# Improving Sorbents for Glycerol Capture in Biodiesel Refinement
## 3 Materials and Methods
### Synthesis of S65-Ph(1) and S85-Ph(1) (Type 1, silicates, Ph Indicates Grafted Phenyl Groups)  
Scaffold materials were synthesized based on a previously published procedure [24; 25]. Pluronic P123 (4.0 g) and 0.65 g (S65) or 0.85 g (S85) mesitylene were dissolved in 12.0 g of 1.0 M HNO\({}_{3}\) with heat (\(\sim\)65 \({}^{\circ}\)C) and magnetic stirring. The mixture was allowed to cool to room temperature before drop-wise addition of 5.15 g tetramethyl orthosilicate, and the mixture was stirred to homogenize (\(\sim\)1 min). The mixture was transferred to culture tubes that were tightly sealed and incubated at 60 \({}^{\circ}\)C overnight. The tubes were unsealed, and the white monolithic gels were heated at 60 \({}^{\circ}\)C for 6 d. The material was calcined under ambient atmosphere: temperature was ramped 1 \({}^{\circ}\)C/min to 650 \({}^{\circ}\)C and held for 5 h. Material was refluxed in 1 M HCl for 1 d, similar to the solvent extraction process for other materials, to condition the surface similarly for grafting. It was then collected by vacuum filtration, washed with ethanol and H\({}_{2}\)O, and dried at 110 \({}^{\circ}\)C. Grafting, sulfonation, and sodium exchange for these sorbents were completed using the protocols described in Section 3.1. The final sulfonated, phenyl grafted materials are referred to as S65-Ph(1) and S85-Ph(1), reflecting their base S65 or S85 scaffold, the phenyl group modification (Ph), and the sorbent type (1).  
Synthesis of D13a(6), D13b(6), D13c(6), D13-Ph1(5), and D13-Ph2(5) (Types 5 and 6, Diethylbenzene-Bridged Organosilates, Ph Indicates Grafted Phenyl Groups)  
Scaffold materials were synthesized by dissolving Pluronic P123 (3.8 g) and mesitylene (1.8 g) in 16.0 g of 0.1 M HNO\({}_{3}\) with heat (\(\sim\)65 \({}^{\circ}\)C) and magnetic stirring. The mixture was allowed to cool to room temperature prior to drop-wise addition of bis(trimethoxysilylethyl)benzene (5.87 g), and the mixture was stirred to homogenize (\(\sim\)1 min). The mixture was transferred to culture tubes that were tightly sealed and incubated in an oven at 60 \({}^{\circ}\)C overnight. The tubes were unsealed, and the white monolithic gels were heated for 2 d at 60 \({}^{\circ}\)C and 2 d at 80 \({}^{\circ}\)C. Block copolymer was extracted from the dried materials by refluxing overnight in 1 M HCl in ethanol; the solid was collected by vacuum filtration. This process was repeated two more times. The collected solid was washed thoroughly with ethanol and water, then dried at 110 \({}^{\circ}\)C. Grafting, sulfonation, and sodium exchange for D13-Ph1(5) and D13-Ph2(5) were completed using the protocols described in Section 3.1. D13a(6), D13b(6), and D13c(6) were not grafted with phenyl groups prior to sulfonation and sodium exchange. The designations a, b, and c refer to similarly but separately synthesized materials. D13b(6), in particular, was sulfonated using 50% H\({}_{2}\)SO\({}_{4}\) rather than undiluted acid. The final sulfonated (Type 6) or sulfonated, phenyl grafted (Type 5) materials are identified by their base scaffold (D13a, D13b, etc.), the phenyl group modification (Ph), and the sorbent type (5 or 6).