Preparation Of Heterogeneous Fenton-like Catalyst By Using Pyrite Cinder And Its Properties

Micropollutants had many kinds and wide distribution,and had great toxic effects.Heterogeneous Fenton-like catalytic technology could quickly and effectively degrade these stubborn organic matters.In this study,the attapulgite-sulfuric acid slag catalyst（Pyc-pal）was successfully prepared by using waste Pyrite cinder,and the modified attapulgite-sulfuric acid slag catalyst（Pyc-pal@Ni）with stronger catalytic performance was prepared by loading nickel.Taking Malachite Green（MG）and Tetracycline hydrochloride（TC-HCl）in micro-pollutant as target pollutants,the catalytic ability of treating pollutants with H₂O₂ was explored,and the influence of reaction conditions,catalyst stability,reaction degradation mechanism and pollutant degradation path were systematically studied.The main contents and conclusions are summarized as follows:（1）The catalytic performance of Pyc-pal was the best when the composition ratio of pyrite cinder and attapulgite was 1:5,the calcination temperatures were 400℃and900℃respectively,the heating rates were 10℃/min and 2℃/min respectively,and the holding time was both 60 min.When the proportion of pyrite cinder,attapulgite and nickel was 2:10:1,and the calcination temperatures of the two stages are 400℃and900℃respectively,the two calcination heating rates were 10℃/min and 2℃/min respectively,the holding time was both 60 min,the catalytic performance of Pyc-pal@Ni was the best.（2）Pyc-pal and Pyc-pal@Ni were characterized by SEM.The surface of Pyc-Pal and Pyc-pal@Ni was found to be smooth,and had irregularly shaped block or granular,also had abundant pore structure.VSM analysis proved that both catalysts had strong magnetic properties and were conducive to recovery.XRD and XPS analysis showed that Pyc-pal and Pyc-pal@Ni had been successfully prepared,and the main catalytic active groups were Fe（Ⅱ）,Fe（Ⅲ）,Ni（Ⅱ）.（3）In a certain range,with the increased of the dosage of Pyc-pal and Pyc-pal@Ni,the dosage of H₂O₂,reaction temperature and p H,the decolorization rate of MG and the degradation rate of TC-HCl also increased.Under the conditions of 45℃,catalyst dosage of 4 g/L,H₂O₂ dosage of 5 m L/L,p H=5 and initial concentration of 50 mg/L,the decolorization rate of mg in Pyc-pal/H₂O₂ and Pyc-pal@Ni/H₂O₂ systems was the highest,which was 97.27%and 100%,respectively.Under the conditions of 25℃,catalyst dosage of 6 g/L,H₂O₂ dosage of 5 m L/L,p H=7 and initial concentration of TC-HCl of 100 mg/L,both Pyc-pal/H₂O₂ and Pyc-pal@Ni/H₂O₂ systems could degrade in10 min and reach the degradation rate of 91%.The efficient degradation of TC-HCl was realized.Under the same conditions,the catalytic effect of Pyc-pal@Ni is better than that of Pyc-pal,which is attributed to the fact that the addition of nickel promotes the electron transfer in the system and accelerates the reaction.（4）Both Pyc-pal and Pyc-pal@Ni had excellent recyclability and stability,and the catalytic activity could be restored by calcination after the activity decreasing.After recycling five times,the decolorization rates of Pyc-pal and Pyc-pal@Ni for MG could still reach 71.27%and 96.67%.（5）Radical quenching experiments and ESR characterization showed that·OH,·O₂^-and h⁺were the main active substances in Pyc-pal/H₂O₂ and Pyc-pal@Ni/H₂O₂systems.The analysis of degradation mechanism showed that the oxidation of pollutants by·O₂^-and h⁺was the main pathway,while·OH oxidize pollutants was the secondary pathway.The degradation intermediates of MG and TC-HCl were analyzed by LC-MS,and it was concluded that MG and TC-HCl began to degrade through two different degradation pathways:demethylation and hydroxylation,and were eventually mineralized into CO₂ and H₂O...