Experimental analysis of a gel layer in dead-end ultrafiltration of a silica suspension

Unstirred dead-end ultrafiltration of a silica suspension was studied using a fully retentive membrane. A constant pressure filtration approach was used to analyze steady-state flux data. The effects of operating conditions such as applied pressure and bulk concentration on specific resistance, thickness, porosity and silica concentration of gel are reported. The specific resistance was obtained from the flux data while the Kozeny-Carman equation was used to determine the silica gel porosity for subsequent calculation of concentration of silica on a deposited layer. Further, experimental verification of time-invariant flux of earlier theoretical work is also presented. Gel concentrations and thickness estimated by utilizing the procedure described in this work were found to be within 1-12% of experimentally determined values.