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

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.

Enhanced Phosphorus Recovery as Vivianite from Anaerobically Digested Sewage Sludge with Magnetic Biochar Addition

“…As the XPS spectra of Fe and O for MBC shows (Figure S2), the Fe2p spectrum exhibited two contributions, i.e., Fe 2+ at 710.1 (27.27%) and Fe 3+ (53.54%) at 712 eV [27]. The ratio of Fe 2+ to Fe 3+ was 0.27:0.54, which was comparable to that in Fe 3 O 4 (0.33:0.67) [28], suggesting the loading of Fe 3 O 4 on MBC.…”

Recent advances on sustainable removal of emerging contaminants from water by bio-based adsorbents

“…The change in the values of area, and specific gravity of the carbon, oxygen, and iron confirmed that the aldehydes, Fe-O-Fe, C-O-Fe, CQO/C-O, Fe 2+ , Fe 3+ , Fe 3 O 4 , and FeOOH played a part in the adsorption of TC onto the Fe 3 O 4 modified waste sludge biochar, implying p-p interaction, hydrogen bonding, cation p-interaction and metal ion complexation. 94 The kinetic study revealed that the adsorption of TC onto Fe 3 O 4 /biochar follows the pseudo second order equation. This confirmed that the adsorption of TC was carried out through the chemical mechanism.…”

“…After five cycles of recycling, Fe 3 O 4 modified waste sludge biochar removed 34% TC, which is possibly due to the irreversible impact of some adsorption sites on the surface of the Fe 3 O 4 /biochar. 94…”

Removal of Antibiotics from Aqueous Solutions by Bentonite Supported-Nanoscale Zero-Valent Iron

“…The main sorption mechanisms of antibiotics include ion exchange, surface complexation, and hydrogen bonding [51]. In previous studies, activated carbon [53], bentonite supported nanoscale Fe/Ni bimetallic particles [54], MCM-41 [55], biochar [56] copolymer/Fe3O4 magnetic nanocomposite [57], MIL-53(Al) metal-organic framework [58], agricultural waste [59], carbon nanotube [60], graphene oxide [61], SiO2 nanoparticles [62] have been used as adsorbent for the water treatment of antibiotics.…”