METHOD FOR WATER PURIFICATION AND SANITIZATION

Abstract

A method of purifying water polluted with one or more organic compounds, includes adding a peroxide source to the polluted water in an alkaline environment in the presence of at least one additive selected from the group consisting of surfactants and phase transfer catalysts, optionally feeding oxygen or an oxygen-releasing substance to the water, separating the so-formed reaction mixture into aqueous and organic phases, to recover a treated water stream by an organic stream, wherein the purification of the water by the removal of organic pollutants is achieved at ambient temperature. The method can also be used for disinfection of water polluted with microbial pollutants.

Claims

1. A method of purifying water polluted with one or more organic compounds, comprising adding a peroxide source to the polluted water in an alkaline environment in the presence of at least one additive selected from the group consisting of surfactants and phase transfer catalysts, optionally feeding oxygen or an oxygen-releasing substance to the water, separating the so-formed reaction mixture into aqueous and organic phases, to recover a treated water stream and an organic stream, wherein the purification of the water by the removal of organic pollutants is achieved at ambient temperature.

2. The method according to claim 1, comprising adding alkali hydroxide to the water to create an alkaline environment and gradually feeding hydrogen peroxide to the water.

3. The method according to claim 2, wherein the surfactant is an anionic surfactant or nonionic surfactant and the phase transfer catalyst is a quaternary ammonium salt consisting of a cation of the formula N.sup.+R.sub.1R.sub.2R.sub.3R.sub.4, wherein each of R.sub.1, R.sub.2, R.sub.3 and R.sub.4 is independently Cl-C18 alkyl group, and a counter anion.

4. The method according to claim 1, wherein the organic pollutants to be removed are devoid of nitrogen and phosphorus atoms.

5. The method according to claim 4, wherein the organic pollutants comprise one or more aromatic compounds selected from the group consisting of benzene, alkyl-substituted benzene, polycyclic aromatic hydrocarbons consisting of two or more aromatic rings fused together, and halogenated aromatic rings.

6. The method according to claim 4, wherein the organic pollutant is a halogen-substituted aliphatic hydrocarbon.

7. The method according to claim 1, wherein the organic pollutants to be removed comprise one or more pharmaceuticals.

8. The method according to claim 7, wherein at least one pharmaceutical is a fused-ring compound.

9. The method according to claim 8, wherein at least one pharmaceutical is dibenzoazepine drug.

10. The method according to claim 9, wherein the dibenzoazepine drug is carbamazepine.

11. The method according to claim 1, wherein the polluted water is groundwater.

12. The method according to claim 1, further comprising bubbling neat oxygen, oxygen-rich air or air through the polluted water.

13. A method of disinfecting water polluted with microbial pollutants, comprising adding a peroxide source to the polluted water in an alkaline environment in the presence of at least one additive selected from the group consisting of surfactants and phase transfer catalysts, optionally feeding oxygen or oxygen-releasing substance to the water, separating the reaction mass into aqueous and organic phases, to recover treated water stream and a recyclable organic stream.

14. The method according to claim 12, comprising adding alkali hydroxide to the water to create an alkaline environment and gradually feeding hydrogen peroxide to the water.

15. The method according to claim 13, wherein the surfactant is an anionic surfactant.

16. The method according to claim 3, wherein the surfactant is an anionic surfactant or nonionic surfactant and the phase transfer catalyst is a quaternary ammonium salt consisting of a cation of the formula N.sup.+R.sub.1R.sub.2R.sub.3R.sub.4, wherein each of R.sub.1, R.sub.2, R.sub.3 and R.sub.4 is independently Cl-C18 alkyl group, and a counter anion.

17. The method according to claim 2, wherein the organic pollutants to be removed are devoid of nitrogen and phosphorus atoms.

18. The method according to claim 3, wherein the organic pollutants to be removed are devoid of nitrogen and phosphorus atoms.

19. The method according to claim 2, wherein the organic pollutants to be removed comprise one or more pharmaceuticals.

20. The method according to claim 3, wherein the organic pollutants to be removed comprise one or more pharmaceuticals.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] FIG. 1 shows an illustrative design of the process.

[0034] FIG. 2 shows spectra recorded to monitor decomposition of Rhodamine B over time, alongside a set of samples indicating the vanishment of the characteristic intense pink color of Rhodamine B.

[0035] FIG. 3 is a photo of the experimental set-up that was used in Example 9.

[0036] FIG. 4 shows conversion percentage versus time curves plotted for Experiments A and Bin Example 10.

[0037] FIG. 5 is a bar diagram showing conversion percentage of carbamazepine.

DETAILED DESCRIPTION

Examples

Methods

[0038] UV-Vis spectroscopy: 1800 UV spectrophotometer, Shimadzu, Japan.

[0039] Gas chromatography - flame ionization detector (GC-FID): Famewax column, 30 m, 0.32 mm ID, 0.25 mm (Restek™ Famewax).

[0040] HPLC: LC-MS, QTOF 6520, manufactured by Agilent.

[0041] TOC: multi N/C pharma UV, TOC analyzer, manufactured by AnalytikJena.

