Pressure-Stable Imprinted Polymers for Waste Water Remediation.
Mann Shane,Johnson Travis,Medendorp Evie,Ocomen Robert,DeHart Luke,Bauer Adam,Li Bingbing,Tecklenburg Mary,Mueller Anja
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 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.
Imprinted polymers for the removal of heavy metal ions from water.
Ashraf Syed,Cluley Angela,Mercado Ckarlos,Mueller Anja
Water science and technology : a journal of the International Association on Water Pollution Research
In wastewater treatment, the removal of heavy metals is difficult due to the limited affinity of heavy metal ions to ion exchange resins. Here imprinting polymerization is used to develop resins with high capacity and selectivity for heavy metal ions for water treatment. A random copolymer of methacrylate and methacrylamide was found to be most effective for the removal of hydrophilic metal complexes, like CdCl2, ZnCI2, and the metalloid NaH2AsO4, particularly when the porosity of these resins is increased. For hydrophobic complexes imprinting emulsion polymerization was developed and data for the effective removal of mercury dithizonate will be described. Complete removal for up to 80 ppm of cadmium and mercury with only 200 mg of imprinted resin was obtained; competition and co-imprinting experiments are described as well.