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

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.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Environ Engr in Civil Engr

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2012

Author dc:creator

• Renkens, Tennie

Contributors dc:contributor

• Mariñas, Benito J.

• reverse osmosis membrane
• fouling
• halogenation

Statement dc:rights

• Copyright 2012 Tennie Renkens

Language dc:language

en

Handle dc:identifier

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

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/31985