CA2160235C - A system for ultra-trace level analysis of water and a trapping medium therefor - Google Patents

Abstract

A system is provided for ultra-analysis of water for trace impurities. An effective trapping media (4) having internal surfaces which bear active hydroxyl groups thereon functions by binding gels that carry ultratrace analytes and contaminants on their surfaces. An X-ray source (28) may be located adjacent to the trapping medium (4) in situ. The X-rays (29) penetrate the media (4) and are reflected back into a combined emitter/receiver (30) which detects the fluorescence generated in the media (4) by the X-rays (29). The receiver (30) provides an output (31), optionally at a remote location (32) via a communication link (33), which provides data on the identity and quantity of analyses, typically heavy metals, present in the trapping media (4). By including in the transmitted data sent to the receiver (30) the output of the water meter (21, 21A) the display at the output (31) can be formatted in terms of the concentration of the measured analyzes within the sampled water stream (1).

Description

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( ( . 'r~ % < ; J i- ~ y A SYSTEM FOR ULTRA-TRACE LEVEL ANALYSIS OF WATER
AND A TRAPPING MEDIUM THEREFOR
of the Invention This invention relates to the analysis of water to detect the presence of minute amounts of trace 05 contaminants - "ultra-trace level analysis" and to the trapping of such contaminants. .More particularly, it relates to procedures, materials and apparatus for the trapping and concentration of anaiytes in order to facilitate the analytic prooess. It also relates to procedures and materials for trapping ultra-trace level contaminants to effect their removal from water.
~ackgxound to the Invention Ultra-trace level analysis, when applied to the testing of water, entails endeavouring to identify and measure the quantities of non-aqueous components of water, "analytes", that are present at levels of generally parts per billion or trillion, or less. Such analytes are either-dissolved in water as molecules and ions are adsorbed on extraneous particulates and/or colloidal matter usually present in water or, in the case of organic micro-organisms, are in suspension.
Thus, trace contaminants in water are distributed between dissolved and non-dissolved components.
This invention relates to analyzing the non-dissolved component of contaminants in fresh, or non-saline water. (Further reference to water herein is directed to non-saline water.) It also relates to analyzing dissolved components in certain cases Where WO 94124553 216 0 2, ~ ~ p~pA94100190 such components may be forced to precipitate from solution.
In general, the most toxic contaminants for chronic diseases present at ultra-trace levels in water 05 are in the non-dissolved form. If a complete analysis of a water sample is required, the contaminants remaining in the permeate, principally those dissolved in the aqueous phase, may also be extracted by means of adsorption on a resin column following standard techniques. However, often it is sufficient to only analyze for the presence of the non-dissolved fraction.
To carry-out ultra-trace level analysis on water it is essential to sample sufficient volumes of water in order to collect a detectable quantity of contaminants.
The cost of analysis increases when only smaller quantities of samples are available for testing.
Therefore, the accumulation of large sample quantities will reduce costs and increase the number of techniques available to effect analysis. Accumulation of trace samples of micro-organisms will also allow identification through culturing samples to be effected more reliably.
Difficulties arise in applying most normal trapping techniques, such as filtration and adsorption, to the ultra-trace analysis of the non-dissolved components in surface or waste water. When suspended matter is present it is typical that only a relatively small volume of water can be made to flow readily -- WO 94/24553 ~ j PCT/CA94/00190 through the normal sieve-type filter medium or the barrier-type filters used in ultra-trace filtration.
This is because such filters have very fine pore dimensions, F~lug-up easily, and rapidly develop a high 05 back-pressure:. These are not convenient characteristics when it is intended to filter large volumes of water.
Depth-filters are less susceptible to blockage than barrier filters. Known depth-filters, on the other hand, are composed of random mats of polymeric materials and rely on t:he density and thickness of the mats to trap particle's. These filters are generally capable of retaining larger quantities of particles within their matrices and this makes filtration of large volumes of fluids more F~ractical. However, such filters are not efficient at trapping micron-level sized particles and colloids. Moreover, commercially available depth-filters usua7.ly contain contaminating binders that bleed during extracaion of the analytes and thereby complicate analytical procedures.
Both sieve and depth filters of conventional design need t:o be of unwieldy size to be able to sample large volume:a of turbid fluids.
Adsorption columns perform poorly as filters and have limited capacity to trap analytes. The consequence is that large: volumes of adsorbers must be used if adsorption columns are to be used to collect significant quantities oi' anal;ytes.

