RETRACTED: Study on the Removal Efficiency and Mechanism of Tetracycline in Water Using Biochar and Magnetic Biochar

Hongwei Sun,Yucan Liu,Yue Wang,Chenjian Cai,Afshin Davarpanah,Jingjie Yang

doi:10.3390/coatings11111354

Hongwei Sun, Yucan Liu + Show 4 more

Open Access

https://doi.org/10.3390/coatings11111354

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Abstract

In this study, a new type of sludge-derived biochar material with high tetracycline removal efficiency, named magnetic Fe3O4 biochar, was accomplished by KOH activated and loaded with magnetic Fe3O4. The particles with spherical pellets observed by SEM, as well as the XRD patterns, indicated that magnetic Fe3O4 nanoparticles were successfully loaded onto the biochar. We studied the adsorption effects and mechanisms of the following three different adsorption materials for tetracycline: biochar (BC), magnetic Fe3O4, and magnetic biochar (MBC), and the loading conditions and reusability of the materials were also considered. The adsorption effects were as follows: Fe3O4 (94.3%) > MBC (88.3%) > BC (65.7%), and the ratio of biochar to ferric salt was 0.2:1; the removal effect reached the best result. Under an acidic condition, the adsorption capacity of all the materials reached the maximum, and the adsorption of tetracycline in water, by three adsorbents, involves chemical adsorption as the leading process and physical adsorption as the auxiliary process. Various characterizations indicated the removal of tetracycline, including pore filling, electrostatic interaction, hydrogen bond action, and cationic-π action. Complex bridging is a unique adsorption mechanism of magnetic Fe3O4 and magnetic biochar. In addition, the magnetic biochar also possesses π–π bond interaction. The magnetic materials can still maintain a certain amount of adsorption capacity on tetracycline after five cycles. This study proved that the magnetic sludge-based biochar are ideal adsorbents for the removal of tetracycline from water, as well as an effective route for the reclamation of waste sludge.

Highlights

The main reason for this is that the magnetic Fe3 O4 belongs to nanoparticles and has a large specific surface area, so it has a high removal efficiency for tetracycline
A biochar was made from waste sludge as a raw material and magnetically modified to remove tetracycline pollution from water bodies
The results showed that the biochar to iron salt ratio was 0.2:1; the prepared magnetic biochar performed best

Summary

Introduction

Since their discovery in the early twentieth century, antibiotics are emerging pollutants widely applied in human healthcare [1,2,3,4,5,6,7,8,9,10], veterinary practices, the livestock industry, and aquaculture [11,12,13,14,15,16,17,18,19,20]. Accumulating evidence has shown that antibiotics strongly inhibit the growth of algae [56], and harm beneficial bacteria [57] and other aquatic organisms [58]. In addition to antibiotics themselves, the antibiotic resistance genes emerge and are transferred to the whole food chain, posing a more long-term hazard, both environmentally and health wise [60]

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