title: Effect of calcium on adsorption capacity of powdered activated carbon.
abstract: We investigated the effect of calcium ion on the adsorption of humic acid (HA) (as a target pollutant) by powered activated carbon. The HA adsorption isotherms at different pH and kinetics of two different solutions including HA alone and HA doped Ca(2+), were performed. It was showed that the adsorption capacity of powdered activated carbon (PAC) for HA was markedly enhanced when Ca(2+) was doped into HA. Also, HA and Ca(2+) taken as nitrate were tested on the uptake of each other respectively and it was showed that the adsorbed amounts of both of them were significantly promoted when HA and calcium co-existed. Furthermore, the adsorbed amount of HA slightly decreased with the increasing of Ca(2+) concentration, whereas the amount of calcium increased with the increasing of HA concentration, but all above the amounts without addition. Finally, the change of pH before and after adsorption process is studied. In the two different solutions including HA alone and HA doped Ca(2+), pH had a small rise, but the extent of pH of later solution was bigger.
authors: College of Environmental and Chemical Engineering, Dalian Jiaotong University, Dalian 116028, China.  lg@djtu.edu.cn
authors: Gang
authors: G
authors: Li
authors: College of Environmental and Chemical Engineering, Dalian Jiaotong University, Dalian 116028, China.
authors: Junteng
authors: J
authors: Shang
authors: College of Environmental and Chemical Engineering, Dalian Jiaotong University, Dalian 116028, China; Liaoning Institution of Higher Learning Key Laboratory for Environmental Science & Technology, Dalian 116028, China.
authors: Ying
authors: Y
authors: Wang
authors: College of Environmental and Chemical Engineering, Dalian Jiaotong University, Dalian 116028, China; Liaoning Institution of Higher Learning Key Laboratory for Environmental Science & Technology, Dalian 116028, China.
authors: Yansheng
authors: Y
authors: Li
authors: School of Materials Science and Engineering of Dalian Jiaotong University, Dalian 116028, China.
authors: Hong
authors: H
authors: Gao
mesh_terms: D000327:Adsorption; D002118:Calcium / Q000737:chemistry*; D002606:Charcoal / Q000737:chemistry*; D006812:Humic Substances / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D011208:Powders; D012996:Solutions; D013696:Temperature
chemical_list: D006812:Humic Substances; D011208:Powders; D012996:Solutions; D002606:Charcoal; D002118:Calcium
keywords: adsorption; calcium; humic acids; powered activated carbon