WO 94/24553 2 ~ ~ O 7 ) 5 PCT~CA94100190 A further concern with adsorbers is that an extraction process is required to recover the analytes.
The adsorber then contributes contaminants to the extract at levels which interfere with ultra-trace 05 analysis. This inherent contamination problem persists in spite of extensive cleaning.
A previously unappreciated aspect of ultra-trace analysis as applied to fresh water is that many ultra-trace analytes have not been reliably quantified because l0 they are entrained within metal hydroxyl, or ~~light metal, colloids such as alumina silica colloids.
Colloids create a problem in filters in that they readily block filter pores, thus limiting sample quantities. Consequently, to collect convenient 15 quantities of colloidally-trapped analytes, large filter areas are required. Larger filters increase contamination.
In the case of adsorbers, while their poor recovery ratios have been recognized, there has 20 apparently been little or no appreciation of the fact that adsorbers must compete with the binding capacity of colloids in order to accumulate trace analytes.
Accordingly, it is desirable to develop a compact form of a binder-free analytical trapping medium 25 that will allow the extraction of ultra-trace level quantities of non-dissolved analytes found in non-saline water. Further, it is desirable to collect such analytes in concentrations that will make analysis WO 94/24553 ~ ~ ~ ~ ~ ~ PCT/CA94/00190 convenient. or simply to remove them as contaminants.
A further advantageous procedure when large volumes of water are being sampled, would be to limit the sampling time to only that required to produce a 05 level of accumulated analytes susceptible to convenient detection.
It is on the basis of this background that the present invention i.s directed to improving the procedure by means of which ultra-trace analysis of large volumes of water and 'the removal of ultra-trace contaminants may be carried-out .
The invention in its general form will first be described, and then its implementation in terms of specific embodiments will be detailed with references to the drawings :following hereafter. These embodiments are intended to demonstrate the principle of the invention, and the manner of its implementation. The invention will then be :Further described, and defined, in each of the individua:L claims which conclude this Specification.
Summary of thEa Invention According to the invention in its broadest sense, improvE:d analytical trapping media have been devised by fo~.-ming .a three dimensional, depth-filter matrix of micro-porous adsorbent material that will provide substantially irreversible binding sites for the entrapment of colloidal carriers and analytes present in non-saline wager. After exposure of such media to water WO 94/24553 ~ ~ ~ ~ ~ PC'TICA94100190 which is to be sampled, ultra-trace analysis may be carried-out either directly on the analytes entrained within the entrapped colloidal carriers (e.g. by spectroscopy techniques), or by extraction.
05 The trapping media may comprise a variety of microporous materials that present "active" hydroxyl groups over the surface of such material. "Active"
hydroxyl groups are those capable of forming new bonds with the hydroxyl-bridges found within the colloidal carriers. This is effected through the release or elimination of a hydrogen ion.
Such hydroxyl groups may be formed on the surfaces of both organic and inorganic materials. An inorganic example would be a micro-porous support coated with freshly-prepared aluminum hydroxide. Suitable supports include zeolites, kieselghur, fuller's or diatomaceous earth, alumina and silica gel. A calcined diatomaceous earth product produced by John Mansville Corporation of the United States of America and sold 2o under the trade mark CELITE is directly effective in this procedure as it contains a degree of active hydroxyl groups in its natural form and has a high internal surface area with voids that readily accommodate colloidal material. CELITE, as with the other referenced micro-porous inorganic materials, will perform in a superior manner if treated to add hydroxyl groups as described above.

-~ WO 94124553 PCT'ICA94/00190 An o~cganic example of a suitable trapping media is the range of porous materials originating from Pharmacia Incorporated of the State of New Jersey, United State: of America, and sold under the trade mark 05 SEPHADEX. This material is a polymerized polysaccharide in the form of beads. Specified pore-sizes can be prepared as required, ranging from 100 to 1 million Daltons. This material contains naturally "active"
hydroxyl groups as part of the sugar structure.
Trapping media provided with active hydroxyl groups have t:he valuable feature that the colloidal carriers become irreversibly bound in the media.
Without restricting the scope of the invention claimed herein, it is. believe that this occurs due to a chemical reconstruction process in which they become bound to the hydroxyl groups. This is suggested by the fact that it has been found that for each ion of the colloid which is bound, a hydrogen ion is released. Under electron-microscopy, the immobilized colloidal gel can actually be seen accumulated within the pores of the trapping media.
It appears, therefore, that the dissociation constant for the colloidal gels, once adsorbed, has been reduced by many orders of magnitude compared to trapping on conventional adsorber materials such as AMBERLITE
(trade mark) resins.
The analytea collected on the basis of this invention may be extracted from the trapping media by WO 94124553 216 0 2 3 5 ~T~CA94100190 _ 8 known procedures. Once extracted, they may be analyzed by known techniques to determine their character and quantity. In this manner the ultra-trace analysis of the original volume of water that passed through the 05 depth-filter may be completed. Because no binders are employed in the preferred embodiment, such chemicals are not present to interfere with the process of analysis.
The efficiency of the trapping of the heavy metals within trapping media can be influenced by l0 adjusting the pH of the water sample being fed to the trapping media. The pH may be adjusted to the optimum values for effecting the precipitation, as hydroxides, of the metal, or groups of metals being isolated.
The method of the invention makes possible the 15 ultra-trace analysis of contaminants of greatest concern to society, e.g. the detection of hydrophobic organic substances and insoluble hydroxides of heavy metals.
Examples include polychlorinated biphenyls (PCB's), dioxins, furans, polycyclic aromatic hydrocarbons 20 (PAH's), most metals such as lead, chromium, cadmium, mercury, and others. The filter medium of the invention will also accumulate and concentrate bacterial, protozoa, diatoms and other microbiota. It does not, however, substantially concentrate "volatiles" (i.e. low 25 boiling point organic liquids) such as chloroform, acetone or methanal. Nor does it concentrate salts or compounds of calcium, potassium or sodium.

