# Utilization of Polymeric Materials toward Sustainable Biodiesel Industry: A Recent Review
## 3 Polymeric Catalysts
### Waste Derived Polymeric Catalysts
\begin{table}
\begin{tabular}{l l c c c c} \hline \hline \multirow{2}{*}{**Polymeric Catalyst**} & \multirow{2}{*}{**Biodiesel**} & \multirow{2}{*}{**Yield (\%)**} & \multicolumn{3}{c}{**Reusability**} & \multirow{2}{*}{**Reference**} \\ \cline{3-3} \cline{5-6}  & & & **Number of Cycles** & & **Yield (\%)** & \\ \hline CCu & Babassu oil & 76.8 & - & - & ([PERSON] et al., 2018) \\ Chitosan immobilized with CaO & Soybean oil & 97 & - & - & ([PERSON] et al., 2018) \\ Chitosan with sulfonic acid groups & Palmitic acid & 89 & 4 & 80 & ([PERSON] et al., 2018) \\ HTCC/Na2 SiO3/ECH & Soybean oil & 97 & 7 & 83 & ([PERSON] et al., 2018) \\ Ferric alginate & Lauric acid & 99 & - & - & ([PERSON] et al., 2018) \\ Tin (Sn2*) alginate & Oleic acid & 98.7 & 8 & 97.6 & ([PERSON] et al., 2018) \\ CB-(AST-HPW) & Yellow horn oil & 96 & 7 & 70 & ([PERSON] et al., 2018) \\ MSNC & Oleic acid & 96 & 5 & 95 & ([PERSON] et al., 2018) \\ Lipase PS enzyme encapsulated with & & palm oil & 100 & 5 & 82 & ([PERSON] et al., 2018) \\ biopolymer \(\kappa\)-carrageenan & & & & & \\ ANL/UIO-66-PDMS-6 h & Soybean oil & 88 & 10 & 83 & ([PERSON] et al., 2018) \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Some of the naturally derived polymeric catalysts. catalytic characteristics, the superiority of the last approach is to reduce the accumulated polymeric wastes from the environment. Reusability is one of the main advantages of the three groups of chemically, naturally, and waste derived polymeric catalyst in biodiesel industry. Most of the reported polymeric catalysts proved reusable efficiency for several cycles. However, the performance of reused catalyst declines compared with the first run. The catalysis reactivity depends on the polymer chemical composition and the cycles number [89]. Synthesized polymers, e.g., Poly (butanesulfonic acid pyrrole) coated magnetic iron oxide, ANL/UiO-66-PDMS-6 h, sPS-S, and p-TSA-PANI have reusable activity reached 10 cycles with remarkable yield 97.5%, 83%, 88%, and 94.3, respectively [66; 82; 86; 88]. This reusability characteristic of polymeric catalysts promotes the circular economy to produce sustainable biodiesel with low costs. \begin{table} \begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Polymeric**} & \multirow{2}{*}{**Biodiesel**} & \multirow{2}{*}{**Yield (\%)**} & \multicolumn{2}{c}{**Reusability**} & \multirow{2}{*}{**Reference**} \\ \cline{3-3} \cline{5-6}  & & & & **Number of Cycles** & & **Yield (\%)** \\ \hline D50w2 & Palmitic acid & 76.8 & 7 & 59.8 & [83] \\ D5081 & Oleic acid & 97 & 4 & 92 & [84] \\ PSS & Oleic acid & 53.4 & 3 & 35.1 & [85] \\ sPS-S & Dodecanoic acid & 100 & 10 & 88 & [86] \\ MSA-Pani & Ricinoleic acid & 92 & 2 & 89 & [87] \\ P-TSA-PANI & Waste cooking oil & 97.1 & 10 & 94.3 & [88] \\ TPC-SO\({}_{3}\)H & Chicken fat & 98.8 & 7 & 48 & [23] \\ \hline \hline \end{tabular} 
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{Evaluation items} & Chemically synthesized polymeric catalysts & Naturally derived polymeric catalysts & Waste derived polymeric catalysts \\ \hline \hline \multirow{2}{*}{_Synthesis simplicity_} & \multirow{2}{*}{\(\times\times\times\)\(\times\)\