Regeneration of Ion-Exchange Resins and Granular Activated Carbon with the Sonochemical Technique for Enabling Adsorption of Aqueous Per- and Polyfluoroalkyl Substances

Abstract

Regeneration of adsorbents for reuse is crucial for reducing operating costs and maintaining sustainable systems. Few researchers have studied the regeneration of sorbents without using chemical solvents or appropriate methods. The purpose of this study was to evaluate the feasibility of the sonochemical technique (ST) for the regeneration of granular activated carbon (GAC), a mixed cation and anion resin (DOWEX MB-50), and an anion resin (IRA910) for the removal of per- and polyfluoroalkyl substances (PFAS). The ST was performed at 120 kW, and the power density was 250 W L−1 for 30 min. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) were used to examine physicochemical properties of the spent adsorbents. The removal efficiency of the spent adsorbent regeneration occurred in the following order: DOWEX > GAC > IRA910. As the PFAS-adsorbed adsorbents disappeared in the spectrum, the FTIR results showed the existence of a sulfonic group that is similar to the peaks of virgin sorbents. However, this method affected the morphology of GAC and IRA910 but not DOWEX MB-50. Consequently, the ST is a potential alternative to chemical regeneration for DOWEX MB-50 resins. It is also a potential method for an eco-friendly approach to regenerate PFAS-adsorbed materials.

Evaluation of the adsorption behavior of mixed perfluoroalkyl and polyfluoroalkyl substances onto granular activated carbon and styrene‐divinylbenzene resins

“…Previous research has investigated spent adsorbents using the sonochemical technique (ST), which does not include the use of chemical reagents and is environmentally friendly. Their findings suggested that the ST is a successful way to produce adsorbents for PFAS adsorbed in water (Sukeesan et al, 2022). Finally, the importance of adsorption performance and adsorbent regeneration for sustainable treatment systems could be used to consider adsorbent selection for PFAS that are otherwise particularly difficult to treat.…”

“…The oxygen atom contained in the head structure of the PFAS may serve as an acceptor and bond with the hydrogen atom (He et al, 2013;Lu et al, 2016), suggesting that particle size distribution, resin functional groups, PFAS molecules, and hydrophobic interactions during the adsorption process play a key role in explaining the kinetics of PFAS. Their findings suggested that the ST is a successful way to produce adsorbents for PFAS adsorbed in water (Sukeesan et al, 2022).…”

A Review on Removal and Destruction of Per- and Polyfluoroalkyl Substances (PFAS) by Novel Membranes

“…Regenerating and disposing of used resins are among the main downsides of ion exchange resins for PFAS removal. Studies reveal that regenerated resins are less efficient in adsorbing PFAS and require a longer contact time than single-use resins [ 31 , 40 , 67 ]. Furthermore, the chemical regeneration process of the resins is expensive; therefore, the destruction of resins is a better option to avoid the loss [ 68 , 69 ].…”