Flocculation of microalgae with cationic polymers — Effects of medium salinity

Bilanovic, Dragoljub; Shelef, G.; Sukenik, Assaf

doi:10.1016/0144-4565(88)90071-6

Cited by 145 publications

(85 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Tenney et al (1969) and Tilton et al (1972) have demonstrated that the bridging mechanism also applies to flocculation of algal cells. Cationic polymers doses of between 1 and 10 mg ml À 1 can induce flocculation of freshwater algae; however, a high salinity of the marine environment can inhibit flocculation by polyelectrolytes (Bilanovic et al, 1988). Effective flocculation with polyelectrolytes has been reported at salinity of less than 5 kg m À 3 (cf.…”

Section: Flocculationmentioning

confidence: 99%

“…The effect of ionic strength on efficiency of cell removal by flocculation with commercial polymers. The polymers tested included the cationic chitosan (400 kDa molar mass), Zetag 63 (a cationic polyacrylamide of 10,000 kDa molar mass) and Zetag 92 (a cationic polyacrylamide of 20,000 kDa) (Bilanovic et al, 1988). not affect flocculation behavior (Tilton et al, 1972).…”

Section: Flocculationmentioning

confidence: 99%

See 1 more Smart Citation

Recovery of microalgal biomass and metabolites: process options and economics

Grima

Belarbi

Fernández

et al. 2003

Biotechnology Advances

1,892

705

View full text Add to dashboard Cite

Commercial production of intracellular microalgal metabolites requires the following: (1) largescale monoseptic production of the appropriate microalgal biomass; (2) recovery of the biomass from a relatively dilute broth; (3) extraction of the metabolite from the biomass; and (4) purification of the crude extract. This review examines the options available for recovery of the biomass and the intracellular metabolites from the biomass. Economics of monoseptic production of microalgae in photobioreactors and the downstream recovery of metabolites are discussed using eicosapentaenoic acid (EPA) recovery as a representative case study. D

show abstract

Section: Flocculationmentioning

confidence: 99%

Section: Flocculationmentioning

confidence: 99%

Recovery of microalgal biomass and metabolites: process options and economics

Grima

Belarbi

Fernández

et al. 2003

Biotechnology Advances

1,892

705

View full text Add to dashboard Cite

show abstract

“…A significant issue that was not addressed in the present project, but that has been addressed previously is the role of salinity in the effectiveness of various flocculants. Sukenik et al [2] studied the effect of salinity and ionic strength on inorganic flocculants and inorganic flocculants combined with cationic polymers (see [15] for a related study focusing on cationic polymers). In saline waters with ionic strength of approximately 0.7 M the required dosage for FeCl 3 and Al 2 (SO 4 ) 3 was five to ten times higher (higher required dosage for motile algae) than for freshwater species.…”

Section: Flocculation With Inorganic Saltsmentioning

confidence: 99%

“…Figure 21 shows the early growth under shear with the collision kernels evaluated from Eq. (15). The growth is expressed as one less than the average floc size following the discussion in Sec.…”

Section: Floc Growth With the Sectional Modelmentioning

confidence: 99%

First-principles flocculation as the key to low energy algal biofuels processing.

Hewson¹,

Wyatt²,

Pierce³

et al. 2012

View full text Add to dashboard Cite

This document summarizes a three year Laboratory Directed Research and Development (LDRD) program effort to improve our understanding of algal flocculation with a key to overcoming harvesting as a techno-economic barrier to algal biofuels. Flocculation is limited by the concentrations of deprotonated functional groups on the algal cell surface. Favorable charged groups on the surfaces of precipitates that form in solution and the interaction of both with ions in the water can favor flocculation. Measurements of algae cell-surface functional groups are reported and related to the quantity of flocculant required. Deprotonation of surface groups and complexation of surface groups with ions from the growth media are predicted in the context of PHREEQC. The understanding of surface chemistry is linked to boundaries of effective flocculation. We show that the phase-space of effective flocculation can be expanded by more frequent alga-alga or floc-floc collisions. The collision frequency is dependent on the floc structure, described in the fractal sense. The fractal floc structure is shown to depend on the rate of shear mixing. We present both experimental measurements of the floc structure variation and simulations using LAMMPS (Large-scale Atomic/Molecular Massively Parallel Simulator). Both show a densification of the flocs with increasing shear. The LAMMPS results show a combined change in the fractal dimension and a change in the coordination number leading to stronger flocs. 4 ACKNOWLEDGMENTSThis program to improve our understanding of algal flocculation and harvesting was initiated through the Laboratory Directed Research and Development (LDRD) program, and the authors of this report are indebted to many people for their continued support. We have benefited in particular from the braider understanding of the bioenergy landscape provided by Ron Pate,

show abstract

“…This method of solid-liquid separation is preferred for harvesting large cells like microalgae due to its low costs compared to other methods such as centrifugation and filtration . The flocculation efficiency of microalgae can be improved by the use of flocculants (Tilton et al, 1972;Bilanovic et al, 1988). Flocculation occurs when solid particles aggregate into large but loose particles resulting from the interaction of the flocculants with the surface charge of the suspended solid and subsequent coalescing of these aggregates into large flocs that settle out of suspension (Knuckey et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Effect of different flocculants on the flocculation performance of microalgae, Chaetoceros calcitrans, cells

Harith¹,

Yusoff²,

Mohamed³

et al. 2009

Afr. J. Biotechnol.

View full text Add to dashboard Cite

The possibility of using flocculation technique for the separation of microalgae, Chaetoceros calcitrans, biomass from the culture broth was investigated. The flocculation experiments were conducted in 500 mL beaker using culture broth obtained from 10 L photobioreactor. The harvesting efficiency of 90 and 60% was obtained in flocculation without flocculants conducted for 10 days at 27ºC (in light and dark) and 4ºC (dark), respectively. Harvesting efficiency higher than 90% with short settling time was achieved by adjusting the culture pH to 10.2 using either sodium hydroxide (NaOH) or potassium hydroxide (KOH). Improved cell viability (> 80%) and settling time with a slight improvement of flocculation efficiency was achieved by the addition of polyelectrolytes flocculant (Magnafloc ® LT 27 and LT 25). However, the flocculants were only functioned when the pH of the microalgae culture was pre-adjusted to a certain value that promotes cells entrapment and surface charge neutralization prior to flocculation process. The flocculation efficiency and cell viability obtained in flocculation with Magnafloc ® (LT 25 and LT 27) was comparable to that obtained in flocculation with chitosan. When chitosan and Magnafloc ® (LT 25 and LT 27) were used as flocculants, the highest flocculation efficiency of C. calcitrans cells was observed at pH 8 and 10.2, respectively. Substantial increased in sedimentation rate was observed with increasing flocculants dosage though the flocculation efficiency and cell viability were not significantly varied.

show abstract

Flocculation of microalgae with cationic polymers — Effects of medium salinity

Cited by 145 publications

References 7 publications

Recovery of microalgal biomass and metabolites: process options and economics

Recovery of microalgal biomass and metabolites: process options and economics

First-principles flocculation as the key to low energy algal biofuels processing.

Effect of different flocculants on the flocculation performance of microalgae, Chaetoceros calcitrans, cells

Contact Info

Product

Resources

About