Figure 9.

(a) Schematic of the mass flows into and out of the precipitate structure. Injection feeds cobalt chloride through the nozzle at the center; silicate ions are driven from the outer fluid and consumed in the precipitation reaction to form a membrane; the concentration gradient established across the membrane drives water into the structure through osmosis. (b) Density changes occur in the system: the reaction forms a precipitate product with a higher density than the liquid reactants, and the overall structure thus consists of the injected inner liquid and the precipitate product, with an effective density ρ_eff. The consumption of silicate ions in the reaction also leads to a decrease in the density of the outer fluid, which is assumed to be negligible here.