Efficient removal of tetracycline from aqueous solution by covalent organic frameworks derived porous carbon

Pursuing high-efficiency adsorbents with high stability and ample porosity for environmental remediation has great practical significance but huge challenges still remain. Herein, porous carbons (PCs) were prepared by using covalent organic framework (COF) as self-template. The as-prepared PCs are of high specific surface area and pore volume, which are beneficial for contaminant capture. In contrast to virgin COF, the obtained PCs exhibited a better application potential for tetracycline (TC) removal from water. Notably, 87% of TC can be removed within 10 min and the kinetic data were consistent with the second-order kinetic model (R2 > 0.998). Moreover, the adsorption isotherm conformed to the Langmuir adsorption model, and the calculated value of saturated adsorption capacity was 285 mg/g. It was speculated that the superior adsorption performance was due to the contribution of π-π stacking, hydrogen bonding and hydrophobic interactions. It is worth noting that the sample prepared from COF heat-treated at 1000 °C, denoted as TpPa-1-1000, had good stability and reusability. Excitingly, TC in actual water samples can be efficiently removed by TpPa-1-1000. The results demonstrated that the strategy of utilizing COFs as the precursor for synthesis PC opens a new avenue to develop highly efficient adsorbents for removing pharmaceutical contaminant in wastewater.