Effect of Organic Matter and Pre-oxidation on Harvesting Algae Using Chitosan and PACl
| Autor: | Ramon Pranowo, 蔡力明 |
|---|---|
| Rok vydání: | 2011 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 99 This study aims to study the effects of two pretreatments processes, i.e. isolation and pre-oxidation, on algal suspension and its separation using coagulation-flocculation. Polyaluminium chloride (PACl) and chitosan are used as coagulant in this study. Characteristics of algae suspension after pretreatment are examined using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), zeta potential measurement, particle sizer, gel filtration chromatography (GFC), emission-excitation matrix (EEM), and wet chemical analysis, including turbidity, dissolved organic carbon (DOC), protein and polysaccharide. Results show that the presence of extracellular organic matter (EOM) decreases algae removal efficiency and increases coagulant demand. In terms of coagulant type, turbidity results show that chitosan has higher efficiency than PACl when used for original algae sample. However, PACl demonstrates better efficiency for isolated algae suspensions. Protein, polysaccharide, DOC, and EEM results confirm that organic matter is hardly removed during coagulation process. Pre-oxidation processes applied in this study include ozonation and combination of ozonation and H2O2. Both affect properties of algal suspension through mineralization of EOM, inactivation of algae cells, release of intracellular organic matter (IOM), and shift of molecular weight distribution to lower molecular weight range. Combination of ozonation and H2O2 provides better performance than ozone alone in enhancing separation efficiency due to stronger oxidation effect. Both turbidity and DOC removal efficiency after pre-oxidation are improved significantly. Judging from the increase in floc size after pre-oxidation, it is proposed that organic matter released after pre-oxidation can act as flocculant and results in enhanced flocculation via dual-flocculation during coagulation process. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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