Development of membranes from bacterial cellulose (nata de coco) for the separation of copper (II) ions using polyelectrolyte-enhanced ultrafiltration

Issue Date

3-2004

Abstract

Polyelectrolyte-enhanced ultrafiltration (PEUF) deals with membrane-based molecular separation wherein an ionic solute binds to a polyelectrolyte which is retained by the membrane. In the absence of the polyelectrolyte, the solute would permeate across the membrane. Two cellulose acetate (CA) membranes, both 0.30 mm thick and containing 25% by weight CA, were prepared from bacterial cellulose (nata de coco) via the phase-inversion method. The mean water flux values during ultra-filtration were 46.0 ± 1.5 L·m -2h-1 and 60.8 ± 2.2 L·m-2h -1 for membranes 1 and 2, respectively; corresponding values for the reduced water flux after the protein runs were 39.0 ± 1.0 L·m -2h-1.and 52.6 ± 2.2 L·m-2h -1. The protein rejection values for bovine serum albumin were 68.7% and 59.9% for membranes 1 and 2, respectively; corresponding values for α-amylase were 49.6% and 48.3%. Scanning electron microscopy revealed the surface structure of both CA membranes. The CA membranes were used to separate copper (II) ions from aqueous solution by PEUF using either polyethyleneimine (PEI) or carboxymethylcellulose (CMC) as polyelectrolyte. Copper rejection by the membrane was enhanced when the polyelectrolyte concentration was increased. The highest copper rejection was 87.96% for membrane 1 and 78.56% for membrane 2 at 0.050% PEI concentration. Total copper rejection was obtained at a CMC concentration of 0.050%. The performance of the prepared CA membrane was compared against commercial polyethersulfone (PES) membrane. At 0.025% PEI solution, copper rejection values were 67.26% and 91.97% using CA and PES membranes, respectively. Total copper rejection was obtained at 0.015% CMC using PES membrane; at this CMC concentration, only 73.78% of copper was removed using CA membrane.

Source or Periodical Title

Philippine Agricultural Scientist

ISSN

317454

Volume

87

Issue

1

Page

87-95

Document Type

Article

Language

English

Subject

Bacterial cellulose, Cellulosic membrane, Copper separation, Nata de coco, Polyelectrolyte, Ultrafiltration

Digital Copy

none

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