Titansorb®

Filter Media for Arsenic removal

by Watch® GmbH

Arsenic in water1. The main cause of Arsenic presence in ground water is believed to be the reductive dissolution of sedimentary Arsenic-containing Iron Oxy-hydroxide by microbial driven oxidation of organic matter. This cause the release of adsorbed Arsenic, since the adsorbed As (V) is reduced to As (III) and leached into ground water.

2. Anthropogenic sources also contribute to Arsenic pollution.

Arsenic compounds were employed as pesticide, herbicide and in wood preservation. Other sources of Arsenic are mining waste and glass industry.

Fertilizers are also suspected to have an important contribution to the contamination of groundwater with Arsenic.

Coal combustion, metal smelting and refining processes release Arsenic in the atmosphere, which eventually it is transported by rain in the surface water and groundwater.

Need for Arsenic treatmentPresence of Arsenic in drinking water leads to many

proved health problems, including cancers.

Adsorbers for Arsenic removal Passive systems – little or no user intervention Easy to operate Almost no waste water In some cases, no hazardous spent material Can achieve the best cost for treated water, especially for medium and small

systems

Appearance: White granulesParticle size: 0.5 – 1.5 mm Moisture content: less than 10%Bulk density: ca. 550 kg/m2

Titansorb

TitansorbTypical Physical and Chemical Properties

Appearance: White granules

Particle size: 0.5 – 1,5 mm

Active surface: 400-450 m2/g

Porosity: ca. 65%

Typical equilibrium capacity (static, 1000 ppb, pH=6.5)

Arsenic (V) 28-30 g / kg

Arsenic (III) 13-15 g / kg

Typical equilibrium capacity (static, 50 ppb, pH=7.0)

Arsenic (V) 14-16 g /kg

Arsenic (III) 5-6 g/ kg

Titansorb

made of Nanosized Titanium Oxyhydrate

Titanium Oxyhydrate TiO(OH)2 or Metatitanic Acid H2TiO3 - reactive material, containing maximum number of active centers: Ti-OH groups.Titanium Oxyhydrate is partially crystallized as Anatase nanocrystals (10 - 20 nm), containing a high density of Ti-OH active centers on their surface:

Ti

OO

O

H

Ti

OO

O

H

Ti

O

H

Ti

OO

O

H

Ti

O

H

Ti

OO

O

H

Ti

O

H

Ti

O

O

H

Active Ti-OH groups on Anatase nanocrystals

TEM image of Anatase

Titansorb

The contaminants are strongly adsorbed on the active surface of nanocrystalline Anatase. As an example, arsenate anion (As5+) may be retained under several possible coordinative structures:

Ti

O

Ti

O

As

Ti

O

OO

O OO

O

H

Ti

O

Ti

O

As

Ti

OTi

O

O

O O

TiO

O

O

O

OH

Ti

O

Ti

O

As

Ti

O

O OO

O

O Chelating bidentate

Chelating tridentate

Brigded bidentate

Chelating tridentate on a „step“

TiTi

O

As

Ti

O

OO

O OO

O

Titansorb

Operation conditions

High service flow rate: 15 - 35 m/h (6 – 14 gpm / ft2) (depending on Arsenic concentration)

Backwash flow rate: 14- 24 m/h (6 - 10 gpm / ft2)

Freeboard: 55% of bed depth

Short contact time: 30 s – 3 min (or more, depending on Arsenic concentration)

Bed depth: at least 0.8 - 1 meter

Operational pH: 4-10

Titansorb

Testing water

NSF/ANSI 53 Standard

Calcium 40 ppm

Magnesium 24 ppm

Sodium 10 ppm

Chloride 100 ppm

Sulfate 50 ppm

Silica (SiO2) 20 ppm

Nitrate 2 ppm

Fluoride 1 ppm

Phosphate 0.04 ppm

Titansorb Comparative Arsenic Adsorption Media Test

Flow rate 20 BV/h, pH=7.5, 300 ppb As(V), silica 10 ppm, hardness 150 mg/l

Titansorb pH influence on Arsenic adsorption

- Activated Alumina, Iron Hydroxide, Titansorb

Flow rate 60 BV/h, 50 ppb As(V), silica 20 ppm, hardness 150 mg/l

Titansorb Service Flow Rate and Arsenic Adsorption

Test water: pH=7.5, 300 ppb As(V), silica 20 ppm, hardness 150 mg/l

Titansorb Comparative Arsenic Adsorption Media Test

- influence of pH fluctuations (pH re-set at 6.5 thereafter)

Flow rate 20 BV/h, pH=6.5, 300 ppb As(V), silica 10 ppm, hardness 150 mg/l

pH = 7.2 pH = 7.0

Why Titansorb? Stronger adsorption of arsenic in comparison with alumina or iron-based media, therefore no

leaching was observed

One of the highest Arsenic adsorption capacity

Fast arsenic adsorption – less media, small footprint

Cost per liter of water treated is lower compared with other adsorbers

Wider pH tolerance (Titanium Dioxide is not soluble in acidic or basic media)

Less prone to Arsenic leaching due to pH fluctuations

Best results at pH 7 or lower

Less sensitive to ionic strength or concurrent anions (phosphate, sulfate, nitrate, etc.)

Removes other hazardous contaminants from water - such as chromate, cadmium, lead, copper, selenium

No staining due to iron leaching

Almost no microbiological contamination (such as iron bacteria) therefore less disinfection required and less disinfection toxic by-products (THM, chloramines, HAAs) are generated

Titansorb - second generation-

Thank you!

Questions?

Watch GmbH

Fahrlachstrasse 14

68165 Mannheim

Germany

Web: www.watchwater.de

Dr. Valentin Cimpeanu

Tel. +49-621-87951-55

Email: cimpeanu@watchwater.de