RU2470051C1 - Heterogeneous sensitising agent and method for photodecontamination of water from viral contamination - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to chemistry and chemical engineering, and particularly to novel heterogeneous sensitising agents which are modified silica gels, and use thereof for photodecontamination of water from viral contamination. Disclosed is a heterogeneous sensitising agent of formula:

, where: X=Cl(OH). A method of treating water using said heterogeneous sensitising agent is also provided.

EFFECT: method provides efficient treatment of water from viral contamination.

2 cl, 1 dwg, 4 tbl, 3 ex

Description

The present invention relates to chemistry and chemical technology, namely to the synthesis of modified silica gels containing covalently linked substituted phthalocyanine molecules, as well as to the use of these silica gels for photo-disinfection of water from viral contamination.

Providing the population with benign drinking water is one of the most important problems not only in Russia, but throughout the world. Discharge of insufficiently treated and disinfected wastewater into water bodies has led to a widespread increase in chemical and microbial pollution of surface and underground water sources. Of particular danger is viral water pollution due to the fact that the currently used water purification methods are not effective against viruses, and the infecting doses of viruses are extremely small (units and tens of virions). Currently, more than 150 pathogens for humans of various types of viruses circulating in water are known.

Of the current methods of water disinfection, chlorine compounds (liquid chlorine, bleach, calcium hypochlorite, etc.) are still the most widely used. After treatment with chlorine compounds, water for indicator bacteria is standard, but may contain viruses. In addition, organochlorine compounds, trihalomethanes, which are carcinogenic and mutagenic, toxic to humans, are formed in water with a high content of organic substances of natural and technogenic origin. At the same time, the content in water of increased doses of chlorine and its derivatives leads to a violation of the biocenosis in water bodies.

In connection with the foregoing, the search and implementation of new effective and safe technological solutions for the purification and disinfection of water against viral contamination is one of the most important problems. As one of the promising methods of water purification is the use of the photodynamic effect of various sensitizers.

Known cationic phthalocyanines, which are poly (trialkylammoniomethyl) substituted phthalocyanines of zinc and aluminum, which are sensitizers of the formation of singlet oxygen under the influence of visible light, as well as a method of photo-disinfection of water using these phthalocyanines [RF patent No. 2281953, cl. C02F 1/30, 2006]. A positive charge of cationic groups ensures the interaction of these sensitizers with negatively charged external membranes of microorganisms, their penetration and effective photodynamic inactivation. Despite the high efficiency, this method has a significant drawback, which consists in the need for subsequent removal of the dye from the solution. This operation is carried out using specially designed selective filters, which significantly complicates and increases the cost of the process and, nevertheless, does not guarantee in all cases the complete removal of the sensitizer and its photodegradation products from the solution.

Heterogeneous (solid-phase) sensitizers of the formation of singlet oxygen are deprived of this drawback. Solid-phase sensitizers can be easily separated from water after photo exposure by simple filtration.

Known heterogeneous sensitizers for the inactivation of microorganisms obtained by adsorption of dyes with light fastness from 4 to 8 points on an inert carrier [A. Yoshino, I. Iwami. US Patent N 4520072]. However, the adsorbed dye can be desorbed and transferred to an aqueous solution, thereby causing chemical contamination.

Heterogeneous sensitizers are known for inactivating microorganisms obtained by chemical sewing of antimony and phosphorus tetraphenylporphyrins onto silica gel granules [N. Yokoi, T. Siragami, J. Hirose, T. Kawauchi, K. Hinoue, Y. Fueda, K. Nobuhara, I. Akazaki, M.Yasuda. World J. Microbial. Biotechnol. 2003, 19, 559; Y. Fueda, H. Suzuki, Y. Komiya, Y. Asakura, T. Shiragami, J. Matsumoto, H. Yokoi, M. Yasuda. Bull. Chem. Soc. Jpn. 2006, 79, N9, 1420-1425]. However, antimony compounds are undesirable to be introduced into the environment due to their potential toxicity.

The objective of the invention is the synthesis of a heterogeneous sensitizer containing, as an active phase, a substituted phthalocyanine covalently bound to a carrier, as well as the development of a method for photo-disinfection of water from viral contamination using the obtained sensitizer.

