Insights into solar photo-Fenton reaction parameters in the oxidation of a sanitary landfill leachate at lab-scale.
This work evaluates the effect of the main photo-Fenton (PF) reaction variables on the treatment of a sanitary landfill leachate collected at the outlet of a leachate treatment plant, which includes aerated lagooning followed by aerated activated sludge and a final coagulation-flocculation step. The PF experiments were performed in a lab-scale compound parabolic collector (CPC) photoreactor using artificial solar radiation. The photocatalytic reaction rate was determined while varying the total dissolved iron concentration (20-100 mg Fe(2+)/L), solution pH (2.0-3.6), operating temperature (10-50 °C), type of acid used for acidification (H2SO4, HCl and H2SO4 + HCl) and UV irradiance (22-68 W/m(2)). This work also tries to elucidate the role of ferric hydroxides, ferric sulphate and ferric chloride species, by taking advantage of ferric speciation diagrams, in the efficiency of the PF reaction when applied to leachate oxidation. The molar fraction of the most photoactive ferric species, FeOH(2+), was linearly correlated with the PF pseudo-first order kinetic constants obtained at different solution pH and temperature values. Ferric ion speciation diagrams also showed that the presence of high amounts of chloride ions negatively affected the PF reaction, due to the decrease of ferric ions solubility and scavenging of hydroxyl radicals for chlorine radical formation. The increment of the PF reaction rates with temperature was mainly associated with the increase of the molar fraction of FeOH(2+). The optimal parameters for the photo-Fenton reaction were: pH = 2.8 (acidification agent: H2SO4); T = 30 °C; [Fe(2+)] = 60 mg/L and UV irradiance = 44 WUV/m(2), achieving 72% mineralization after 25 kJUV/L of accumulated UV energy and 149 mM of H2O2 consumed.
LSRE - Laboratory of Separation and Reaction Engineering - Associate Laboratory LSRE/LCM, Departamento de Engenharia Química, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal. Electronic address: tania.silva@fe.up.pt.
Tânia F C V
TF
Silva
LSRE - Laboratory of Separation and Reaction Engineering - Associate Laboratory LSRE/LCM, Departamento de Engenharia Química, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
Rui
R
Ferreira
LSRE - Laboratory of Separation and Reaction Engineering - Associate Laboratory LSRE/LCM, Departamento de Engenharia Química, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
Petrick A
PA
Soares
LSRE - Laboratory of Separation and Reaction Engineering - Associate Laboratory LSRE/LCM, Departamento de Engenharia Química, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal; Programa de Pós-Graduação em Engenharia Química da Universidade Estadual de Maringá, Av. Colombo 5790, Maringá-PR, Brazil.
Diego R
DR
Manenti
Efacec Engenharia e Sistemas S.A. (Unidade de Negócios Ambiente), SA, Rua Eng. Frederico Ulrich - Guardeiras, Apartado 3003, 4471-907 Moreira da Maia, Portugal.
Amélia
A
Fonseca
Efacec Engenharia e Sistemas S.A. (Unidade de Negócios Ambiente), SA, Rua Eng. Frederico Ulrich - Guardeiras, Apartado 3003, 4471-907 Moreira da Maia, Portugal.
Isabel
I
Saraiva
LSRE - Laboratory of Separation and Reaction Engineering - Associate Laboratory LSRE/LCM, Departamento de Engenharia Química, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
Rui A R
RA
Boaventura
LSRE - Laboratory of Separation and Reaction Engineering - Associate Laboratory LSRE/LCM, Departamento de Engenharia Química, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal. Electronic address: vilar@fe.up.pt.
Vítor J P
VJ
Vilar
D005427:Flocculation; D006861:Hydrogen Peroxide / Q000737:chemistry; D007501:Iron / Q000737:chemistry*; D010084:Oxidation-Reduction; D010777:Photochemistry / Q000379:methods*; D012722:Sewage; D013472:Sunlight; D013696:Temperature; D014466:Ultraviolet Rays; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000737:chemistry*
D012722:Sewage; D014874:Water Pollutants, Chemical; D006861:Hydrogen Peroxide; D007501:Iron
Ferric ion speciation diagrams; Lab-scale prototype; Photo-Fenton parameters; Sanitary landfill leachate