Influence of Oxyranylmethanol as a Catalytic Cross-linking Agent over Physiochemical Properties and Pb (II) Adsorption Performance of Resorcinol Formaldehyde Aerogels: a Comparative Study

In this study, the influence of oxyranylmethanol over physiochemical properties and Pb (II) adsorption potential of RF aerogels was investigated. Three variants of RF aerogels were catalyzed with 1 mL (RF-1), 2 mL (RF-2), and 3 mL (RF-3) of oxyranylmethanol respectively. The color of the aerogels changed from light orange, dark orange, and reddish brown as the catalyst concentration increased from 1 to 3 mL. Similarly, higher catalyst concentration resulted in higher surface area, pore volume, and porosity; however, the pore size and density decreased. The best morphological and structural properties were indicated by the sample (RF-3) that was catalyzed with 3 mL of oxyranylmethanol with surface area of 290 m2/g, pore volume of 0.7 cm3/g, pore size of 4.8 nm, and density of 90 mg/cm3 respectively. The synthesized oxyranylmethanol catalyzed RF aerogels were investigated for Pb (II) adsorption from synthetic solutions. As per results, RF-3 indicated highest removal % than RF-2 and RF-1 with maximum adsorption capacity (Qm) of 210 mg/g. On the other hand, RF-2 indicated second highest removal with Qm of 153 mg/g followed by RF-1 with Qm of 112 mg/g respectively. When compared with 15 relevant studies that used other agents as catalysts/functionalizing agents for aerogel synthesis, RF-3 indicated the second highest maximum adsorption capacity (Qm). Overall, the present investigation confirmed that the higher catalyst concentration (oxyranylmethanol) in RF aerogel promotes higher degree of polymerization between R and F; hence, results in lower density, higher surface area, higher pore volume, smaller pore size, and enhanced Pb (II) adsorption from synthetic wastewater.