Effective Removal of Cyanide and Heavy Metals from an Industrial Electroplating Stream Using Calcium Alginate Hydrogels

Molecules

卷:25

Benita Pérez-Cid¹  Sergio Calvar²  AnaBelén Moldes²  Jose Manuel Cruz² 

[1] Department of Analytical and Food Chemistry, Faculty of Chemistry, University of Vigo, As Lagoas-Marcosende s/n, 36310 Vigo, Spain;

[2] Department of Chemical Engineering, School of Industrial Engineering, University of Vigo, As Lagoas-Marcosende s/n, 36310 Vigo, Spain;

关键词: cyanide;    heavy metals;    electroplating wastewater;    alginate beads;    kinetic sorption;   

DOI  :  10.3390/molecules25215183

来源: DOAJ

【 摘 要 】

A real electroplating wastewater, containing 51,190 mg/L of free cyanide (CN_f), 4899 mg/L of Ni and 1904 mg/L of Cu, was treated with calcium alginate hydrogel beads (CAB), pure or impregnated with biodegraded grape marc (EBGM) or activated carbon (EAC) in order to reduce the elevated load of toxic pollutants below the regulatory limits. It was evaluated the effect of increasing the amount of bioadsorbent as well as the influence of two successive adsorption cycles in the removal efficiency of pollutants. The most favourable sorption conditions onto CAB provided removal percentages of 85.02% for CN_f and between 93.40–98.21% for heavy metals regarding the raw wastewater. The adsorption capacity of each pollutant onto CAB was considerably increased during the first 30 min of contact time, but after achieving the equilibrium, the following sorption capacities were obtained: 1177, 107.3, 39.5 and 1.52 mg/g for CN_f, Ni, Cu and Zn, respectively. The kinetic adsorption of pollutants onto the CAB was adjusted to different kinetic models, observing that kinetic data agreed with the pseudo-second-order model. The information about intraparticle diffusion mechanisms in the bioadsorption process was also interpreted.

【 授权许可】

Unknown