Controlling the ash content of coconut shell activated carbon primarily involves two key aspects: raw material selection and post-production processing. Ash mainly originates from inorganic minerals in the raw materials and residues from incomplete carbonization during the production process.

1. Raw Material Selection and Pre-treatment

Selecting High-Quality Coconut Shells: Prioritize high-quality coconut shells from tropical regions (such as Indonesia) that are free of mold and have few impurities. Inferior or contaminated coconut shells will introduce more ash, affecting the purity of the final product.

Raw Material Pre-treatment: Clean, screen, and dry the coconut shells to remove surface dirt, salt, and other soluble inorganic substances, reducing ash content from the source.

2. Production Process Control

Optimizing Carbonization and Activation Processes: The carbonization process requires controlled temperature and time to ensure uniform carbonization inside the coconut shell and avoid excessive surface carbonization that produces large amounts of ash powder. The activation stage (usually using steam or carbon dioxide) requires precise temperature (850–950℃) and time control to fully develop the pore structure while minimizing inorganic residue. 3. Controlling Carbon Particle Size: The carbonized material is crushed to a uniform particle size to prevent uneven activation or ash clogging of pores due to excessively fine particles.

3. Post-treatment Purification (Key Step)

Acid Washing: This is the most commonly used industrial method for reducing ash content. Activated carbon is soaked in dilute acid (such as hydrochloric acid or nitric acid) to dissolve the metal oxides (such as potassium, sodium, calcium, and iron), and then washed with water until neutral. This process significantly reduces ash content and improves product purity and adsorption performance.

Washing and Dehydration: After acid washing, thorough washing with water is necessary to remove residual acid and dissolved inorganic salts, followed by dehydration and drying to prevent secondary contamination.

Dust Removal: Fine dust generated during production is removed through physical methods such as sieving and airflow separation to improve product cleanliness.