Interactions between Antibiotics and Graphene-Based Materials in Water: A Comparative Experimental and Theoretical Investigation

Abstract

Complex interactions between antibiotics and graphene-based materials determine both the adsorption performance of graphene-based materials and the transport behaviors of antibiotics in water. In this work, such interactions were investigated through adsorption experiments, instrumental analyses and theoretical DFT calculations. Three typical antibiotics (norfloxacin (NOR), sulfadiazine (SDZ) and tetracycline (TC)) and different graphene-based materials (divided into two groups: graphene oxides-based ones (GOs) and reduced GOs (RGOs)) were employed. Optimal adsorption pHs for NOR, SDZ, and TC are 6.2, 4.0, and 4.0, respectively. At corresponding optimal pHs, NOR favored RGOs (adsorption capability: ∼50 mg/g) while SDZ preferred GOs (∼17 mg/g); All adsorbents exhibited similar uptake of TC (∼70 mg/g). Similar amounts of edge carboxyls of both GOs and RGOs wielded electrostatic attraction with NOR and TC, but not with SDZ. According to DFT-calculated most-stable-conformations of antibiotics-adsorbents complexes, the intrinsic distinction between GOs and RGOs was the different amounts of sp(2) and sp(3) hybridization regions: π-π electron donor-acceptor effect of antibiotic-sp(2)/sp(3) and H-bonds of antibiotic-sp(3) coexisted. Binding energy (BE) of the former was larger for NOR; the latter interaction was stronger for SDZ; two species of TC at the optimal pH, i.e., TC(+) and TC(0), possessed larger BE with sp(3) and sp(2) regions, respectively.

Noncovalent interactions between cisplatin and graphene prototypes

“…As a matter of a fact, on the experimental framework it has been shown that GO platelets can act as an effective medium for the transportation of aromatic environmental pollutants and elimination of organic matter and antibiotics in water solutions. Graphene‐based carriers have also emerged as optimal candidates in therapeutics delivery: they have served for the transportation of water soluble and insoluble drugs as well as for nucleic acids loading .…”

Mechanism of adsorption of tetracycline–Cu multi‐pollutants by graphene oxide (GO) and reduced graphene oxide (rGO)

“…In the aqueous solution, TC has three ionization equilibrium constants, i.e. pK a1 = 3.30, pK a2 = 7.68, and pK a3 = 9.68 . Therefore, at different pH values, TC can be dissolved into four different forms, including the positive ion form (TC + ), amphoteric ion (TC ± ), negative ion form (TC − ), and dianion form (TC 2− ).…”

“…pK a1 = 3.30, pK a2 = 7.68, and pK a3 = 9.68. 43 Therefore, at different pH values, TC can be dissolved into four different forms, including the positive ion form (TC + ), amphoteric ion (TC ± ), negative ion form (TC − ), and dianion form (TC 2− ). With a low initial pH, TC would lose all its electrons, thus appearing in the form of TC + .…”

Removal of Sulfadiazine Using 3D Interconnected Petal-Like Magnetic Reduced Graphene Oxide (MrGO) Nanocomposites

“…Mesoporous materials are used as adsorbents because of their high surface area and versatile surface functional groups, which have attracted increasing attention [10,11]. Reduced graphene oxide (rGO), a derivative of graphene, shows great promise as an effective adsorbent because of its large specific surface area and abundant pore structures [12,13]. During the past few years, many studies have been carried out to investigate the removal of heavy metal ions and dyes using rGO and very promising results have been achieved.…”