Preparation Of Transition Metal/Biomass Carbon Composite Materials And Its Application In Environmental Catalysis

Bisphenol A（BPA）which has applied extensively in plastic industry,is a representative of endocrine disruptors（EDCs）.Previous research demonstrated BPA had an adverse impact on human beings and animals even at very low exposure levels.In current years,Sulfate radical-based Advanced Oxidation Process（SR-AOPs）has been universally employed in the field of oganic pollutants degradation on account of its high efficiency,low cost and wide pH range.Persulfate（PS）,including permonosulfate（PMS）and perdisulfite（PDS）,can be activated by biomass activated carbon loaded with transition metal and its oxides nanoparticles to generate SO₄^·-.Therefore,in our study,biomass activated carbon loaded with Ni,Co,Fe and their corresponding oxides were synthesized through one-pot calcination method with NiCl₂·6H₂O,CoCl₂·6H₂O,FeCl₃·6H₂O,and cherry stone as raw materials and were utilized to catalytic activate PMS and PDS for BPA degradation.The primary research contents of this thesis are as follows:（1）A nickel-loaded cherry core carbon composite（Ni/C）was fabricated successfully through one-step calcination method with cherry stone powder as carbon source and NiCl₂·6H₂O as precursor.The characterization of X-ray diffraction（XRD）,X-ray photoelectron spectroscopy（XPS）and high-resolution transmission electron microscopy（HR-TEM）revealed the presence of Ni⁰ and Ni O in 50%Ni/C.As a novel catalyst,Ni/C can catalytic activate PS effectively to remove BPA.0.03g of 50%Ni/C could degrade 20 mg·L^-1 BPA totally within 10 mins in the presence of 1.0 g·L^-1 PMS and PDS.Quenching experiments and electron paramagnetic resonance（EPR）detection elucidated that both SO₄^·-and·OH dominated radical pathway and ¹O₂dominated non-radical pathway were involved in the degradation process.The 50%Ni/C-PS system has potential application prospects in the field of actual wastewater treatment of organic pollutants.（2）A cobalt-loaded cherry core carbon composite（Co/C）with Co⁰ and CoO crystals was synthesized for using as PS activator for the oxidative degradation of BPA in this chapter.In the 50%Co/C-PMS catalytic system,BPA achieved a complete degradation in 8 min(m_50%Co/C=0.0050 g,[PMS]=0.25 g·L^-1)with the pseudo-first-order kinetic rate constant（k₁）of 0.538 min^-1,and 54.13%of Total Organic Carbon（TOC）removal was observed.Similarly,in the 50%Co/C-PDS system,BPA obtained a fully decontamination in 10 min at the optimum experimental conditions(m_50%Co/C=0.04 g,[PDS]=1.0 g·L^-1)with k₁ of 0.586 min^-1 and about 90.76%of TOC removal was achieved.Scavenging experiments exhibited that free radical,surface-bound radical and nonradical pathways all participated in the degradation process.In conclusion,50%Co/C has certain potential in wastewater disposal containing organic pollutants and environmental protection.（3）An iron/cobalt-loaded cherry core carbon composite（Fe Co/C）synthesized by one-step calcination method was utilized as catalyst to generate SO₄^·-,·OH and ¹O₂by activating PMS and PDS for BPA degradation in the water.The characterization proved Fe⁰,Fe₃O₄,Co⁰ and CoO were the crystals of Fe_0.6Co_0.4/C.The experimental results demonstrated the prepared Fe Co/C promoted significantly the activation of PMS and PDS for removing BPA,and the removal of BPA followed the pseudo first-order kinetics model.The effects of the mass ratio of iron and cobalt elements,dosages of catalyst,PS and BPA concentration,initial pH and temperature on BPA decontamination were investigated systematically.The synergistic effect among Fe,Co,and biomass carbon endowed the Fe Co/C high catalytic efficiency,favorable stability,good pH adaptability and reusable ability.