Effective Degradation of Aqueous Tetracycline Using a Nano-TiO₂/Carbon Electrocatalytic Membrane.

Zhimeng Liu,Zheng Wang,Hong Wang,Kui Li,Mengfu Zhu,Cheng Deng

doi:10.3390/ma9050364

Abstract

In this work, an electrocatalytic membrane was prepared to degrade aqueous tetracycline (TC) using a carbon membrane coated with nano-TiO2 via a sol-gel process. SEM, XRD, EDS, and XPS were used to characterize the composition and structure of the electrocatalytic membrane. The effect of operating conditions on the removal rate of tetracycline was investigated systematically. The results show that the chemical oxygen demand (COD) removal rate increased with increasing residence time while it decreased with increasing the initial concentration of tetracycline. Moreover, pH had little effect on the removal of tetracycline, and the electrocatalytic membrane could effectively remove tetracycline with initial concentration of 50 mg·L−1 (pH, 3.8–9.6). The 100% tetracycline and 87.8% COD removal rate could be achieved under the following operating conditions: tetracycline concentration of 50 mg·L−1, current density of 1 mA·cm−2, temperature of 25 °C, and residence time of 4.4 min. This study provides a new and feasible method for removing antibiotics in water with the synergistic effect of electrocatalytic oxidation and membrane separation. It is evident that there will be a broad market for the application of electrocatalytic membrane in the field of antibiotic wastewater treatment.

Highlights

In recent years, the emergence of antibiotics in the environment has received increasing attention [1,2]
Antibiotics are gradually enriched in the environment resulting in antibiotic pollution
The results showed that the chemical oxygen demand (COD) removal rates were up to 87.4 and 100 with the liquid hourly space velocity of 7.2 h1 and 21.6 h1, respectively [25]

Summary

Introduction

The emergence of antibiotics in the environment has received increasing attention [1,2]. The presence of antibiotics in water affects the water quality, and causes potential adverse effects on humans and ecological systems [4]. The concentration of antibiotics is very low in the environment (ng L1 or μg L1 ), the antibiotics are hard to be degraded by microorganism due to the complex structure and the antibacterial nature [5]. Antibiotics are gradually enriched in the environment resulting in antibiotic pollution. When long-term exposure to an antibiotic-polluted environment, human health would be affected even at very low concentrations [6]. Among all of the antibiotics, tetracycline (TC) is wildly used in human and veterinary medicine [7]. TC has been detected in sewage water, surface water, groundwater, drinking water, and sludge due to its ineffective removal by conventional water treatment processes [8,9,10]

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Results

Conclusion