WO1998058733A1

WO1998058733A1 - Enhanced absorption materials

Info

Publication number: WO1998058733A1
Application number: PCT/US1998/012932
Authority: WO
Inventors: Richard Kraemer
Original assignee: Richard Kraemer
Priority date: 1997-06-20
Filing date: 1998-06-22
Publication date: 1998-12-30
Also published as: AU7983698A

Abstract

An enhanced absorbent material formed from a carrier material having a high porosity. The carrier material is treated with a hydrophilic surfactant or a lipophilic surfactant or a mixture of both. In a preferred embodiment, the carrier material is formed of expanded perlite particles. The surfactants include anionic surfactants, cationic surfactants, amphoteric surfactants and nonioic surfactants.

Description

ENHANCED ABSORPTION MATERIALS

Field of the Invention: This invention relates to the field of absorbent materials and particularly to the field of absorbent materials for treating liquid spills.

Background of the Invention: A problem that is of great environmental concern is the treatment of liquid spills. This is of particular concern when the spill involves harmful, toxic and/or hazardous materials. Such spills must be quickly contained to prevent or minimize the leaching of these materials into the ground and into groundwater supplies. The effectiveness of the treatment includes the efficiency, the rate of the treatment and the ability to dispose of the saturated absorbent materials. A critical factor in treating such liquid spills is the speed in which the treatment occurs. The longer period of time that elapses while the spill (or aqueous solution) is being cleaned increases the opportunity for the liquid to leach into the surrounding surfaces or to contaminate the environment.

Another problem with such spills is the disposal of the absorbent material once the material is fully saturated or the spill has been absorbed. Most of the prior absorbent materials are organic in nature and will often-interact with the particular solution being treated. This interaction may cause the contaminate to be re-released back into the environment.

A number of absorbent materials are presently utilized in such instances with varying degrees of success. One type of absorbent material often used previously has a clay base. This type of absorbent material has previously been used for treating oil spills as well as for kitty litter. However these clay-based absorbent materials do not work well for many types of spills, and tend to deteriorate te upon absorption. Another popular type of absorbent material is cellulose-based, usually in the form of pellets. These materials may be treated to improve absorption but again, are organic based, and do not work well for many materials.

Thus a need exists for an absorbent materials that can quickly and efficiently absorb liquid spills, including liquids having particulates dissolved therein.

Summary of the Invention

The present invention accomplishes those needs by providing an enhanced absorbent material capable of quickly, effectively and efficiently absorbing a variety of liquid spills. In a preferred embodiment of the present invention, the enhanced absorbent material uses an inorganic material having a relatively high porosity level. The material is then enhanced with a surfactant material that effectively reduces the surface tension of the liquid to increase the rate of absorption of the liquid spill. The inorganic material is relatively chemically inert so that it does not degrade when it is saturated. This provides an opportunity to dispose of the absorbed material.

In one preferred embodiment, the absorbent material includes expanded perlite. Other embodiments use vermiculate as well. These materials include high porosity due to irregularities formed in the particulates, such as micro-cavities, voids and cracks.

The expanded perlite is treated with a surfactant of the groups of hydrophilic surfactants and lipophilic surfactants. These groups of surfactants are further subdivided into anionic surfactants, nonionic surfactants, cationic surfactants and amphoteric surfactants. Nonionic lipophilic surfactant coated perlite particles may be used to treat liquid spills involving an oil soluble material. An anionic hydrophilic surfactant treated perlite particle may be used to treat a particulate spill in water. In another embodiment, an amphoteric surfactant treated perlite particle may be used in treating a commercial solvent spill.

In yet another embodiment of the present invention, a blend of perlite particles treated with a variety of surfactants may be used to be able to treat a number of possible spills to minimize environmental damage. These and other features of the claimed invention will be evident from the ensuing detailed description of preferred embodiments.

Detailed Description of Preferred Embodiments

A preferred embodiment of the present invention is described herein. It is to be expressly understood that this exemplary embodiment is provided for descriptive purposes only and is not meant to unduly limit the scope of the present inventive concept. Other embodiments, and variations of the absorbent of the present invention are considered within the present inventive concept as set forth of the claims herein. It is to be expressly understood that other variations are contemplated for use with the present invention as well.

Carrier The absorbent of the present invention utilizes a carrier which is capable of absorbing several times it's weight in liquid. This carrier is treated with one or more surfactants having unique characteristics to enhance the speed of the carrier in absorbing the liquid. In one preferred embodiment of the present invention, the carrier is formed from perlite. Perlite is a naturally occurring siliceous volcanic rock. When particles of perlite are quickly heated to above sixteen hundred degrees

Fahrenheit, it expands by creating myriad micro-cavities and cracks within the particles and on the surfaces of the cavities. These expanded perlite particles are characterized by low density and high porosity. This high porosity allows the particles to absorb relatively large amounts of water by capillary action into the voids (cracks and micro-cavities) of the particles.

Another important feature of the perlite particles is their inorganic composition. The particles are chemically inert and will not interact with the liquid spills in which they are utilized. Thus, the liquid spill, particularly toxic or hazardous materials, will be retained until such time as they can be disposed without the danger of the particles suffering significant deterioration ion which might release the materials back into the environment.

- In another preferred embodiment, the carrier is formed from vermiculite.

Vermiculate is an expanded form of mica, characterized by multiple layers.

Vermiculate typically has a porous structure with relative large pore structures.

Liquids are entrapped within the layers of mica. The vermiculate particles are also inorganic and chemically inert.

In another alternative embodiment, the carrier includes diatomaceous earth. This material also has high absorbency qualities but is essentially of an organic nature. The organic nature may in some instances be offset by it's low cost.

