DE10352460A1 - Material for adsorbing trihalomethane and AOX and for removing chloramines from water, e.g. in swimming baths, comprises active carbon powder and-or other adsorbents plus sodium hydrogen sulfate or other acid - Google Patents

Abstract

Material for absorption of trihalomethanes and AOX and for removing chloramines from water, comprises active carbon powder and/or other adsorbents (e.g. zeolites) plus sodium hydrogen sulfate and/or other acid salts and/or acids and/or water and/or tabletting aids such as talcum. Material (I) for the absorption of trihalomethanes and AOX and for removing chloramines from water, especially from swimming baths and from water for baths or spas, comprises active carbon powder and/or other adsorbents such as perlite and/or diatomaceous earth (kieselguhr) and/or zeolites, plus sodium hydrogen sulfate and/or other acid salts and/or acids and/or water and/or tabletting aids such as talcum. An independent claim is also included for a method for improving the adsorption efficiency of adsorbents (especially active carbon as above) by the application of an electromagnetic field, in which the electrodes for producing the field are insulated and current flow only occurs due to the increased adsorption efficiency, corresponding to the additional heat of adsorption released (no electro-sorption); the improvement in efficiency is not limited to adsorption from aqueous solutions but is also naturally applicable to air filtration.

Description

The The invention relates to a means for adsorbing trihalomethanes (Haloforms) and AOX and for the reduction of chloramines from water, in particular from swimming and bathing water.

When disinfecting swimming pool water, chlorine and organic substances (carbon and nitrogen compounds) produce undesirable reaction products. These pollutants can reach the pool water both through the filling water (eg humic substances) or through the bather (dirt entry). The reaction products of organic matter and chlorine are primarily trihalomethanes, here for the most part chloroform, AOX and chloroamines (bound chlorine), here for the most part monochloramine (NH ₂ Cl).

These Substances and groups of substances can, too high concentration in the bath water, human health damage. For example, trihalomethanes are suspected carcinogenic and to have mutagenic properties. The design of the swimming pool water regulation and the DIN 19643 (treatment and disinfection of swimming and Bathing water) therefore contain limits for the above mentioned substances. The maximum values for chloramine are 0.2 mg / l and for Trihalomethane maximum 20 μg / l.

As already in the German patents DE 43 27 598 and DE 43 27 599 has been shown, extensive studies of the Federal Health Office have shown that the use of powdered activated carbon adsorbs trihalomethanes and chloramines are reduced, resulting in a significant improvement in the quality of the pool water. By reducing the bound chlorine, you also get an odor-free swimming pool water, thereby preventing the typical smell of chlorine in the hall air.

These just mentioned writings describe that special powdered activated carbon in the recirculation cycle is metered in the case of single or multi-layer filters before the Filter. Meanwhile, this procedure has become established. Also at Precoat filters or membrane filters become powdered activated carbon now dosed.

This takes place either dry or from metering as an aqueous suspension.

These Suspensions can react strongly alkaline. This causes a partial or complete precipitation of hardeners the suspension water and leads to incrustations in the suspension tank, the dosing system and the dosing lines. Furthermore, it was found that in the neutral or basic environment a strong bacterial contamination of the stockpiled powdered activated carbon suspension occurs, a circumstance in the treatment of swimming pool water absolutely must be avoided. Therefore, o.g. DIN 19643 a pH of less than or equal to pH 2 for powdered activated carbon suspensions required. Another point is the good filterability of the added Pulverkohleproduktes to such a penetration on the one hand as well on the other hand to avoid too fast clogging of the filter. Too fine a product strikes through, too coarse product is washed ashore only on the filter surface and clog the filter too fast. For precoat filters or membrane filters this is usually the other way around. The just mentioned fonts set grain sizes in one narrow spectrum. However, this spectrum is specific to precoat filters or the latest developments in membrane technology relatively tight. The Filter life or adsorption are in others Grain size ranges to increase significantly. This shows that coarser particle sizes (> 100 μm) reduce the service life of Significantly increase precoat filters. Also a use of others Adsorbents such as zeolites, also in admixture with activated carbon acted in terms of service life positive, characterized in that the permeability through a mixture could be increased considerably.

Further can by a very fine spectrum turn the adsorption, especially in combination with membrane technology significantly increased. It was found in microfiltration that at fine grain size of the used Powder activated carbon (1-60μm) the degradation rate of bound chlorine and AOX increased significantly could be.

It The object of the invention is thus to develop a generic agent in such a way that that the problems mentioned above are avoided.

