Insight into core-shell microporous zinc silicate adsorbent to eliminate antibiotics in aquatic environment under the COVID-19 pandemic

Under the new crown pneumonia (COVID-19) epidemic, the intensive use of therapeutic drugs has caused certain hidden danger to the safety of the water environment. Therefore, the core-shell microporous zinc silicate (SiO2@ZSO) was successfully prepared and used for the adsorption of chloroquine phosphate (CQ), tetracycline (TC) and ciprofloxacin (CIP) for eliminating the threat of COVID-19. The adsorption efficiencies of 20 mg L-1 of CQ, TC and CIP by SiO2@ZSO were all up to 60% after 5 min. The adsorption capacity of SiO2@ZSO for CQ, TC and CIP can reach 49.01 mg g-1, 56.06 mg g-1 and 104.77 mg g-1, respectively. The adsorption process is primarily physical adsorption, which is heterogeneous, spontaneous and preferential. Moreover, the effects of temperature, pH, salinity, and reusability on the adsorption of CQ, TC, and CIP on SiO2@ZSO were investigated. The adsorption mechanism mainly involves electrostatic attraction, partitioning and hydrogen bonding, which is insightful through the changes of the elements and functional groups before and after adsorption. This work provides a solution to the problems faced by the treatment of pharmaceuticals wastewater under the COVID-19 epidemic.

Automated summary

Under the COVID-19 epidemic, the use of therapeutic drugs poses a hidden danger to the water environment. A core-shell microporous zinc silicate (SiO2@ZSO) was prepared and used for the adsorption of chloroquine phosphate (CQ), tetracycline (TC), and ciprofloxacin (CIP) to eliminate the threat of COVID-19. SiO2@ZSO exhibited high adsorption efficiencies for CQ, TC, and CIP within a short period of time. The adsorption mechanism involved physical adsorption and various factors were investigated.