~w WO 94/1A553 216 0 2 3 5 PCTICA94/00190 ~n Y
-A convenient method of analysis for the presence of heavy metals in the trapping media is by X-ray fluorescence. (XRF). This technique will identify both an element and its quantity, while it is still entrained 05 within the trapping media. XRF analysis is convenient because it is inexpensive and portable. The use of XRF
is made possible because of the relatively large quantities of anal.ytes made available for analysis by the preconcentrati.on method of the invention.
For XRF to be utilized, the trapping media must be sufficiently X-ray transparent. It is ideally suited where an organic trapping media is employed. Where less transparent inorganic trapping media are used, analytes and heavy metals can often still be detected using back-scatter compensation.
A further advantage of the trapping media of this invention arises from its efficiency in removing suspended matter from the water. Subsequent analysis of the permeate for dissolved material is simplified because of the reduced incidence of contamination from suspended matter.
The :foregoing summarizes the principal features of the invention. The invention may be further understood b~~ the description of the preferred embodiments, in conjunction with the drawings, which now follow.

WO 94!24553 216 0 2 3 5 ~'~CA94100190 The invention in its general form will first be described, and then its implementation in terms of specific embodiments will be detailed with reference to the drawings following hereafter. These embodiments are 05 intended to demonstrate the principle of the invention and the manner of its implementation. The invention will then be further described, and defined, in each of the individual claims which conclude this Specification.
Summary of the Figures Figure 1 is a schematic depiction of a basic continuous-flow system for trapping contaminants in fresh water.
Figure 2 is a more versatile version of the system of Figure 1.
Figure 3 is a schematic depiction of the equipment layout for effecting X-ray fluorescence analysis of a sample of trapping media containing an analyte.
Figure 4 is a side view of an assembly for carrying the trapping media in a cartridge form.
Figure 5 is an exploded side perspective view of the assembly of Figure 5.
Figure 6 is a schematic depiction of the entrapment of a colloid on the surface of the trapping media of the invention.
Description of the Preferred Embodiments In Figure 1 a flow of water 1 enters a cylinder 2 containing a column 3 of trapping media 4 supported on WO 94/24553 ~ ~ ~ ~ ~ PCT/CA94/00190 filter paper 5. Above the media 4 is a glass fiber matrix 6 for the removal of larger sized particulates.
In a preferred embodiment the trapping media 4 is CELITE
(trade mark) upon whose surfaces has been deposited a 05 thin layer oi: alum:inum hydroxide, preferably freshly-prepared. Alternately, magnesium hydroxide, for example could be deposited if it was desired to test for aluminum comF>ounds as an analyte. A meter 15 registers the flow of water :L.
The column 3 receives the flow of water 1 in the manner of a depth filter. Colloids, typically aluminum sulphate colloids, become bound to the surface and within the pores of the trapping media 4. Analytes within the colloids thereby become immobilized and accumulate within t:he trapping media 4.
The flow of: water 1 is maintained until, gradually, the accumulation of trapped analytes reaches a concentration which will be convenient for analysis. Analysis; is carried-out, in one variation, by transportation of t:he trapping media 4 to a laboratory where standard procedures are applied. Alternately, as shown in Figure 3, x-ray fluorescence analysis may be effected in-situ.
In Figure 2 a more complex double filtering system is provided with two branches, a first combined organic and i:norgan.ic extraction branch 7, and a second inorganic extraction branch 8. Water may enter from a self-pressurized source through feed valve 9, or from WO 94/24553 PC'TICA94100190 an unpressurized source through a feed valve 10 wherein a pump 11 provides the pressure. A bleed valve 12 may be connected on the down-stream side of these valves to release water from the system.
05 A pressure meter 13 may be provided and an auto-shut-off pressure limiting valve 14 installed to protect system components from over-pressure conditions. Branch valves 15, 16 provide water access to the respective branches.
In the first, combined analysis branch 7, a mixer 17 may be included to incorporate "spiked" or injected standard quantities of a calibration compound into the water flow. A bypass valve 18 permits water to bypass the subsequent filter components for flushing-out the rest of the system and to allow for stabilization on a continuous flow basis to be established.
In branch 7 a cylinder 2 with filter column 3 according to the invention is provided, followed by a resin column 19. A check valve 20 passes the exiting water through a flow meter 21 to enter the return supply line 22. Up to the check valve 20 it is preferable to form all conduits from non-organic matter e.g. stainless steel, as branch 7 is intended to analyze for organic analytes.
In the inorganic branch 8, the mixer 17A is placed within a recirculating loop 23 powered by a recirculating pump 24 and incorporating an alkali reservoir 25 and pH sensor and controller 26. A

