Sentence:  Whereas the usual organic surface-active agent is strongly sorbed at oil-water interfaces , the highly <WSD>charged</WSD> ions are most strongly sorbed at interfaces between water and insoluble materials exhibiting an ionic structure ( see Table 26 - 2 on p. 1678 ) . 
Meaning of the word marked with <WSD> tags:  of a particle or body or system; having a net amount of positive or negative electric charge