Adsorption purification is critical to edible oil purity, stability, and flavor. Traditionally, diatomaceous earth and activated bleaching clay dominated due to low cost, but suffered from poor selectivity, high oil loss, and contamination risks. In recent years, food-grade silica has emerged as a preferred adsorbent for high-end oil production and green refining, thanks to its unique physicochemical properties. It delivers irreplaceable advantages in degumming, decolorization, and impurity removal, driving the industry toward efficiency, quality, and environmental sustainability.

Traditional degumming with diatomaceous earth or clay requires high-temperature water washing, involving multiple acid/alkali rinses. This consumes substantial energy and generates large volumes of oil-containing wastewater with high treatment costs. Silica’s "silica-based degumming" technology revolutionizes this process: its porous structure and surface polarity enable targeted adsorption of phospholipids and soaps. With only 0.2%-0.4% moisture retained in oil, impurities are removed directly via centrifugation or filtration—no additional water washing needed.

Experimental data shows R92-type silica achieves 99.6% phosphorus removal in rapeseed oil refining, far outperforming traditional clay. The final phosphorus content drops below 5ppm, meeting physical refining requirements. This anhydrous process eliminates water-washing centrifuges, reduces energy consumption by over 30%, and achieves zero wastewater discharge, aligning with green low-carbon trends in the food industry.

Unlike the "broad-spectrum adsorption" of diatomaceous earth/clay (which causes loss of beneficial oil components), silica’s high specific surface area (300-500m²/g) and controlled porous structure enable "selective adsorption—retaining nutrients while removing impurities."

Traditional clay adsorption operates at high temperatures, over-removing pigments and depleting natural flavors/nutrients—contradicting the "moderate refining" concept. Silica’s low-temperature adsorption (30-60℃) and gentle mechanism preserve oil’s natural value while deep impurity removal.

Studies confirm:

Silica not only performs independently but also synergizes with traditional adsorbents:

Food-grade silica (amorphous SiO₂ ≥96% purity) meets China’s GB 2760, US FDA, and other global standards. Its heavy metal content is well below national limits. Chemically stable under refining temperatures and pH conditions, it does not react with oil or accumulate in the human body—residue in finished oil is nearly undetectable.

In contrast, some traditional clays may introduce trace heavy metals or earthy odors (increasing deodorization burden). Silica is odorless, avoiding secondary flavor impacts and ensuring product consistency.

The shift from diatomaceous earth/clay to food-grade silica represents progress in technology and response to the industry’s demand for quality, efficiency, and sustainability. Silica’s anhydrous degumming, precise adsorption, nutrition retention, and cost-saving benefits make it the preferred choice for high-end oil refining, specialty oil processing, and recycled oil purification. With ongoing technological innovation, silica will be more widely applied, delivering safer, more nutritious, and flavorful edible oils while driving the industry toward high-quality development.