For explanatory purposes, the carrier described in the preferred embodiment is perlite. However other materials, preferably inorganic, having irregularities, such as cracks, micro-cavities and voids may be used as well. These materials are able to absorb aqueous solutions by the capillary action of those irregularities as well as by surface tension on their surfaces.

Treating Material

The surfactants of the preferred embodiment are preferably include hydrophilic (water-soluble) surfactants for water soluble spills, and lipophilic (oil- soluble) surfactants for oil-based spills. The surfactants are further sub-divided into four subgroups: anionic (able to disassociate to yield a surfactant ion whose polar group is negatively charged) surfactants, cationic (able to disassociate to yield a surfactant ion whose polar group is positively charged) surfactants, amphoteric (the ionic character of the polar group depends on the solution pH) surfactants, and nonionic (polar group is not electrically charged) surfactants.

The use of a selected surfactant breaks down the surface tension of the spill, and thus enables the carrier to absorb the spill at a much faster rate. This speed can often reach up to eight hundred (800) times faster than non-treated absorbents. The selection of a desired surfactant is dependent upon the liquid spill being absorbed, and on the solution in which the liquid is contained. For instance, an anionic surfactant may be used in which a hazardous material is dissolved in an aqua solution, for instance when a particulate is dissolved in water or other hydrophillic material. If the aqueous solution being cleaned involves a hydrophobic material, that is an oil, oil soluble product, petroleum based or lipophilic material, then a nonionic surfactant is used to allow the hydrophobic material to access deeper within the irregularities of the carrier at a much faster rate. The surface tension of the hydrophobic material is reduced which allows the material to move at a faster rate. If the aqueous solution has both ionic and nonionic properties, which is the case in products such as certain alcohols, ketones. aldehydes and esters and also substances involved in solutions containing those products, then an amphoteric surfactant may be used. Many commercial solvents have both ionic and nonionic properties. These types of solvents are often involved in clean-up efforts to prevent or minimize contamination which can trigger costly repercussions.

Manufacture

The absorbent particles are manufactured by placing the carrier particles in a solution of the surfactants. Once the solution has been given time to be absorbed by the carrier particles, the remaining solvent is drained away. The carrier particles are then dried to allow the solvent carrying the surfactant to disappear. The remaining surfactants are then coated onto the micro-cavities, cracks and voids of the carrier particles. This allows the absorbent particles are able to be stored in a dried form until needed. The absorbent particles can be bagged or transported in bulk form as long as they are kept dry.

Other manufacturing techniques may be used as well. For instance the particles can be sprayed with a solution of the surfactants and a solvent. The drying process can also be advanced by heating the particles. Also, the surfactant may be "baked" on as a coating. In use, the enhanced absorbent particles (that is, the absorbent particles coated with the appropriate surfactant) are stored until needed for a particular liquid spill. The absorbent particles are then poured into that liquid spill until the liquid spill is fully absorbed. For instance, absorbent particles treated with a nonionic surfactant may be used to quickly absorb an oil or gasoline spill before it can leach into the ground and into the groundwater supply. Absorbent particles treated with an ionic surfactant may be used to quickly absorb a spill having a particulate dissolved in an water solution. A solvent spill having alcohol or other commercial solvents may require absorbent particles treated with amphoteric surfactants.

In one preferred embodiment, a blend of these different surfactant treated particles may be maintained to have an inventory for various spills, or in the event that the particular composition of the liquid is not known.

It is to be expressly understood that other variations of the present invention are included within the scope of the inventive concept as claimed.

Claims

CLAIMSI claim:

1. An absorbent material for cleaning up liquid spills, said absorbent material comprises: a carrier particle having a high porosity for absorbing liquids; a surfactant for reducing the surface tension of the liquid spill to increase the speed of absorption of the liquid spill into the irregularities of the carrier particle.

2. The absorbent material of claim 1 wherein said carrier particle includes: expanded perlite particles.

3. The absorbent material of claim 1 wherein said carrier particle includes: vermiculate particles.

4. The absorbent material of claim 1 wherein said carrier particle includes: diatomaceous earth.

5. The absorbent material of claim 1 wherein said surfactant includes: an amphoteric surfactant.

6. The absorbent material of claim 1 wherein said surfactant includes an anionic surfactant.

7. The absorbent material of claim 1 wherein said surfactant includes: an ionic surfactant.

8. The absorbent material of claim 1 wherein said surfactant includes: a nonionic surfactant.

9. The absorbent material of claim 1 wherein said surfactant includes: a hydrophilic surfactant.

10. The absorbent material of claim 1 wherein said surfactant includes: a lipophilic surfactant.

1 1. The absorbent material of claim 1 wherein said absorbent material includes: a plurality of carrier particles treated with a variety of surfactants.

12. An absorbent material for treating aqueous solutions, said material comprising: an inorganic material having a high porosity for the abso╧åtion of an aqueous solution; and a surfactant coating to increase the rate of abso╧åtion of the aqueous solution by reducing the surface tension of the aqueous solution.

13. The absorbent material of claim 12 wherein said surfactant coating includes: hydrophilic surfactants.

14. The absorbent material of claim 12 wherein said surfactant coating includes: lipophilic surfactants.

15. The absorbent material of claim 12 wherein said inorganic material includes: expanded perlite.

16. An absorbent material for treating aqueous solutions, said absorbent material comprising: expanded perlite particles coated with a surfactant to reduce the surface tension of the aqueous solution.

17. The absorbent material of claim 16 wherein said surfactant includes: a hydrophilic surfactant.

18. The absorbent material of claim 16 wherein said surfactant includes : a lipophilic surfactant.