Is a triple divorce effected by saying "You are divorced, divorced, divorced" in a text message, bearing in mind that a previous divorce occurred during a period of purity in which the wife was intercoursed?

The first pronouncement of divorce (talaq) is effective. The consideration then shifts to the three pronouncements. The written form of divorce is an indirect expression (kinayah), thus it does not take effect unless there is an intention (niyyah). Assuming the intention of divorce, the husband's statement to his wife, "You are divorced, divorced, divorced," results in a single pronouncement of divorce, unless the husband intended all three, in which case three take effect. If you intended divorce but did not intend three pronouncements, then it is permissible for you to take your wife back after the expiry of her 'iddah (waiting period) with a new marriage contract. Anger does not prevent the occurrence of divorce.