FTIR. FTIR spectroscopy was used to understand PFOA adsorption mechanism onto MIL-96-RHPAM2 and the linker interaction with added polymer (Figure ). Detailed analysis of the IR peaks is displayed in Table . The collected spectra of spent MIL-96-RHPAM2 in Figure confirms that PFOA was adsorbed through electrostatic interaction with the MOF. A previous study also inferred the increased intensities of vs to vas (COO -) after PFOA adsorption in relation to an inner-sphere complexation with the metal centers. In this case, the carboxylate head groups of PFOA may have formed covalent bond to the surface of MIL-96-RHPAM2. 61 Adsorption Kinetics. Apart from knowing the equilibrium adsorption capacity of sorbents (Figure ), it is equally important to understand the adsorption kinetics involved in the PFOA removal by MIL-96-RHPAM2. Based on previous studies, the experimental data obtained herein is fitted using a pseudo second order (PSO) kinetic model. Figure highlights the severe diffusion limitation exhibited by MIL-96-RHPAM2 as the material's adsorptive capacity only reached its plateau after 186 hours of contact time. Concurrently, the PFOA adsorption data can also be described by the Elovich kinetic model. Non-linear plots using both models showed high regression coefficients with PSO (R 2 = 0.983) and Elovich (R 2 = 0.996), suggesting chemisorption is the rate limiting step as supported by the FTIR analysis. Since the Elovich equation gave superior approximation to the experimental data, it may be concluded that the adsorption proceeded in a highly heterogenous system. Earlier discussions have highlighted the abundance of chemical functional groups comprising of -NH2, -OH, -COOH, -NH3 + and the Al 3+ metal centers on MIL-96-RHPAM2 which may readily bind to PFOA.