By using different flocculant concentrations and temperatures with a tannin‐based flocculant, chitosan, and ferric chloride, the performance of a combined flocculation and membrane separation process in microalgal suspensions was evaluated. Permeate flux experiments were conducted for 30 min, and the effects of the flocculant concentration and temperature were analyzed. The zeta potential of the culture with and without flocculant approached zero with increasing temperature, in favor of microalgal cell agglomeration. At 40 °C, crossflow microfiltration showed a 27 % improvement in the permeate flux compared to 20 °C. Overall, the results showed a significant potential use of flocculants with increasing temperature, by providing considerably higher permeated fluxes.

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The ever growing demand of energy generation and distribution has been one of the concerns of governments and the focus of research institutions.  Likewise, how to supply the energy demands necessary for the development of nations having the lowest environmental impact possible has also been studied. Biofuels have been pointed out as an alternative for that energy challenge, since their use reduce the carbon footprint of industries and vehicles. Biofuels can be obtained from microalgae with the advantage of not competing for space with corn, sugar cane or other crops for food industry. Even though attractive, the biofuel production from microalgae presents some challenges, as for example the separation process required to obtain microalgae biomass. The culture is very diluted and the dewatering must be efficient, low cost and cause no damage to the cell. With the intent to address this issue, the herein paper presents a study of an alternative way to increase flocculation efficiency according to the temperature of the culture with the potential to improve the filtration efficiency in a continuous process. An increasing in the flocculation temperature from 20°C to 60°C increased the flocculation efficiency from 97.79% to 98.64%, using ferric chloride as a flocculant agent.