**3.2. Company literature**

Several examples are available in literature provided by Metre-General, Inc. [28].

A *first exampl*e involved a Colorado plating shop with numerous plating lines, removal of Cr, Cu, Ni, and Zn was a matter of concern. The existing precipitation process did not consistently reduce heavy metal concentrations to less than required limits. By use of an Octolig® column chromatography system (cf. Figure 4), the plating shop was able to recycle the treated water and reduce the fresh water usage from 18,000 GPD (gallons per day) to 8,000 GPD [28].

electroplating aircraft parts. The area became contaminated with solvents that were used for cleaning parts as well as solutions of cadmium and chromium. Waste material was dumped into sand pits on the company property during the 1930s and 1940s. As a consequence, ground water became contaminated with low levels of solvents and low levels of cadmium and chromium, ca.0.300 mg/L (ppm). US Environmental Protection Agency designated the area as

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Metre-General, Inc. tested undiluted groundwater samples as received and at two dilutions to test the efficiency for removal at different influent concentrations. Dilute organics were removed by charcoal column chromatography. Heavy metals were removed by Octolig® column chromatography The removal system was one like that shown in Figure 4. Some 10 columns made of HDPE plastic about 35 in (89 cm) in diameter held 300 kg of Octolig®21. The columns were arranged in two banks of five each operated in parallel and designed to treat 300 GPM ( gallons per minute). The results in Table 3 indicate that concentrations of metals of

The data also indicate that Octolig® can have a long "recycling life" because the heavy metal ions were removed, not comparatively innocuous ones like calcium that affect TDS (Total Dissolved Salts). The contrast between removal of cadmium or chromium versus non-removal of calcium ion shows the advantage of being able to design supported chelators for specific purposes. Supported iminodiacetic acid, for example would have removed cadmium, but also

calcium ions as well, reducing in this instance the useful capacity of this material..

**Table 3.** Summary of results of bench-scale treatment of Liberty Industrial Finishing Superfund Site.

Quantitative removal of uranyl ion, UO2 ++, from aqueous solutions (well water)was demon‐ strated using the standard chromatography technique. Solutions of uranyl acetate (50 ppm)

**Dilution Element Influent Concentration, ppm Effluent Concentration, ppm**

None Cd 0.280 0.029 1:5 Cd 0.061 0.007 1:10 Cd 0.032 <0.005 None Cr 0.090 <0.005 1:5 Cr 0.023 <0.005 1:10 Cr 0.010 <0.005 None Ca 25.0 25.0 1:5 Ca 5.1 4.8 1:10 Ca 2.7 2.5

a Superfund site in the 1990s [28],

From [28] and used with permission

**3.3. Refereed literature**

concern were reduced to below required limits.

**Figure 4.** Application example –The Octolig® ENVIRO-4000 of Metre-General, Inc.

Specifications included two 56-gallon HDPE tanks, a 120 V pump, on/off float switch, rota‐ meter with flow-rate adjustment, two pre-filters, and four filters with refillable Octolig® cartridges. Size is 52"x52" with a 68 gallon spill containment. From [28] and reproduced with permission.

The results of the study are summarized in part in Table 2 and demonstrate two useful consequences. The first result was an effective removal of nuisance transition metal ions: 98% removal of zinc ion, 93% removal of nickel(II), 73% removal of copper(II) species. The second result, as a consequence, was the ability to reduce the fresh water intake by recycling reducing water usage by 67%.


**Table 2.** Effect of Octolig® treatment on concentrations, ppm, of selected metals [28]

A *second example* involved a similar unit installed at a gold mine located in mountains west of Denver, Colorado [27].The chief contaminant in the mine drainage water was zinc, and about 4 million gallons of mine drainage waster was discharged yearly at the gold mine. A two-fold treatment was tested. First, water flowing into a settling pond (33 ft. by 40 ft., 3 ft. deep) was crudely treated with lime. Second, the overflow was pumped through pre-filters then into an Octolig® MRP (metal removal plant) unit. In a pilot study, treated water contained only 0.02 ppm zinc. It was calculated that costs of the installation were less than \$0.70 per 100 gallons of drainage water [28]. And probably one should remember the value of water in certain arid parts of the western United States.

