Effect of the interlamellar anion on CuMgFe-LDH in solar photo-Fenton and Fenton-like degradation of the anticancer drug 5-fluorouracil

The influence of the interlamellar anion in Layered Double Hydroxide was investigated for the first time in Fenton-like and solar photo-Fenton processes for the degradation of the anticancer drug 5-fluorouracil (5-FU). LDHs of the MgFeCu type were synthesized by coprecipitation with the insertion of CO32-, NO3-, SO42- and B(OH)4-. A strong effect of the interlamellar anion was observed on the catalytic activity with pseudo-first-order rate constant sequence (k): CuMgFe-B(OH)4 > CuMgFe-NO3 > CuMgFe-SO4 > CuMgFe-CO3. Using CuMgFe-B(OH)4, 5-FU was completely degraded under solar radiation after 20 min and after 40 min in the dark, with degradation efficiency maintained above 90% until the fourth cycle of use. It was found that molecular B-O and B-OH interactions induced modifications of the CuMgFe-B(OH)4 surface charge density, accelerating the reduction of Cu(II) and Fe(III), thus favoring reactive oxygen species generation. This performance denotes the excellent potential of CuMgFe-B(OH)4 for 5-FU degradation.