Development / Optimization of the new High-Efficiency Nano-Catalyst

Immobilization Technology for ex-situ treatment of

contaminated waters

K. Cross, Cross Consulting Engineers, Cardiff, CA and

Charles Schaefer, Ph. D., Shaw Environmental, Inc., Lawrenceville, NJ

Overall Introduction and Outline•Section 1: Overview of treatment w micro/nano-particles

•Section 2: HENCI Technology Overview•HENCI TOP•Phase 1 tests of late ’04

•Section 3: Phase 2 Testing•Objectives and key issues•Scope of Experiments•HENCI Reactor sub-optimization and sizing

•Section 4: Phase 3 Pilot Test•Objectives•Approach•Potential Sites•HENCI System Process PID’s•Cost Evaluations

Section 1

Micro / Nano-Catalyzed Remediation Overview

Micro/Nano-Catalysis Highlights

NanoTech now has ~2000 Application Categories - all sectors http://azonano.com/Applications.asp

CNST / CBEN at Rice University: “We developed high-performance nano-scale catalysts for treating particularly challenging contaminants in water that must be removed to a very low level.”

In-Situ Success with Pd/Fe on TCE by Zhang, Schrick, et. al. Rapid, Complete, Inexpensive Breakdown of ~50 (so far)

ubiquitous recalcitrant carcinogenics at sub-ppb levels Cl’d Olefinics, Cl’d Aromatics, THMs, Pesticides, PCHs,

PCBs, Dyes, NDMA, TNT, Cr2O2,AsO3, NO, Hg, Ni,

City Redlands, CA Env. Council: “TCE and PCPs contamin-ating about half the wells in Midwest and Western U.S. Many in Redlands have been closed due to the high levels of TCE”

Ex Situ Treatment of Waters Containing Organic Contaminants

• Groundwater

• Drinking water

• Leachate

• Wash Down

Bio-reactors

Activated Carbon

UV-oxidation

Thermal CATOX

Zero Valent Metal Particles for Treatment of Organic

Contaminants

Metal Diameter(µm)

Surface Area (m2/g)

Composition

ZVI filings 1,000 1.0 Fe0

MZVI 80 2.0 Fe0

NZVI 0.01 25 Fe0

Metal Catalysts 1.0 190 60% Pd or Ni on alumina support

Bimetallic MZVI/NZVI

0.01 25 Fe0 doped with 0.1% Pd or Ni

Zero Valent Metal Particles

Zero Valent metals have been show to treat a wide range of compounds:

•Chlorinated solvents•Explosives (e.g., TNT, RDX)•NDMA•Nitrate•Perchlorate (?)

Limited use in ex situ treatment systems due to:

• Longevity• Matrix Effects • Particle Retention

Conceptual Model

RX

RH + X- + Fe2+

Fe

H+

Un-catalyzed ZVI

Catalyzed ZVI

RX

Fe2+ + H2

Fe

H+

Catalyst RH + X-

H2OH+

e-

Reactor Data

0.0

1.0

2.0

3.0

4.0

0 5 10 15 20

R e a c to r Vo lu m e s

In f lu e n t E ff lu e n t

• 3 hour residence time

• 10g Ni catalyst

• TCE converted to ethane

• No sulfate reduction

• No nickel in effluent

• Influent DO = 8 mg/L

Influent = artificial groundwater containing TCE, sulfate, nitrate, carbonate, and manganese

Reactor Data

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0 5 10 15 20 25 30 35

R e a c to r Vo lu m e s

T C E In flu e n t ND M A In flu e n t T C E E ff lu e n t ND M A E ff lu e n t

• 3 hour residence time

• 10g Ni catalyst

• No sulfate reduction

• Influent DO = 8 mg/L

• Nitrate reduction

Influent = artificial groundwater containing sulfate, nitrate, carbonate, and manganese

0.0

0.2

0.4

0.6

0.8

1.0

0 20 40 60 80 100 120 140 160

Reactor Volumes

Re

mo

va

l E

ffic

ien

cy

Catalyst regeneration using dilute acid

Reactor Data

Influent = artificial groundwater containing sulfate, nitrate, carbonate, and manganese

Influent TCE 1 ppm

Geochemical Effects on observed PCE Degradation Rate Constants

Soil Slurry pH Fluoride Bromide Chloride Sulfate Nitrate Nitrite CarbonateSoil A 7.5 <0.1 <0.1 20 22 <0.1 <0.1 0.03Soil B 9.7 0.14 0.17 308 51 0.17 0.4 35.1

0.44 ± 0.060 0.22 ± 0.048 0.16 ± 0.0410.048 ± 0.007 0.20 ± 0.057 0.23 ± 0.062

Soil A Soil B Soil B (buffered)Ni

NZVI

pH7.2

Rate Constants normalized to catalyst surface area (day-m2 cat)-1

Batch Data - Mixtures

• Timescale of weeks

• NDMA inhibits PCE decay

•1st-order decay

• Negligible sorption

0

0.2

0.4

0.6

0.8

1

1.2

0 5 10 15 20

Time (days)

