Iron-Based Redox Polymerization of Acrylic Acid for Direct Synthesis of Hydrogel/Membranes and Metal Nanoparticles for Water Treatment

Abstract

Functionalized polymer materials with ion exchange groups and integration of nano-structured materials is an emerging area for catalytic and water pollution control applications. The polymerization of materials such as acrylic acid often requires persulfate initiator and a high temperature start. However, is generally known that metal ions accelerate such polymerizations starting from room temperature. If the metal is properly selected, it can be used in environmental applications adding two advantages simultaneously. This paper deals with this by polymerizing acrylic acid using iron as accelerant and its subsequent use for nanoparticle synthesis in hydrogel and PVDF membranes. Characterizations of hydrogel, membranes and nanoparticles were carried out with different techniques. Nanoparticles sizes of 30–60 nm were synthesized. Permeability and swelling measurements demonstrate an inverse relationship between hydrogel mesh size (6.30 to 8.34 nm) and membrane pores (222 to 110 nm). Quantitative reduction of trichloroethylene/chloride generation by Fe/Pd nanoparticles in hydrogel/membrane platforms was also performed.

Functionalization of Flat Sheet and Hollow Fiber Microfiltration Membranes for Water Applications

“…The decline in TCE concentration is lower as time passes because of mass transfer limitations from the bulk solution to the NP core. However, the k SA from HF obtained is higher (0.108 to 0.284 L/m 2 ·h) to the reported (0.068 to 0.130 L/m 2 ·h) 5a, 20b, 44 with the same concentrations of Pd used (1 to 3 wt. % Pd).…”

Engineered iron/iron oxide functionalized membranes for selenium and other toxic metal removal from power plant scrubber water

“…The mesh size of PAA hydrogel also increased with increasing pH, resulting in higher swelling ratio. Our gel swelling study shows that PAA synthesized through thermal polymerization had a weight gain around 194% at pH 1.9 and 1676% at pH 9.3 [38]. With PAA incorporated in membrane pores as a “smart” valve, one can manipulate the water permeability of membranes by adjusting the water pH [10].…”

Naphthenic acids removal from high TDS produced water by persulfate mediated iron oxide functionalized catalytic membrane, and by nanofiltration

“…The swelling of PAA gel in the membrane domain will lower the pore volume for water to flow and therefore, reduce its permeance [46]. The membrane flux was measured at different pH to confirm polymerization in the membrane pores, as indicated in Fig.…”