The The object is achieved by the characterizing features of claim 1 solved The above-mentioned writings narrow the spectrum into one area between 4 and about up to 200 microns one.

The inventive agent shows in its fine fraction regarding the Adsorption of trihalomethanes and the degradation of chloramines a surprise good effect. In his rough group, however, it shows especially good effect on the Precoat filter or membrane service lives.

The sodium hydrogen sulfate, one of the possible These additives, or other acidic salts or acids, are intended to advantageously prevent precipitation of the hardness formers of the suspension water, as well as microbial contamination of the suspension.

The inventive agent allows it first, an activated carbon suspension with a pH smaller equal to pH 2 by simple addition of the sodium hydrogen sulfate, other acid salts or acids as part of the agent in water produce and the second through the powdered activated carbon, as a further constituent of the agent, the substances present in chlorine-treated water under the to reduce the required directing concentrations.

there is the first reaction after addition of the agent, the pH of the Suspension water brought to the required value. In this Case occur in parallel two chemical reactions: By the Partially alkaline surface oxides of the Powdered activated carbon undergoes a pH increase while at the same time the sodium hydrogen sulfate or metal salts or acids Lower pH. The mixing ratio is adjusted so that the pH is independent of the particular composition of the necessary for the suspension Water is below pH 2.

For the others Reactions in the water to be treated will be the o.g. Suspension before the respective filter, in the case of a flocculation stage between flocculant addition and filters, dosed and then completely from the respective Filter caught.

in the Fall of precoat filters is due in part to the acid addition waived when the powdered activated carbon directly into the soaking tank is given. Because here, due to the existing here in the water Disinfectants usually no germs occur.

there The fine fraction of the powdered activated carbon deposits deep in the sand filter and guaranteed the required filter service lives. The reactions with the o.g. pollutants find immediately after addition of the powdered activated carbon, but also during the Stay the powder activated carbon in the filter, until its backwashing, instead.

in the Case of precoat filters or other membrane filters, the future also in the field of water treatment of the circulating water or the Mudwater find their way, then powdered activated carbon is preferred the coarser one Faction on this surface membranes (micro, ultra or nanofiltration). Even the fine fraction can be used here, when it comes to high To achieve degradation rates. In combination with filter aids or other adsorbents such as diathoms, kieselguhr, perlite, pulp, Zeolites, etc. can so specific adsorption properties with filter hydraulic Properties can be combined as desired, with or without acids. in this connection For precoat filters, it makes sense to use the coarser particle size distribution. This increases the filter life, since the pressure increase in this case, essential weaker fails. Further showed that when coarser Grain at many powdered activated carbon also the permeability is greater So the pressure loss on the membrane or the precoat filter element is smaller.

When Another advantage has been found, so-called doped powder activated carbons or also powdered catalytic charcoals (e.g., catalytic properties through the use of uric substances such as uric acid in production), which accelerate the degradation of chloramines and AOX partly in some swimming pools.

• 1. Adsorption von Trihalogenmethanen (Haloformen) und AOX an der Pulveraktivkohle
• 2. Abbau von Chloramin durch die Pulveraktivkohle

The following reactions occur:

• 1. Adsorption of trihalomethanes (haloforms) and AOX on the powdered activated carbon
• 2. Degradation of chloramine by the powdered activated carbon

To a maximum filter life, with sand filters beats the DIN Two days before in 19643, with precoat filters / membrane technology partly over ten days, the filter is rinsed and remove the spent or loaded powdered activated carbon from the system, so that again and again new funds can be supplied. The invention is based on an embodiment explained in more detail, its expediency proved in experiments and by comparative measurements.

• • Pressling 1 entsteht durch Pressung eines Gemisches aus Pulveraktivkohle, Wasser und Natriumhydrogensulfat oder anderer saurer Salze sowie gegebenenfalls eines Tablettenhilfsmittels wie Talkum.
• • Pressling 2 entsteht durch die Pressung von 2 Schichten aus Pulveraktivkohle und Natriumhydrogensulfat oder anderer saurer Salze sowie gegebenenfalls eines Tablettenhilfsmittels.
• • Pressling 3 entsteht durch Pressung eines Gemisches aus Pulveraktivkohle und flüssiger Säure sowie gegebenenfalls eines Tablettenhilfsmittels.

