| The pollution of organic compounds in water causes many adverse effects on human health.Polycyclic aromatic hydrocarbons?PAHs?are teratogenic,carcinogenic and mutagenic.Phenolic compounds are common environmental endocrine disruptors,and their reproductive toxicity has a long-term impact on people and even their offspring.Nitroaromatic compounds pose a serious threat to public safety and cause carcinogenic risk.Phthalate ester plasticizers not only influence the cardiovascular and respiratory system but also have reproductive and developmental toxicity.It is urgent to harness the organic pollutants.The magnetic nanomaterial adsorbents show a great advantage in the field of pollutant removal from water in recent years due to their significant properties such as high adsorption efficiency,easy recovery ability,eco-friendly merit and low cost.Nanoscale zero-valent iron?NZVI?is a kind of magnetic nanomaterials with satisfactory magnetic property,but it is rarely used as adsorbent.The surface modification can not only avoid agglomeration and oxidation but also provide the material with some specific properties,such as hydrophilicity,thermal-sensitivity and selective adsorptive ability to some compounds.This thesis can be divided into six parts:Part 1:Liquid phase reduction method using sodium borohydride,solvothermal method and iron oxide reduction method were applied to synthesize stable NZVI materials with small size.And then,these materials were functionalized with polydopamine,reductive graphene oxide,amino silane,thermal-sensitive polymers and molecular imprinted polymers through oxidic self-polymerization,synchronous solvothermal method,amino silane dehydration condensation and seed precipitation polymerization,respectively.Transmission electron microscopy?TEM?,Energy dispersive X-ray spectroscopy?EDS?,Fourier transform infrared spectroscopy?FTIR?,X-ray diffraction?XRD?,X-ray photoelectron spectroscopy?XPS?,BET surface area analysis and hysteresis measurement were employed to characterize the material's morphology,composition and magnetic characteristics.Part 2:The adsorption of phenanthrene?PHE?and anthracene?ANT?in water by Fe@SiO2@PDA was investigated.The adsorption of two polycyclic aromatic hydrocarbons showed that the adsorption process was influenced by pH,ionic strength and the concentration of humic acid.The adsorbent showed higher adsorption capacity with the increase of initial concentration.Compared to PHE,ANT had higher adsorption capacity.The adsorption process followed pseudo second-order kinetic model and Frendlich model,indicating that the adsorption was heterogeneous adsorption process.The adsorption process was manipulated by a variety of forces,such as?-?interaction and hydrophobic interaction,which was an exothermic,spontaneous and physical adsorption process.Part 3:The adsorption of 4-heptylphenol?4-HP?,4-tert-octylphenol?4-OP?and4-nonylphenol?4-NP?in water using Fe@rGO was studied.The results showed that the pH value and ionic strength of the solution had a great influence on the adsorption efficiency.The adsorption capacities of 4-NP,4-OP and 4-HP reached as high as 989.7mg g-1,959.3 mg g-1 and 739.2 mg g-1,respectively.The adsorption process followed pseudo second-order model?all the three alkylphenols?and Frendlich model?except for that of 4-HP with NaCl addition?.The adsorption process was manipulated by a variety of forces,such as van der Waals force,?-?interaction,hydrophobic interaction,hydrogen bonding and electrostatic interaction.The adsorption processes of three alkylphenols exhibited different adsorptive interaction in different degrees.Part 4:The adsorption of three nitro aromatic compounds including 2-nitrotoluene?NT?,2,6-dinitrotoluene?DNT?and 2,4,6-trinitrotoluene?TNT?by Fe@SiO2-NH2 was investigated.The results showed that the adsorption efficiency was impacted by pH value,ionic strength,humic acid concentration and the additive amount of APTES in modification of Fe@SiO2.The adsorption efficiency of TNT by Fe@SiO2-NH2increased 21%in comparison with that by Fe@SiO2.The adsorption capacity of TNT was about three times and twice of that of NT and DNT,respectively.Therefore,it could be concluded that Fe@SiO2-NH2 had selective adsorption ability.The adsorption process followed the pseudo second-order model and the Frendlich model,indicating a multi-layer adsorption process.Electrostatic interaction and hydrophobic effect played important roles in the adsorption process.Part 5:The adsorption of four phenols including bisphenol?BPA?,tetrabromobisphenol A?TBBPA?,4-tert-octylphenol?4-OP?and 4-nonylphenol?4-NP?by thermal sensitive Fe@SiO2 materials was discussed.The experimental results showed that temperature,pH value and ionic strength played pivotal roles in this process.The adsorption capacities of BPA,4-OP,TBBPA and 4-NP reached 3.66,6.34,24.85 and 49.34 mg g-1,respectively.The adsorption process fitted with the pseudo second-order model and the isotherm models of D-R?BPA and 4-NP?and Temkin?TBBPA and 4-OP?models.The results demonstrated that the surface of the adsorbents was heterogeneous and the adsorption was a multilayer adsorption.The adsorption process was mainly controlled by hydrogen bond,hydrophobic interaction and electrostatic interaction.What's more,Fe@SiO2@PNIPAM was successfully used as the adsorbent to develop a new magnetic solid phase extraction method in combination with high performance liquid chromatography?MSPE-HPLC?for simultaneous detection of the four phenols in the real water samples.Part 6:The adsorption of phthalates was carried out utilizing molecularly imprinted polymer modified Fe@SiO2?Fe@SiO2@MIP?as adsorbent.The results showed that pH value,ionic strength and temperature had significant effects on adsorption efficiency.Selective analysis declared that Fe@SiO2@MIP had selectivity towards DnPP in comparison with other four PAEs except for DnBP,the one most similar to DnPP in structure.The adsorption capacity of DnPP was 194.15 mg g-1 at 25°C.The adsorption process followed pseudo second-order model and Frendlich model,indicating a heterogeneous and multiplelayer adsorption process.Hydrogen bond interaction and hydrophobic interaction played important roles in adsorption.The process was a spontaneous,exothermic,and physical adsorption process.Meanwhile,Fe@SiO2@MIP had been successfully applied to the determination of trace DnPP in water through MSPE-HPLC process,which indicated it had a great application prospect in the field of environmental analysis. |
PDF Full Text Request