Rel

ativ

e P

CE

Aq

. C

on

cen

trat

ion

Soil A Soil A+NDMA Expon. (Soil A)

NZVI Treatment

Section 2

HENCI Overview

•As Previously noted, due to their size (and also structure / morphology), micro/nano-particles rapidly degrade many dissolved contaminants

•However, due to their small size, there has been no way to cost-effectively immobilize large

quantities of MNPs in a flow-through reactor

•HENCI cost-effectively immobilizes most nano- & micro-catalysts in a new and novel way, free of the main technical and financial drawbacks inherent to today’s less viable technologies:

•Homogeneous, Dense Dispersion – no channeling•Insignificant Del-P even at high flows = Low Cost• Often NO NEW CONTACT MATERIALS exposed to stream

HENCI High-Efficiency Nano-Catalyst Immobilization

What HENCI Means to the Process Engineer

All advantages of a Continuous Packed-Bed ReactorNo moving partsNanoparticle agglomeration can be tuned outHENCI can immobilize any new macro-structured nanocatalysts which have high-µ or paramagnetic components

Multiple Standardized HENCI units can be Manifolded Valved in series, parallel or any combination ‘on-line’ Process any combination of Inlet stream flow rate and concentration

Phase 1 Results (late 2004)

• Prototype Rxrs Immobilized ¼ g of BNPC’s per cm3 @ ~2gpm

•Video Clip shows release of particles upon unit power-down•Greater loading capacities very likely achievable

• HENCI Immobilization force more than adequate for all app’s

• Negligible Pressure Drops: allows High Flows, Long Reactors

• HENCI Prototypes operated with TCE - polluted inlet stream

•Preliminary Trial Report Circulated to NWRI Early ’05

•TCE Run data yield fast Pseudo First-Order Rate Constants

•No effect on efficacy of catalyst by HENCI observed

Verification of results is one task of phase 2

Section 3: Phase II Development

1: NMCR Database Gather data from Treatability Studies and literature Compile into ever-growing NMCR Database

2: Treatability Studies / RXR Development Build several bench-scale rxrs, install in Shaw’s Lab verify degradation of target contaminants in site groundwater determine the most appropriate metallic particles determine degradation kinetics reactor residence time estimate extent of particle “change-out” or regeneration Use data and experience to incorporate improvements to reactors

Locations:Shaw Environmental, Inc.Lawrenceville, NJCross ConsultingCardiff, CA

Objectives

1. Batch Screening Tests

Phase II Testing

• site groundwater• degradation end products• kinetics

2. Bench scale Reactor Testing• reactant loading in HENCI reactor • degradation rates• daughter product generation• reaction longevity• hydraulic properties

3. Data Evaluation & Conceptual Design• calculate rate constants• reactor sizing and optimization

Reactor Sizing and Optimization

1st-order degradation rate constant

for ZVI/Pd, area ≥ 7130 m2/L

2mh

L01.0k

2mh

L001.0

to

Key parameter: area = m2/L of catalyst in reactor

Basic Design Equation

k´= k • area

x1

1

k

1

area

ln

For 99.9% conversion, = 12 minutes For 1 gpm flow, Reactor volume = 12 Gal

Process Optimization Parameters

RXR Eff = (% Conversion/ (Tresx MassBNMC) )

Fluid Dyn. Eff = SABET / (PSID / GPM / Axs)

= SABET / (PSID / v)

dEff / dPD goes thru max for each material

Scale-Up Using Optimal RXR tres

Reactor / system configuration det’d from Tresmin and Inlet stream flowrate

Total DelP then allows pump sizing, system design, add controls

Section 4: Phase III - Pilot Demonstration

ObjectivesDemonstrate HENCI particle retention system at the field scale

Remediate in-field: Verify treatment effectiveness of target contaminants

Evaluate long-term operation

Identify potential design improvements and modifications

Potential SitesPicatinny Arsenal, Dover, NJ• Existing P&T system operated by Shaw• TCE1000 µg/L• Low ppb levels CT, DCE, VC

Former Naval Surface Warfare Ctr, White Oak, MD

• former waste water discharge area• TCE, TNT, RDX

19th St. GAC PlantCity of San Bernardino

• ~7ppb TCE, ~ 5ppb NDMA

Approach

• Construct and install HENCI System with selected nano/micro particles, controls, redundancies

• Treat and monitor for 3 to 4 months (1 gpm flow)

• Perform O&M activities as needed

• Evaluate results with respect to overall treatment effectiveness and costs

Typical HENCI Process PID

SummaryRapid and cost-effective ex-situ treatment of a variety of contaminants

HENCI technology applicable to wide range of nano/micro particles

Significant Potential to revolutinize CHC Site remediation – Point-of-Distribution Systems: Pump/Treat, and USE!

Reactor-based nanocatalysis will merit applications in other Environmental sub-sectors as Rural P.O.D., portable/Field unit, and other non-Groundwater applications arise

Potential to Usher in new era in water remediation globally