WO 94124553 216 0 2 3 5 ~T~CA94f00190 controllable bypass valve 18A permits diversion of flow through a bypass 27, allowing a steady-state level of pH
to be established for the water arriving at the bypass valve 18A. .A preferred pH level is in the range of l0 05 to 12. The ;pH level is established by control of the flow through the reservoir 25 in response to a preset target pH pr~wided to the sensor 26. Control is effected thr~~ugh a link 50. Once the desired pH is established, flow is diverted through the trapping media 4A. Water tlhen exits the branch 8 through check valve 20A, flow meter 21A and leaves the system via the return supply line 22.
In the inorganic branch 8, organic conduits, such as poly~aropylene piping may conveniently be used.
The 'trapping media 4 in the combined branch 7 helps to avoid exposure of the resin column 19 to particulates. It also may be used to accumulate particulates and to trap a portion of the organics at the pH level of the infeed.
The strapping media 4A in the inorganic branch may be removed and replaced with fresh media 4A as different pH levels are established. The establishment of different pH levels will allow for maximized concentration of differing analytes that are pH
sensitive.
In Figure 3 an X-ray source 28 is located adjacent to i~he trapping media 4 in situ. The X-rays 29 WO 94/245°' 216 0 2 3 5 ~T/~~4/00190 penetrate the media 4 and are reflected back into a combined emitter/receiver 30 which detects the fluorescence generated in the media 4 by the X-rays 29.
The receiver 30 provides an output 31, optionally at a 05 remote location 32 via a communication link 33, which provides data on the identity and quantity of analytes, typically heavy metals, present in the trapping media 4.
By including in the transmitted data sent to the receiver 30 the output of the water meter 21,21A the display at the output 31 can be formatted in terms of the concentration of the measured analytes within the sampled water stream 1.
In Figure 3, the X-ray source 28 may be provided with a pre-set level for the concentration of a target analyte before providing an output. This will ensure that results are obtained with a desired level of confidence and not prolonged unduly. This level may typically be 10 times the threshold level for detection.
When the pre-set level of concentration in the trapping media 4 has been reached, the X-ray source 28 may provide a signal that further sampling is no longer required. The sampling procedure may then be terminated. This may be effected by an automatic shut-off device that closes the relevant valves 9, 10.
Figure 4 and 5 show a detail for a holder 30 that carries the column 2 containing the trapping media 4.

"' WO 94/24553 ,'~~ PCT/CA94/00190 The ~aedia 4, in the form of a compressed cake, is placed between upper 31 and lower 32 screens respectively of coarser and finer meshes. These components a:re in turn contained within a portable 05 cartridge 33 container having a upper containment rim 34 with a centr~il hole, and a lower cup 35, also with a central hole.
The :Lower cup 35 sits within a pressure cylinder 36. The assembly is compressed by a screw 37 between a lower adjustable carrier plate 38 and an upper lid 39.
"O" rings 40 positioned at the interfaces provide pressure resisting seals when the screw 37 is tightened.
Inleit 41 allows water to enter the assembly.
Bleed valve ~42 permits trapped air to be bled-off.
Outlet 43, conveniently mounted into the pressure cylinder 36 through its flat lower surface, permits water to escape. A notch 44 in the carrier plate 38 provides cle~~rance for the outlet 43.
The advantage of this assembly is that users in the field can readily load and remove the cartridge 33 for transport to a remote location for analysis.
Turning to the performance of trapping media 4, tests have b~sen carried-out using both uncoated CELITE
and CELITE wlZich has been treated by exposure to 0.4 millimoles o:E aluminum hydroxide per gram of CELITE.
Table 1 list;a the recovery on untreated CELITE of amounts of grace metals from water to which the listed WO 94/24553 PC'fICA94100190 metals have been added, or "spiked", at a concentration of 20 parts per billion, with varying levels of pH.

