Study On Modified Activated Carbon For Treating Phenol-containing Wastewater

Acetaminophen（APAP）is a commonly used antipyretic and analgesic.A large amount of phenol-containing wastewater will be produced during the production of acetaminophen.If it is not properly treated,it will cause serious pollution to the water body.The commonly used method for treating phenol-containing wastewater is the Fenton method,but the traditional Fenton method still has problems such as the failure of the catalyst to be recycled and the secondary pollution of iron sludge.Therefore,three sound of solid catalysts were prepared in this paper to replace the catalysts in the traditional Fenton reaction.This method can transform a homogeneous reaction into a heterogeneous reaction and realize the recovery of the catalyst.First,a catalyst(AC-Fe²⁺)loaded with ferrous ions was prepared using activated carbon as the catalyst carrier.Explore the effects of AC-Fe²⁺dosage,reaction time,initial concentration of acetaminophen-containing wastewater and the p H range of acetaminophen-containing wastewater on the removal of COD from wastewater.The optimal treatment conditions for each 50 m L of wastewater containing acetaminophen are:the dosage of AC-Fe²⁺is 0.6 g,the initial concentration of wastewater containing acetaminophen is 200 mg/L,and the p H range is 6.05 to 10,the reaction time is 60 min.At this time,the COD removal rate of the acetaminophen-containing wastewater can reach92.31%.After AC-Fe²⁺was reused five times,the COD removal rate of acetaminophen-containing wastewater could still reach 83.24%.Use scanning electron microscopy analysis（SEM）,phase analysis of x-ray diffraction（XRD）,Energy Dispersive X-Ray Spectroscopy（EDX）and other methods to characterize and analyze AC-Fe²⁺.The research results show that Fe²⁺is successfully loaded on the surface of activated carbon.Analysis by the Brunner-Emmet-Teller（BET）measurements shows that both AC and AC-Fe²⁺have a mesoporous structure,and the specific surface area of AC-Fe²⁺is slightly smaller than that of AC.The experimental results show that AC-Fe²⁺can be used as a catalyst in the process of catalytic oxidation of APAP wastewater,making the catalyst easy to separate.Secondly,using activated carbon as a carrier,a magnetic activated carbon（MAC）was prepared by the co-precipitation method and used as a catalyst in the APAP wastewater treatment process.The effects of the amount of MAC,reaction time,the concentration of the simulated APAP wastewater and the p H range of the use process on the COD removal rate of the APAP wastewater were studied.The optimal treatment conditions for each 50m L of the APAP wastewater are:MAC dosage is 0.4 g,reaction time is 50 min,p H is 4.90,and the initial concentration of the APAP wastewater is 100 mg/L to 200 mg/L.SEM,TEM,and XRD were used for analysis to prove that Fe₃O₄ was successfully loaded on activated carbon.BET was used to compare and analyze the changes in the pore structure of activated carbon before and after modification.After MAC treats the APAP wastewater,it can be recycled only by magnetic separation.Finally,a kind of magnetic activated carbon（B-MAC）was prepared by using waste biomass as raw material and using a one-step method.The best preparation conditions are:the mass fraction of zinc chloride is 30%,the liquid-to-solid ratio is 2:1,the activation temperature is 450℃,the activation time is 1 h,and the loading rate is 28.67%.At this time,the COD removal rate in the wastewater reaches 94.96%,the yield was 90%.Catalytic oxidation of each 50 m L of simulated APAP wastewater with B-MAC as a catalyst,the best conditions for use are 0.5 g of B-MAC,reaction time 80 min,initial concentration of APAP wastewater 200 mg/L,and initial p H of APAP wastewater 4.90.SEM,TEM and XRD proved that Fe₃O₄ was successfully supported on activated carbon.Using BET to analyze the pore structure of B-MAC,it is found that B-MAC has a mesoporous structure.The magnetic particles in B-MAC are directly produced in the process of activation and pore formation,which makes the catalyst more stable.