Study On Degradation Of BP-3 By MOFs Preparation Of Persulfate Catalyst

The ultraviolet absorber BP-3 is one of the representatives of emerging pollutants of PPCPs in the water environment.Because BP-3 has a benzophenone structure,it is difficult for the traditional activated sludge process to degrade such organic pollutants,leading to its continuous accumulation in the water environment and organisms,threatening the safety of the water environment.Advanced oxidation technology generates active free radicals with high oxidation-reduction potential,which can destroy refractory organics without selection,and is theoretically suitable for the treatment of BP-3.Therefore,this paper proposes to use MOFs and multi-walled carbon nanotubes to synthesize a nano-scale catalyst to accelerate the generation rate of persulfate（PMS）free radicals and achieve the purpose of rapid degradation of BP-3.At the same time,the system is tested under experimental conditions.Analysis of influencing factors and reaction mechanism.In this paper,Co（NO₃）₂·6H₂O,2-methylimidazole C₄H₆N₂,carboxylated carbon nanotubes were used as raw materials,and PVP was added as a dispersant.ZIF-67@MWCNTs was synthesized by self-assembly method and calcined to obtain the catalyst Co₃O₄@MWCNTs.Characterization and water treatment experiment results show that the catalyst synthesized by this method restrains the agglomeration of Co₃O₄,uniformly disperses,and the crystal state is stable.The specific surface area increases with the increase of the specific gravity of the carbon tubes in the component.Catalysts with different ratios And all the components of the catalyst promote the degradation of BP-3 by PMS.When the C:Co mass ratio is 1:3,the synthesized catalyst has the highest catalytic efficiency,which is 9.2 times faster than that without adding catalyst.The specific surface area of the catalyst with this ratio is 28.23m²/g and the average size is between25-40nm,which belongs to nanometer grade catalyst.The single-factor experiment results show that the p H of the system has a wide applicable range and has a faster degradation efficiency in a medium alkaline environment.BP-3’s degradation by using the Co₃O₄@MWCNTs/PMS system under the experimental conditions of p H=7,BP-3 concentration 20μM,PMS=0.2m M,5m M phosphate-sodium hydroxide buffer solution,0.1g/L catalyst dosage,and 150r/min shaking water bath.During processing,the degradation rate can reach 98%after 60minutes of reaction.Common anions also have a certain effect on the system,SO₄^2-has an inhibitory effect,Cl^-has a dual effect,low concentration has an obstructive effect,high concentration has an accelerating effect,HCO₃^-has a promoting effect,and HA has a very strong inhibitory effect on the system effect.Mechanism analysis experiments show that during the degradation of BP-3 in the Co₃O₄@MWCNTs/PMS system,sulfuric acid radical SO₄^-·and hydroxyl radical·OH both participate in the reaction,and SO₄^-·radical plays a leading role.The oxygen vacancy V₀ on Co₃O₄@MWCNTs can also undergo a series of reactions with PMS to generate ¹O₂ and then undergo a non-radical reaction to oxidize BP-3.The catalytic mechanism of Co₃O₄@MWCNTs is to build a high-speed channel for the reaction between BP-3 and PMS.PMS and BP-3 are first adsorbed by the catalyst,and then transferred to the reactive site through the channel of carbon nanotubes.Co₃O₄ contains Co.（Ⅱ）and Co（Ⅲ）electrons are transferred rapidly,and the peroxy bond in PMS is broken rapidly to generate a large number of free radicals to degrade organic matter.The Co₃O₄@MWCNTs synthesized by this method still has a degradation efficiency of 91%after 5 cycles of experiments,and the dissolution of Co²⁺is only0.037mg/L,the phase is stable before and after the reaction,it has strong recyclability,and has broad application prospects.Contains 28 pictures,3 tables,129 references...