Promotion effect of ZnO on the photocatalytic activity of coupled Al 2 O 3 -Nd 2 O 3 -ZnO composites prepared by the sol − gel method in the degradation of phenol

Biomass-derived nitrogen-doped hierarchically porous carbon networks as efficient absorbents for phenol removal from wastewater over a wide pH range

“…Phenols that are commonly discharged from the wastewater of petroleum reneries and steel foundries, pose a great threat to the health and safety of both human beings and animals due to their high toxicity and carcinogenicity even at low concentrations. 1 Many technologies including membrane separation, 2 photocatalytic degradation, 3 and adsorption 4 have been developed for phenol removal from wastewater. Among them, the adsorption technique is regarded as a competitive and effective approach due to its simplicity and high efficiency.…”

Photocatalytic Degradation of Diclofenac Using Al2O3-Nd2O3 Binary Oxides Prepared by the Sol-Gel Method

“…The spectrum of γ-Al2O3 presented a broad absorption in the 240-330 nm range, which is associated with electronic charge transfer and also with the accumulation of defects in the structure of this compound [25]. Regarding the Nd2O3 sample, the spectrum contains an intense band in the 200-290 nm range associated with an exchange of electrons between the valence and conduction bands [9,26]; also, a set of sharp absorption bands between 330 and 760 nm correspond to electron transitions within the 4f shell of neodymium [3,27]. Regarding the spectra of the binary oxides, the band between 240 and 315 nm from the alumina is present.…”

“…The sol-gel method was selected since this procedure allows for the simultaneous formation of metal oxides [8][9][10][11]. First, a solution with a certain amount of aluminum tri-sec-butoxide (97.0%, Aldrich, St. Louis, MO, USA) and 10 mL of 2-methylpentane 2,4-diol (99.999%, JT Baker, Phillipsburg, USA) as a complexing agent was stirred in a round glass flask for 60 min while the temperature was kept at 70 • C. Thereafter, the temperature was reduced to 50 • C and mixed with a second solution prepared by dissolving neodymium acetylacetonate (99.99%, Aldrich) in toluene (99.999%, Aldrich) at 40 • C. The resulting solution was stirred at 50 • C, then, after 60 min, 10 mL of deionized water was added dropwise to promote the hydrolysis of the aluminum and neodymium reagents to produce a gel.…”

“…According to previous reports, the modified surface can be considered a new phase with different properties associated to new surface chemistry and chemical activity [4][5][6]. We have reported that the sol-gel method is suitable to produce γ-Al 2 O 3 with photocatalytic activity to degrade organic pollutants in water [7][8][9], however it is desirable to enhance photocatalytic performance in order to reach a higher conversion in the lowest time. In earlier works, the photocatalytic activity of γ-Al 2 O 3 in the degradation of phenolic compounds has been improved by impregnating noble metal (PdO or'Ag 0 ) onto Al 2 O 3 -Ln 2 O 3 (Ln = Nd or Gd) binary oxides [8,10,11] or by doping Al 2 O 3 -Nd 2 O 3 with the semiconducting ZnO to form Al 2 O 3 -Ln 2 O 3 -ZnO ternary oxides [9].…”

“…We have reported that the sol-gel method is suitable to produce γ-Al 2 O 3 with photocatalytic activity to degrade organic pollutants in water [7][8][9], however it is desirable to enhance photocatalytic performance in order to reach a higher conversion in the lowest time. In earlier works, the photocatalytic activity of γ-Al 2 O 3 in the degradation of phenolic compounds has been improved by impregnating noble metal (PdO or'Ag 0 ) onto Al 2 O 3 -Ln 2 O 3 (Ln = Nd or Gd) binary oxides [8,10,11] or by doping Al 2 O 3 -Nd 2 O 3 with the semiconducting ZnO to form Al 2 O 3 -Ln 2 O 3 -ZnO ternary oxides [9]. Although the experimental evidences demonstrated that the photocatalytic activity of γ-Al 2 O 3 enhances with the addition of rare earth oxides, semiconducting oxides, or noble metals, the performance against degradation of drug pollutants in water is still unknown; therefore, we proposed to study the photocatalytic degradation of diclofenac in aqueous medium catalyzed with Al 2 O 3 -Nd 2 O 3 binary oxides and the efficiency related to the Nd 2 O 3 content.…”