Investigation on Changes in Physical and Technological Properties of Water Soluble Sizing Agents During the Ultrafiltration Process. Part I: Ultrafiltration of Hydroxy Propyl Starch

Abstract

The effect of ultrafiltration (UF) operation on the stability of a sizing agent based on starch has been studied. Hydroxypropyl starch (HPS) has been used as a water soluble modified starch. The investigation was carried out in two categories: effect of UF time (the concentration of the solution was kept constant by recirculating the permeate), and raising the concentration by discharging the permeate. The changes in the HPS solution properties were assessed by investigating the rheological properties (apparent viscosity as a function of filtration time, temperature and activation energy of flow) and molecular properties (Infra‐Red spectroscopy (IR), number of average molecular weight (Mn) and molecular weight distribution). The investigation was carried out on HPS solutions before, after and during the ultra‐filtration process. The results indicated that some degradation takes place during UF process.

Fractionation of dextran solutions by cross‐flow filtration

“…In a dextran balance, a significant increase of dextran with an intermediate (2 -20 kD) molecular weight in the retentate can be seen. This could be due to the increase of viscosity that produces a less turbulent flow and decreases the mass transfer coefficient and the diffusivity [4], and the force balance between the steric repulsion of the solute that increases with the molecular weight and the attraction between the solute and the membrane [5], as well as the separation of molecule aggregates because of stress shears during the process, resulting in the physical decreasing of the molecular weight [6]. From these data the membrane rejection was calculated.…”

Decolorisation of effluent with ozone and re-use of spent dyebath

“…Various separation techniques including microfiltration, nanofiltration, ultrafiltration and reverse osmosis have been applied in the textile industry for the recovery of sizing agent from effluent [37][38] and some of these methods have also been investigated for colour removal. Among them, microfiltration is no use for wastewater treatment because of its large pore size, and the other separation systems have very limited use for textile effluent treatment.…”