The problem is solved by synthesis of a heterogeneous sensitizer, which can be represented by the following formula:

Where X = Cl (OH)

This sensitizer is obtained by chemical grafting of tetrakis [bis (chloromethyl) phenylthio] phthalocyanine aluminum to aminopropylated silica gel and subsequent processing of the obtained product with dimethylaminoethanol:

... -Si-O (CH ₂ ) ₃ NH ₂ + Al (Cl) Pc (SPh) ₄ (CH ₂ Cl) ₈ →

→ ... -Si-O (CH ₂ ) ₃ NHCH ₂ - [Al (Cl) Pc (SPh) ₄ (CH ₂ Cl) ₇ ] →

→ ... -Si-O (CH ₂ ) ₃ NHCH ₂ - {Al (X) Pc (SPh) ₄ [CH ₂ N ⁺ (CH ₃ ) ₂ C ₂ H ₄ OH] ₇ } Cl ₇ ^-

where X = Cl or OH.

A heterogeneous sensitizer containing tetrakis [bis (cholinyl) phenylthio] phthalocyanine aluminum as an active phase absorbs light with a wavelength in the regions from 300 to 450 nm and from 600 to 800 nm. Thiophenyl substituents in position 3 are located outside the plane of the phthalocyanine macro ring and prevent the approach of molecules and the formation of inactive π-π dimers and aggregates, which positively affects their antimicrobial activity. Aluminum complexes are highly photo-stable, which, unlike, for example, zinc and titanyl complexes, allows them to be used in several cycles of photodynamic water treatment. A significant positive charge of the phthalocyanine molecule ensures good adsorption of negatively charged viruses on silica gel and their inactivation under the action of reactive oxygen species generated by irradiation.

Figure 1 presents the electronic absorption spectrum of a suspension of the proposed sensitizer in glycerol.

The task is also achieved by the development of a method of photo-disinfection of water from viral contamination using the above-described heterogeneous sensitizer and visible radiation in the presence of oxygen.

Aluminum phthalocyanine used for the synthesis of (tetrakisphenylthio) was obtained as described in [Derkacheva V.M., Lukyanets E.A. // Journal. total Chemistry. 1980.V.50. S.2313-2318]. Its chloromethylation to tetrakis [bis (chloromethyl) phenylthio] phthalocyanine aluminum was carried out according to known methods described, for example, in RF patent No. 2405785 dated 10.13.2010.

The invention is illustrated by the following examples.

Example 1

Synthesis of a heterogeneous sensitizer

For chemical inoculation with aminopropylated silica gel, aluminum tetrakis [bis (chloromethyl) phenylthio] phthalocyanine Al (Cl) Pc (SPh) ₄ (CH ₂ Cl) _{8 was} found (found%: Cl 20.02; calculated%: Cl 20.59). The proof of the position of chloromethyl groups in phenyl rings is the proton signal shift in the 1H NMR spectrum (5.0 ppm), which differs from the proton shift of the CH ₂ Cl groups directly associated with the phthalocyanine ring (5.5-5.8 ppm) .).

To 5 · 10 ^-6 mol Al (Cl) Pc (SPh) ₄ (CH ₂ Cl) ₈ add 20 ml of dimethylformamide and after dissolving the dye 1 g washed with water and dried at 100 ° C aminopropylated silica gel. The mixture is stirred under heating and a temperature of 80-85 ° C for 1-2 hours until the solution discolors, then 5 · 10 ^-3 mol of N, N-dimethylaminoethanol is added and heating is continued for another hour. The product is filtered off, washed with water, then dried at a temperature of 100-105 ° C.

The electronic absorption spectrum of a suspension of a heterogeneous sensitizer in glycerol (4 g / l) indicates a predominantly monomeric state of the active phase (a well-resolved spectrum with a pronounced absorption band Q at 715 nm and an vibrational satellite at 650 nm, FIG. 1). This should provide effective sensitization of cytotoxic reactive oxygen species.

Example 2

Determination of the activity of the heterogeneous sensitizer obtained in Example 1 in the photoinactivation of poliovirus in water.

Experimental studies were carried out in model reservoirs prepared using filtered autoclaved tap water, into which a heterogeneous sensitizer was added at a concentration of 4 g / l and poliovirus at a concentration of n · 10 ⁴ CPD _{50 / ml} . After vigorous stirring, one part of the ponds was illuminated for 30, 60, 90, and 120 minutes, while the other remained in the dark in contact with a heterogeneous sensitizer for the same time without being illuminated and sparged. The temperature of the water when illuminating the samples was 20-24 ° C.

The following fractions were investigated.

1) Suspension - 10 ml of a mixture of supernatant and heterogeneous sensitizer.

