title: Room-Temperature Oxidation of Formaldehyde by Layered Manganese Oxide: Effect of Water.
abstract: Layered manganese oxide, i.e., birnessite was prepared via the reaction of potassium permanganate with ammonium oxalate. The water content in the birnessite was adjusted by drying/calcining the samples at various temperatures (30 °C, 100 °C, 200 °C, 300 °C, and 500 °C). Thermogravimetry-mass spectroscopy showed three types of water released from birnessite, which can be ascribed to physically adsorbed H2O, interlayer H2O and hydroxyl, respectively. The activity of birnessite for formaldehyde oxidation was positively associated with its water content, i.e., the higher the water content, the better activity it has. In-situ DRIFTS and step scanning XRD analysis indicate that adsorbed formaldehyde, which is promoted by bonded water via hydrogen bonding, is transformed into formate and carbonate with the consumption of hydroxyl and bonded water. Both bonded water and water in air can compensate the consumed hydroxyl groups to sustain the mineralization of formaldehyde at room temperature. In addition, water in air stimulates the desorption of carbonate via water competitive adsorption, and accordingly the birnessite recovers its activity. This investigation elucidated the role of water in oxidizing formaldehyde by layered manganese oxides at room temperature, which may be helpful for the development of more efficient materials.
authors.affiliation: State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University , Beijing 100084, China.|Collaborative Innovation Center for Regional Environmental Quality, School of Environment, Tsinghua University , Beijing 100084, China.
authors.forename: Jinlong
authors.initials: J
authors.lastname: Wang
authors.affiliation: State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University , Beijing 100084, China.|Collaborative Innovation Center for Regional Environmental Quality, School of Environment, Tsinghua University , Beijing 100084, China.
authors.forename: Pengyi
authors.initials: P
authors.lastname: Zhang
authors.affiliation: State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University , Beijing 100084, China.
authors.forename: Jinge
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Civil and Environmental Engineering, Duke University , Durham, North Carolina 90287, United States.
authors.forename: Chuanjia
authors.initials: C
authors.lastname: Jiang
authors.affiliation: State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University , Beijing 100084, China.
authors.forename: Rizwangul
authors.initials: R
authors.lastname: Yunus
authors.affiliation: State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University , Beijing 100084, China.
authors.forename: Jeonghyun
authors.initials: J
authors.lastname: Kim
mesh_terms: D000327:Adsorption; D005557:Formaldehyde / Q000737:chemistry*; D006860:Hydrogen Bonding; D017895:Manganese Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry*; D011196:Potassium Permanganate; D013696:Temperature; D014867:Water / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D017895:Manganese Compounds; D010087:Oxides; C505018:birnessite; D011196:Potassium Permanganate; D014867:Water; D005557:Formaldehyde; C027424:manganese oxide