Removal of Escherichia Coli and Heavy Metals from Wastewater Using Silver-modified Clinoptilolite
نویسنده
چکیده
The aim of this study was to investigate the removal of Escherichia coli and heavy metals (Pb, Cd 2+ and Zn ) from wastewater using silver-modified clinoptilolite under different experimental conditions through the combined disinfection of pathogenic microorganisms by the silver ions and sorption of heavy metals on clinoptilolite. Batch experiments were conducted to look at the effects of initial metal concentration, pH and contact time on the disinfection, ion exchange and sorption mechanisms involved in the removal process. Silver-modified zeolites were suspended at 10g/l in single and bicomponent synthetic solutions containing Escherichia coli (10-10 CFU/100ml) as an indicator of faecal contamination and metals (Pb, Cd 2+ and Zn) at concentrations ranging from 0.1 to 5mg/l. The silver-modified zeolites exhibited good antibacterial activity with complete elimination of Escherichia coli in the single and bi-component solutions occurring within the first 30 minutes of contact and high metal removal efficiencies of up to 99% in the single component metal solutions at pH 5. In the bi-component solutions the presence of metals at 0.5mg/l did not significantly influence the rate of disinfection. However there was a slight decrease in the metal removal efficiencies in the presence of Escherichia coli. The results of this study show that silver-modified zeolites could potentially be applied in the treatment of complex wastewater effluents while highlighting the need for further studies to understand the mechanisms occurring in multi-component solutions with a view to optimizing the system.
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