Decolorization And Degradation Of Rhodamine B Based On Iron/Carbon Activated Peroxymonosulfate

The complexity and intractability of the dye make a single processing method insufficient to remove dye from industrial wastewater.Over the years,many researchers have studied the use of joint treatment methods to increase the efficiency of the treatment process to meet increasingly stringent laws and regulations related to wastewater discharge.However,the continuous operation of governance methods can be complicated and time consuming.In order to further improve the dye wastewater treatment process,a mixing process that integrates multiple processing processes into one process has attracted considerable attention and is under development.In recent years,the advanced oxidation process（AOP_S）has been rapidly developed in water treatment,and the generation of sulfate radicals through the activation of peroxymonosulfate（PMS）has attracted much attention.In fact,it is becoming a substitute for hydrogen peroxide and persulfate,Therefore,the use of PMS for dye processing has far-reaching significance.In this paper,advanced oxidation technology was used as the treatment method,and dye wastewater（using Rhodamine B as the simulated pollutant）was the target of treatment.Through the use of iron and carbon materials as catalysts,PMS-activated homogeneous and heterogeneous countermeasure dyes were respectively decolorized and degraded.The effects of different methods on the treatment of dyes were discussed,and the operating parameters were optimized to provide a better reference for the treatment of dye wastewater.The specific research scheme is as follows:（1）The homogeneous reaction of ultraviolet light（UV）radiation on the degradation of rhodamine B（RhB）by trace Fe²⁺activated potassium persulfate（PMS）was studied.The effects of initial pH value,Fe²⁺dosage,initial PMS concentration and initial RhB concentration on the degradation of RhB by UV/Fe²⁺/PMS system were investigated.The influence of reactive free radicals,common ions and humic acids in the reaction system on the reaction system,and the mineralization of RhB have also been investigated.The results showed that the degradation rate of 10 mg/L RhB in the reaction system for 10 min under the optimal conditions of pH value of solution 3,Fe²⁺dosage of 50μmol/L and PMS concentration of 500μmol/L.It can reach 99%.Free radical quenching experiments showed that sulfate radicals（SO₄^-·）and hydroxyl radicals（HO·）are active radicals that attack RhB molecules,and SO₄^-·play a major role.The common bicarbonate ions and humic acids in water promote degradation at low concentrations and inhibit degradation at high concentrations,while chloride ions inhibit degradation reactions.The analysis of TOC showed that the mineralization degree of RhB reached 48%at 60 min.By evaluating the degradation of RhB by the UV/Fe²⁺/PMS system,the enhancement effect of UV radiation on the degradation reaction was verified,demonstrating the effectiveness of the UV/Fe²⁺/PMS system for the degradation of RhB.（2）The use of ultraviolet（UV）and activated carbon（AC）synergistic activation of potassium persulfate（PMS）produces sulfate radicals（SO₄^-·）to degrade dyes.Rhodamine B（RhB）was used as a target pollutant.The effects of PMS concentration,AC dosage,and initial pH of the wastewater on the degradation of RhB were investigated.Feasible experiments show that UV/AC configuration can effectively activate PMS.When the AC dosage 0.5g/L,PMS concentration 2.0mmol/L,the degradation rate of 10mg/LRhB reached89%in 5 minutes.The degradation rate of RhB increases with the increase of initial PMS concentration and AC consumption,but when it exceeds a certain amount,the promotion of degradation is not obvious.The degradation reaction follows Quasi-first-order kinetics.The free radical scavenging experiment proved that sulfate radical（SO₄^-·）is the main active radical,and hydroxyl radical（HO·）also played a certain role.At the same time,it is proved that the contribution of UV to PMS activation is greater than AC.Through UV-visible spectroscopy and FT-IR spectroscopy,it is preliminarily inferred that the degradation of RhB molecules is mainly due to the effects of conjugated structure cleavage and N-position deethylation.After five cycles of experiments,the decolorization rate of RhB can still reach 85%,which proves the stability of the degradation system.（3）In the field of advanced oxidation（AOP_S）,the development of heterogeneous catalysts is an important research direction.In this paper,activated carbon fiber（ACF）was used as a carrier,and iron citrate was innovatively loaded on the surface of ACF and sulfur element（S）was introduced to prepare a new heterogeneous catalyst ACF@Cit-Fe/S,using it as a catalyst to activate potassium peroxymonosulfate（PMS）degradation dye Rhodamine B（RhB）.The effects of ACF@Cit-Fe/S concentration,PMS concentration,and temperature on the degradation of RhB were investigated.The experimental results show that ACF@Cit-Fe/S can effectively activate PMS degradation dyes.A certain concentration of ACF@Cit-Fe/S and PMS can promote the degradation of RhB,the decolorization rate of RhB can reach 98%（after 120min reaction）,and the catalyst has good reusability.The effect of temperature on the degradation rate of RhB accords with the Arrhenius model,the calculated activation energy is 39.47 kJ/mol.Free radical scavenging experiments using tert-butyl alcohol,methanol,and phenol as molecular probes show that SO₄^-·and HO·are the main active free radicals in the degradation process.It was initially verified that the degradation of pollutants mainly occurred on and around the catalyst surface.