Fouling of a ceramic microfiltration membrane by corn starch hydrolysate

The effect of operating parameters on fouling of a ceramic microfiltration membrane by corn starch hydrolysate of 95 dextrose equivalence was studied. Transmembrane pressures above 100 kPa had little or no effect on flux. Cross-flow velocity had a significant beneficial effect. The rate of flux decline was reduced significantly when the feed was adjusted from its natural pH of 4.2 to 10. However, this resulted in a dark brown clarified syrup (permeate). Scanning electron microscopy showed extensive fouling layers on the alumina surface with conventionally processed dextrose solutions and the least fouling layer with corn starch hydrolysate adjusted to pH 10. Maximum steady state flux for unconcentrated hydrolysate at its natural pH was 178 LMH obtained at low transmembrane pressures (103 kPa, 15 psi) and high cross-flow velocities (5 m s⁻¹). Adjustment of the pH to 10 can increase the flux by 40%.