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.

Performance enhancement and optimization of photocatalytic cyanide degradation in aqueous solution using Zn (II) and Fe (III) oxides as nanostructure supported on activated carbon

“…Cyanide, which is highly toxic, exists in many industrial wastewaters especially metal finishing, electroplating, gold and silver mining, iron and steel industry, and coke extraction . More than 100 000 tons of cyanide enters the environment annually, while total global hydrogen cyanide production alone amounts to 1.1 million tons . The presence of cyanide even at extremely low concentrations in aqueous systems poses a serious threat to the human ecosystem .…”

Adsorption performance of CuFe2O4/rGO nanocomposites towards organic dye

“…Polluted water caused by dyes has been of great concern because of their high color degree and toxicity. Since it is a global environmental issue, some technologies to treat waste water have been developed, such as chemical oxidation [1], biological method [2], ion-exchange [3], adsorption [4], and electrodialysis [5]. Of all these methods, adsorption is of special interest due to its high separation efficiency, low-cost and simple operation process.…”

Separation of cyanide from an aqueous solution using armchair silicon carbide nanotubes: insights from molecular dynamics simulations

“…Cyanide is widely used in diverse industries including electroplating, mining, photoprocessing, fertilizer production, gas production, pharmaceuticals and plating. 1 The existence of cyanides in wastewater poses a high risk and hence, it should be removed from wastewaters before release. 2 Cyanides cause extensive sh death and affect the microscopic and invertebrate organisms in water.…”

“…[6][7][8][9][10] For example, Simsek et al conducted column and batch studies with a Purolite resin in order to remove cyanide ions from aqueous solutions. 1 Moreover, Hijosa-Valsero et al tested plasma discharge technology for cyanide removal from water with an initial concentration of 1 mg L À1 . 11 They proposed a coaxial DBD plasma reactor only for the treatment of dilute solutions such as drinking water.…”

“…Moreover, they produce poisonous residues and cannot completely reduce all cyanide complexes. 1,16 In this regard, for water purication and to meet qualication requirements, nanotechnology has emerged as a novel and powerful tool. 17,18 Nanotubes are an excellent and appropriate choice as ion selective materials.…”