Using Avrami equation in the studies on changes in granulometric composition of algal suspension

Abstract

In recent years, it has been recognized that the laser diffraction gives valuable information on particle size distribution for all types of dry inorganic or even organic materials. With use of the laser diffraction and the laser granulometer, this paper presents the changes occurring in the granulometric distribution of algal agglomerates and the changes in values of percentiles 10, 50 and 90%, determined basing on volume distribution. While assessing the granulometric composition, the existence of a proportional relationship between the diameter values corresponding to the percentile of 10, 50 and 90% was observed. What is more, the obtained results give insight into the possibility of application of the general Avrami equation to describe the granulometric composition of the algal suspension through the analogy of crystals formation from saturated solutions. The analysis shows that the model described by the modified Avrami equation adequately matched the regression to the experimental data on the granulometric composition of algal suspensions. The values of the correlation coefficients were close to 1, which proves that the regression model explained nearly all cases by the dependent variable V i = F(d i ).

Analysis of Changes of Particle Size Distribution and Biological Composition of Flocs in Wastewater During the Growth of Algae

“…Researchers are searching for the relationship between the size of flocs and the growth of microalgae (Kuśnierz and Łomotowski 2015). The growth dynamics of algae determines the conditions of their cultivation and the harvesting method.…”

“…During their growth, microalgae concentrate in colonies. Thanks to the produced extracellular substances in the form of polymers, their adhesive properties increase (Kuśnierz and Łomotowski 2015;Fettweis et al 2014;Jarvis et al 2005). The process of algae combining to form larger aggregates can be initiated by a single cell to which other cells adhere as a result of turbulent motions in water.…”

“…The process of algae combining to form larger aggregates can be initiated by a single cell to which other cells adhere as a result of turbulent motions in water. That process can be described using the modified Avrami equation relating to the precipitation of solids from a solution (crystallisation process) (Bawiec et al 2018;Kuśnierz and Łomotowski 2015;Tran et al 2013). The Avrami model, introduced in 1940, assumes sphericity of precipitated particles and is based on two processes: nucleation and growth.…”

“…The Avrami model, introduced in 1940, assumes sphericity of precipitated particles and is based on two processes: nucleation and growth. Nucleation is responsible for the appearance of very small particles in the solution, the socalled crystallisation nuclei, which then grow as a result of combining with other particles, forming larger aggregates after a specific period of time (t) (Bawiec et al 2018;Kuśnierz and Łomotowski 2015;Tran et al 2013). According to Tran et al (2013), the Bnucleation-growth^mechanism can be successfully applied for the description of the phenomenon of biological colonisation.…”

“…The microscopic methods are effective and more accurate. However, they are complicated and time-consuming methods, and also require specialist knowledge in the field of phycology (Kuśnierz and Łomotowski 2015). Particle size distribution in the analysed material can be characterised on the basis of laser light dispersion with the use of a laser granulometer (Kuśnierz and Wiercik 2016).…”