title: Surface-treated carbon electrodes with modified potential of zero charge for capacitive deionization.
abstract: The potential of zero charge (Epzc) of electrodes can greatly influence the salt removal capacity, charge efficiency and cyclic stability of capacitive deionization (CDI). Thus optimizing the Epzc of CDI electrodes is of great importance. A simple strategy to negatively shift the Epzc of CDI electrodes by modifying commercial activated carbon with quaternized poly (4-vinylpyridine) (AC-QPVP) is reported in this work. The Epzc of the prepared AC-QPVP composite electrode is as negative as -0.745 V vs. Ag/AgCl. Benefiting from the optimized Epzc of electrodes, the asymmetric CDI cell which consists of the AC-QPVP electrode and a nitric acid treated activated carbon (AC-HNO3) electrode exhibits excellent CDI performance. For inverted CDI, the working potential window of the asymmetric CDI cell can reach 1.4 V, and its salt removal capacity can be as high as 9.6 mg/g. For extended voltage CDI, the salt removal capacity of the asymmetric CDI cell at 1.2/-1.2 V is 20.6 mg/g, which is comparable to that of membrane CDI using pristine activated carbon as the electrodes (19.5 mg/g). The present work provides a simple method to prepare highly positively charged CDI electrodes and may pave the way for the development of high-performance CDI cells.
authors.affiliation: State Key Lab of Fine Chemicals, Liaoning Key Lab for Energy Materials and Chemical Engineering, PSU-DUT Joint Center for Energy Research, Dalian University of Technology, Dalian, 116024, China.
authors.forename: Tingting
authors.initials: T
authors.lastname: Wu
authors.affiliation: State Key Lab of Fine Chemicals, Liaoning Key Lab for Energy Materials and Chemical Engineering, PSU-DUT Joint Center for Energy Research, Dalian University of Technology, Dalian, 116024, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Wang
authors.affiliation: State Key Lab of Fine Chemicals, Liaoning Key Lab for Energy Materials and Chemical Engineering, PSU-DUT Joint Center for Energy Research, Dalian University of Technology, Dalian, 116024, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Zhan
authors.affiliation: State Key Lab of Fine Chemicals, Liaoning Key Lab for Energy Materials and Chemical Engineering, PSU-DUT Joint Center for Energy Research, Dalian University of Technology, Dalian, 116024, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Dong
authors.affiliation: State Key Lab of Fine Chemicals, Liaoning Key Lab for Energy Materials and Chemical Engineering, PSU-DUT Joint Center for Energy Research, Dalian University of Technology, Dalian, 116024, China.
authors.forename: Qidi
authors.initials: Q
authors.lastname: Ren
authors.affiliation: State Key Lab of Fine Chemicals, Liaoning Key Lab for Energy Materials and Chemical Engineering, PSU-DUT Joint Center for Energy Research, Dalian University of Technology, Dalian, 116024, China.
authors.forename: Jianren
authors.initials: J
authors.lastname: Wang
authors.affiliation: State Key Lab of Fine Chemicals, Liaoning Key Lab for Energy Materials and Chemical Engineering, PSU-DUT Joint Center for Energy Research, Dalian University of Technology, Dalian, 116024, China. Electronic address: jqiu@dlut.edu.cn.
authors.forename: Jieshan
authors.initials: J
authors.lastname: Qiu
mesh_terms: D000327:Adsorption; D002244:Carbon / Q000737:chemistry*; D002606:Charcoal / Q000737:chemistry; D025802:Electric Capacitance; D055664:Electrochemical Techniques / Q000295:instrumentation* / Q000379:methods; D004566:Electrodes; D004867:Equipment Design; D017942:Nitric Acid / Q000737:chemistry; D011145:Polyvinyls / Q000737:chemistry; D015203:Reproducibility of Results; D054712:Salinity; D012965:Sodium Chloride / Q000737:chemistry / Q000302:isolation & purification*; D013499:Surface Properties; D018508:Water Purification / Q000295:instrumentation* / Q000379:methods
chemical_list: D011145:Polyvinyls; D002606:Charcoal; C019535:poly(4-vinylpyridine); D017942:Nitric Acid; D012965:Sodium Chloride; D002244:Carbon
keywords: Asymmetric capacitive deionization; Extended voltage capacitive deionization; Inverted capacitive deionization; Potential of zero charge; Quaternization; Surface charge