Poly (N-isopropylacrylamide) microgel-based assemblies for organic dye removal from water

Area of Science:

• Materials Science
• Polymer Chemistry
• Environmental Science

Background:

• Poly(N-isopropylacrylamide)-co-acrylic acid (pNIPAm-co-AAc) microgels are thermoresponsive polymers.
• Microgel aggregates can be synthesized by polymerizing a cross-linker in the presence of microgels.
• Dye removal from water is a significant environmental challenge.

Purpose of the Study:

• To synthesize pNIPAm-co-AAc microgel aggregates.
• To investigate the dye removal efficiency of these aggregates for Orange II.
• To compare the performance of aggregates with unaggregated microgels.

Main Methods:

• Synthesis of pNIPAm-co-AAc microgel aggregates via N,N'-methylenebisacrylamide (BIS) polymerization.
• Testing dye removal efficiency at room and elevated temperatures.
• Evaluating the effect of thermal cycling and cross-linker concentration on removal efficiency.

Main Results:

• Microgel aggregates demonstrated enhanced removal of Orange II dye compared to unaggregated microgels.
• Removal efficiency increased with elevated temperature due to the thermoresponsive nature of the aggregates.
• Dye removal improved with increased heating/cooling cycles and higher cross-linker concentrations, reaching a maximum of 73.1% at elevated temperatures.

Conclusions:

• pNIPAm-co-AAc microgel aggregates are effective for Orange II dye removal from water.
• The thermoresponsive and structural properties of the aggregates contribute to enhanced dye uptake.
• The Langmuir sorption isotherm model describes dye removal at room temperature.