Document LgxbMpGK3EBrj12dRvdvRQ69b

PFAS contaminant adsorption on all-silica zeolite Beta cMACS - Centre for Membrane separations, Adsorption, Catalysis and Spectroscopy Faculty Bioscience Engineering KU Leuven @kuleuven.be Angew. Chem. Int. Ed. 2020, 59, 14086-14090 Zeolites Crystalline microporous material (pores < 1 nm) Inorganic Commercially produced Beta topology (*BEA) 3D channel structure 12-membered rings Straight channels in a & b direction (6.6 x 6.7 ) Tortuous channels in c direction (5.6 x 5.6 ) 2 Faculteit Bio-Ingenieurswetenschappen All-silica zeolite Beta No framework aluminum Fluoride mediated synthesis Defect-free (no silanol nests) Hydrophobic channels Silanol nests Siliceous zeolite Beta with silanol defects (Green Chem., 2014, 16, 2281-2291 3 Faculteit Bio-Ingenieurswetenschappen Adsorption isotherms; capacity b PFOA b PFOS All-silica zeolite Beta () Commercial activated carbons: Filtrisorb 400 (AC1) Norit SX 1G (AC2) q = saturation capacity = 0- ; . Ce = equilibrium PFAS concentration after 24 h Beta zeolite >> commercial carbon materials 4 Experimental: 5 mg of adsorbent was contacted for 24 hours with 5 mL of an aqueous solution containing PFOA (left, concentrations ranging from 0.1 to 500 mg/L) and PFOS (right, concentrations ranging from 0.1 to 250 mg/L) Isotherms: affinity High affinity Quantified by = () All-silica zeolite Beta (); Commercial activated carbons: Filtrisorb 400 (AC1), Norit SX 1G (AC2) Adsorbent C0 (mg PFAS/L) AC1* 0.1 AC2* 0.1 ** 0.1 Adsorbent loading (g/L) 2.5 2.5 1 Log Kd for PFOA 3.6 3.7 >5.3 Log Kd for PFOS 3.9 4.3 >5.5 *Experimental: 100 mg of adsorbent was contacted for 7 days with 40 mL of a 0.1 mg/L PFAS solution (Data adapted from: J. Environ. Chem. Eng., 2020, 8, 103744 ) ** Experimental: 5 mg of adsorbent was contacted for 24 hours with 5 mL of a 0.1 mg/L PFAS solution Beta zeolite >> commercial carbon materials Experimental: 5 mg of adsorbent was contacted for 24 hours 5 with 5 mL of an aqueous solution containing PFOA (concentrations ranging from 0.1 to 500 mg/L) Isotherms: selectivity Adsorption selectivity experiments in presence of 5 organic competitors: Caprylic acid Sodium dodecylsulfate Phenol (~humic acid) b b Benzoic acid (humic acid) Adipic acid (dicarboxylic acid) Beta zeolite >> commercial carbon materials Experimental: 5.0 mg of adsorbent was contacted for 24 hours with 5 mL of an aqueous solution containing 100 M PFAS 6 and either 100 or 300 M of each competitor, creating either a 5-fold molar excess of organic competitors (5:1) or a 15-fold molar excess (15:1) Scalability:column experimenys Lab-scale column experiment 140 PFOA outlet concentration (mg/L) 120 100 80 After 26 h: 35 wt% zeolite loading 60 40 20 0 0:00:00 After 18 h: 24 wt% zeolite loading 4:48:00 9:36:00 14:24:00 19:12:00 24:00:00 Time (h) 28:48:00 33:36:00 38:24:00 43:12:00 48:00:00 7 Experimental: empty HPLC-column (15 cm x 4.6 mm) filled with 750 mg granulated all-silica zeolite Beta. A PFOA solution (Cinlet = 97 mg/L) was continuously pumped over the zeolite bed at a downward flow of 1.7 mL/min in a vertical setup. Zeolite Beta adsorbent Scalable material (industrially produced) Excellent regeneration: thermal / liquid phase Open challenges Expand zeolite adsorbents to wider range of PFAS Best interface between desorption and destruction Destruction technique in fully contained system - with 100 % mass balance on inorganic fluoride 8