title: Design of a fixed-bed ion-exchange process for the treatment of rinse waters generated in the galvanization process using Laminaria hyperborea as natural cation exchanger.
abstract: In this study, the removal of zinc from galvanization wastewaters was performed in a fixed bed column packed with brown macro-algae Laminaria hyperborea, acting as a natural cation exchanger (resin). The rinse wastewater presents a zinc concentration between 9 and 22 mg/L, a high concentration of light metals (mainly Na and Ca), a high conductivity (0.5-1.5 mS/cm) and a low organic content (DOC = 7-15 mg C/L). The zinc speciation diagram showed that approximately 80% of zinc is in the form of Zn(2+) and ≅20% as ZnSO4, considering the effluent matrix. From all operational conditions tested for zinc uptake (17 < bed height<27 cm, 4.5 < flow rate<18.2 BV/h, 0.8 < particle equivalent diameter<2.0 mm), the highest useful capacity (7.1 mg Zn/g algae) was obtained for D/dp = 31, L/D = 11, 9.1 BV/h, τ = 6.4 min, corresponding to a service capacity of 124 BV (endpoint of 2 mg Zn/L). Elution was faster and near to 100% effective using 10 BV of HCl (1 M, 3.0%, 363 g HCl/L of resin), for flow rates higher than 4.5 BV/h. Calcium chloride solution (0.1 M) was selected as the best regenerant, allowing the reuse of the natural resin for more than 3 saturation/elution/regeneration cycles. The best operation conditions were scaled-up and tested in a pre-pilot plant. The scale-up design of the cation exchange process was proposed for the treatment of 2.4 m(3)/day of galvanization wastewater, resulting in an estimated reactants cost of 2.44 €/m(3).
authors.affiliation: LSRE - Laboratory of Separation and Reaction Engineering, Associate Laboratory LSRE-LCM, Chemical Engineering Department, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal.
authors.forename: Luciana P
authors.initials: LP
authors.lastname: Mazur
authors.affiliation: LSRE - Laboratory of Separation and Reaction Engineering, Associate Laboratory LSRE-LCM, Chemical Engineering Department, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal.
authors.forename: Tatiana A
authors.initials: TA
authors.lastname: Pozdniakova
authors.affiliation: Laboratório de Transferência de Massa e Simulação Numérica de Sistemas Químicos, Federal University of Santa Catarina, PO Box 476, CEP 88040-900 Florianópolis, SC, Brazil.
authors.forename: Diego A
authors.initials: DA
authors.lastname: Mayer
authors.affiliation: LSRE - Laboratory of Separation and Reaction Engineering, Associate Laboratory LSRE-LCM, Chemical Engineering Department, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal.
authors.forename: Rui A R
authors.initials: RAR
authors.lastname: Boaventura
authors.affiliation: LSRE - Laboratory of Separation and Reaction Engineering, Associate Laboratory LSRE-LCM, Chemical Engineering Department, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal. Electronic address: vilar@fe.up.pt.
authors.forename: Vítor J P
authors.initials: VJP
authors.lastname: Vilar
mesh_terms: D000327:Adsorption; D018533:Biomass; D002412:Cations; D002852:Chromatography, Ion Exchange / Q000379:methods; D004867:Equipment Design; D006863:Hydrogen-Ion Concentration; D007474:Ion Exchange; D007477:Ions; D007795:Laminaria; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater; D014867:Water; D014871:Water Microbiology; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000302:isolation & purification; D018508:Water Purification / Q000295:instrumentation* / Q000379:methods*; D015032:Zinc / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification
chemical_list: D002412:Cations; D007477:Ions; D062065:Wastewater; D014867:Water; D014874:Water Pollutants, Chemical; D015032:Zinc
keywords: Elution; Galvanization wastewater; Natural cation exchanger; Regeneration; Scale-up; Zinc