Wastewater Treatment Using Novel Impregnated

Membranes in Forward Osmosis

CE 498 Undergraduate Research

Ananthan BalachandranMay 8th, 2015

Presentation Outline• Objective • Introduction of forward osmosis in wastewater treatment• Type of membranes

• TFC membrane, SW30 XLE membrane & impregnated membrane

• Structure difference of membranes• Research apparatus of forward osmosis• Result

• Data for commercial membrane• Data comparison

• Discussion • Conclusion

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Objective• Currently, the commercial membrane structure

is thin film composite membrane which has larger water transport resistance because of the thickness.

• To determine whether the impregnated membranes are suitable for the wastewater treatment using forward osmosis.

• To determine the water flux and salt rejection of the impregnated membranes in forward osmosis.

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Introduction• Water becoming an scarce resource due to population growth &

economic development• Lack access to clean water

• Methods of water filtration & purification • Forward osmosis.

• Forward osmosis uses a semi-permeable membranes to get portable water from the seawater.

• The driving force of forward osmosis is osmotic pressure difference between draw & feed solutions.

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Figure 2: Forward osmosis process

Figure 1: Water

Filtration

APEC Water System. (2013). A Complete Resource Guide on Osmosis. Retrieved from Free Drinking Water: http://www.freedrinkingwater.com/resource-a-complete-resource-guide-to-osmosis.htm

Types of membranes used in Forward Osmosis

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Figure 3: TFC membrane(Commercial Membrane)

Figure 5: Impregnated Membrane

Figure 4: SW30 XLE membraneReverse Osmosis Membrane

Thickness of the impregnated membrane & commercial membrane

a) Impregnated membrane

b) Commercial membrane

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Research apparatus for forward osmosis

B

DE

AC

Figure 6: Schematic of forward osmosis membrane test apparatus

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Coat the polymer on both side of the support, using ethyl alcohol as the solvent

Method to prepare impregnated membrane

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Result

Total Time (min)

Salt Rejection (%)

Water Flux (LMH)

Salt Flux (gMH)

50 98.6 10.71 7.93

60 98.7 11.57 7.84

95 99.0 11.14 5.85

130 98.9 11.27 5.86

Theoretical Flux : 75.5 LMH

Experimental Flux : 11.1 LMH

Performance Ratio : 0.15

TFC Membrane from HTI ( Commercial Membrane)

Table 1: Data of TFC Membrane in Forward Osmosis

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Result

Type of membranesWater Flux

(LMH/bar)

Expected Water

Flux (LMH/bar)

Salty Water Flux

(LMH/bar)Performance Ratio Salt Rejection (%)

TFC 0.23 1.54 N/A 0.15 98.9

SW30 XLE 0.05 1.47 N/A 0.04 99.0

80 PEGDA 20

Ethanol0.05 0.28 0.23 0.23 95.3

60 PEGDA 40

Ethanol0.08 0.41 0.31 0.25 96.8

Comparison Between The Membranes

Table 2: Data comparison between commercial membrane, RO membrane and impregnated membrane

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Discussion

• Water flux & salt flux in impregnated membrane is lower because of concentration polarization.

-decrease the driving force

• The absolute water flux of impregnated membrane is lower than the commercial membrane.

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Conclusion

• Impregnated membrane has higher performance ratio and acceptable salt rejection although water flux is lower

• The novel impregnated membrane has higher efficient in forward osmosis in wastewater treatment

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Questions?