The mixture is pressed with a press in tablet form. This results in essentially 3 variants of compacts:

• • Pressling 1 is formed by pressing a mixture of powdered activated carbon, water and sodium hydrogen sulfate or other acidic salts, and optionally a tablet aid such as talc.
• • Pressling 2 is produced by pressing 2 layers of powdered activated carbon and sodium hydrogen sulfate or other acidic salts and optionally a tablet auxiliary.
• • Pressling 3 is produced by pressing a mixture of powdered activated carbon and liquid acid and optionally a tablet assistant.

It turns out to be expedient if the powdered activated carbon and the sodium hydrogen sulfate, other acidic salts or acids as a mixture of these individual substances with a mixing ratio of 500: 1 to 1: 1. It is also possible to provide the powdered activated carbon and the sodium hydrogen sulfate or the acids shaped as a tablet with a tablet assistant, which contributes to improving the dissolution properties of the tablet or the compact. It is advantageous if the proportion by weight of powdered activated carbon to sodium hydrogen sulfate or the acids is between 500: 1 and 1: 1. It is furthermore advantageous if the powdered activated carbon is water vapor activated, has an iodine value of at least 300 mg iodine / g and has a particle size distribution of 1 to 100 μm for sand and multilayer filters and 4 to 300 μm for precoat filters. Also, it has proved to be useful when the powdered activated carbon has a bulk density of 100-800 g / l. Sodium hydrogen sulfate is used as a dry product for use, preferably as fine beads with a particle size distribution of 0.01-10 mm or liquid acids.

Claims (18)

