title: The effect of operational parameters on electrocoagulation-flotation process followed by photocatalysis applied to the decontamination of water effluents from cellulose and paper factories.
abstract: Cellulose and paper pulp factories utilize a large amount of water generating several undesirable contaminants. The present work is a preliminary investigation that associates the electrocoagulation-flotation (EC) method followed by photocatalysis to treat such wastewater. For EC, the experiment with aluminium and iron electrodes showed similar efficiency. Iron electrodes (anode and cathode) were chosen. By applying 30min of EC/Fe(0), 153A m(-2) and pH 6.0, the COD values, UV-vis absorbance and turbidity underwent an intense decrease. For the subsequent UV photocatalysis (mercury lamps) TiO(2) was employed and the favourable operational conditions found were 0.25g L(-1) of the catalyst and solution pH 3.0. The addition of hydrogen peroxide (50mmol L(-1)) highly increased the photo-process performance. By employing the UV/TiO(2)/H(2)O(2) system, the COD reduction was 88% compared to pre-treated effluents and complete sample photobleaching was verified. The salt concentration on EC (iron electrodes) showed that the electrolysis duration can be reduced from 30 to 10min by the addition of 5.0g L(-1) of NaCl. The biodegradability index (BOD/COD) increased from 0.15 (pre-treated) to 0.48 (after EC) and to 0.89 (after EC/photocatalysis irradiated for 6h), showing that the employed sequence is very helpful to improve the water quality. This result was confirmed by biotoxicity tests performed with microcrustaceous Artemia salina.
authors.affiliation: Departamento de Química, Universidade Estadual de Maringá, Maringá, PR, Brazil.
authors.forename: Marcela
authors.initials: M
authors.lastname: Boroski
authors.forename: Angela Cláudia
authors.initials: AC
authors.lastname: Rodrigues
authors.forename: Juliana Carla
authors.initials: JC
authors.lastname: Garcia
authors.forename: Adriana Passarella
authors.initials: AP
authors.lastname: Gerola
authors.forename: Jorge
authors.initials: J
authors.lastname: Nozaki
authors.forename: Noboru
authors.initials: N
authors.lastname: Hioka
mesh_terms: D000818:Animals; D001156:Artemia; D001673:Biodegradation, Environmental; D001938:Brazil; D002384:Catalysis; D002482:Cellulose; D004563:Electrochemistry; D007202:Indicators and Reagents; D007220:Industrial Waste / Q000032:analysis* / Q000331:legislation & jurisprudence; D010209:Paper; D010777:Photochemistry; D014025:Titanium / Q000737:chemistry; D014466:Ultraviolet Rays; D014865:Waste Disposal, Fluid / Q000331:legislation & jurisprudence / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000633:toxicity
chemical_list: D007202:Indicators and Reagents; D007220:Industrial Waste; D014874:Water Pollutants, Chemical; C009495:titanium dioxide; D002482:Cellulose; D014025:Titanium