A *third example* [28] involved a Superfund site. Octolig® was used in a bench test of material from the Liberty Industrial Finishing Superfund site, a 30-acre parcel in the village of Farm‐ ingdale, Nassau County, New York state. At this location, Republic Aviation produced military aircraft for the US government from the late 1930s until the 1960s. Operations involved electroplating aircraft parts. The area became contaminated with solvents that were used for cleaning parts as well as solutions of cadmium and chromium. Waste material was dumped into sand pits on the company property during the 1930s and 1940s. As a consequence, ground water became contaminated with low levels of solvents and low levels of cadmium and chromium, ca.0.300 mg/L (ppm). US Environmental Protection Agency designated the area as a Superfund site in the 1990s [28],

Metre-General, Inc. tested undiluted groundwater samples as received and at two dilutions to test the efficiency for removal at different influent concentrations. Dilute organics were removed by charcoal column chromatography. Heavy metals were removed by Octolig® column chromatography The removal system was one like that shown in Figure 4. Some 10 columns made of HDPE plastic about 35 in (89 cm) in diameter held 300 kg of Octolig®21. The columns were arranged in two banks of five each operated in parallel and designed to treat 300 GPM ( gallons per minute). The results in Table 3 indicate that concentrations of metals of concern were reduced to below required limits.

The data also indicate that Octolig® can have a long "recycling life" because the heavy metal ions were removed, not comparatively innocuous ones like calcium that affect TDS (Total Dissolved Salts). The contrast between removal of cadmium or chromium versus non-removal of calcium ion shows the advantage of being able to design supported chelators for specific purposes. Supported iminodiacetic acid, for example would have removed cadmium, but also calcium ions as well, reducing in this instance the useful capacity of this material..


From [28] and used with permission

chromatography system (cf. Figure 4), the plating shop was able to recycle the treated water and reduce the fresh water usage from 18,000 GPD (gallons per day) to 8,000 GPD [28].

Specifications included two 56-gallon HDPE tanks, a 120 V pump, on/off float switch, rota‐ meter with flow-rate adjustment, two pre-filters, and four filters with refillable Octolig® cartridges. Size is 52"x52" with a 68 gallon spill containment. From [28] and reproduced with

The results of the study are summarized in part in Table 2 and demonstrate two useful consequences. The first result was an effective removal of nuisance transition metal ions: 98% removal of zinc ion, 93% removal of nickel(II), 73% removal of copper(II) species. The second result, as a consequence, was the ability to reduce the fresh water intake by recycling reducing

A *second example* involved a similar unit installed at a gold mine located in mountains west of Denver, Colorado [27].The chief contaminant in the mine drainage water was zinc, and about 4 million gallons of mine drainage waster was discharged yearly at the gold mine. A two-fold treatment was tested. First, water flowing into a settling pond (33 ft. by 40 ft., 3 ft. deep) was crudely treated with lime. Second, the overflow was pumped through pre-filters then into an Octolig® MRP (metal removal plant) unit. In a pilot study, treated water contained only 0.02 ppm zinc. It was calculated that costs of the installation were less than \$0.70 per 100 gallons of drainage water [28]. And probably one should remember the value of water in certain arid

A *third example* [28] involved a Superfund site. Octolig® was used in a bench test of material from the Liberty Industrial Finishing Superfund site, a 30-acre parcel in the village of Farm‐ ingdale, Nassau County, New York state. At this location, Republic Aviation produced military aircraft for the US government from the late 1930s until the 1960s. Operations involved

**Element Cr Cu Ni Zn** Untreated water 0.30 0.80 0.60 4.20 Treated water N/D 0.21 0.04 0.0

**Table 2.** Effect of Octolig® treatment on concentrations, ppm, of selected metals [28]

**Figure 4.** Application example –The Octolig® ENVIRO-4000 of Metre-General, Inc.

permission.

