Chemical adsorption of oxytetracycline from aqueous solution by modified molecular sieves

Abstract

The removal of oxytetracycline (OTC) from aqueous solution on modified molecular sieve via adsorption was investigated in the present work. The copper(II) modified molecular sieve had the much higher adsorbed amount than unmodified one. The bigger pore, the more adsorption sites benefitted for the adsorbed amount of OTC. The exchanged amount of copper(II) and the acid-base property of solution were important factors influencing the removal efficiency. The adsorption kinetics, the adsorption isotherm, the adsorption thermodynamics and the proposed adsorption mechanism were studied. The analysis of adsorption isotherm indicated it is a monolayer adsorption. The fitting with adsorption kinetics, pseudo-second-order model, deduced chemical adsorption is the main rate controlling step. And the new formation of Cu-O chemical bond and the changes at bands of N-H vibration and C-N vibration by Fourier transform infrared spectrometer further confirmed the proposal adsorption mechanism was the chemical complexation of copper(II) in modified 13X with NH group of OTC. As the real exchanged amount of copper(II) was 149.07 mg·g and the solution pH 7.0, the adsorption capacity of modified 13X for OTC reached the maximum of 2,396 mg·g (with the initial concentration of 1,000 mg·L).

Facile Fabrication of Flocculent Magnesium Silicate for the Adsorption of Oxytetracycline

“…To date, various methods have been explored to remove OTC from water such as electric irradiation, photocatalytic degradation, ultrasonic degradation, microbial degradation, flocculation, and adsorption. − Among them, adsorption method is considered to be the most feasible and effective and has received the most widespread attention because of its easy operation, low cost, and no secondary pollution to the environment. , Many adsorbents have been developed to treat OTC-containing water such as biochar, activated carbon, multiwalled carbon nanotube, graphene oxide, carboxymethyl cellulose, synthetic resin, activated sludge, hydroxyapatite, nano zero-valent iron, kaolinite, and montmorillonite. − For instance, cotton linter fiber-derived activated carbon prepared by fused NaOH activation exhibited a maximum adsorption capacity of 1340 mg/g for OTC at 323 K . In another work, Harja and Ciobanu studied the adsorption performance of hydroxyapatite nanopowder toward OTC in an aqueous medium, and a maximum adsorption capacity of 291 mg/g was achieved .…”

Preparation of Biochar with Developed Mesoporous Structure from Poplar Leaf Activated by KHCO3 and Its Efficient Adsorption of Oxytetracycline Hydrochloride

“…Adsorbents are the key to adsorption technology [ 16 , 17 , 18 , 19 , 20 ]. In the past decades, researchers have developed a variety of adsorbents, including metal oxides [ 21 ], molecular sieves [ 22 ], MOFs [ 23 ], carbon nanotubes [ 24 ], MXenes [ 25 ], etc. Recently, biochar has been widely used to remove antibiotics from the environment due to its porous structure and low cost [ 26 , 27 , 28 ].…”