Pressure-Stable Imprinted Polymers for Waste Water Remediation

Abstract

Abstract:In wastewater treatment, the removal of heavy metal ions is difficult. Ion exchange resins are ineffective since heavy metal ions cannot compete with "hard ions" in binding to the resins. Imprinting polymerization can increase the specificity of ion exchange resins to allow heavy metal ions to compete. Unfortunately, a high capacity is also needed. When high porosity and surface area are used to increase capacity, polymeric resins lose pressure stability needed for water treatment. In this research, a bulky, hydrophobic co-monomer was used to prevent Zn +2 imprinted sites from collapsing. Both the co-monomer and crosslinking density were optimized to allow for maximum pore access while maintaining pressure stability. IR and SEM studies were used to study phase separation of the hydrophobic co-monomer from the hydrophilic resin. Capacity was measured for just the imprinting ion first, and then in combination with a competing ion and compared with porosity and pore-size measurements. Capacity under pressure was also characterized. A resin with high capacity was identified that allowed for the heavy metal ion to compete while still maintaining pressure stability.

Development of Adsorptive Membranes for Selective Removal of Contaminants in Water

“…In these compounds, the carbonyl region (1750 to 1600 cm −1 ) overlapped with the C=C and C=N region (1700 and 1550 cm −1 ). The carboxylic acid peak of the methacrylate shifted to lower values when deprotonated to the anion, as well as with different amounts of hydrogen bonding [ 25 ]. Forming dimers with itself or an amide, the carboxylic acid peak shifted to higher values.…”

“…MIPs have shown promising results for the removal of arsenate and other contaminants from water [ 1 , 17 , 22 , 23 , 24 ]. However, when used in pressurized and varying pH environments, MIPs can lack stability and the necessary strength and surface area needed for large scale operation [ 16 , 25 ]. Graphitic carbon nitride (g-C 3 N 4 ) is a promising scaffold for constructing adsorptive membranes, due to its facile synthesis, chemical versatility, intrinsic porosity, high strength, and natural abundance [ 26 ].…”