Particle formation and growth over the 1-40 μm size range in dilute aluminum solutions (approx. 2 × 10-4 M) have been studied using an electronic particle counter. Sulfate, fulvate and hydroxide ion accelerate the rate of particle formation and changes of the particle size distribution over time. Increasing ionic strength (inert electrolyte) produces similar but less dramatic effects. Combinations of sulfate and fulvic acid or sulfate and inert electrolyte further accelerate the rate of particle formation. Aluminum chloride solutions at moderate ionic strength are devoid of supramicron particles after several days. A conceptual pathway model is developed which suggests that two different solids are formed when aluminum is added to fulvic acid solutions: an aluminum-fulvate precipitate and Al(OH)2(s). The first solid dominates in fulvic acid solutions at pH ∼5.5.
ASJC Scopus subject areas
- Ecological Modeling
- Water Science and Technology
- Waste Management and Disposal