Photosensitive composition

摘要

A method for combating Gram positive and/or Gram negative bacteria in water involves contacting the contaminated water with a photosensitiser (I) of the tetrapyrrole and/or tetraazapyrrole series carrying at least one positive charge, then irradiating with electromagnetic radiation. Also claimed are (i) the use of (I) for treating water containing bacteria and (ii) a composition comprising (I) and a solid carrier (preferably a polymer).