| Share | Phrase |
|---|
| 16.54% | remove impurity [perform operation] |
| 12.05% | unavoidable impurity |
| 10.97% | volatile [time periodicity] impurity |
| 5.76% | contain impurity [perform operation] |
| 5.52% | filter impurity [perform operation] |
| 4.59% | adsorbing [physical/chemical] impurity |
| 4.42% | impurity concentration |
| 3.94% | impurity removal |
| 3.87% | acidic [physical/chemical] impurity |
| 3.81% | gaseous [state] impurity |
| 3.78% | accumulated [increase] impurity |
| 3.66% | oxidize impurity [perform operation] |
| 3.65% | solid [state] impurity |
| 3.13% | evacuate impurity [perform operation] |
| 2.52% | impurity in fuel |
| 2.51% | particle impurity |
| 2.18% | liquid [state] impurity |
| 2.14% | separate impurity [perform operation] |
| 1.79% | find impurity [perform operation] |
| 1.47% | water impurity |
| 0.82% | cause impurity [perform operation] |
| 0.76% | prevent impurity [perform operation] |