Agent for the adsorption of trihalomethanes (haloforms) and AOX and for the reduction of chloramines from water, especially from swimming pool water, characterized in that the means of the individual substances or mixtures of powdered activated carbon and / or other adsorbents such as perlite and / or diathomeene (Diatomaceous earth) and / or zeolites and / or sodium hydrogen sulfate and / or other acidic salts and / or acids and / or water and / or tabletting additives such as talc or other Means according to claim 1, characterized in that the powder activated carbon - one Iodine number of at least 300 mg iodine / g and a particle size distribution between 1 and 400 μm and / or a fine fraction of 1 to 100 μm or a coarse fraction of up to 400 μm having. Agent according to Claims 1 to 2, characterized that the powdered activated carbon and / or other adsorbents and the Sodium hydrogen sulfate, other acid salts or the acids as dry or through a liquid like water pasty made mixture of these individual substances with a mixing ratio of 500: 1 to 1: 1, or placed in this mixing ratio at the place of use become. Agent according to claim 1 to 3, characterized that the powdered activated carbon and the sodium hydrogensulfate, others acid salts or the acids as solid tablet or compact are designed. Agent according to one of claims 1 to 4, characterized that the powdered activated carbon and the sodium hydrogen sulfate or others acid salts as a solid tablet or compact of at least one Layer of powdered activated carbon and at least one layer of sodium bisulfate or other acidic salts and that the proportion by weight of Powder activated carbon to sodium hydrogen sulfate or other acid salts between 500: 1 and 1: 1. Agent according to one of claims 1 to 5, characterized that the agent is present as a suspension Agent according to one of claims 1 to 6, characterized that the powdered activated carbon has a bulk density of 100-800 g / l having. Agent according to one of claims 1 to 7, characterized that the sodium hydrogen sulfate or other acid salts dry than fine beads or crystals having a particle size distribution of 0.01-10 mm is present. Agent according to one of claims 1 to 8, characterized in that the powdered activated carbon is present in a precisely defined particle size distribution, and thus has optimum filterability. ( 1 ) Agent according to one of Claims 1 to 9, characterized that the powdered activated carbon has catalytic properties and / or doped with substances, preferably silver or copper germicidal effect to exhibit or otherwise matter such as platinum or gold to other catalytic To have effect. Agent according to claims 1-10 characterized in that that the substances mentioned under 1 in different Variations and mixing ratios are used and / or produced before use, So be mixed, preferably by a vacuum, for example in the powdered activated carbon. Agent according to claims 1-11 characterized in that that with the substances mentioned under 1 special highly reactive filter beds, also without sand or Mebrabmaterial, are manufactured. Method according to 1 to 12 for improving the adsorption efficiency of adsorbents, in particular of activated carbon and the substances mentioned under 1, by applying electromagnetic fields, characterized in that the necessary electrodes for generating the fields are isolated and consequently a current flow only due to the increased adsorption arises, which corresponds to the released additional heat of adsorption. (no electrosorption) The improvement of the adsorption efficiency is by no means limited to adsorption from aqueous solutions, but of course also relates to air filtration. Adsorption is a quantum mechanical phenomenon whose determining forces are dipole-dipole-induced van der Waals forces. By applying an external field, this interaction can now be manipulated. Thus, a homogeneous electric field of about 3000 V per meter increases the adsorption of butane on activated carbon already by 30%, as well as an increased reaction kinetics is to be noted, in the sense that the coal already at the same Butankonzentration has a higher load. As the field strength increases, the adsorption efficiency increases. This effect is achieved on the one hand by an externally induced dipole moment, which is superimposed on the self-induced superposition principle, and on the other hand by the alignment of the interacting particles in the homogeneous field. In contrast to the electrosorption on surfaces already used, however, the electrodes are insulated in the proposed application, so that the voltage is limited in principle only by the breakdown voltage of the insulation. Likewise, dangerous chemical reactions due to current flow in the adsorption bed do not occur because the only current flow occurring between the electrodes due to an increase in capacity of the device due to increased adsorption and thus increasing dielectric constant on the power source necessary for generating the field and not within the adsorption. Method according to claims 1 to 13, characterized that the adsorption process by a homogeneous electric field, that with a device in the manner of a plate capacitor is generated, amplified becomes. To 14 The simplest way of influencing The adsorption performance consists in the application of a homogeneous electrical Feldes, with two electrodes in the arrangement of a plate capacitor is produced. The field strength can either over the distance of the plates or over the applied voltage will be affected. Appropriate experiments for the adsorption specifically of butane to activated carbon were carried out. Method according to Claims 1 to 14, characterized that an inhomogeneous electric field that passes through any Geometry of the electrodes is generated, optimizing the adsorption process. To 15 Is not a homogeneous field due to technical reasons feasible, so can resort to an inhomogeneous field because of the size of the adsorbed Ponds the field can be considered locally homogeneous. there is it secondarily by which electrode geometry the field is generated, important is that the gradient of the field on molecular size (angstrom) small is, and as a result can be considered locally homogeneous. A simple realization of an inhomogeneous field is e.g. alternately positive and negative charged wires within the adsorption bed. Method according to one of claims 1 to 15, characterized in that the orientation polarization takes place in a magnetic field and the enlargement of the attractions the adsorption process is optimized. To 16 Becomes a homogeneous magnetic field applied, so the situation is designed a bit more complicated. The constant of Van der Waals force does not just hang from the states the interacting atoms or molecules, but also from the mutual orientation, i. from the angular momentum projection ω on the Connecting line between the influencing particles. An external magnetic field now causes an orientation of the angular momentum, so that an increased adsorption takes place. Both particles have non-zero orbital angular momenta and total angular momentum, the following situation arises. The mean of the dipole moment is zero in any atomic state. The mean of the quadrupole moment is (in states with L, J not equal to zero S = 1/2) is different from zero. The quadrupole quadrupole member in the Stöterperator therefore already gives in the first approximation a non-zero Result, and the interaction energy of the particles does not decrease with the sixth, but with the fifth power of the distance from. Complex, especially toxic, compounds such as e.g. dioxins, Furans and poison gases, etc., generally have a non-vanishing one Total angular momentum, so for the reasons above through Applying an external magnetic field and the resulting mutual orientation increased adsorption results. Method according to one of claims 1 to 16, characterized in that targeted by a suitably selected alternating field, an increased adsorption performance for individual compounds is achieved. 17 A suitably chosen alternating electromagnetic field brings the atoms or molecules to be adsorbed into an energetically higher state generally associated with a higher total angular momentum. Due to the spin-dependence of the van der Waals forces, an increase of the adsorption power is to be expected and due to the additional magnetic moment an influence by magnetic fields is also possible. By choosing the frequency of the electromagnetic field, individual compounds can be selectively brought to increased adsorption, depending on the resonances that occur in each case. Of course, the particles to be adsorbed may be excited in front of the filter if the lifetime of the excited states is long enough. This can be used specifically to filter radioactive contaminants in nuclear facilities, especially radioactive noble gases, since they do not have a total angular momentum, but this can be induced by a suitably chosen alternating field. Method according to one of claims 1-17, characterized that by sudden Turn on the fields an increased Adsorption power is used. To 18 There to maintain a magnetic field constantly energy needed is (if no superconductivity is present), the increased adsorption process in case of emergency or if a special cleaning procedure takes place should be triggered by switching on the fields, and thus the energy for the Continuous operation can be minimized. This is when applying a static electric field, however, not necessary.