RECOVERY OF TRACE METALS BY UNCOATED CELITE
05 (20ppb Spiked Ultra Pure Water Sample) (averaged recoveries over 6+ tests) pH Pb Cu Cd Hg Cr As 6 14.3 0.0 13.4 11.0 1.9 2.4 7 10.1 0.0 6.9 7.9 3.0 10.7 8 7.2 0.0 7.0 9.4 2.0 15.3 9 14.8 0.2 9.1 5.7 6.0 6.9 10 19.6 19.7 14.2 16.2 8.0 10.0 11 19.9 19.4 19.6 12.3 0.0 12.1 12 19.2 14.1 19.3 19.3 0.0 11.2 From Table 1 it is apparent that differing pH levels are suitable for maximizing the recovery of different metals. Further, the recovery ratios can be calibrated to permit projections to be made of the full content of analyte within a sample, when a standard proportion is recovered at a specific pH level.

WO 94/24553 ~ ~ PCT/CA94/00190 Table 2 lists similar results for treated CELITE.

PERFORMANC1~ OF COATED CELITE WITH VARIOUS HYDROXIDES

(Percentages of Metals Trapped In The Filter) 05 Hydroxide Treatment p1i Pb Cd As Cr Cu Hg 8 92.00 97.00 28.64 34.67 63.67 78.67 Mg 9 89.67 80.67 15.00 33.33 34.33 73.00 92.64 97.32 21.34 32.00 40.00 79.00 10 l:l 90.67 96.00 52.67 20.00 64.32 83.33 8 92.00 98.33 92.33 24.00 51.67 74.33 Fe 9 92.00 96.33 59.67 27.33 55.33 76.00 10 92.00 98.00 73.33 20.67 50.00 72.00 1~L 91.33 98.00 65.34 26.65 56.00 76.30 8 92.00 51.67 29.00 17.33 2.33 64.60 A1 9 91.67 82.67 22.00 10.65 9.67 63.67 1() 91.69 97.65 18.00 14.00 25.00 72.30 17L 92.00 98.64 99.30 16.00 81.00 82.33 Spiked with analytes at a level of 30.00 ppb Measured Background Amount (ppb) 2.00 0.30 0.20 0.80 3.30 0.00 The c:oatirng procedure in respect of the ia med used to generate Table 2 was to dissolve an hydroxide, such as aluminum magnesium or iron hydroxide in wat er and then to impregnate the CELITE with the ater. The w CELITE is thE:n dried by a flow of air to remove the water and leave the pores impregnated with the hydroxide. 7a has been found preferable to use a freshly prepared h:Ydroxide solution, and not one at th is over 10 days old to obtain improved results.

- is -Tests have been effected with manganese hydroxide -Mg(OH)2. Other divalent metal ion hydroxides such as iron, cobalt, nickel, copper and zinc are believed to be suitable. Further, trivalent metal ion hydroxides such 05 as those of manganese, iron and chromium are also believed to be suitable.
A pesticide spiking experiment was carried out using 20L of ultra pure water. The spiking solution contained 20 uL of SUPELCO PESTICIDE MIXTURE (trade mark) and 1 ug of 4-4'dibromooctafluorobiphenyl (surrogate compound) in 100 mL of distilled water. A
CELITE-based media was prepared as per the standard aluminum hydroxide treatment procedure and 20L of spiked water was allowed to pass through the system. The extract was analysed using Gas Chromatograph-Electron Capture Detector (GC-ECD) and Mass Spectrometer (GC-MS) technology. The results are shown in Table 3.

~' WO 94/24553 PCT/CA94/00190 EFF7:CIENC'.~C OF RECOVERY FOR PESTICIDES
PESTICIDE SPIKED RECOVERY RECOVERY

AMOUNT GC-ECD GC-MS

05 (PPt) (%) ($) sxc l0 53 73 Lindane 10 52 65 Heptachlor 10 64 61 Heptachlor Ep~oxide 10 50 50 Aldrin 10 61 77 Endosulfan I 20 32 58 Endosulfan II 20 37 50 pp-DDE 20 62 73 Dieldrin 20 32 73 Endrin 20 50 75 pp-DDD 60 51 72 Endrin Aldehyde 60 70 59 Endosulfan Sulfate 60 193' 61 pp-DDT 60 56 80 Surrogate 50 56 61 ' An unknown chlorocompound co-eluted Table 4 shows the results of sampling 25 litres of Rideau River water in the vicinity of Ottawa, Canada.
In this Table 4 the recovery is broken-down between the proportions o:f analyte detected on the trapping media 4 and the resin column 19. The CELITE of Table 4, as in the previous 'tests, had been treated with aluminum hydroxide as described above.

