Preparation Of Iron-based Nanoparticles And Removal Of Amoxicillin From Aqueous Solution

Antibiotics are often used in medical treatment, animal husbandry and aquaculture. However, the residual antibiotics releasing to in environment has attracted attention due to their potential hazardous risk to human health and ecological system. Amoxicillin, as one of the important β-lactam antibiotics, has been widely used in various applications. Despite the fact that nanoscale zero valent iron (nZVI) is possible to use for the degradation of amoxicillin, nZVI used for degradation of amoxicillin is still unclear. Indeed, the fundamental issues need to be solved. For example, the degradation mechanism, the reduction of aggregation and the oxidation of nZVI, the degradation of mixed contaminants such as amoxicillin and metal ion, the development green synthesis nZVI with a low cost and environmental friendly used for a large scale of remediation. These issues are the highlights of environmental materials and environmental remediation. Unfortunately, these have not been solved so far. Hence, to address these issues, various iron-based nanoparticles have been synthesized and used for the degradation of amoxicillin to improve their reactivity and understand the degradation mechanism. The outcome from this study provides a new insight of relation between environmental nanomaterial and nanoremediation.Firstly, to reduce the aggregation and to improve oxidation and hence improve the reactivity and stability of nZVI, bentonite supported nanoscale zero-valent iron (Bent-nZVI) was prepared by chemical reduction in aqueous solution and used to degrade amoxicillin. On the basis of these results, the degradation mechanism of AMX could be attributed that β-lactam ring was opened by Bent-nZVI and finally this ring was broken.Secondly, bentonite-supported bimetallic Fe/Ni (Bent-Fe/Ni) nanoparticles were used to degrade AMX in aqueous solution since Ni acts as a catalyst and hence the degradation rate is improved. The potential degradation pathway was deduced by analyzing the reaction products via UV-Vis spectral and liquid chromatography-mass spectrometry (LC-MS). Finally, a catalytic mechanism for degrading AMX was proposed.Thirdly, chitosan-stabilized Fe/Ni nanoparticles (CS-Fe/Ni) were prepared by chemical reduction and co-precipitation in aqueous solution, repectively since chitosan is green and biodegradable natural material. CS-Fe/Ni used to remove mixed contaminants such as amoxicillin and Cd (Ⅱ) and the rusults showed that CS-Fe/Ni exhibited functions such as the catalytic reduction of amoxicillin and the adsorption of Cd (Ⅱ). This is first report on the use of functional nanomaterial to removal of mixed contaminant. The potential removal pathway of amoxicillin and Cd (Ⅱ) using CS-Fe/Ni was deduced by analyzing the reaction products.Finally, to develop the environmental friendly material and to reduce the cost, green synthesized iron nanoparticle (ELE-Fe NPs) and Fe/Ni nanoparticles (ELE-Fe/Ni NPs) were synthesized by green methods based on eucalyptus leaves extracts, which were used to degrade amoxicillin in aqueous solution. The ELE-Fe NPs and ELE-Fe/Ni NPs were characterized using SEM, EDS, FTIR, TG, XRD and XPS techniques to confirm the formation of ELE-Fe NPs and ELE-Fe/Ni NPs. ELE-Fe NPs and ELE-Fe/Ni NPs were successfully coated on calcium alginate (CA-ELE-Fe/Ni), which were used to degrade amoxicillin. This study clearly shows that it is pssosible to use green synthesized iron based nanoparticles for the large scale of remediation.