A co-precipitation route for the preparation of eco-friendly Cu-Al-layered double hydroxides with efficient tetracycline degradation

The construction of novel efficient catalysts for the treatment of organic pollutants in the aqueous environment is essential. The lamellar-like Cu-Al layered double hydroxides (CuAl-LDHs) with various mole ratios were synthesized by a simple route of co-precipitation, and the corresponding degradation characteristic was tested for the removal of tetracycline (TC) using PMS activation. The degradation efficiency of TC over CuAl-LDHs increased up to 93% within 10 min for the Cu/Al mole ratio of 3:1 and almost not changed at a higher mole ratio. For further calcining the optimal catalyst at 300 celcius, the degradation efficiency of TC was found to be increased to 96%. Sulfuric radicals and singlet oxygen were analyzed to be the main reason for the change in degradation characteristics, which was proved by radical quenching experiments and electron paramagnetic resonance technique. The parameters including PMS concentration, catalyst dosage, and reaction temperature on the TC degradation as well as the degradation mechanism for PMS activation were elaborated. The best proportion of CuAl-LDHs owned splendid stability and catalytic activity after reusing, which showed enormous potential in practical application.

Automated summary

The construction of efficient catalysts for the treatment of organic pollutants in water is crucial. In this study, lamellar-like Cu-Al layered double hydroxides (CuAl-LDHs) were synthesized and tested for the degradation of tetracycline (TC) using PMS activation. The results showed that the degradation efficiency of TC increased up to 93% within 10 minutes for a Cu/Al mole ratio of 3:1. Calcination of the optimal catalyst at 300 degrees Celsius further increased the degradation efficiency to 96%. Sulfuric radicals and singlet oxygen were identified as the main factors influencing the degradation characteristics.