Metakaolin-Based Geopolymers for Removal of Ammonium from Municipal Wastewater

Abstract

A new geopolymer adsorbent based on papermill sludge was prepared in the form of powder and granules and its efficiency for removing ammonium nitrogen from aqueous solution was investigated using batch and column adsorption experiments. The geopolymer was characterized by XRD and XRF. During adsorption tests, an influence of contact time, initial concentration, and adsorbent concentration on ammonium nitrogen removal were studied with powdered form of material. The maximum adsorption capacity of adsorbent towards ammonium nitrogen removed from model solution was found to be 36 mg/g when the adsorbent dose was 2 g/L and pH 7.4, respectively. Synthetic water as well as municipal wastewaters pretreated by flocculation and sedimentation techniques were used in order to prove efficiency of material in a complex matrix. Results obtained indicate that the new geopolymer composition is a promising low-cost material for ammonium nitrogen removal. It has been shown over continuous column experiments that exhausted adsorbent granules could be regenerated with different regeneration agents.