Effects of pH, Salinity, Biomass Concentration, and Algal Organic Matter on Flocculant Efficiency of Synthetic Versus Na
- PDF / 1,359,126 Bytes
- 11 Pages / 595.276 x 790.866 pts Page_size
- 54 Downloads / 163 Views
Effects of pH, Salinity, Biomass Concentration, and Algal Organic Matter on Flocculant Efficiency of Synthetic Versus Natural Polymers for Harvesting Microalgae Biomass Fabio Roselet 1 & Dries Vandamme 2 & Milene Roselet 1 & Koenraad Muylaert 2 & Paulo Cesar Abreu 1
# Springer Science+Business Media New York 2016
Abstract This study investigated the effects of pH, salinity, biomass concentration, and algal organic matter (AOM) on the efficiency of four commercial cationic flocculants. The tanninbased biopolymers Tanfloc SG and SL and the polyacrylamide polymers Flopam FO 4800 SH and FO 4990 SH were tested for flocculation of two microalgae models, the freshwater Chlorella vulgaris and the marine Nannochloropsis oculata. Both biomass concentration and AOM presence affected all polymers evaluated, whereas salinity and pH affected only Flopam and Tanfloc, respectively. A restabilization effect due to overdosing was only observed for Flopam polymers and increasing Tanfloc dose resulted in improved efficiency. Flopam polymers showed a significant decrease in the maximum quantum yield of photosystem II as function of polymer dose for Chlorella, which supported the need for toxicological studies to assess the potential toxicity of Flopam. In overall, Tanfloc was not affected by salinity nor presented potential toxicity therefore being recommended for the flocculation of both freshwater and marine species.
Keywords Coagulation . Flocculation . Biopolymer . Photosystem II . Toxicity
Fabio Roselet and Dries Vandamme contributed equally to this work * Fabio Roselet [email protected]
1
Laboratory of Microalgae Production, Institute of Oceanography, Federal University of Rio Grande-FURG, Av. Itália, Km 08, Rio Grande, RS 96201-900, Brazil
2
Laboratory for Aquatic Biology, KU Leuven Kulak, Etienne Sabbelaan 53, 8500 Kortrijk, Belgium
Introduction Harvesting is one of the major bottlenecks in large-scale microalgae production for biofuels and other low-value bioproducts [1]. According to Gudin and Therpenier [2], harvesting can comprise up to 30% of the total costs for biomass production. Harvesting costs are considered high, mainly because of the difficulty in concentrating the small-size microalgae cells (3–30 μm) present at relatively low concentrations in culture media ( 0.05; Fig. 1a– d). Both Flopam FO 4800 SH and FO 4990 SH are polymers substituted with quaternary ammonium functional groups with a degree of substitution of 80% and 100%, respectively. Cationic polymers with quaternary ammonium groups are salts of a strong base and therefore, according to Kam and Gregory [27], not subjected to loss of charge density, regardless of pH. Similarly, Graham et al. [28] reported that polyDADMAC, which has a degree of substitution of 90%, was permanently charged and insensitive to pH changes.
Bioenerg. Res.
Fig. 1 Effect of pH (5, 7, and 9) on Flopam (FO 4800 SH and FO 4990 SH) and Tanfloc (SG and SL) efficiencies. Experiments were run in freshwater (0 g sea salt L−1 for C. vulgaris) and marine (30 g sea
salt L−1 f
Data Loading...