WO 94/24553 2 ~ 6 0 2 ~T~CA94/00190 ANALYSIS OF RIDEAU RIVERWATER FOR PESTICIDES

Using Hydroxide-Enhanced CELITE

(parts per trillion)]

PESTICIDES MEDIA COLUMN TOTAL

DBCP 1.90 0 1.90 HCB 0.80 0.17 0.97 AIDRINE 0.21 0.17 0.97 op-DDE 0.50 0.76 1.26 CHLORDANE 0.00 0.00 0.00 pp-DDE 0.10 0.00 0.10 DIEDRIN + op-DD 0.13 0.00 0.13 pp-DDD + op-DDT 0.34 0.41 0.75 pp-DDT 0.00 1.16 1.16 PERMETHRINE 55.93 14.31 70.24 CYPERMETHRINE 3.31 1.57 4.88 Comment: On-site sampling of Rideau River water.
Sample volume = 25L
In all Tables the pesticides are identified using the nomenclature of the United States Environmental Protection Agency "Analytical Reference Standards and Supplemental Data for Pesticides and Other Organic Compounds", document EPA-600/9-78-012, May 1978.
Analysis was effected using gas chromatography for separation and then either mass spectroscopy or an electron capture detector for quantification.

- WO 94124553 ~ ~ PC'TlCA94100190 Table 5 snows the recovery of a series of Polychlorodibenzo-~p-Dioxins from a combined organic and inorganic analysi~~. A VARIANtm brand gas chromatograph with an electron capture detector was used. The pH was 05 at the natural level (circa pH=7). As a source of dioxins 10 litres of ultra pure water was spiked with 50 parts per trillion of dioxin mixtures (5 micrograms per millilitre each intoluene) supplied by Chromatographic Specialties Inc. of Brockville, Ontario, Canada, Catalogue No. AM8280A. The components of the spiking mixture are listed. in the first column of Table 5. The second and third columns list percentage recoveries from the filter a:nd column respectively, based on GC-ECD and GC-MS respectively. The last two columns show results from water samples taken from local rivers.

W0 94/2ds~' 216 0 2 3 5 INVESTIGATION OF SYSTEM EFFICIENCY
FOR POLYCHLORODIBENZO-p-DIOXINS
(ON CPRT'S PLAIN CELITE FILTER AND RESIN COLUMN)1 DIOXIN TRAPPED (ppt) RECOVERY RIVER RIVER
FILTER/COLUMN (ppt) (ppt) TODD 14.6 24.9 39.5 78 20.8 15.1 PnCDD 4.5 35.7 40.2 80 1.2 2.1 HxCDD 24.5 129.4 153.9 308 3.2 0.8 HpCDD 6.8 29.0 35.8 72 0.4 2.3 OCDD 10.4 35.9 46.3 93 1.0 5.1 pH 7 1 lOL ultrapure water spiked at 50 ppt level 2 30L of river water was sampled at a site downstream of the Eddy/Scott Paper Mills 3 A lOL Grab sample was pumped through the system at CPRT
Laboratories Results obtained using Kieselghur that had been impregnated with A1(OH)3 at a level of 0.2 mmole A1(OH)3 per gram of Kieselhur at pH 11 as the trapping media are as follows in Table 6:

TABi.E 6 RECOVERY OF METALS
(KIESELGHURC AS TRAPPING MEDIA) Metals Pb Cd Cr 05 Amount of spike (ppb) 20 20 20 Amount recovere~3 20 19 . 8 7 , 7 g Recovery 100 9g 3g,5 Table 7 shows. a comparison of the performance of a series of filter media in terms of the volumes of water trot may lbe sampled before significant back-praacure Erom filter plugging develops.

