A novel imprinted CoFe2O4/MWCNTs photocatalyst was prepared through the combination of a hydrothermal method and suspension polymerization based on 2-mercaptobenzothiazole (MBT) as the molecular template, pyrrole as the imprinted functional monomer and conductive polymerizable monomer, and CoFe2O4/MWCNTs as the matrix material. The results indicated that the surface imprinted layer was successfully coated on the surface of CoFe2O4/MWCNTs and polypyrrole (PPy) was formed and existed in the surface imprinted layer, the magnetic saturation value of the novel imprinted CoFe2O4/MWCNTs photocatalyst was 19 emu g−1. Moreover, compared with other photocatalysts, the novel imprinted CoFe2O4/MWCNTs photocatalyst not only had a high photocatalytic efficiency (57.09%), but also possessed a strong ability for selective recognition and photodegradation of MBT (the coefficients of selectivity of the novel imprinted CoFe2O4/MWCNTs photocatalyst relative to CoFe2O4/MWCNTs and the non-imprinted CoFe2O4/MWCNTs photocatalyst was 3.37 and 3.28, respectively). In addition, in the process of the photodegradation reaction, h+ and ˙OH were the main oxidative species, ˙O2− played a very small role.
Junyuan Guo,Yihua Chen,Wenjing Chen,Ziyi Chen,Fengyuan Gao,Jin Wang,Yuting Fu
Bimetal oxide-based compounds have potential in the degradation of antibiotics in wastewater. In this study, cobalt-ferrite-coated multi-walled carbon nanotubes (CoFe 2 O 4 /MWCNTs) have been synthesized by solvothermal method and characterized. Then, the degradation of sulfadiazine (SDZ) by CoFe 2 O 4 /MWCNTs activated peroxymonosulfate (PMS) system was determined, mainly including the effects of CoFe 2 O 4 /MWCNTs dosage, PMS concentration, solution pH, initial SDZ concentration, and co-existing anions on the degradation of SDZ. Based on reactive oxygen species identification and XPS analysis, the possible reaction mechanisms were investigated. In addition, the potential degradation pathways of SDZ were discussed. The results showed that CoFe 2 O 4 /MWCNTs exhibited superior catalytic activity and stability toward SDZ removal, and 97.5% of SDZ was degraded within 30 min under the condition of CoFe 2 O 4 /MWCNTs dosage 0.3 g/L, PMS concentration 0.5 mM and solution pH 7. The possible mechanism of PMS activation by CoFe 2 O 4 /MWCNTs involved both free-radical and non-radical pathways, and the generated reactive species (SO 4 •− , • OH, O 2 •− and 1 O 2 ) were responsible for the degradation of SDZ. In addition, four potential degradation pathways were proposed and 15 intermediates were identified. In view of the ecotoxicity assessment, it was found that the toxicity of the degradation intermediates was lower than that of SDZ. Overall, this study established an effective strategy for PMS activation to remove recalcitrant organic pollutants in wastewater.
Cobalt ferrite nanoparticles loaded on multiwalled carbon nanotube (MWCNT) magnetic hybrids have been demonstrated to be promising magnetic resonance imaging contrast agents and drug carriers. However, the hydrophobic, less biocompatible characteristics and low loading capacity for the drug hamper their wide biological applications. To solve the above problem, an alternative strategy is to coat the MWCNTs@CoFe2O4 nanoparticles with a mesoporous silica (mSiO2) shell. Herein, the reasonable fabrication process results in successful coating mSiO2 on the as-obtained MWCNTs@CoFe2O4 nanoparticles, forming well-defined core–shell-structured MWCNTs@CoFe2O4@mSiO2 nanocomposites. The as-synthesized mesoporous nanocarrier possesses a high surface area and large pore volume for the loading of the drug, and has a superparamagnetic feature for drug targeting. Moreover, the anticancer drug doxorubicin (DOX)-loaded MWCNTs@CoFe2O4@mSiO2 nanoplatforms show an excellent pH-responsive drug release character within 48 h. Therefore, a novel nanocarrier based on MWCNTs@CoFe2O4@mSiO2 was proposed, and its potential application for targeted cancer therapy was highlighted.
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