Experimental investigation on the performance of air–gap diffusion distillation with foamed ceramics

•The foamed ceramic (FC) was selected as hot stream channel of air–gap diffusion distillation (AGDD).•The influence of structure and operation parameters was experimentally discussed.•The effect of different FCs with different pretreatment on water productive flux was compared.•The desalination rate of AGDD with three different FCs is higher than 99.1%.•ZrO2 FC has a stable water production flux and desalination rate under long-term operation conditions.