Sorption behavior of heavy metals on poorly crystalline manganese oxides: roles of water conditions and light.
The objective of this study was to determine the effects of solution properties and light on the metal uptake and release in a nanosized, poorly crystalline manganese oxide (δ-MnO2) system. The results from synthetic water matrices revealed that the aggregation state was strongly affected by ionic strength, Ca(2+), and humic acid, and the particle aggregation subsequently changed the ability of δ-MnO2 to adsorb and sequester heavy metal ions (Cu(ii)). The extent of Cu(ii) uptake onto δ-MnO2 exhibited a negative correlation with the attachment efficiency value, which suggested that a lower sorption capacity could be achieved under aggregation-inducing conditions. Upon exposure to light, the adsorbed Cu(ii) was released from the δ-MnO2 surface via photoinduced dissolution of MnO2. The concentration of Cu(ii) desorbed was substantially higher when the humic acid was present together with Ca(2+). The present investigation enables us to better understand the adsorption-desorption processes of heavy metals occurring at the MnO2-solution interface in response to common environmental stimuli.
School of Environmental Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 790-784, Republic of Korea. yschang@postech.ac.kr.
Eun-Ju
EJ
Kim
Jungwon
J
Kim
Sung-Chan
SC
Choi
Yoon-Seok
YS
Chang
D000327:Adsorption; D006812:Humic Substances; D007700:Kinetics; D008027:Light; D017895:Manganese Compounds / Q000737:chemistry*; D019216:Metals, Heavy / Q000032:analysis / Q000737:chemistry*; D008956:Models, Chemical; D010087:Oxides / Q000737:chemistry*; D055668:Photochemical Processes; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*
D006812:Humic Substances; D017895:Manganese Compounds; D019216:Metals, Heavy; D010087:Oxides; D014874:Water Pollutants, Chemical; C027424:manganese oxide