Synchronous removal of tetracycline and water hardness ions by capacitive deionization

Here, a low-cost, efficient and eco-friendly capacitive deionization (CDI) technology has been introduced to simultaneously remove tetracycline (TC) and water hardness ions (Ca2+ and Mg2+) from water. In the process of CDI electrosorption, hierarchical porous carbon material derived from kelp was used as symmetric electrodes, and achieved the maximum capacity of 925.3 mg g(-1)- for TC removal, which is much higher than other materials reported so far. More importantly, high removal efficiency still maintained over 90% even after five CDI adsorption-desorption cycles. Meanwhile, the metal ions with opposite charges were adsorbed on the counter electrode with a preferential ion electrosorption performances as: Ca2+ (8.04 mg g(-1)) > Mg2+ (3.24 mg g(-1)) > K+ (2.59 mg g(-1)) > Na+ (0.75 mg g(-1)), proving the effective CDI technology in synchronous removal of tetracycline and water hardness ions for water purification. This work has paved a way to synchronously eliminate multiple organic and inorganic contaminants from water by using CDI technology.

Automated summary

A low-cost, efficient and eco-friendly capacitive deionization (CDI) technology was introduced to simultaneously remove tetracycline (TC) and water hardness ions. Hierarchical porous carbon material derived from kelp was used as electrodes, achieving high TC removal capacity and maintaining over 90% removal efficiency even after five CDI cycles. The study demonstrated the effective CDI technology in synchronous removal of tetracycline and water hardness ions for water purification.