirow{2}{*}{[57]} \\  & polyacrylamideonitrile & Herbicide paraquat: 91 & 100 ppm & & \\  & mg/g/40 min & & & \\ \hline \multirow{2}{*}{7.} & Polyacrylonitrile- & \multirow{2}{*}{Cf\({}^{b}\): 374.90 mg/g/120 min} & \multirow{2}{*}{448.7 ppm} & \multirow{2}{*}{2.0} & \multirow{2}{*}{[59]} \\  & based porous carbon & & & & \\ materials & & & & & \\ \hline \multirow{2}{*}{8.} & NaOH-hydrolyzed & \multirow{2}{*}{Pb2\({}^{+}\): 78.34 mg/g} & \multirow{2}{*}{200 ppm} & \multirow{2}{*}{-} & \multirow{2}{*}{[121]} \\  & kapok- & Polyacrylonitrile & & & \\  & nanocomposites & & & & \\ \hline \multirow{2}{*}{9.} & Chelating & Pb2\({}^{+}\): 145 mg/g/180 min & \multirow{2}{*}{50–200 ppm} & \multirow{2}{*}{7.0} & \multirow{2}{*}{[122]} \\  & polyacrylamide peptidase beads & Cd2\({}^{+}\): 156 mg/g/1800 min & & & \\ \hline \multicolumn{6}{c}{MEMBRANES} \\ \hline \multirow{2}{*}{3.} & PVAm-CNF & Cr6\({}^{+}\): 23.55 mg/g/30 min & 100 ppm & \multirow{2}{*}{6.0} & \multirow{2}{*}{[77]} \\  & membrane & Cr6\({}^{+}\): 44.95 mg/g/90 min & 200 ppm & & \\ \hline \multirow{2}{*}{4.} & Aminated- & \multirow{2}{*}{Cu2\({}^{+}\): 116.522 mg/g/20 min} & \multirow{2}{*}{-} & \multirow{2}{*}{6.0} & \multirow{2}{*}{[73]} \\  & polyacrylamideplanoffier membranes & & & & \\ \hline \multirow{2}{*}{5.} & Bilayer & \multirow{2}{*}{Pb2\({}^{+}\): 461 mg/g/5 min} & \multirow{2}{*}{150–800 ppm} & \multirow{2}{*}{5.0} & \multirow{2}{*}{[107]} \\  & polyacrylonitrile & Cd2\({}^{+}\): 389 mg/g/60 min & & & \\ \hline \multirow{2}{*}{6.} & PAN/PANI-nylon & \multirow{2}{*}{Pb2\({}^{+}\): 960 mg/g/7 min} & \multirow{2}{*}{50 ppm} & \multirow{2}{*}{6.5} & \multirow{2}{*}{[20]} \\  & core–shell nanofiber & Cd2\({}^{+}\): 911.72 mg/g/7 min & & & \\  & membranes & & & & \\ \hline \multirow{2}{*}{7.} & PAN/PANI & Pb2\({}^{+}\): 290.12 mg/g/180 min & \multirow{2}{*}{5–350 ppm} & \multirow{2}{*}{7.0} & \multirow{2}{*}{[108]} \\  & membranes & Cr6\({}^{+}\): 1202.53 mg/g/180 min & & & \\ \hline \multirow{2}{*}{8.} & PAN-EDA membrane & \multirow{2}{*}{Congo red dye: 90\%/60 min} & \multirow{2}{*}{10–70 ppm} & \multirow{2}{*}{-} & \multirow{2}{*}{[91]} \\  & PAN-NH2 membrane & & & & \\ \hline \multirow{2}{*}{9.} & PAN-CONH2 & \multirow{2}{*}{Congo red dye: 82\%/90 min} & \multirow{2}{*}{448.7 ppm} & \multirow{2}{*}{2.0} & \multirow{2}{*}{[59]} \\  & PAN-CONH2 & & & & \\ \hline \hline \end{tabular}
\end{table}