Control of N-nitrosodimethylamine(NDMA)in drinking water could be achieved by removing its precursors as one practical way.Herein,superfine powdered activated carbons with a diameter of about 1μm(SPACs)were successfu...Control of N-nitrosodimethylamine(NDMA)in drinking water could be achieved by removing its precursors as one practical way.Herein,superfine powdered activated carbons with a diameter of about 1μm(SPACs)were successfully prepared by grinding powdered activated carbon(PAC,D50=24.3μm)and applied to remove model NDMA precursors,i.e.ranitidine(RAN)and nizatidine(NIZ).Results fromgrain diameter experiments demonstrated that the absorption velocity increased dramatically with decreasing particle size,and the maximum increase in k2 was 26.8-folds for RAN and 33.4-folds for NIZ.Moreover,kinetic experiments explained that rapid absorption could be attributed to the acceleration of intraparticle diffusion due to the shortening of the diffusion path.Furthermore,performance comparison experiments suggested that the removal of RAN and NIZ(C_(0)=0.5 mg/L)could reach 61.3%and 60%,respectively,within 5 min,when the dosage of SAPC-1.1(D_(50)=1.1μm)was merely 5 mg/L,while PAC-24.3 could only eliminate 17.5%and 18.6%.The adsorption isotherm was well defined by Langmuir isotherm model,indicating that the adsorption of RAN/NIZ was a monolayer coverage process.The adsorption of RAN or NIZ by SAPC-1.1 and PAC-24.3 was strongly pH dependent,and high adsorption capacity could be observed under the condition of pH>pk_(a)+1.The coexistence of humic acid(HA)had no significant effect on the adsorption performance because RAN/NIZ may be coupled with HA and removed simultaneously.The coexistence of anions had little effect on the adsorption also.This study is expected to provide an alternative strategy for drinking water safety triggered by NDMA.展开更多
基金supported by the Key Technology Research and Development Program of Shandong(No.2020CXGC011406)the National Natural Science Foundation of China(No.22076091)the State Key Joint Laboratory of Environment Simulation and Pollution Control,China(No.21L01ESPC).
文摘Control of N-nitrosodimethylamine(NDMA)in drinking water could be achieved by removing its precursors as one practical way.Herein,superfine powdered activated carbons with a diameter of about 1μm(SPACs)were successfully prepared by grinding powdered activated carbon(PAC,D50=24.3μm)and applied to remove model NDMA precursors,i.e.ranitidine(RAN)and nizatidine(NIZ).Results fromgrain diameter experiments demonstrated that the absorption velocity increased dramatically with decreasing particle size,and the maximum increase in k2 was 26.8-folds for RAN and 33.4-folds for NIZ.Moreover,kinetic experiments explained that rapid absorption could be attributed to the acceleration of intraparticle diffusion due to the shortening of the diffusion path.Furthermore,performance comparison experiments suggested that the removal of RAN and NIZ(C_(0)=0.5 mg/L)could reach 61.3%and 60%,respectively,within 5 min,when the dosage of SAPC-1.1(D_(50)=1.1μm)was merely 5 mg/L,while PAC-24.3 could only eliminate 17.5%and 18.6%.The adsorption isotherm was well defined by Langmuir isotherm model,indicating that the adsorption of RAN/NIZ was a monolayer coverage process.The adsorption of RAN or NIZ by SAPC-1.1 and PAC-24.3 was strongly pH dependent,and high adsorption capacity could be observed under the condition of pH>pk_(a)+1.The coexistence of humic acid(HA)had no significant effect on the adsorption performance because RAN/NIZ may be coupled with HA and removed simultaneously.The coexistence of anions had little effect on the adsorption also.This study is expected to provide an alternative strategy for drinking water safety triggered by NDMA.
