Category Nuances for null:

• particulate,
• active,
• macromolecular,
• important,
• sophisticated,
• adsorbent,
• common,
• combustible,
• radioactive,
• solid,
• raw,
• interfering,
• chemical,
• expendable,
• costly,
• weak,
• commercial,
• analytical,
• heterogeneous,
• functional,
• binding,
• basic,
• auxiliary,
• sensitive,
• industrial,
• operational,

Simple Categories for null:

• polymer,
• waste,
• material,
• affinity,
• substance,
• substrate,
• solid,
• particle,
• matter,
• system,
• sorbent,
• component,
• mineral,
• resin,
• acid,