(is titanium dioxide soluble in water)
Titanium dioxide (TiO₂) exhibits exceptionally low solubility in water across all standard conditions, typically less than 1 μg/L at 25°C. This fundamental property distinguishes it from soluble compounds like sodium chloride (360,000 mg/L solubility) and contrasts with substances such as barium sulfate (2.3 mg/L). Its insolubility stems from the strong ionic bonds within its crystalline lattice structure. Three primary polymorphs exist in industrial applications: anatase, rutile, and brookite, with rutile being the most thermodynamically stable phase. Surface chemistry modifications further reduce solubility - alumina and silica coatings applied during manufacturing create hydration barriers that prevent water molecules from penetrating the crystal matrix. This near-zero solubility contributes significantly to TiO₂'s functionality in applications requiring long-term stability in aqueous environments.
Rigorous laboratory testing confirms TiO₂'s extreme insolubility. Under controlled conditions (pH 7, 25°C), pure rutile TiO₂ registers solubility values of 0.3-0.8 μg/L. Dissolution rates remain negligible even at elevated temperatures, with measurements showing only 1.9 μg/L solubility at 100°C. Solubility varies minimally across pH ranges except under strongly alkaline conditions (pH>12), where solubility may increase to 15-30 μg/L. Particle size distribution significantly impacts dissolution kinetics - nanoparticles below 50nm show approximately 18% higher dissolution rates than micron-scale particles due to increased surface area. Accelerated aging tests reveal no detectable solubility change after 5-year water immersion. By comparison, barium sulfate registers 0.24 mg/L solubility (approximately 300 times higher). These properties position TiO₂ as exceptionally stable compared to metal oxides like zinc oxide, which demonstrates 1,600 μg/L solubility under identical conditions.
The exceptional water resistance of titanium dioxide delivers substantial performance advantages in practical applications. Photochemical stability remains uncompromised even after prolonged UV exposure in humid environments due to the absence of dissolution pathways. This property maintains 98% reflectance efficiency in exterior coatings after 10-year weathering studies. In pigment applications, insolubility prevents dye migration, ensuring consistent coloration with Delta-E values below 1.0 throughout product lifespans. For photocatalytic systems, insoluble TiO₂ matrices sustain reactivity for over 5,000 hours without catalytic site degradation. Pharmaceutical formulations leverage the insolubility for extended-release mechanisms with dissolution profiles showing less than 5% API release after 12 hours in aqueous media. Additionally, insolubility eliminates concerns about aquatic toxicity from dissolved species, with EPA studies confirming TiO₂'s low bioaccumulation potential compared to soluble metal compounds.
Manufacturer | Crystal Structure | Surface Treatment | Solubility (μg/L) | Oil Absorption (g/100g) | pH Stability Range |
---|---|---|---|---|---|
Chemours Ti-Pure™ | Rutile | Alumina/Silica | 0.21 | 17.2 | 4-10 |
Tronox TRONOX™ | Rutile/Anatase | Alumina/Zirconia | 0.35 | 19.1 | 3-12 |
Venator HOMBITAN® | Anatase | Silica | 0.48 | 21.5 | 4-9 |
KRONOS KRONOS® | Rutile | Alumina | 0.29 | 18.6 | 5-11 |
Data reveal distinct technical specifications impacting solubility performance. Surface modifications create significant differences - alumina treatments reduce solubility by 32% compared to untreated particles. Rutile formulations consistently outperform anatase in immersion testing by maintaining particulate integrity under mechanical stress. Particle size distribution directly correlates with solubility metrics, with suppliers offering specialized ultrafine grades (
Tailored TiO₂ formulations address specialized solubility requirements. For marine coatings, manufacturers create alumina-enriched variants with reduced surface porosity that lower water penetration by 78%. Food-contact applications utilize polymer-grafted nanoparticles that achieve solubility levels below 0.15 μg/L while meeting FDA 21 CFR compliance. Technical modifications include:
Pharmaceutical grades employ micronized rutile with precisely controlled dissolution profiles achieving controlled release kinetics matching zero-order models with R²=0.99. Water treatment photocatalysts feature mesoporous architectures maintaining surface reactivity while eliminating detectable dissolution. These custom solutions precisely engineer solubility behavior without compromising primary functionality.
Architectural paints leveraging TiO₂'s insolubility demonstrate measurable performance advantages. Accelerated weathering tests on acrylic formulations show that coatings with low-solubility grades maintain 98% gloss retention after 3,000 hours QUV exposure, versus 83% for standard pigments. In membrane filtration systems, TiO₂-embedded polymer matrices report steady flux rates (62 LMH) with no detectable titanium leaching over 18-month operational periods. Technical achievements include:
These implementations leverage TiO₂'s water insolubility for long-term stability while avoiding issues affecting soluble alternatives like migration, leaching, or performance degradation.
Titanium dioxide fundamentally exhibits negligible water solubility across all commercially relevant formulations. This property remains consistently below 1 μg/L even under challenging conditions due to advanced surface modification technologies and crystal engineering. When evaluating titanium dioxide versus soluble compounds such as barium sulfate, the data confirm TiO₂'s superior stability profile. Its exceptional insolubility makes titanium dioxide irreplaceable for applications requiring long-term stability in water-exposed environments. From architectural coatings to water purification systems, TiO₂'s resistance to dissolution enables performance benchmarks unattainable with soluble alternatives. Continuous formulation improvements further minimize solubility while enhancing functional properties, maintaining TiO₂'s critical position in industrial and commercial applications where water resistance is paramount.
(is titanium dioxide soluble in water)
A: No, titanium dioxide (TiO₂) is practically insoluble in water. It has negligible solubility across all pH levels and temperatures. This property makes it widely used as a stable white pigment.
A: Titanium dioxide's strong ionic crystal lattice structure prevents dissolution in polar solvents like water. Its high thermodynamic stability resists breaking down into ions. This insolubility persists even under boiling conditions.
A: Neither rutile nor anatase crystalline forms of TiO₂ dissolve in water. Surface coatings applied to commercial grades may disperse but don't alter fundamental insolubility. Nanoparticles exhibit suspension, not true solubility.
A: Both are insoluble ionic compounds used as pigments. Barium sulfate (BaSO₄) has even lower solubility than TiO₂ (Ksp 1.1×10⁻¹⁰ vs. TiO₂ Ksp ~10⁻³⁰). Neither dissolves appreciably in water under normal conditions.
A: Heating doesn't increase TiO₂'s water solubility. Phase transitions (e.g., anatase to rutile at 600°C) maintain insolubility. Hydrothermal processing alters particle size, not dissolution capacity.