RU2496751C1 - Method of cleaning living quarters from ammonia - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to construction. The method of cleaning living quarters from ammonia involves applying an ammonia-releasing oxidant solution onto concrete structures in order to saturate concrete with said solution. The oxidant solution is sodium hypochlorite solution with addition of fulleroid-type carbon clusters - fullerenes. The fullerenes are a modifier of the solution which enables the solution to penetrate concrete, i.e. enhance penetration properties of the solution. To endow the solution with effective penetration properties, concentration of fullerenes is in the range of 10^-4-10^-5% of the volume of the oxidant solution. The invention is developed in subclaims.

EFFECT: reduced emission of ammonia from concrete structures, deeper cleaning of building structures from contaminants.

3 cl, 1 tbl, 1 ex

Description

The invention relates to the field of construction production, in particular to a method of sanitation of residential premises, aimed at reducing the emission of ammonia from concrete structures, and can be used for cleaning residential premises from ammonia.

In the production of concrete structures, additives such as diamide of carbonic acid (urea), cement with fly ash, etc. are used. Ammonia in concrete is obtained by hydrolysis of urea by the reaction:

CO (NH ₂ ) ₂ + H ₂ O → 2NH ₃ ↑ + CO ₂ .

In the formation of concrete structures at the initial stage, concrete works as a reactor in which reactions of hydration of cement components, hydrolysis of urea and other ammonium-containing substances take place with the formation of a number of compounds, including ammonia. The concrete structure adsorbs ammonia, which is retained in the pores of the concrete. Next, there is an emission of ammonia from the pores into the volume of the premises, which creates uncomfortable living conditions and a threat to human health.

A known method of reducing the emission of ammonia from concrete by lowering the porosity of building structures. A method of colmatization is proposed (research report No. State registration 01201065826 SPb GASU, 2011). The process of mating consists of two stages:

1. priming of concrete "Granite" -th (a mixture of granite dust and liquid glass).

2. application of the polyurethane composition "Elacor-PU".

This treatment creates the effect of "conservation" of ammonia in the pores of concrete.

The disadvantage of this method is that gaseous products (ammonia) have no exit from the pores and accumulate in the pores of concrete, can cause unexpected changes in the structure of concrete.

A known method of processing a pozzolanic additive, which, when introduced into a cement binder, is capable of releasing ammonia. This additive is based on the use of fly ash (fly ash), which contains ammonia. According to this method, an oxidizing agent was added to fly ash in the form of hypochlorites: calcium hypochlorite — Ca (OCl) ₂ , lithium hypochlorite — LiOCl, sodium hypochlorite — NaOCl, or trichloroisocyanuric acid — C ₃ N ₃ O ₃ Cl ₃ . During the interaction between hypochlorite and ammonia, monochloramine and chloride salts are formed, which are at relatively low levels of concentration and are harmless to concrete and concrete products. Monochloramine and chloride salts are stable and do not disperse in air. This eliminates odorous emissions that are produced from a cement slurry containing untreated ammonia-containing fly ash (US Patent No. 2003205173 IPC A62D 3/00; A62D 3/38; C04B 18/08; G01N 33/00; G01N 33/38 ; A62D 101/08; A62D 101/45; (IPC 1-7): B01J 8/00; C04B 18/06 from 11/06/2003).

The disadvantage of this method is the limited application. An oxidizing agent was used for fragmented (dispersed) systems, and not for monolithic concrete products.

Closest to the technical nature of the present invention is a method of processing concrete structures containing antifreeze additive based on the use of urea. Urea, being in an alkaline environment in the presence of moisture, is split with the subsequent release of ammonia into the interiors of the building (patent SK 151099 IPC C04B 41/00, C04B 41/53, C04B 41/00 from 06/11/2001). The solution is based on exposure to hardened concrete of damaged building structures of a composite material containing some of inorganic and / or organic acids (phosphoric acid, Lewis acid, citric acid, tartaric acid, paratoluenesulfonic acid, benzoic acid, oxalic acid) as an active substance. After applying this composite to damaged concrete, the chemical elimination of the produced ammonia begins - the acid present in the composite reacts with the produced ammonia, binding it to the ammonium salt. This salt is in an inert and stable state with respect to the interiors of the building in which ammonia is removed.

The disadvantage of this method can be attributed to the absence of prerequisites for the deep penetration of the composite into the body of the concrete structure and, as a consequence, the occurrence of an ammonia slip that did not react with the active substance of the composite.

The aim of the invention is to intensify the process of sanitation of ammonia released from building materials, and thereby a deeper cleaning of building structures from pollutants.

