Research On Corrosion Resistance And Photocatalytic Properties Of Go-pyrite

In recent years,the reuse of tailings waste is important.Pyrite has received much attention as a main component of tailings waste.As one of the most abundant sulfide minerals in nature,pyrite is the main cause of acid mine wastewater due to its oxidation in humid air.Although pyrite is easy to oxidize,it has the characteristics of semiconductor materials.Pyrite has a narrow band gap of 0.95 e V,a wide light absorption range.Therefore,pyrite can be used as a photocatalytic material to treat pollutants in the environment.However,the stability of pyrite need to improve.In addition to oxidization by O₂ and H₂O,pyrite will also be photocorroded by irradiation conditions in environmental media.In order to better use of the photocatalytic performance of pyrite,this study selected graphene oxide(GO)to inhibit pyrite oxidation corrosion and photocorrosion while improving its photocatalytic property.On this basis,the study has designed a real-time monitor system displayed on the host computer.This monitor system can observe the pH and temperature of solution.Combining the monitor system with the photocatalytic reactor can control the efficiency of pollutant degradation.The research results are as follows:(1)Successfully prepared GO-pyrite sample by using environmentally friendly physical grinding method to load graphene oxide onto the surface of pyrite.The GO-pyrite samples were characterized by SEM,XRD,FT-IR,Raman spectroscopy and XPS,which confirmed that graphene oxide was successfully loaded on the surface of pyrite.The interaction between C=O(carboxyl group and carbonyl group)in graphene oxide and Fe(II)-O on pyrite surface forms a covalent bond,which forms a stable and smooth protective film on the surface of pyrite.(2)Iron ion dissolution experiment,SEM,CV curve and XPS characterization results show that irradiation promote the corrosion of pyrite,and GO passivation film can effectively inhibit the oxidation corrosion and photocorrosion of pyrite.(3)The results of photocatalytic degradation experiments of rhodamine B(Rh B)by GO-pyrite and active oxide species capture experiments showed that GO increased the specific surface area of pyrite.The GO enhanced adsorption capacity and photocatalytic performance of pyrite.The main active oxide species in the process of photocatalytic degradation was·OH,h⁺and·O₂^-.The active oxide species·OH played a major role.(4)The photoelectric performance results of pyrite and GO-pyrite showed that GO enhanced the light absorption capacity of pyrite and reduced its band gap.GO effectively suppressed the recombination of photogenerated electrons and holes.The separation of photogenerated electrons and holes were accelerated.And the lifetime of photogenerated carriers increased.The conduction band(CB)and valence band(VB)energy levels of GO-pyrite shifted positively,which directly affected the generation of reactive oxide species in the irradiation system.(5)Better separation of photogenerated electrons and holes,stronger light absorption capacity,smaller band gap and positively shifted energy band position determine that GO-pyrite has stronger light catalytic capacity.At the same time,the GO passivation film will react with h⁺,·OH,·O₂^-and other oxide species to suppress the photocorrosion of pyrite through the sacrificial substitution effect of GO when the external electron acceptors are absent.In addition,the high impermeability of GO prevented the O₂ and H₂O in the surrounding environment of pyrite to inhibit the oxidative corrosion of pyrite.(6)The pH sensor module with E201-BNC as the probe and the DS18B20 digital temperature sensor was used to collect the pH and temperature of the solution.Then the collected analog signals are converted into digital signals through ADC0832 and the digital signals are transmitted to the STC89 single-chip microcomputer.The single-chip microcomputer is the main control chip for data transmission,processing and display.At the same time,the signal is output to the Lab VIEW software on the host computer(PC).Lab VIEW is used to complete the human-computer interaction task.Finally,the real-time display of the pH and temperature of the host computer was realized.The research results confirm the influence of light on sulfide minerals.It enrich the photocorrosion mechanism of pyrite and broaden people understanding on the causes of acid mine wastewater.On this basis,the photocatalytic ability of pyrite is utilized and the pH of the photocatalytic system is monitored by the control system to ensure the efficiency of photocatalytic degradation,thereby providing a new idea for the recycling of tailings waste pyrite.