130 Column Chromatography

water usage by 67%.

parts of the western United States.

**Table 3.** Summary of results of bench-scale treatment of Liberty Industrial Finishing Superfund Site.

### **3.3. Refereed literature**

Quantitative removal of uranyl ion, UO2 ++, from aqueous solutions (well water)was demon‐ strated using the standard chromatography technique. Solutions of uranyl acetate (50 ppm) were quantitatively removed by Ferrilig, Thorilig, or Octolig® [29]. Uranium is a contaminant of the mineral apatite in Florida that is a basis of the phosphate industry. Uranium can also contaminate sources of drinking water in certain areas of Colorado, and is a matter of concern for water supplies for small towns [29].

The role of coordination in reducing the oxidation potential of iron(II) is well known, and was noted by Moeller [33], a process that is enhanced when the coordinating agent is a chelating agent. Thus the oxidation potential for hydrated ferrous-ferric species is - 0.771V; whereas the value in the presence of oxalate ion is -0.02 V [34]. Octolig® has a plethora of chelating species, i. e., ethylenediimino moieties or extended ethylenediamines, that should be capable of lowering the oxidation potential of coordinated iron(II). Accordingly, the ease of oxidation should hardly be surprising. Nevertheless, it was surely interesting to note and watch. Species

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Considering the effectiveness of Ferrilig, the study of other metal derivatives ("metalloligs") was effected using what may be described as facile syntheses. The metals used were cop‐ per(II), cobalt(II), nickel(II), manganese (II), and thorium(IV) [32]. An exhaustive study can not be claimed, e.g., for all metalloligs and all anions. But all six metalloligs exhibited 99% remov‐ al of arsenic by means of column chromatography using 280 x a10-3 ppm As as Na2HAs04 [32].Other anionswere testedusingvariousmetalloligs, andquantitative removal(98-99%)was achieved for nitrate, nitrite, phosphate, sulfate, and fluoride ions in deionized water [31, 32, 35].

A *standard test* for removal ions by chromatography involved the following: A Spectra/chron peristaltic pump was used to deliver aqueous samples to a chromatography column, 2 cm (id) by 31cm and equipped with a glass frit and a Teflon stopcock. The column was packed with about 22 cm of Octolig® or other solid. Before packing, the solid was suspended in water, swirled, and the fines were decanted, a process that was repeated until no fines were observed. Water samples were chromatographed using a rate of 10 mL/min. Usually, the first three or four 50-mL aliquots of effluent were discarded, and later ones were used for analysis (Table 4). Total dissolved solids were measured, and used as a guide to assess a state of equilibrium

**ppm**

**% Removal**

II was white, species III was green, and species IV was rust-brown.

**Element Form Sample Initial Concentration,**

**Table 4.** Effect of column chromatography of nuisance species using Ferrilig [31]

As Na2HAsO4 Well water 280x 10-3 99.3 Cr Na2CrO4 DI water 50.6 95.5 Mo (NH4)6 Mo7O24•4H2O DI water 50.7 94.7 Se Na2SeO3 Well water 258 99.9

In a subsequent study, some attention was focused on the use of Cuprilig, obtained by a truly facile synthesis by shaking a suspension of Octolig® in deionized water and a standard solution of copper sulfate in deionized water. Cuprilig was tested for removal of perchlorate ion, which is a serious problem in certain areas, most notably in Rialto, California where one source of well water contained 10,000 ppb perchlorate. This remarkable concentration was probably a consequence of a plume of contaminated water, owing to proximity to a facility that produced ammonium perchlorate, the propellant for the sidewinder missile [37]. Obvi‐

[29-31, 35-38].

Gao and co-workers measured the absorption properties of an Octolig®- like material [13] by a batch and a flow methods. Quantitative reaction was reported, and the absorbing ability of the PEI-silica material followed the order of Cu2+ > Cd2+ > Zn2+ at a pH of 6-7 [13]. They also measured the saturated absorption uptake and reported values for copper(II) of 25.95 mg/g and 50.01 mg/g, respectively, for static and dynamic conditions [13].
