title: Removal of aqueous cyanide with strongly basic ion-exchange resin.
abstract: The removal of cyanide (CN-) from aqueous solutions using a strongly basic ion-exchange resin, Purolite A-250, was investigated. The effects of contact time, initial CN- concentration, pH, temperature, resin dosage, agitation speed, and particle size distribution on the removal of CN- were examined. The adsorption equilibrium data fitted the Langmuir isotherm very well. The maximum CN- adsorption capacity of Purolite A-250 was found to be 44 mg CN- g(-1) resin. More than 90% CN- adsorption was achieved for most CN- solutions (50, 100, and 200 mg CN- L(-1)) with a resin dose of 2 g L(-1). The equilibrium time was ∼20 min, optimum pH was 10.0-10.5, and optimum agitation speed was 150 rpm. An increase in adsorption of CN- with increasing resin dosage was observed. Adsorption of CN- by the resin was marginally affected (maximum 4% variation) within an environmentally relevant temperature range of 20-50 °C. Fixed-bed column (20.5 mm internal diameters) experiments were performed to investigate the effects of resin bed depth and influent flow rate on breakthrough behaviour. Breakthrough occurred in 5 min for 0.60 cm bed depth while it was 340 min for 5.40 cm bed depth. Adsorption capacity was 25.5 mg CN- g(-1) for 5 mL min(-1) flow rate and 3.9 mg CN- g(-1) for 20 mL min(-1) flow rate. The research has established that the resin can be effectively used for CN- removal from aqueous solutions.
authors.affiliation: a Department of Agricultural and Biosystems Engineering , North Dakota State University , Fargo , ND , USA.
authors.forename: Halis
authors.initials: H
authors.lastname: Simsek
authors.forename: Mehmet
authors.initials: M
authors.lastname: Kobya
authors.forename: Eakalak
authors.initials: E
authors.lastname: Khan
authors.forename: Achintya N
authors.initials: AN
authors.lastname: Bezbaruah
mesh_terms: D000327:Adsorption; D003198:Computer Simulation; D003486:Cyanides / Q000737:chemistry / Q000302:isolation & purification*; D006863:Hydrogen-Ion Concentration; D007475:Ion Exchange Resins / Q000737:chemistry*; D007700:Kinetics; D008956:Models, Chemical; D014462:Ultrafiltration / Q000379:methods; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods*
chemical_list: D003486:Cyanides; D007475:Ion Exchange Resins; D014874:Water Pollutants, Chemical
keywords: adsorption; cyanide; industrial pollution control; ion-exchange resin; isotherms