Adsorption Behavior and Mechanism of Antibiotic Sulfamethoxazole on Carboxylic-Functionalized Carbon Nanofibers-Encapsulated Ni Magnetic Nanoparticles

Abstract

In this work we developed a one-step process for synthesizing carboxylic-functionalized carbon nanofibers (CNFs)-encapsulated Ni magnetic nanoparticles (Ni@CNFs) that exhibit an excellent magnetic response and a large content of hydrophilic carboxylate groups with a negative charge (RCOO(-)) on the carbon surface. The carbon-encapsulated magnetic Ni nanoparticles could be rapidly separated from water, and they showed high efficiency for adsorption of the antibiotic sulfamethoxazole (SMX) in aqueous solution. The adsorption of SMX on Ni@CNFs as a function of pH was investigated, and the greatest adsorption occurred at pH 7.0. The adsorption isotherms for SMX on Ni@CNFs depended on different pH values. A Monte Carlo simulation was used to probe the relationship between molecular conformation and π-π interaction. The high adsorption of SMX on Ni@CNFs at pH 7.0 could be ascribed to deprotonated SMX being easily converted to a planar-like conformation, thereby resulting in the formation of π rings that were approximately parallel to the graphite surface and that enhanced strong π-π interaction. Electrostatic and π-π interactions both contributed to deprotonated SMX adsorption at pH 7.0, and they influenced the adsorption isotherm toward the Freundlich model. However, in weakly acidic environments (pH 2.0 and 4.0), the electrostatic interaction alone could induce an adsorption pattern that was similar to the Langmuir model.

Highly Selective Fluorescence Sensor Based on Graphene Quantum Dots for Sulfamethoxazole Determination

“…Therefore, SMZ molecules were observed to bind to GQDs@SMIP more strongly, which caused a strong fluorescence quenching effect. In addition, SMZ is known to be a good hole or electron acceptor [38], and an electron transfer process might occur after the entry of SMZ into the imprinted cavities; this is confirmed by a change in the zeta potential of the GQDs@SMIP suspension from −14.75 to −9.08 mV after the addition of SMZ (140 µM). This process also contributes to the quenching phenomenon.…”

Fabrication of a novel separation-free heterostructured photocatalyst with enhanced visible light activity in photocatalytic degradation of antibiotics

“…The sulfaclozine molecules primarily exist as the anion when the pH is higher than 5.5, the electrostatic interaction between the contaminant and adsorbent plays a significant role in the adsorption process. 34,47…”

Au Nanoparticles Deposited on Magnetic Carbon Nanofibers as the Ultrahigh Sensitive Substrate for Surface-Enhanced Raman Scattering: Detections of Rhodamine 6G and Aromatic Amino Acids

“…The formation of a weak base likely depends on the presence of R-COO − groups on CNFs. 41 3.2. Characterization of Ni@CNFs@Au(x) Materials.…”

“…We have developed a novel CO 2 utilization process to produce carboxylic-functionalized carbon nanofiber-encapsulated magnetic Ni NPs (Ni@CNFs) that are directly synthesized from the catalytic hydrogenation of CO 2 on a Ni catalyst . The Ni@CNF material uniquely combines strong magnetization and a high surface area (>100 m 2 /g) and shows improvements in the drawbacks of previous materials, as described above. , The Ni@CNF material has the potential to increase the hotspot density, while providing a good magnetic response. In this work, we report the design of Ni@CNFs with Au NPs as a SERS substrate (Ni@CNFs@Au) for high-sensitivity SERS detection, and the SERS activities of the Ni@CNF@Au substrates were estimated using R6G and aromatic amino acids, such as phenylalanine and tyrosine, as probe molecules.…”