Preparation Of MOF/Bagasse Cellulose Based Hybrid Aerogel And Its Application In The Degradation Of Organic Pollutants In Water

Bagasse is the residue remaining after sugar cane has been extracted.Due to the extensive area and high yield of sugar cane,bagasse has become a green,renewable and low-cost raw material.In this paper,bagasse,an agricultural by-product,was used as a raw material and a carrier for metal-organic framework materials（MOF）to synthesize MOF/bagasse cellulose composite aerogels and apply them to water purification.The composite aerogel improves the characteristics of MOF which are mainly in powder form and cannot be easily recycled.MOF/bagasse cellulose hybrid aerogels were prepared using direct doping and in situ synthesis,respectively,and used to activate peroxymonosulfate（PMS）to produce oxidatively active molecules for the oxidative decomposition of organic pollutants.In this thesis,the structure and morphology of the MOF/bagasse cellulose hybrid aerogels were investigated.Using Rhodamine B（Rh B）and p-nitrophenol（PNP）as pollutant models.The effects of different reaction conditions（addition of PMS,initial solution p H,catalyst dosage）and the number of cycles on the degradation performance were investigated,and the degradation mechanism of the composite aerogel for Rh B and PNP was explored.The main research contents and results are as follows:1)Bagasse cellulose aerogels were prepared by the sol-gel method.The bagasse cellulose aerogel has a three-dimensional network structure with smooth,thin and light pore walls,a porosity of 95.9%and a density of 22-28 mg/cm³,making it a good carrier for functional nanomaterials.2)Co-ZIF@GEL bagasse cellulose composite aerogel was prepared by in situ synthesis using bagasse aerogel as the matrix.The composite aerogel maintained the original structure and morphology of the aerogel and demonstrated excellent degradation performance in the activated PMS degradation of PNP,which could degrade 98.5%of PNP（10 mg/L）within 70 min.3)The Zn/Co-ZIF@GEL bagasse cellulose composite aerogel was prepared by direct doping,and the Zn/Co-ZIF@GEL/PMS system exhibited efficient catalytic activity and could completely decompose Rh B within 30 min.The cycling test results showed that the Zn/Co-ZIF@GEL had good cycling performance and maintained good degradation performance even after 4 cycles.Meanwhile,the composite aerogel can effectively reduce the leaching of metallic cobalt and avoid secondary pollution.4)The mechanism of organic pollution degradation by MOF/bagasse cellulose composite aerogel activated PMS was investigated:Co-ZIF@GEL and Zn/Co-ZIF@GEL mainly produce oxidation-active molecules SO₄^·-and OH^·through the activation of PMS by transition metal cobalt,where ¹O₂ and O₂^·-are also produced in the Zn/Co-ZIF@GEL/PMS system.Oxidationally active molecules decompose difficult-to-degrade organic pollutants into non-toxic small molecules or even mineralise them into CO₂ and H₂O.further investigation by free radical scavenging experiments revealed that in the Co-ZIF@GEL/PMS system,SO₄^·-played an important role in the degradation of PNP and OH^·played a weaker effect on the degradation of PNP;in the Zn/Co-ZIF@GEL/PMS system,¹O₂ played a major role,while SO₄^·-,OH^·and O₂^·-played a minor role.