A well treatment material for introduction into a subterranean formation is provided. The well treatment material can include a biocide collected onto a sorbent. The biocide can be capable of being desorbed at a generally constant rate over an extended period of time into the subterranean formation. The biocide can be an oxidizing biocide or a non-oxidizing biocide. The sorbent material can include one or more of an absorbent material and an adsorbent material. The biocide can be chlorine dioxide. The sorbent can be one or more of silica gel and graphite.