Application of citrus sinensis solid waste as a pseudo- catalyst for free cyanide conversion under alkaline conditions
Santos, Bruno Alexandre Quistorp
Ntwampe, Seteno Karabo Obed
Doughari, James Hamuel
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In this study, Citrus sinensis (C. sinensis) solid waste was used to catalyze the conversion of free cyanide (F-CN) under alkaline conditions; conditions which represent most industrial wastewater containing F-CN. Acid hydrolysis of the solid waste increased the catalytic conversion of F- CN by 3.86 compared to the unhydrolysed solid waste. The conversion of F-CN using unhydrolysed and hydrolysed solid waste increased linearly with an increase in pH and temperature. The maximum catalytic conversion of a 100 mg F-CN/L solution containing 0.1% (w/v) of unhydrolysed and hydrolysed C. sinensis solid waste was 17.82% and 62.48%, respectively, at a pH of 12 and a temperature of 50 °C. The catalytic process was largely dependent on the availability of activated hydroxyl groups in the solid waste. As most wastewater contains heavy metals, it was determined that the presence of metallic species (Ni, Zn, and Cu) reduced the conversion of F-CN as the metallic ions attached to the hydroxyl groups. The observed reduction was 26.35% when 10 mg/L of heavy metals were present in the F-CN solution containing the hydrolysed solid waste at a pH of 12 and 40 °C.
Additional Citation InformationSantos, B., Ntwampe, S., Doughari, J., & Muchatibaya, G. (2013). Application of Citrus sinensis Solid Waste as a Pseudo-Catalyst for Free Cyanide Conversion under Alkaline Conditions. BioResources, 8(3), 3461-3467. doi:10.15376/biores.8.3.3461-3467
SponsorThis research was sponsored by a Cape Peninsula University of Technology, University Research Fund (URF RK16). Ms. H. Small, Prof. V. Hugo, Ms. M. Ackerman and Mr. Alvyn Bester are hereby acknowledged for their technical contribution to this study.