Studying the efficiency of Regenerated Spent Bleaching Earth (RSBE) in 
removing cyanide from coke industry wastewater in Kerman

Mohammad Hassan Ehrampoush
1; Ali Almasi
2; Behnam Salmani
3

Abstract

Studying the efficiency of Regenerated Spent Bleaching Earth (RSBE) in removing cyanide from coke industry wastewater in Kerman

Author(s): Mohammad Hassan Ehrampoush 1 , Ali Almasi 2 and Behnam Salmani 3*

Cyanide is a toxic pollutant found in different ind ustrial wastewater, and wastewater of these industr ies is discharged to the environment without any treatment . The main aim of this research was to remove cyani de from aqueous solutions using bleaching earth adsorbent r ecycled from vegetable oil industries. In this stud y, Regenerated Spent Bleaching Earth (RSBE) obtained from vegetabl e oil industries was used to remove cyanide from aq ueous solutions. Effects of pH, cyanide initial concentra tion, contact time and adsorbent dose were investig ated in a batch reactor. The optimum conditions obtained in this st udy on Kerman coke industry wastewater were also ex amined. Finally, kinetics and isotherms of cyanide adsorpti on were analyzed. Results showed that the regenerat ed bleaching earth with a concentration of 1 N NaOH had a higher adsorption capacity than other regenerated agents. The maximum cyanide adsorption was achieved at a pH of 7 and a contact time of 140 minutes. As cyanide ini tial concentration increased, adsorption rate increased but removal efficiency decreased. Moreover, as adso rbent dose increased, removal efficiency increased but adsorbe nt capacity decreased. The effect of bleaching eart h on coke industry wastewater in optimal conditions revealed that cyanide removal rate was 86%. The data of this research had the greatest conformity with Langmuir-2 isother m. The maximum adsorption capacity of cyanide on RS BE was 13 mg/g. In addition, Elovich was the most appropri ate model to determine the reaction kinetics. The r esults of this study showed that treatment costs of cyanide-contai ning wastewater could be reduced by regenerating th is industrial waste.

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