Examples 1 to 8

Degradation of Organic Pollutants in Water by the Combined Action of Sodium Hydroxide and Hydrogen Peroxide in the Presence of Organic Additive

[0042] A 50 ml round bottom flask equipped with a magnetic stirrer was charged with 10 ml of water polluted with an organic compound as tabulated in Table 1. The initial concentration of the organic compound (Ci) in the water is set out in Table 1.

[0043] Sodium hydroxide in a solid form was rapidly added and dissolved, followed by addition of either a phase transfer catalyst or a surfactant. Next, hydrogen peroxide solution (30% strength) was added very slowly over an ‘addition time’. Upon complete addition of the hydrogen peroxide, the mixture was held under stirring for a period of time (‘hold time’). The amount of sodium hydroxide added (m.sub.NaOH), the additive employed, the volume of H.sub.2O.sub.2 solution added (V.sub.H2O2), the addition time of H.sub.2O.sub.2 and the hold time are set out in Table 1 for each experiment.

[0044] The reaction mixture was extracted with dichloromethane (10 ml). The mixture was separated into organic and aqueous phases and the organic (dichloromethane) phase was analyzed by GC-FID to measure the final concentration of remnant of organic pollutant (C.sub.f) and calculate percentage of decomposition achieved. The experimental conditions and results are tabulated in Table 1.

TABLE-US-00001 Ex pollutant C.sub.i (ppm) m.sub.NaOH (g) Additive A, B or C (ml) V.sub.H202 (ml) Addition time (min) Hold time (min) C.sub.f (ppm) Decom. % 1 Rhodamine B 1000 1 A 0.5 1.5 ~1 60 2 99 2 Rohdamine B 125 0.1 A 0.05 0.15 ~1 60 0.16 99 3 ClCH.sub.2CH.sub.2Cl 850 0.1 A 0.05 0.15 ~1 60 0 100 4 CCl.sub.4 800 0.1 A 0.05 0.15 ~1 60 0 100 5 chlorobenzene 500 0.2 B 0.1 0.35 ~1 60 9 98 6 toluene 500 0.1 C 0.05 0.15 ~1 60 5 99 7 Xylene* 100 0.1 A 0.05 0.15 ~1 60 1 99 8 Naphthalene 30 0.5 B 0.2 0.75 ~1 60 0 100 * Xylene used in the experiments described herein consists of a mixture of the three xylene isomers. A - Aliquat 336 B - sodium lauryl sulfate (SLS) C - Alkanol 6112

[0045] Rhodamine B (RhB) is a water-soluble chemical dye which is commonly used as a benchmark to assess the potency of oxidants to decompose organic pollutants in aqueous solution and measure the rate of degradation. De-colorization of RhB solution, that is, the disappearance of the characteristic intense pink color, is readily visible as the decomposition of the dye advances under the action of the tested oxidant and the oxidation reaction can be monitored with UV-Vis spectroscopy. FIG. 2 shows the spectra recorded to monitor RhB decomposition over time (note the characteristic strong absorption peak at ~560 nm which gradually vanishes). A photograph of a set sample solutions exhibiting the color change, from intense pink to colorless solution, is also provided. Decolorization of 1000 ppm and 125 ppm RhB solutions was completed within eleven minutes and two minutes, respectively, i.e., well before the end of the experiments.

Example 9

Inactivation of Bacteria in Water by the Combined Action of Sodium Hydroxide and Hydrogen Peroxide and Oxidation of Carbon Content of the Bacteria

[0046] The procedure described in the previous set of Examples was repeated, this time using water polluted with E-coli. The experimental conditions and results are set out in Table 2. The organic additive used was anionic surfactant sodium lauryl sulfate (SLS) .

TABLE-US-00002 Ex pollutant C.sub.i (CFU/ml) mNaOH (g) Additive (ml) V.sub.H2O2 (ml) Addition time (min) Hold time (min) C.sub.f (CFU/ml) Decom. % 9 E-coli 3*10.sup.7 0.01 0.1 0.015 ~1 60 0 100

[0047] The data in Table 2 demonstrates the bactericidal effect generated by the combination of hydrogen peroxide and alkaline hydroxide with the aid of sodium lauryl sulfate.

[0048] To show the decomposing activity of the H.sub.2O.sub.2.sup.+NaOH combination, the experimental set-up (20) shown in FIG. 3 was used. A round single-necked flask which contains the reaction mixture (21) is provided with an adapter (22) fitted with a pipe (23) to deliver gaseous reaction products into a beaker (24) charged with barium chloride solution. The water used in the experiment is devoid of carbonate and the set-up is designed to collect carbon dioxide which may be generated by the reaction due to partial or complete oxidation of the carbon content of the bacteria. Formation of carbon dioxide could manifest itself in two ways: [0049] (i) generation of water soluble sodium carbonate in flask (21), as a result of CO.sub.2 conversion to carbonate by the action of radicals such as superoxide produced on addition of hydrogen peroxide to alkaline environment; and [0050] (ii) precipitation of the water insoluble barium carbonate salt in beaker (24), which takes place when carbon dioxide evolving in the reaction mixture escapes from flask (21), flows through pipe (23) and dissolves in the barium chloride solution (24).

