Production, characterization and application of bioflocculant on Cu (II) and Pb (II) removal in synthetic wastewater
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Date
2009
Authors
Razali, Hazana
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Abstract
Bioflocculants are polymer produced by microorganisms during their growth with their flocculating activity being dependent on the characteristics of the flocculants. Bioflocculant producing bacteria were isolated from wastewater and sediments of Close Drainage Systems (CDS) located at the Prai industrial area and Juru River. Polyglutamic Acid (PGA) medium was used as a selective medium to grow the bioflocculant producing bacteria. The cultures were cultivated at 30 to 50 oC for 43 to 77 hours. The flocculating activity was obtained by measuring the optical density (OD) at wavelength 550 nm of the kaolin suspension (hydrated aluminum silicate) after the addition of culture broth. More than 300 colonies were screened and isolated from microbial source samples based on their ability to grow on PGA medium. Two types of bacteria with the highest flocculation rate of 96.82% and 97.01% were identified as Staphylococcus lentus and Sphingomonas paucimobilis respectively. Crude bioflocculant was extracted from the supernatant of the culture medium by cold ethanol precipitation named as SC-F1 and SC-F3 respectively. Characterization of crude bioflocculant secreted from the two types of bacteria was investigated. Scanning electron microscopy (SEM) studies showed the surface morphology of crude bioflocculant was crystal linear structure. The infrared spectra of crude bioflocculant extracted from these two bacteria revealed that carboxyl, hydroxyl and amino groups
play an important role in bioflocculation process. The ability of the bacteria and crude bioflocculants in industrial applicability were evaluated using synthetic wastewater of copper ion (Cu(II)) and lead ion (Pb(II)). Effect of factors such as pH of synthetic wastewater, initial metal ion concentration and volume/amount of culture broth/crude bioflocculants were considered in determination of Cu(II) and Pb(II) removal in synthetic wastewater using bacteria and crude bioflocculants. The best Cu(II) removal (54.63 %) and Pb(II) removal (71.35 %) was shown by crude bioflocculants SC-F3 and SC-F1, respectively. Culture broth of bacteria and crude bioflocculant showed similar ability in removal of Cu(II) and Pb(II) in synthetic wastewater. Pb(II) removal by crude bioflocculants (SC-F1 and SC-F3) and alum was compared. It revealed that crude bioflocculant was more effective than alum to remove Pb(II) at low initial metal ion concentration (10 mg/L) in synthetic wastewater.
Description
Master
Keywords
Biological Science , Bioflocculant , Synthetic wastewater