2) The supernatant in a volume of 10 ml was taken after settling for 5 minutes to precipitate the sensitizer. Next, the sample was subjected to antibacterial treatment and was used to infect cell cultures.

3) Sediment. After selection of the supernatant and removal of its residues, desorption of the poliovirus from the sediment was carried out using 10 ml of a 3% bifextract solution with a pH of 9.1. This desorbent is used in virological studies for desorption of viruses from various adsorbents in the process of concentration of viruses. The precipitate with desorbent was thoroughly shaken and sedimented for 5 minutes to precipitate a sensitizer. Then the supernatant was collected and the pH was adjusted to 7.0. Next, the sample was subjected to antibacterial treatment and was used to infect cell cultures.

The need for desorption was due to the following: first, the poliovirus, having a negative charge, must be adsorbed on a positively charged heterogeneous sensitizer; secondly, the use of directly solid sediment in titration of the virus in cell culture is practically not possible.

The obtained samples after antimicrobial treatment were infected tubes with a monolayer of BGM cells. The appearance of CPE was monitored for 2 weeks. All negative samples were examined in the second passage to confirm the absence of viruses, and then the titer of the virus in the sample was calculated by the method of Reed and Menck.

Data on the conditions and results of photo-disinfection of poliovirus in a suspension sample (10 ml of a mixture of supernatant and heterogeneous sensitizer) are shown in table 1.

Table 1. Data on photo-disinfection of poliovirus in suspension in the presence of a heterogeneous sensitizer Try Bleeding time, min The concentration of poliovirus in the CPD _{50 / ml} Inactivation% Original (before processing) - 2.6 · 10 ⁴ After consecration thirty 3.310 ² 98.73 60 1,0 · 10 ² 99.62 90 6.5 99.97 120 1.05 99,99

The data in table 1 indicate the presence of a high (4 order) decrease in the concentration of poliovirus during photodynamic treatment of water using the proposed heterogeneous sensitizer.

The dynamics of the concentration of poliovirus in the supernatant and in the sediment (desorbent with a pH of 9.1) in the presence of the proposed heterogeneous sensitizer without coverage is presented in table 2.

As can be seen from table 2, the poliovirus after 30 minutes of contact with the particles of the heterogeneous sensitizer is mostly adsorbed on it, the concentration of poliovirus in the supernatant is three orders of magnitude lower. Further, the established equilibrium depends little on the contact time (30-90 minutes).

Table 2. Change in poliovirus concentration in the supernatant and sediment (desorbent with a pH of 9.1) in the presence of a heterogeneous sensitizer without bleaching and sparging Try Contact time, min The concentration of poliovirus log in CDD _{50 / ml} in fractions Supernatant Sediment After dark contact with the sensitizer thirty 0.55 3.84 60 0.84 3,55 90 0.84 3.47 Initial before the introduction of the sensitizer 4.47

In the next series of studies, the photo-disinfecting effect of the heterogeneous sensitizer against viruses was studied under the same conditions during illumination and sparging. The research results are presented in table 3.

As can be seen from Table 3, with an increase in the coverage time, the concentration of poliovirus in both the supernatant and sediment gradually decreases, and after 120 minutes of irradiation, the virus is not detected in both fractions. These results indicate that a decrease in the concentration of the virus in water under irradiation conditions is associated not only with adsorption on the particles of a heterogeneous sensitizer, but also with its photoinactivation in the photodynamic process.

Thus, two factors can be noted, due to which there is a decrease in the concentration of poliovirus in a pond:

1) adsorption of poliovirus on particles of a heterogeneous sensitizer;

2) photoinactivation of poliovirus by a heterogeneous sensitizer due to the generation of reactive oxygen species by its active phase - chemically grafted phthalocyanine.

Table 3. Change in the concentration of poliovirus in the supernatant and in the sediment (desorbent with a pH of 9.1) in the presence of a heterogeneous sensitizer and during illumination. Try Bleeding time, min The concentration of poliovirus in log CPD _{50 / ml} in fractions Supernatant Sediment After baking with a sensitizer thirty 0.42 2.47 60 0.22 2.2 90 0 1,2 120 0 0 Initial before the introduction of the sensitizer and bleaching 4.47

Example 3

Determination of the activity of the heterogeneous sensitizer obtained in example 1, in the photoinactivation of coliphage in water.

