Deep Application and Technical Analysis of Activated Clay in the Food Industry

1. Material Characteristics and Mechanism of Action

Activated Clay (Activated Clay) is a functional material obtained by acid activation of montmorillonite, a layered silicate. It plays an indispensable role in the food processing field. Its typical physicochemical parameters include:

- SiO₂ content: 60-70%

- Al₂O₃ content: 15-20%

- Specific surface area: 100-300 m²/g (BET method)

- Pore size distribution: 2-50 nm (mainly mesopores)

- Free acid content: 0.1-0.5%

- Cation exchange capacity: 60-120 mmol/100g

Activated Clay mainly functions through three mechanisms in food processing:

1) Physical adsorption: It retains impurity molecules by relying on its developed pore structure (pore volume ≥ 65%);

2) Chemical adsorption: It catalyzes the decomposition of undesirable components through surface acidic sites;

3) Ion exchange: The interlayer can exchange cations and replace metal ions.

Laboratory studies have confirmed that the optimized activated clay can adsorb 120 mg/g of phospholipids in oil and remove more than 90% of aflatoxin B1.

2. Main Application Areas and Technical Indicators

2.1 Edible Oil Refining

Activated Clay performs exceptionally well in the oil decolorization process:

Decolorization efficiency: Red value reduction rate ≥ 80% (measured at 450 nm)

Adsorption selectivity: Phospholipid adsorption capacity 80-150 mg/g

Process adaptability: Working temperature 90-110℃

Economy: Dosage 0.5-3% (oil-based)

Data from a soybean oil refining plant show that after using a specific type of activated clay:

- Decolorization time is shortened by 30%

- Activated clay consumption is reduced by 25%

- Product oil peroxide value ≤ 5 mmol/kg

- Phospholipid residue ≤ 10 ppm

2.2 Sugar Juice Purification

Key parameters of activated clay in sugar production processes:

- Color reduction: ICUMSA value reduction 40-60%

- Ash removal rate: 25-35%

- Polysaccharide retention rate: ≥ 95%

- Optimal pH range: 5.0-6.5

Comparative tests show that compared with traditional carbonic acid method:

- Process flow is shortened by 50%

- Energy consumption is reduced by 40%

- Sugar loss is reduced by 2-3 percentage points

3. Technical Advantages and Innovation Directions

3.1 Performance Advantage Matrix

| Evaluation Dimension | Activated Silica | Activated Carbon | Diatomite | Molecular Sieve |

| Specific Surface Area (m²/g) | 100-300 | 800-1200 | 20-60 | 400-800 |

| Selective Adsorption | Excellent | Average | Good | Excellent |

| Cost Index | 1.0 | 3.5 | 0.8 | 5.0 |

| Regeneration Performance | Can be recycled 3-5 times | Can be recycled 5-8 times | Not possible | Can be recycled 10 times |

| Food Safety | Excellent | Good | Excellent | Good |

3.2 Technological Innovation Trends

1) Precise Activation Technology: Control the acid concentration (15-30%), temperature (90-110°C), and time (2-4 hours) as the three key factors to develop a targeted activation process;

2) Composite Modification Technology: Enhance specific adsorption capacity through metal ion (Fe³⁺, Zn²⁺) intercalation or organic modification;

3) Nano-Structure Regulation: Construct a mesoporous - macroporous hierarchical structure to improve mass transfer efficiency;

4) Green Regeneration Technology: Develop a combined process of low-temperature (<200°C) thermal regeneration and chemical regeneration.

4. Typical Application Case Analysis

4.1 Edible Vegetable Oil Refining Project

Technical transformation of a 100,000-ton soybean oil enterprise:

- *Process Parameters:

- Active white soil model: AC-300 (decolorization rate ≥ 85%)

- Dosage: 1.2% (combined with 0.3% activated carbon)

- Operating temperature: 105 ± 2°C

- Contact time: 25 minutes

- Implementation Results:

- Decolorization efficiency increased by 40%

- Trans fatty acid production < 1%

- Active white soil consumption reduced by 30%

- Certified by ISO 22000

5. Quality Control and Safety Standards

5.1 Food Grade Quality Standards

- **Physical and Chemical Indicators**:

- Moisture ≤ 12%

- Free acid ≤ 0.3%

- Total heavy metal content ≤ 20mg/kg

- Arsenic content ≤ 3mg/kg

- Microbial requirements:

- Colony count ≤ 1000 CFU/g

- Escherichia coli: Not detected

- Mold: ≤ 50 CFU/g

5.2 Application control points

1) Pre-treatment requirements:

- Activation temperature control (105 ± 5℃)

- Moisture regulation (8 - 10%)

- Particle size screening (200 - 400 mesh)

2) Process monitoring:

- Online pH monitoring (4.5 - 6.5)

- Contact time control (20 - 40 minutes)

- Temperature fluctuation range (±2℃)

3) Post-treatment specifications:

- Solid-liquid separation efficiency ≥ 99.5%

- Residue detection (< 50 ppm)

- Equipment cleaning cycle ≤ 24 hours

6. Industry development trend

6.1 Market prospect forecast

Global market size: Reach 850 million US dollars in 2025 (CAGR 6.2%)

Application structure change:

- Oil refining accounting for 45%

- Alcoholic beverages rising to 30%

- Expansion of emerging application fields by 25%

- Low consumption (< 0.8% addition amount)

- High selectivity (targeted adsorption)

- Intelligence (online monitoring and regulation) 

7. Conclusions and Recommendations

As an important processing aid in the food industry, the future development of active white soil should focus on:

1) Development of high-performance products:

- Prepare macroporous active white soil (with pore size > 10nm) through column-supported modification

- Develop organic-inorganic hybrid materials to enhance adsorption selectivity

- Research on bio-template methods to prepare biomimetic structural materials

2) Process optimization directions:

- Establish an activated process control system based on big data

- Develop micro-interface reaction enhancement equipment

- Optimize compounding techniques (in collaboration with molecular sieves and activated carbon)

3) Industry standard recommendations:

- Develop specific standards for food-grade active white soil

- Establish a full life cycle safety assessment system

- Improve application technical specifications (GMP standards)

As the food industry moves towards higher quality, the application of active white soil will place greater emphasis on precision, greenness, and intelligence. It is recommended that the upstream and downstream of the industry strengthen collaborative innovation, focus on breaking through key material technologies and equipment bottlenecks, and promote overall technological upgrading in the industry. It is expected that the market penetration rate of new active white soil products in the high-end food processing field will increase to over 40% in the next five years.