| Sulfamethoxazole (Sinomine) is an antibacterial drug, Ibuprofen (Fenbid) is ananti-inflammatory analgesic, and the two medicines are common pollutants in water.Adsorption is an advisable treating method. As an adsorbent, activated carbon is usedmost widely currently; however the treating effect of traditional carbon for the twopharmaceuticals is not so good. This paper studied the removal efficiency of modifiedcarbons adsorption and the adsorption breakthrough curves of carbon column as wellas the regenerating behavior.This paper selected Hydrochloric acid, Sulfuric acid, Nitrate, Hydrogen peroxidesolution and Ammonia as chemical Modifier, systematically maked research on themodifying effect on the granular activated carbon and determined the optimalconcentration of each modifier. Acording to the adsorption kinetics and isothermaladsorption tests, adsorption rate and isotherms of the optimal modified carbon wereaslo determined. The tests showed that: the optimal concentration of each modifier is15%Ammonia,15%Hydrogen peroxide solution,0.5mol/L Hydrochloric acid,0.5mol/L Sulfuric acid and0.5mol/L Nitrate. Compared with original carbon, theadsorption capacity of sulfamethoxazole and ibuprofen increased respestively by anaverage of48%and31%in pure water, by46%and33%in the tap water. In the studyof adsorption kinetics, the optimal modified carbons adsorption rates of the twopollutants fited very well with both pseudo-first and pseudo-second-order kineticmodel. In the isothermal adsorption test, the adsorption isotherm of the modifiedcarbons was closer to the Freundlich model, indicating that the adsorption process wasa multilayer adsorption.The physical and chemical properties of activated carbon were characterized byBET and Bohem titration. Correlation analaysis between each physical and chemicalindex and adsorption amount was studied by Pearson method and the significancetesting was verified by t-test. The analysis of characterizing showed that, for physicalindex the surface area, micropore’s volume have no significant changes while themid-pore volume increased significantly for the optimal modified carbons, forchemical index the carboxyl content were increased while the carbonyl contentreduced significantly. Correlation analaysis showed that, the correlation between adsorption capacity and physical indicators is weak, carboxyl and the adsorption ofsulfamethoxazole has a strong positive correlation, carboxyl and lactone, carbonyl andtotal alkaline functional groups have a strong positive and negative correlation with theamount of the adsorption ibuprofen respectively, t-test results are in line with thestatistical requirements. The results also showed that: although the surface area,micropore and mesopore volume of the modified carbon with0.5mol/L sulfuric acidare low, it existed a maximum of lactone carboxyl and lactone group, and a minimumtotal amount of carbonyl and alkaline functional groups, which also has the bestremoval effects for the two pollutants.Dynamic adsorption and adsorption breakthrough curves of actived carbon withmodifier of0.5mol/L Sulfuric acid was stydied, and a breakthrough curve model wasbuilt and vertifated. Selecting0.1mol/L hydrochloric acid and Sodium hydroxide asregeneration agent, the regeneration beheavior was also studied. The results showedthat: in the initial adsorption, activated carbon column owned an adsorption penetrationpoint and adsorption failure point of30h and75h respectively for sulfamethoxazole,and22h and57h for ibuprofen. Based on the Constent-patten wave approach theary,the adsorption breakthrough curve model was fited well with the Experimental datas,which means the model had some practical significance. In the regeneration behaviorstudy, the results showed that the hydrochloric acid regeneration agent had a betterregeneration efficiency than sodium hydroxide, besides that the results also showedthat the longer regeneration time the better Recovery effects for adsorption capacities. |
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