FI: LTER PERFO~RNCE
Run ~ Flow Fil~tar Turbidity Prosaure Volume Rate 4 . 7 ~cM dia, NTU gm/cm ( L
. 2 ps i ) mL/min Input/output 1. 200 W-934-AH l.5uia 0.15/0.13 l4Cb {20) 10 2. 200 W-GE/F 0.7um 0.15/0.08 1406 (20) 4 3. io0 CJ~:BRIpG~l.Oum 0.15/0.13 l4os (20) 40 4. 200 CAMBRIDGEI.Oum 5.0 /Z.0 1406 (20) 4 5. 100 ACTIYRT$D~ 10.C/1.45 1758 (25) 10 CARBON

6. 100 CELLUIDSE~ 10.0/0.6 1758 (25) 1 7. 100 SiL;IC~A GEL 5. o /<1. 1758 (z5) i 8. 100 GAC 5.0 /<1.0 1758 (25) Z

9. 100 SEP;H?~DEX 5.0 /<1.0 1758 (25) 1 10. 100 CELITE 0.15/O.IO 351 { 100 5) - (unmodifi.erl) 11. 200 C:BLZTE 5.0 /0.a 70 { 20 1) ( ~unmodi, f fed ) 12. 200 C'ELITB 10.0/0.67 700 (10) 20 ( unmod i. r ied ) 13. 200 CBLITE 10.0/0.50 633 ( 60 9) l~f ied) 14. - 100 CELITE 10.0/0. 67 351 ( 30 5) (uamodi,fied) ~' WO 94124553 PCTICA94100190 1. W-934-AH :L.S um Filter Paper from the Cambridge Filter Pa~~er Company, U.S.A.
2. W-GF/F 0.'7 um Filter Paper from the Cambridge Filter Paper Company, U.S.A.
05 3. Cambridge 1.0 um Filter Paper from the Cambridge Filter Paper Company, U.S.A.
4. Cambridge 1.0 um Filter Paper from the Cambridge Filter Paper Company, U.S.A.
8. GAC Granular Activated Carbon supplied by Aldrich Chemicals, U.S.A.
9. SEPHADEX Gel Filtration Resin supplied by Aldrich chemicals, U.S.A.
Electron microscope scans of CELITE have been taken at a ma~gnific.ation of 4000. These images show uncoated CELI'TE, C'.ELITE coated with 0.2 mmoles per gram of aluminum hvydroxide on CELITE and the same type of treated sample of C'ELITE after it has been exposed to water containing 20~ ppb/litre quantities each of arsenic, copper, chromium,' cadmium, mercury and lead.
The degree of occlusion of the pores progressively with the coating of the media, and after exposure to water containing contaminents is apparent in these microscans.
While not wishing to be bound by the following, Figure 6 depicts one theory of the operation of the trapping media of this invention. In Figure 6 the wall 35 of a portion of microporous trapping media 4, such as diatomaceous earth, surrounding a pore 36 is shown in cross-section. Along the inside surface 39 of the pore 36, an hydroxide complex 37 presents an "active"

~1~'023 hydroxidQ group 38 outwardly from the inner surface 39.
In the adjacent, surrounding water 40, colloidal carriers 41 are present to which are adhered analytes 42. The colloidal carrier 41.A upon entering tre pare 36, is t» believed to form new bonds with the hydroxyl group 38, releasing hydro~~en ions 43, converting the distributed colloids into a gel. 'This irreversibly fixes the colloid 41A to the trap~~ing media 4 to a degree not present with adsorbers.
The analyt~ss 42 are entrained within the colloids 41 and become similarly entrapped. They are then available for analysis by the customary procedures.
It has also green found that CELITE (tm) in particular wil3. trap bacteria and protozoa ~tnd, it is believed, diato~~as and other taulticell rniCrobiota.
Samples of giax~dia azid cryptospirodiurn protozoa, and salatonella bacteria have been concentrated in the CE?~ITE
filtor modium. The effectiveness of filter media of the invention in effecting :uch a concentration may be due in part to the pr~ser~ce of a charge distribution on such organic micro-c=rgani~sias .
Once conci~ntratad in the filter medium by whatever mechanism, a w~3shing solution taken from the medium was able to innocttlate gel and produce cultures of these bacteria. Acc~ordin~gly, the invention extends to the concentration of such micro-organisms as a class of analytes.

wWO 94124553 ~r PCT/CA94100190 ~~
_ _ Conclusion The foregoing has constituted a description of specific embodiments showing how the invention may be applied and put into use. These embodiments are only 05 exemplary. The invc=ntion in its broadest, and more specific aspects, ia~ further described and defined in the claims which now follow.

Claims (20)

WHAT IS CLAIMED IS:

1. A trapping medium for trapping naturally occurring metallic colloids, having as analyte entrained therein, that are present in non-saline water flowing through the trapping medium, the trapping medium comprising a three-dimensional matrix of micro-porous adsorbent support material, which provides irreversible binding sites for the entrapment of colloids and analytes, the support material having internal surfaces, and a substance, which bears active, hydrated hydroxyl groups, deposited thereon for immobilizing said colloids on said surfaces through the release of hydronium/hydrogen ions from the hydroxyl groups.

