title: Cadmium Removal from Aqueous Solution by a Deionization Supercapacitor with a Birnessite Electrode.
abstract: Birnessite is widely used as an excellent adsorbent for heavy metal ions and as active electrode materials for supercapacitors. The occurrence of redox reactions of manganese oxides is usually accompanied by the intercalation-deintercalation of cations during the charge-discharge processes of supercapacitors. In this study, based on the charge-discharge principle of the supercapacitor and excellent adsorption properties of birnessite, a birnessite-based electrode was used to remove Cd2+from aqueous solutions. The Cd2+removal mechanism and the influences of birnessite loading and pH on the removal performance were investigated. The results showed that Cd2+was adsorbed on the surfaces and interlayers of birnessite, and the maximum electrosorption capacity of birnessite for Cd2+was about 900.7 mg g-1(8.01 mmol g-1), which was significantly higher than the adsorption isotherm capacity of birnessite (125.8 mg g-1). The electrosorption specific capacity of birnessite for Cd2+increased with an increase in initial Cd2+concentration and decreased with an increase in the loading of active birnessite. In the pH range of 3.0-6.0, the electrosorption capacity increased at first with an increase in pH and then reached equilibrium above pH 4.0. This work provides a new method for the highly efficient adsorption of Cd2+from polluted wastewater.
authors.affiliation: Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural University , Wuhan 430070, China.
authors.forename: Qichuan
authors.initials: Q
authors.lastname: Peng
authors.affiliation: Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural University , Wuhan 430070, China.
authors.forename: Lihu
authors.initials: L
authors.lastname: Liu
authors.affiliation: Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural University , Wuhan 430070, China.
authors.forename: Yao
authors.initials: Y
authors.lastname: Luo
authors.affiliation: Department of Chemistry, University of Connecticut , 55 North Eagleville Road, Storrs, Connecticut 06269-3060, United States.
authors.forename: Yashan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural University , Wuhan 430070, China.
authors.forename: Wenfeng
authors.initials: W
authors.lastname: Tan
authors.affiliation: Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural University , Wuhan 430070, China.
authors.forename: Fan
authors.initials: F
authors.lastname: Liu
authors.affiliation: Department of Chemistry, University of Connecticut , 55 North Eagleville Road, Storrs, Connecticut 06269-3060, United States.
authors.forename: Steven L
authors.initials: SL
authors.lastname: Suib
authors.affiliation: Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural University , Wuhan 430070, China.
authors.forename: Guohong
authors.identifier: http://orcid.org/0000-0002-1181-3707
authors.initials: G
authors.lastname: Qiu
keywords: Cd2+; birnessite; deionization supercapacitor; electrochemical removal; galvanostatic charge−discharge