In the experiments, the MS2 coliphage (VKPM strain RN 1505 strain) was used, which was obtained from the All-Russian collection of industrial microorganisms of the State Research Institute of Genetics. To isolate coliphages from the studied samples, the E. coli strain VKPM B-3254, E. coli F ⁺ K-12 KS 507, which was obtained from the All-Russian collection of industrial microorganisms of the Research Institute of Genetics, was used as a lysable culture. This strain makes it possible to isolate both wild strains circulating in water of various reservoirs, and the model strain MS-2. The coliphage on the lawn of the daily culture of E. coli after 24 hours forms lytic plaque spots (plaque-forming units). The concentration of coliphages was expressed in plaque forming units (PFU). The initial concentration of coliphages was n × 10 ⁴ -n × 10 ⁵ PFU / ml. The photo-disinfection time in the experiments was 30, 60 and 90 minutes. The study of water samples for the presence of coliphages was carried out in accordance with the document MUK 4.2.1018-01 "Sanitary and microbiological analysis of drinking water" using two methods: the direct sowing method and the growing method.

Studies have shown that after a joint stay of the photosensitizer and coliphages in an aqueous suspension in the dark for 30 minutes, the concentration of coliphages remained at the same level. These data indicate that the proposed heterogeneous sensitizer at a concentration of 4 g / l toxic effect against coliphages does not. When exposed to visible light, the level of coliphages decreased.

Data on the conditions and results of photo-disinfection of coliphage in water in the presence of a heterogeneous photosensitizer are shown in table 4.

Table 4. Data on the decrease in the concentration of coliphage in the presence of a heterogeneous sensitizer (4 g / l) and when illuminated Bleeding time, min Supernatant Sediment Coliphage in PFU inactivation,% Coliphage in PFU inactivation,% thirty 28 99.86 600 97 80 99.60 600 97 60 0 PFU / ml one hundred 150 99.25 4 PFU / ml 99.98 200 pfu / ml 99.0 90 0 PFU / ml one hundred 1 PFU / ml 99,995 0 PFU / ml one hundred 2 PFU / ml 99,99 Baseline 20,000 PFU / ml

As can be seen from the materials of table 4, at an initial concentration of coliphages at a level of 20,000 PFU / ml, after photoinfection of water for 30 minutes, coliphages were isolated from 1.0 ml of a sample at a level of 28-80 PFU / ml. Thus, photo-disinfection was accompanied by an intensive decrease in the concentration of coliphages in the supernatant by 3 orders of magnitude, while the percentage of inactivation of coliphage was 99.6-99.86%.

When studying the sediment, it was found that the concentration of coliphages in it was an order of magnitude higher than in the aqueous phase, and amounted to 600 PFU / ml. Thus, sampling for 30 minutes is not sufficient to inactivate coliphages, and a decrease in its concentration in the aqueous phase occurs not only due to the photo-disinfecting effect, but also due to sorption on the photosensitizer particles.

With an increase in the flash time to 60 minutes, the concentration of coliphages in the aqueous phase decreases by another order of magnitude, reaching single plaque-forming units in 1 ml of the studied water (0-4 PFU / ml). The inactivation level under these experimental conditions reached 99.98-100%. When studying the sediment, it was found that the concentration of coliphages in it was two orders of magnitude higher than in the aqueous phase of the sample, and amounted to 150-200 PFU / ml, the inactivation level reached 99.25-99%.

When the sample was illuminated for 90 minutes, the coliphage was not sown from the aqueous phase of the sample and the inactivation level reached 100%. When studying the sediment, single coliphages were sown; the level of inactivation was 99.99-99.995%.

The data obtained indicate a two-stage mechanism for purifying water from the coliphage using the proposed heterogeneous sensitizer - sorption and photodynamic disinfection of the sorbed coliphage.

Thus, examples 2 and 3 show that a heterogeneous sensitizer containing tetrakis [bis (cholinyl) phenylthio] phthalocyanine aluminum covalently attached to aminopropylated silica gel as an active phase is active in photoactivation of viral infection of the aqueous medium. The obtained experimental data showed that water purification against negatively charged viruses when using the proposed heterogeneous sensitizer is associated with a two-stage mechanism - sorption and photodynamic disinfection of the sorbed virus. It is very promising to use it for water treatment.

Claims (2)

1. A heterogeneous sensitizer of the formula

where X is Cl (OH). 2. The method of photo-disinfection of water from viral contamination using a sensitizer and visible radiation in the presence of oxygen, characterized in that the heterogeneous sensitizer according to claim 1 is used as a sensitizer.

Images