Cu/Fe Bimetallic Modified Fly Ash: An Economical Adsorbent for Enhanced Phosphorus Removal from Aqueous Solutions

摘要

Excessive phosphorus in water causes eutrophication and leads to the ecological unbalance. The main treatment for eutrophication is to remove the phosphorus in aqua system effectively and efficiently. A composite of fly ash (FA) and metal compound was proposed as the effective sorbent for phosphorus removal, attributed to the active metal compositions and stable structure, as well as the wide source availability of economy. Copper and iron were co-precipitated as a bimetallic compound (BM), well adhered onto fly ash, to acquire the composite sorbent of Cu/Fe-BM@FA. Through the characterizations of XPS, FTIR etc., phosphorus adsorption was achieved mainly upon heterogeneous chemisorption and electrostatic attraction. Consequently, from pH 3 to pH 6, phosphorus of 98% on average was removed in solutions of 0 ～ 40 mg P/L, and the maximum adsorption capacity was up to 32.88 mg/g. Promisingly, the composite sorbent of FA and copper/iron bimetallic compound was a potential and economic selection for phosphorus removal.