Copper removal from sludge permeate with ultrafiltration membranes using zeolite, bentonite and vermiculite as adsorbents

• Published in: Water science and technology 2010-01, Vol.61 (3), p.581-589
• Main Authors: Malamis, S, Katsou, E, Stylianou, M, Haralambous, K J, Loizidou, M
• Format: Article
• Language: English
• Subjects: Activated sludge; Adsorption; Air; Aluminum Silicates; Bentonite; Capacity; Copper; Copper - isolation & purification; Exchange capacity; Fouling; Hydrogen-Ion Concentration; Industrial Waste; Industrial wastes; Industrial wastewater; Membrane processes; Membranes; Minerals; Removal; Sewage - analysis; Sludge; Ultrafiltration; Ultrafiltration - instrumentation; Ultrafiltration - methods; Vermiculite; Vermiculites; Waste Disposal, Fluid - methods; Wastewater; Wastewater treatment; Water Pollutants, Chemical - isolation & purification; Zeolites
• ISSN: 0273-1223; 1996-9732
• DOI: 10.2166/wst.2010.859

The aim of this work is to examine copper removal from sludge permeate with the use of low-cost minerals of Mediterranean origin combined with ultrafiltration membranes. The minerals used were zeolite (clinoptilolite), bentonite and vermiculite. Activated sludge was enriched with 0.01 N (317.7 ppm) of Cu(II). Fixed concentrations of minerals were added to sludge and the pH value was adjusted at 5.5. The mixture was agitated for 2 hours at 800 rpm at room temperature and was then filtered through a batch ultrafiltration system for 1 hour. This experiment was repeated, for comparison purposes, with sludge enriched with 0.01 N of Cu(II) with no mineral addition. The results showed that ultrafiltration membranes with no mineral addition were able to remove a significant amount of copper with removal efficiencies ranging from 59.4-78.3%. The addition of 10 g/l and 20 g/l of bentonite combined with ultrafiltration membranes resulted in removal efficiencies of 94.9% and 99.4% respectively and that of 10 g/l and 20 g/l of vermiculite in removal efficiencies of 93.8% and 96.8%, respectively. The ion exchange capacity of minerals followed the order bentonite > vermiculite > zeolite. Furthermore, membrane fouling was investigated. The addition of zeolite and bentonite reduced membrane fouling, while the addition of vermiculite did not impact on fouling. The use of low-cost minerals in combination with ultrafiltration membranes can be employed to treat industrial wastewater, resulting in a final effluent with very low copper concentrations.