title: NiO111 nanosheets as efficient and recyclable adsorbents for dye pollutant removal from wastewater.
abstract: Semiconductor single-crystalline polar NiO(111) nanosheets with well-defined hexagonal holes have been investigated for application in dye adsorption and combustion processes. With regard to adsorption technologies, high surface area metal oxides have an advantage over activated carbon in that the adsorbed species can be combusted and the adsorbent reused in the case of metal oxides while regeneration of activated carbon remains challenging and thus the adsorbent/adsorbate system must be disposed of. Here, three typical textile dyes, reactive brilliant red X-3B, congo red and fuchsin red, were studied for removal from wastewater with two NiO systems and activated carbon. These studies revealed that the NiO(111) nanosheets exhibited much more favorable adsorptive properties than conventionally prepared nickel oxide powder (CP-NiO) obtained from thermal decomposition of nickel nitrate. The maximum adsorption capabilities of the three dyes on NiO(111) nanosheets reached 30.4 mg g(-1), 35.15 mg g(-1) and 22 mg g(-1) for reactive brilliant red X-3B, congo red and fuchsin acid, respectively, while the maximum adsorption capabilities of the three dyes on CP-NiO were only 8.4, 13.2 and 12 mg g(-1) for reactive brilliant red X-3B, congo red and fuchsin acid. To simulate the adsorption isotherm, two commonly employed models, the Langmuir and the Freundlich isotherms, were selected to explicate the interaction of the dye and NiO(111). The isotherm evaluations revealed that the Langmuir model demonstrated better fit to experimental equilibrium data than the Freundlich model. The maximum predicted adsorption capacity was 36.1 mg g(-1). In addition, adsorption kinetic data of NiO(111) followed a pseudo-second-order rate for congo red. These studies infer that NiO(111) nanosheets possess desirable properties for application in adsorption and combustion applications.
authors.affiliation: Key Laboratory of Catalysis and Materials Science of the State Ethnic Affairs Commission and Ministry of Education, South-Central University for Nationalities, Wuhan 430074, People's Republic of China.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Song
authors.forename: Lifang
authors.initials: L
authors.lastname: Chen
authors.forename: Juncheng
authors.initials: J
authors.lastname: Hu
authors.forename: Ryan
authors.initials: R
authors.lastname: Richards
mesh_terms: D000327:Adsorption; D004396:Coloring Agents / Q000302:isolation & purification*; D017743:Equipment Reuse; D007220:Industrial Waste / Q000032:analysis; D007700:Kinetics; D046529:Microscopy, Electron, Transmission; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D009532:Nickel / Q000737:chemistry*; D009994:Osmolar Concentration; D045663:Quantum Dots; D013783:Textile Industry; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods; D014961:X-Ray Diffraction
chemical_list: D004396:Coloring Agents; D007220:Industrial Waste; D014874:Water Pollutants, Chemical; D009532:Nickel; C028007:nickel monoxide