Changes in the structure of SW30HR RO membrane exposed to chloraminated seawater and synthetic solutions

Renkens, Tennie

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https://hdl.handle.net/2142/31985 Copy

Description

Title

Changes in the structure of SW30HR RO membrane exposed to chloraminated seawater and synthetic solutions

Author(s)

Renkens, Tennie

Issue Date

2012-06-27T21:23:10Z

Director of Research (if dissertation) or Advisor (if thesis)

Mariñas, Benito J.

Department of Study

Civil & Environmental Eng

Discipline

Environ Engr in Civil Engr

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• reverse osmosis membrane
• fouling
• halogenation

Abstract

Changes in the structure of the SW30HR RO membrane exposed to seawater, phosphate buffer, and standard seawater disinfected with monochloramine (NH2Cl) are investigated. Three types of experiments were performed: (1) exposure of RO membrane (active and support layers) to monochloramine (2, 20 and 200 mg/L as Cl2) and target proportional levels of iodide (0.06, 0.6 and 6 mg/L) or bromide (60, 600 and 6,000 mg/L) at constant exposure CT=384 mg×h/L; (2) exposure of support layer only to monochloramine at CT values of 1,000 and 30,000 mg×h/L at a monochloramine concentration of 200 mg/L as Cl2; (3) exposure of RO membrane (active and support layers) to monochloramine at CT values of 1,000, 5,000 and 30,000 mg×h/L at a monochloramine concentration of 200 mg/L as Cl2 in the presence of only 6 mg/L of iodide, only 6,000 mg/L of bromide, and both 6 mg/L of iodide and 6,000 mg/L of bromide. Results revealed that monochloramine may be reacting with the polysulfone support of RO membranes. RBS analyses have revealed that the RO membrane support might undergo damage. Recent work involves determining the effect of active layer-bound halogens on carboxylic group accessibility. Cesium (Cs+), silver (Ag+), and barium (Ba2+) were used as ion probes to quantify the changes associated with membranes exposed to three different batch reactor conditions (1) seawater with 2 ppm NH2Cl; (2) phosphate buffer with 2 ppm NH2Cl and 65 mg/L KBr as Br-; (3) standard seawater with 2 ppm NH2Cl and 65 mg/L KBr as Br-. Preliminary results indicate a shift in the pKa values of active layer carboxylic groups in batch reactors containing NH2Cl in comparison to control reactors.

Graduation Semester

2012-05

Permalink

http://hdl.handle.net/2142/31985

Copyright and License Information

Copyright 2012 Tennie Renkens

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