Water purification using porous ceramics prepared by recycling volcanic ash and waste glass

Abstract

Abstract Water purification was examined using porous ceramics prepared by sintering a powder mixture of volcanic ash, waste glass and a small amount of wood charcoal. The porous ceramics had cross-linked 3D-channels of which the diameter ranged from several nm to several μm. Three kilograms of porous ceramics placed in 90 L of circulating artificial seawater, in which several tropical fishes were actually living under aeration, caused a decrease in COD from 23.8 to 13.1 mg L−1 in a week. The number of coliform bacteria was almost constant in a range of 52–65 mL−1 despite that a lot of excrements were discharged frequently. The number of the coliform bacteria in the seawater examined “without the tropical fishes” decreased from 900 to 1 mL−1 in 2 weeks, and COD decreased from 37.9 to 7.9 mg L−1. It proved that several aerobic bacteria proliferating in the macropores inside the porous ceramics could effectively decompose several organic materials. Graphical abstract

Keywords

• Water purification
• Porous ceramics
• Recycling
• Volcanic ash
• Waste glass
• Mössbauer spectroscopy