[0051] In a typical experiment, the barium chloride solution retained its clarity and no cloudiness indicative of barium carbonate precipitation was observed in beaker (24). But on drying the reaction mixture (21) in an oven at 200° C. to completely remove the water, a solid was collected which was found to consist essentially of sodium carbonate Na.sub.2CO.sub.3, as determined by X-ray powder diffraction analysis.

Example 10

Degradation of an Aromatic Pollutant by the Combined Action of Sodium Hydroxide and Hydrogen Peroxide in the Presence of Organic Additive and Added Oxygen

[0052] Experiment A: In the reference experiment, a 50 ml round bottom flask equipped with a magnetic stirrer was charged with 10 ml of water polluted with 100 ppm of xylene. Sodium hydroxide (0.5 g) was rapidly added followed by addition of 0.02 ml of a phase transfer catalyst (Aliquat 336) Next, 1 ml of aqueous hydrogen peroxide (30% solution) was introduced over 5 minutes. After the addition of hydrogen peroxide solution has been completed, the mixture was held under stirring for ten minutes.

[0053] Experiment B: To assess the effect of added oxygen, the procedure set forth above was repeated but after the addition of hydrogen peroxide, pure oxygen was bubbled to the system at a flow rate of 1 ml/min over 30 minutes. Upon completion of O.sub.2 addition, the mixture was stirred for ten minutes.

[0054] For each experiment, samples (0.5 ml) were taken from the reaction mixture at intervals of one minute during the ten minutes hold time and the concentration of remnant xylene was measured by GC-FID. The final reaction mixture was extracted with dichloromethane (10 ml) and analyzed by GC-FID as previously described. Conversion percentage versus time curves are plotted in FIG. 4 for Experiments A and B. The results indicate the enhancement of conversion rate achieved with the aid of added oxygen, reaching complete oxidation of the pollutant after a hold time period of about six minutes (compared to ten minutes hold time needed in Experiment A in the absence of added oxygen).

Example 11

Degradation of a Pharmaceutical by the Combined Action of Sodium Hydroxide and Hydrogen Peroxide in the Presence of Phase Transfer Catalyst and Added Oxygen

[0055] A series of experiments was carried out to examine the decomposition of carbamazepine by the method of the invention.

[0056] A 50 ml round bottom flask equipped with a magnetic stirrer was charged with 10 ml of water polluted with 1-100 ppm of carbamazepine (concentrations of 1, 10 and 100 ppm were examined). Sodium hydroxide (0.5 g) was rapidly added followed by addition of 0.02 ml of a phase transfer catalyst (Aliquat 336) Next, 1 ml of aqueous hydrogen peroxide (30% solution) was introduced over 5 minutes. After the addition of hydrogen peroxide, the mixture was held under stirring and pure oxygen was bubbled to the system at a flow rate of 0.5 ml/min over 10 minutes. For each experiment, at the end of the process the final reaction mixture was extracted with 5 ml of Acetone: hexane solution (1:1) and carbamazepine remnant concentration was measured by LC-MS, QTOF 6520, manufactured by Agilent.

[0057] The results are shown by a bar diagram appended as FIG. 5. It is seen that very high decomposition rates of the drug were achieved (>90% conversion) for the 10 and 100 ppm concentrations. The Elimination of pollutants present at very low concentrations (1 ppm) is difficult to achieve but it is seen that surprisingly high conversion rate (~70%) was measured also for the 1 ppm carbamazepine.

Example 12

Purification of Groundwater by the Combined Action of Sodium Hydroxide and Hydrogen Peroxide in the Presence of Phase Transfer Catalyst and Added Oxygen

[0058] The goal of the experiment was to test the NaOH+H.sub.2O.sub.2 action in the treatment of a sample of contaminated groundwater (by organic C.sub.6-C.sub.40 pollutants) from the Netherlands, Rotterdam area. The initial contamination level was 315 ppm, measured by multi N/C pharma UV, TOC analyzer, manufactured by AnalytikJena.

[0059] A 50 ml round bottom flask equipped with a magnetic stirrer was charged with 10 ml of groundwater polluted with organic contaminants. Sodium hydroxide (0.4 g) was rapidly added followed by addition of 0.02 ml of a phase transfer catalyst (Aliquat 336). Next, 0.8 ml of aqueous hydrogen peroxide (30% solution) was introduced over 3 minutes. After the addition of hydrogen peroxide, the mixture was held under stirring and pure oxygen was bubbled to the system at a flow rate of 0.5 ml/min over 30 minutes.

[0060] The treatment reduced pollution level in the water to 2.6 ppm measured the TOC analyzer, i.e., 99% conversion rate.

[0061] While the present disclosure has been illustrated and described with respect to a particular embodiment thereof, it should be appreciated by those of ordinary skill in the art that various modifications to this disclosure may be made without departing from the spirit and scope of the present disclosure.