NANOTECHNOLOGY APPLICATIONS FOR TREATMENT: COST EFFECTIVE AND RAPID TECHNOLOGIES; SMART MATERIALS OR ACTIVE SURFACE COATINGS Wilfred Chen Chemical and Environmental Engineering University of California, Riverside

Why Nanomaterials? Ability to manipulate, control and build materials at the atomic and molecular level Provide novel affinity, capacity, and selectivity because of their unique physical, chemical and biological properties. Create large structures with new molecular organization that will facilitate recovery

Types of Nanomaterials for Environmental Treatments 1. Smart modified surfaces or membranes 2. Nanostructured materials 3. Molecularly imprinted polymers 4. Nanoscale Biopolymers

Smart Surfaces or Membranes

Active Membranes for Heavy Metal Removal

Types of modifying peptides poly-L-glutamate or aspartate poly-L-lysine or arginine poly-L-cysteine Ritche et al. ES&T 2001

Metal Chelating Behavior poly-L-lysine or arginine - oxyanion such as As

Results with poly-cysteine membrane The temperature profile for turbidity formation was used to measure the onset of folding and aggregation of the biopolymers. The value of Tt, which is defined as the temperature at which 50% turbidity occurred, was used to indicate the phase transition properties of the different biopolymers.

Tunable Surfaces for Biofouling Ista et al. Appl. Environ. Microbiol. 1999

Nanostructured Materials

Poly(amidoamine) Dendrimers Diallo et al. ES&T 1999

Binding properties Repeating cycles of metal binding with Ela78H12 biopolymers. Five microgram of cadmium were added in each cycle. S: Cd2+ remained in solution; P: Cd2+ removed by biopolymers; AS: Average amount of Cd2+ remained in biopolymers after stripping.

Polymeric Nanoparticles Tungittiplakorn et al. Appl. Environ. Microbiol. 2004

Enhance PAH Desorption

Amphiphilic Polyurethane Nanoparticles Kim et al. Journal of Applied Polymer Science 2004 90 nm in size

Enhanced PAH Solubility

PHEMA Beads containing N-Methacryloylhistidine Say et al. Macromol. Mater. Eng. 2002

Metal Removal

Molecularly Imprinted Polymers

Atrazine-Imprinted Polymers Cacho et al. Anal Bioanal Chem 2002

Imprinted Polymers for Virus Removal Infection Frequency of Spodoptera frugiperda 9 (Sf9) cells 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% 6.89E+05 6.89E+04 6.89E+03 6.89E+02 Dilution (pfu/mL)

Reactive Polymer Hydrogel for Phosphate Removal Kiofinas et al. ES&T 2003

Efficiency of Removal

Perchlorate Removal Kioussis et al. Journal of Applied Polymer Science 2001

Efficiency of Removal

Tunable Biopolymer with Metal-Binding Property Elastin Domain Metal Binding Domain Fine tune affinity with different binding sequence Fine tune DT by controlling amino acid sequence and no. of repeating unit (VPGXG)n

Genetic and Protein Engineering Methodology Synthetic gene Recombinant plasmid Plasmid Enzyme ELP biopolymers Microbial expressions of artificial genes provides a means of easily producing ELP. amino acid sequences are chosen to create specific folding patterns and desired material properties. The primary amino acid sequence can then be reverse-translated into a corresponding nucleotide sequence. There are 2 methods of obtaining the needed DNA fragments. One possibility is to clone these sequences from an organism that produces the desired structural protein. The second option is to synthesize artificial genes by solid phase techniques. The second method of course allows maximum freedom in designing the target sequence. Because many structural proteins are characterized by repetitive amino acid sequences, it is often possible to multimerize a smaller oligonucleotide sequence to prepare an artificial gene that codes for proteins of high molecular weight.

Metal Removal Recycling DT Cd2+ + Cd2+ Regeneration Cd2+ DT Cd2+

Production of Biopolymers A B C D E Biopolymer Protein yield (mg/3 L) A, Ela38H6 B, Ela58H6 C, Ela78H6 D, Ela78 E, Ela78H12 Ela38H6 289 Ela58H6 295 Ela78H6 Ela78 Ela78H12 207 191 168 Kostal et al. Marcomolecules, 34, 2257-2261, 2001

MerR can serve as a specific mercury binding domain Hg2+ C123 C79 C114 C114 C79 C123 The high binding affinity of mercury binding by MerR is in accordance with the fact that three different cysteine residues from the two MerR subunits are involved in sequestering mercury, which results in a high-affinity tricoordinate mercury binding site. MerR-Hg complex

Selective Binding of Mercury by Ela153-MerR Biopolymer Acidic waste water (pH 4) Selectivity of the ELP153MR biopolymer. Binding of mercury by ELP153MR in the presence of competing heavy metals. One nmol of biopolymer was mixed with 0.5 nmol of HgCl2 and various amounts of competing heavy metals. Kostal et al. ES&T 2003

Exploratory Research: Nanotechnology Acknowledgement R829606 Exploratory Research: Nanotechnology