Study On The Adsorption Efficiency And Mechanism Of Typical PPCPs Contaminants By Activated Coke In Water

Pharmaceutical and Personal Care Products(PPCPs)are an emerging contaminants,mainly including drugs and personal care products.In recent years,low-concentration PPCPs have been found in surface water,groundwater and drinking water due to the use of drugs frequently and imperfect sewage treatment technologies,which endangering the safety of humans and other living.At present,the clean utilization of coal has become a new direction of exploration and application.Activated coke is an activated carbon-based adsorbent that is not fully retorted or activated,which is characterized by low cost,pore structure mainly composed of mesopores and macropores,and riching in oxygen-containing functional groups on the surface.In this paper,through a series of experiments,the physicochemical properties and pore structure characteristics of different types of activated cokes were compared to explore the adsorption efficiency and mechanism of activated cokes for typical PPCPs in water.The following conclusions were obtained:(1)The adsorption capacity of bituminous coal activated coke DT-AC for diclofenac sodium(DCF)was slightly higher than that of anthracite activated coke MKY-AC.The results showed that the adsorption equilibrium was about 500 min and the maximum adsorption capacity of DCF on MKY-AC and DT-AC was 6.20 and9.65 mg/g,respectively.The adsorption data was were consistent with the pseudo-second-order kinetic model and Freundlich model.The performance was almost independent of pH and ionic strength.The adsorption efficiency of DCF on DT-AC was maintained at a high level after repeated cycles of regeneration(87%).In addition,a good removal for sulfamethoxazole(SMX)and cimetidine(CTD)on DT-AC was achieved,and in the composite system of pollutants in DCF,SMX and CTD,adsorption capacity for three pollutants was:DCF>CTD>SMX.(2)Comparing the characterization results of two bituminous coals LAC-1 and LAC-2,it was found that LAC-2 has a more developed pore structure,and contains more functional groups such as phenolic hydroxyl groups and amino groups,which is beneficial to the improvement of adsorption.LAC-2 could rapidly remove DCF under neutral conditions,and achieved adsorption equilibrium within 15 min,which was much lower than LAC-1 for 180 min,and the adsorption was in accordance with the pseudo-second-order kinetic model,indicating the existence of chemical action.The maximum adsorption capacity of LAC-2 for DCF was 223.97 mg/g,which was far higher than 44.33 mg/g of LAC-1,and the adsorption was consistent with the Freundlich model.The adsorption efficiency of LAC-2 on DCF was less affected by pH,and the adsorption capacity in neutral was 217 mg/g.After repeated cycles,LAC-2 still had a high removal for DCF(78%).LAC-2 had a good adsorption efficiency on low-concentration DCF.When C_e=1 ppm,the adsorption capacity was168.74 mg/g.Boehm titration and specific surface area analysis showed that the adsorption process of DCF on LAC-2 was determined by the pore structure and physicochemical properties of the adsorbent,including electrostatic interaction,hydrogen bonding andπ-πinteraction.(3)The types of PPCPs were expanded,and the adsorption performance of LAC-2 on SMX and CTD was further studied experimentally.The results showed that LAC-2 could remove SMX and CTD efficiently and quickly in water.LAC-2 can effectively remove a variety of PPCPs in water,including common non-steroidal anti-inflammatory drugs and sulfa antibiotics,and have good application prospects.