2. A trapping medium as described is claim 1, wherein said micro-porous support material comprises diatomaceous earth.

3. A trapping medium as described is claim 2, wherein said diatomaceous earth comprises calcined diatomaceous earth.

4. A trapping medium as described in claim 1, 2 or 3, wherein the deposited substance comprises a metal hydroxide.

5. A trapping medium as described in claim 4, wherein the metal hydroxide is selected from the group consisting of divalent or trivalent aluminum hydroxide, magnesium hydroxide, divalent or trivalent iron hydroxide, divalent or trivalent manganese hydroxide, nickel hydroxide, cobalt hydroxide, copper hydroxide or zinc hydroxide.

6. A trapping medium as described in claim 3, r the medium being the calcined diatomaceous earth product produced by John Mansville Corporation of the USA and sold under the trademark CELITE®.

7. A trapping medium as described in claim 1, the medium being an organic medium produced by Pharmacia Inc. of the State of New Jersey, USA and sold under the trademark of SEPHADEX®.

8. A trapping medium as described in any one of claims 1 to 7, and a pH adjusting substance in association with the trapping medium for locally adjusting the pH level of said water.

9. A method of preparing a trapping medium for trapping metal colloids present in non-saline water, the method comprising the steps of:
(a) providing a three dimensional matrix of a micro-porous support material having internal surfaces;
(b) impregnating the micro-porous support with a water solution having a metal hydroxide dissolved therein; and (c) drying the impregnated micro-porous support by a flow of air, thereby removing the water and leaving the internal surfaces of the support material impregnated with the hydroxide to provide irreversible binding sites for the entrapment of metallic and analytes entrained therein, when the impregnated support material is exposed to a non-saline water containing said colloids and analytes, by immobilizing said colloids and analytes on said surfaces through the release of hydronium/hydrogen ions from the hydroxyl groups.

10. A method as described in claim 9, wherein the step (a) comprises providing the micro-porous support comprising diatomaceous earth or calcined diatomaceous earth.

11. A method as described in claim 9, wherein the step (b) comprises impregnating the micro-porous support material with the water solution having a metal hydroxide, which is selected from the group consisting of divalent or trivalent aluminum hydroxide, magnesium hydroxide, divalent or trivalent iron hydroxide. divalent or trivalent manganese hydroxide, nickel hydroxide, cobalt hydroxide, copper hydroxide or zinc hydroxide.

12. A method as described in claim 9, wherein the step (b) comprises preparing said water solution less than 10 days before impregnating the micro-porous support material with said water solution.

13. A system for analyzing water for the presence of an analyte is the presence of colloids, comprising:
means for exposing inorganic trapping media, which is a three-dimensional matrix of micro-porous adsorbent material providing irreversible binding sites for the entrapment of colloids and analytes, the adsorbent material having internal surfaces which bear active, hydrated hydroxyl groups thereon, to a measured volume of continuously flowing non-saline water under alkaline conditions containing naturally occurring metallic colloids and an analyte entrained therein at ultra trace levels being a concentration of less than one part per billion, to allow said hydrated hydroxyl groups immobilize said colloids on said surfaces to progressively accumulate a coating of colloids as a gel through the release of hydronium/hydrogen ions, until a measurable quantity of analytes is deposited within the trapping media; and means for analyzing said trapping media to determine the identity and quantity of analyte therein.

14. A system as described in claim 13, wherein the means for analyzing comprises means for spectroscopic or chromatographic analysis of the analyte.

15. A system as described in claim 13, wherein said means for exposing and said means for analyzing respectively comprise means for exposing and means for analyzing suitable for performing exposing and analyzing in-situ.

16. A systems as described in claim 13, wherein said means for exposing comprises a pH adjusting means associated with the trapping medium for locally adjusting the pH of the flowing water to effect the precipitation of the dissolved metals from solution in the vicinity of the trapping media.

17. A system as described in claim 16, wherein the pH
adjusting means comprises the pH adjusting means capable of maintaining the pH of the flowing water in the range of about to 12.

18. A cartridge container for housing a trapping medium for trapping metallic colloids present in non-saline water, comprising: a lower cup covered with an upper containment rim housed within the cartridge container, and the trapping medium of claim 1 disposed between an upper screen and a lower screen within the lower cup, both the cup and the rim having respective holes for allowing the water to flow through the trapping medium, the cartridge container to be planed in a pressures environment.

19. The cartridge container as described is claim 18, wherein the upper and lower screens are comprised of coarser and finer meshes respectively.

20. A cartridge container for housing a trapping medium for trapping metallic colloids present in non-saline water, the cartridge container housing the trapping medium as described in claim 1.