造纸白泥基吸附剂净化电镀废水中PFOS和F-53B性能及机制OA

Aiming at the lack of low-cost purification technologies for perfluorooctane sulfonate(PFOS)and its alternative,6:2 chlorinated polyfluoroalkyl ether sulfonic acid(F-53B),in acidic electroplating wastewater,a new method was proposed,the papermaking white mud-based adsorbent was prepared by high-temperature calcination,using calcium-containing solid waste(papermaking white clay)as the core raw material and bentonite as the binder.Taking adsorption performance and compressive strength as evaluation indicators,the optimal mass ratio of bentonite to papermaking white mud was determined to be 20:80.The effects of solution pH and coexisting ions on the adsorption performance of B20-P80 adsorbent were systematically investigated.The results showed that the adsorbent B20-P80 maintained high removal efficiencies for both PFOS and F-53B over a wide pH range of 3-7.Notably,the adsorption of F-53B by B20-P80 was barely affected by coexisting ions(CO32-,Cl-,SO42-,NO3-,Cr6+).The results of adsorption kinetic and isotherm experiments indicated that the adsorption process conformed to the pseudo-first-order kinetic model and Langmuir isotherm model,and the maximum adsorption capacities of B20-P80 for PFOS and F-53B reaching 125.65 μmol·g-1 and 969.19 μmol·g-1,respectively.The adsorption characterization results demonstrated that B20-P80 had a high zero charge point(pHpzc=12.5),and its surface was positively charged within the actual pH range of electroplating wastewater,forming a strong electrostatic attraction with PFOS and F-53B anions.Additionally,the hydrophobic microdomains formed after high-temperature modification underwent hydrophobic association with the fluorinated alkyl chains of the pollutants.The adsorption mechanism was mainly the synergistic effect of electrostatic interaction and hydrophobic interaction.The above research results can provide an efficient and low-cost solution for the removal of per-and polyfluoroalkyl substances(PFASs)from electroplating wastewater,and provide a new approach for the resource utilization of calcium-containing industrial solid waste.