Pillared bentonite from Al-Fe-Cu polymeric precursor in solid state for the catalytic oxidation of amoxicillin

A Colombian bentonite is successfully pillared with Al, Al-Fe, Al-Cu and Al-Fe-Cu polyhydroxications in solid state. The effect of the Fe and Cu content on the physicochemical properties of the pillared bentonite was evaluated using characterization techniques such as X-ray fluorescence (XRF), X-ray diffraction (XRD) and textural analysis (nitrogen physisorption). The Box-Behnken statistical experiment design was used to determine the optimal parameters of the independent variables hydrogen peroxide (0.120-0.144 M), catalyst load (0.5-1.5 g/L) and type of catalyst (PILC FeCu1, FeCu5, FeCu10) in the catalytic oxidation (CWPO) of amoxicillin. The optimized conditions of hydrogen peroxide (0.137 M) and catalyst loading (0.7 g/L) were used to compare the catalytic performance of the catalysts with 1%, 5% and 10% Al-Fe, Al-Cu and Al-Fe-Cu reaching a removal between 91% and 100% of amoxicillin at T and ambient pressure. The rate constants determined allowed the identification of the best catalyst of each series to study the degree of mineralization and choose the best catalyst: the pillared clay with AlFeCu10, with a TOC removal of 24.6% after 2 h of reaction. After three cycles of reuse, the catalyst maintained its catalytic activity in removing amoxicillin without leaching any metal.

Automated summary

A Colombian bentonite was successfully pillared with Al, Al-Fe, Al-Cu and Al-Fe-Cu polyhydroxications in solid state. The effect of the Fe and Cu content on the physicochemical properties of the pillared bentonite was evaluated. The optimized conditions were used to compare the catalytic performance of the catalysts, and pillared clay with AlFeCu10 showed the best performance.