The method of cleaning residential premises from ammonia consists in applying an oxidizing agent solution to concrete structures that emit ammonia using a foam roller or other means of applying liquid materials, in order to impregnate concrete with a solution. The method is characterized in that the oxidizing agent solution is a sodium hypochlorite solution with the addition of fulleroid type carbon clusters (fullerenes). Fullerenes are a solution modifier, facilitating penetration into the depths of concrete, i.e. enhance the penetration properties of the solution. To give the solution an effective penetration property, the concentration of fullerenes is 10 ^-4 -10 ^-5 % of the volume of the oxidizing solution.

The concentration of the oxidizing agent depends on the ammonia content in the concrete and is 40-190 g / l. Depending on the concentration of ammonia in concrete, the latter is subjected to a single treatment or two times.

The processing of building materials is carried out with the simultaneous purification of the air from the released gaseous products using an absorber. As the absorption solution in the absorber, a solution of H ₂ SO ₄ , H ₃ BO ₃ with a concentration of 20-50 g / l is used.

Depending on the concentration of ammonia in concrete, the latter is subjected to a single treatment or two times. Penetrating into the pores of concrete, the oxidizing agent reacts violently with a reducing agent - NH ₃ , urea, and other ammonium-containing impurities. The redox reaction is accompanied by intensive evolution of gaseous products, while ammonia is mainly converted to nitrogen and other impurities.

Due to the violent reaction, gas pressure is created in the pores, and they are intensively released into the atmosphere, and unreacted ammonia can partially be released. Due to overpressure, unreacted ammonia can partially be squeezed out of the pores. Partial ammonia emission is observed if concrete contains ≈400 mg / kg NH ₃ . To prevent possible consequences, the gas emitted into the atmosphere is cleaned in absorbers (bubbler, film type). As an absorption solution, a solution of 20 g / l H ₂ SO ₄ , H ₃ BO _{3 is used} . The capacity of the absorber in the air is 250 m ³ / h for a room with a volume of 150 m ³ .

An example of a pilot implementation of the invention.

Before processing concrete floors, the ammonia content in the core of the concrete structure is determined. If the concrete has an ammonia content of 300 mg / kg, then in the room atmosphere the concentration of ammonia in the air is 20-30 MPC. In this case, a modified oxidizer solution (Ox / Red) is prepared containing 8.5% sodium hypochlorite with the addition of fullerenes 10 ^-5 % of the solution volume. This solution is applied to the concrete surface using a foam roller. Due to the leakage of ammonia into the volume of the room, re-processing is carried out with the simultaneous purification of the air using an absorber. As an absorption solution in the absorber, a solution of H ₂ SO ₄ or H ₃ BO ₃ with a concentration of 30 g / l is used. This method of cleaning residential premises from ammonia can be attributed to non-waste technology, since the spent absorption solution from the absorber can be used as nitrogen fertilizer.

The effectiveness of the method of cleaning residential premises from ammonia is presented in table 1.

Table 1 The effectiveness of the method of cleaning residential premises from ammonia The ammonia content in the core core, mg / kg Volume of a two-room apartment, m ³ The initial concentration of ammonia in the room in units MPC The concentration of the oxidizing agent solution Ox / Red,% Multiplicity of processing concrete floors The concentration of ammonia in the premises in units MPC 200-350 150 25 8.5 disposable 3 200-350 150 25 8.5 two-time 0 Note. MAC of ammonia - 0.04 mg / m ³ , in the second case an absorber was used.

The technical result consists in the intensification of the process of rehabilitation of ammonia released from building materials, and thereby a deeper cleaning of building structures from pollutants.

Claims (3)

1. The method of cleaning residential premises from ammonia consists in applying to concrete structures that emit ammonia, an oxidizing solution with a foam roller or other means of applying liquid materials to impregnate concrete with a solution, characterized in that the oxidizing solution is a solution of sodium hypochlorite with the addition of carbon clusters of fulleroid type (fullerenes), fullerenes are a solution modifier, facilitating penetration deep into concrete, i.e. enhance the penetration properties of the solution, to give the solution an effective penetration property, the concentration of fullerenes is 10 ^-4 -10 ^-5 % of the volume of the oxidizing solution. 2. The method according to claim 1, characterized in that the concentration of the oxidizing agent depends on the ammonia content in concrete and is 40-190 g / l, depending on the concentration of ammonia in concrete, the latter is subjected to a single treatment or two times. 3. The method according to claims 1 and 2, characterized in that the processing of building materials is carried out with simultaneous purification of the air from the gaseous products by means of an absorber, a solution of H ₂ SO ₄ , H ₃ BO ₃ with a concentration is used as an absorption solution in the absorber 20-50 g / l.