AgriTitan TM. Effective, Safe, & Smart. Harvest the Power of Light To Control Bacterial Plant Disease. EcoActive Surfaces, Inc.

Transcription

1 AgriTitan TM Effective, Safe, & Smart Harvest the Power of Light To Control Bacterial Plant Disease 1

2 What is AgriTitan TM? AgriTitan TM is a proprietary water-based formulation of extremely small particles of crystalline Titanium Dioxide and Zinc. The nanoscale of these crystals and their chemical composition provides useful antimicrobial properties. 2

3 How does TiO 2 work? The first step is absorption of light Photons (light) have energy; red has low energy, violet has high energy. TiO 2 primarily absorbs high energy photons TiO 2 Plant surface Plant Surface 3

4 Light energy creates mobile electrons and holes in TiO 2 which can then form highly reactive chemicals. TiO 2 + hν e - + h + O 2 hν (light) (e - + h +) conduction band valence band band gap energy (E g ) = 3.2 ev e- h+ superoxide O 2 - OH hydroxyl radical CHEM. RXNS. H 2 O 4

5 Small particles have greater surface area per unit of mass Mass varies as the CUBE of the linear dimension Surface area varies as the SQUARE of the linear dimension 8 nm length = ONE average AgriTitan particle 40 nm length = FIVE x 8 nm particles 40 nm particle = 125 x 8 nm particles EQUAL MASS FIVE-FOLD GREATER SURFACE AREA 5

6 Nanoscale TiO 2 is a mineral catalyst that creates reactive chemicals using energy from light. It is photocatalytic. 6

7 Doping TiO 2 with Zn increases energy capture from sunlight Absorbance, or Irradiance (W/m 2 /nm) Solar energy TiO 2 TiO 2 /Zn Wavelength, nm 7

8 AgriTitan TM is composed of nanoscale mineral crystals Titanium Dioxide (TiO 2 ) Zinc (Zn) as dopant Regulatory agencies are very familiar with both TiO 2 and Zn EPA: FDA: EPA/600/R-09/057F 21 CFR EPA/600/R-10/ CFR EPA 40CFR CFR EPA 40CFR CFR FR CFR CFR

9 Won t it damage plants? Median radius of diffusion, OH radical: ~8 nm Thickness of bacterial cell wall: ~10 nm Thickness of plant cell wall: >100 nm Thus, the greater plant cell wall thickness (and overall size of plant cells) offers the opportunity to achieve selectivity. 9

10 Field Trials of AgriTitan TM Multiple (4) completed field trials. Significant and dose dependent protection shown by AUDPC. Protection comparable to grower standard. Very little phytotoxicity observed. No adverse effects on yield observed. Additional trials are underway. Protection continues to be seen. Residual phytotoxicity appears controllable. Altered spray techniques eliminate phytotoxicity. 10

11 Summary Nanoscale TiO 2 is photocatalytic, and the products of photocatalysis are bactericidal. Photocatalysis can be made more efficient by doping with heteroatoms (TiO 2 /Zn - AgriTitan TM ). These materials protect tomatoes from bacterial spot disease TiO 2 and Zn are well known and offer a less toxic alternative to copper based bactericides. 11

12 Risk Considerations Worker safety during application? Residue on crops? Environmental effects? 12

13 Risk during application Aqueous colloidal suspension product Spray application Droplet sizes generally > 40 micrometers Easy protection with basic respiration mask TiO 2 /Zn is an inherently safe material What if droplets evaporate in air? Resulting dust particle is not nanoscale. 13

14 Dust particles from spray droplets are NOT nanoscale 7500 TiO 2 particle dimension, nm Dilution from stock 10X 20x Sprayed droplet diameter, micrometers 40 m droplets result in TiO 2 particles larger than ~1.2 m 14

15 NIOSH Dust Limits 2.4 mg/m 3 for fine TiO 2 (> 100 nm) 0.3 mg/m 3 for ultrafinetio 2 (< 100 nm) time-weighted average continuous concentration (10 hours/day, 40-hour work week) For 1 L AgriTitan, completely dispersed in air as 40 micrometer droplets from10x dilution, this is a volume 3 meters high across an area of 0.11 hectare 15

16 Risk Considerations Worker safety during application? Residue on crops? Environmental effects? 16

17 Residue on Crops Actual form of TiO 2 /Zn on the surface Nano-scale has photocatalytic activity Macro-scale well known to EPA, FDA Total amount of TiO 2 /Zn Marketed component Waste component 17

18 Residue on Crops: Form TiO 2 /Zn is sprayed to form a thin surface layer. Agglomeration is likely ( water spot effect). Layer characteristics are of substantial interest. Fully dispersed nanoparticles very unlikely Dimensions alter risk considerations Porosity maintains nano-like activity in micro-layer Electron Microscopy? Atomic Force Microscopy? 18

19 Residue on Crops: Amount Total amount of TiO 2 /Zn Upper limit estimates from applied amounts Measure by Atomic Emission Spectroscopy? Marketed component Ingestion of residual macroscale TiO 2 or Zn is safe nano TiO 2 known to be not genotoxic Waste component Adherent to plant waste, limited mobility Nanoparticles agglomerate at soil ph 19

20 Risk Considerations Worker safety during application? Residue on crops? Environmental effects? 20

21 Residue in Environment Sources Spray drift Not nanoscale Crop waste Likely not nanoscale Improper disposal Avoid dumping liquid into bodies of water. 21

22 AgriTitan TM Effective, Safe, & Smart Harvest the Power of Light To Control Bacterial Plant Disease 22