CHEMICALLY SURFACE MODIFIED ZEOLITE – ZMM® CSMZ
Natural Clinoptilolite Zeolite provides an excellent matrix for creating Chemically Surface Modified Zeolites (CSMZ) which can remove cations as well as anions from contaminated water. Zeolite is classified as a hydrated, aluminosilicate and the crystal structure has a two-dimensional 8-ring and 10-ring channel configuration, with the largest cavity dimension measuring 4.4 by 7.2 angstroms. The basic aluminosilicate structure consists of infinitely, extending, three-dimensional networks of AlO4 and SiO4, tetrahedral, crystal linked to each other via shared oxygen atoms. These oxygen atoms occupy two, structurally different positions representing framework oxygen and cavity/void (or channel water) oxygen.
The Zeolite has high surface area (24-25 m2/gm @ Dry Bul Wt.; ~50% Void Volume; a network of channels in the mineral; and net negative surface charge. The net negative surface charge imparts cation exchange capacity to the mineral but no affinity for anions or for nonpolar organics. Treatment of natural zeolites with ZMM’s proprietary chemical treatment dramatically alters their surface properties from hydroscopic to hydrophobic and imparts adsorbent properties analogous to Ground Activated Carbon. For example, the surface treatment chemicals react with the mineral to form a stable coating on the external surfaces of the zeolite to sorb nonpolar organic solutes and anions.
ZMM® CSMZ COMPOSITION AND FUNCTION
The modifying ZMM® chemicals are applied to the zeolite mineral using spray techniques. The ZMM® chemicals are applied to the zeolite mineral surface to form an active layer. Calcium, Potassium or Sodium ions in the crystal structure of the zeolite function as cation exchange ions for these phenomena. Figure 1 illustrates how the molecules are associated with the surface of the zeolite mineral surface to form the CSMZ granules.
A bilayer of molecules forms on the zeolite mineral surface and reverses the charge on the zeolite from negative to positive. This molecular, bilayer provides sites for exchange of anions, such as arsenate, and functions as solvent-like coating into which nonpolar, organic solutes can partition. Inorganic cations exchange via internal ZMM® cation exchange sites and/or are selectively bound on external mineral surface sites. Importantly, the chemically applied molecules are stable on the zeolite to provide an efficient, adsorption surface when used in water, or when added to sumps or lagoons. ZMM® CSMZ zeolite adsorbent product provides an effective, adsorbent/absorbent for removal of a wide range of anionic and cationic contaminants. ZMM® CSMZ removes nonpolar, organic solutes, toxic heavy metals plus organic and hydrocarbon contaminants from water.
Conceptual model for the ZMM® CSMZ illustrating sorption mechanisms for anions, cations and non-polar, organics [D. Schulze-Makuch et al (2002): EOS Transactions, American Geophysical Union, April 30, 2002].
The ZMM® CSMZ adsorbent product has a low abrasion loss coefficient; is chemically stable in terms of the molecule association with the zeolite; and is thermally stable over the range of temperature water filters. Table II outlines the physical properties of the CSMZ adsorbent product.
ZMM® CSMZ Physical Properties
Water Processing with Natural ZMM® CSMZ
Testing conducted at a state university has demonstrated that Natural Clinoptilolite Zeolite, Hydrous Sodium Aluminosilicate, and treated Clinoptilolite Zeolite (“ZMM® CSMZ”) can effectively treat contaminated water.
Natural Clinoptilolite Zeolite, Hydrous Sodium Aluminosilicate, provides economical ion exchange properties. Under the appropriate conditions Clinoptilolite Zeolite can exchange with common cations such as:
Tests show that 50-70% of Copper, Lead and Iron cations in the concentration ranges of 1-2,000 ug/L can be removed with a single pass treatment of Zeolite at 500 mg/L. Multi-pass column treatment indicated Copper, Lead and Iron cation removal can approach the 80-90% range.
% Removal from Aqueous Solutions with Clinoptilolite Zeolite
ZMM® CSMZ is far more effective removing 70-90% Copper, Lead and Iron as well as metal cations of Zinc, Manganese, Mercury, Cadmium and Chromium under similar condition.
ZMM® CSMZ have demonstrated removal of 70-80% of Arsenate and Phosphate anions.
% Removal from Aqueous Solutions with ZMM® CSMZ