JPS5891787A - Method for conditioning planting medium - Google Patents

Abstract

PURPOSE:To enable sludge to be effectively utilized as a planting medium, by conducting a solid-liquid separation of various aludges by using a phosphonitrile polymer as a flocculating agent, and using the resulting agglomerate as soil (conditioner). CONSTITUTION:Solid-liquid separation of, for example, digested sludge in a sewage disposal plant is conducted by using a polymer composed of a unit of the formula (wherein R<1>, R<2>, R<3>, R<4> are each a cation-contg. group, an anion-contg. group, a hydrogen-bondable group, halogen or an inactive org. group with the proviso that at least one of them is a cation-contg. group, an anion-contg. group or a hydrogen-bondable group) as a flocculating agent. This PN polymer flocculating agent is adsorbed on an agglomerate and remains after agglomeration or filtration, is slowly decomposed and fertilizes soil. Therefore, sludge can be effectively utilized as a planting medium by using the resulting agglomerate as soil or a soil conditioner.

Description

DETAILED DESCRIPTION OF THE INVENTION The present inventor has been conducting research on phosphonitrile compounds for some time, and found that those with a certain structure among these compounds have decomposition properties, and this decomposition property is It has become clear that this compound has disadvantages when used as an industrial material, etc., but this property can be used to the contrary, and
The present invention was completed based on another study, that is, research on flocculants.

Organic polymer flocculants having a main chain containing carbon atoms are known and are currently widely used.

The present inventors have discovered a polymer flocculant having a phosphorus-nitrogen based main chain that is substantially different from the above-mentioned known polymer flocculants having a carbon based main chain. This substance belongs to the so-called phantom phosphonitrile (PN) polymer, and has the general formula (where R, R, R, R are cation-containing groups, anion-containing groups, or hydrogen-bonding groups). a group,...a location or an inert organic group, consisting of 2-2, 2-2, etc., where at least one of R, RX, R, and H is a cation-containing group, an anion-containing group, or a hydrogen-bonding group. It is a polymer. This phosphonitrile polymer differs not only in the type of main chain atoms from the above-mentioned known organic flocculants, but also has the following unique advantages.

In other words, the unique feature of this PN-based polymeric flocculant is that it slowly decomposes in liquid, especially water, or in moist soil, and it can be used to easily dissolve simple low-molecular weight compounds such as phosphoric acid, ammonium phosphate,
Instead of other phosphates, these decomposition products serve as a nutritional source for microorganisms. However, the decomposition rate at this time is quite slow, and can be made to the same degree as the decomposition (corrosion) rate of wood and dried grass in moist soil.

This decomposition is mainly due to hydrolysis of the PN main chain, but decomposition of the PN main chain by microorganisms, that is, biochemical decomposition can also occur.

Additionally, both chemical (hydrolysis) and biochemical degradation may occur.

Another great advantage of this PN-based polymer flocculant is that the main chain extends substantially linearly in the liquid due to the mutual repulsion of the atoms (P and N) forming the main chain. The active groups attached to the main chain contact particles suspended or dissolved in water very effectively. On the other hand, conventional polymer flocculants generally exist largely bent in the liquid, that is, in the form of a ``string'', and the active groups present in the center of this ``string'' do not work effectively. . For reference, the state of existence of the above two types of polymers in liquid is schematically shown.

[Thread-shaped main chain] Therefore, the present invention uses a flocculation product obtained by performing a solid-liquid separation operation using a phosphonitrile polymer having the above general formula as a flocculant, as a soil conditioner. The present invention relates to a method for preparing a plant culture medium, which is characterized in that it is used as a plant culture medium.

Sludge, activated sludge, etc. generated by coagulation and sedimentation methods or biological treatment methods have traditionally been incinerated, landfilled, or dumped into the ocean, but recently they are being put to effective use as useful resources. It is said that In other words, it is used as an organic gallbladder or a soil conditioner.

In the coagulation-sedimentation method, the sediment obtained by using a coagulation-sedimentation agent (streak 7) and the surplus activated sludge produced by the biological treatment method have a high water content, so they cannot be treated by filtration, drying, etc. It is intended to be made into a form that is easy to handle, but p
A filtration accelerator is used to accelerate dehydration during the filtration process. These known C group gathering agents, filtration accelerators, etc. used are as follows:
It is recognized that they remain without separation and cause soil contamination, causing various problems. In contrast, one book (
5) By using the above-mentioned phosphonitrile polymer as a flocculating sedimentation agent or a filtration accelerator according to the invention, it not only exhibits the effects of flocculation sedimentation and filtration acceleration, but also decomposes at a certain point and produces phosphorus and ammonium compounds. It has the characteristics of being used as a fertilizer ingredient. In other words, this flocculant remains adsorbed in the condensate after the flocculation operation or filtration operation, and when the condensate is stored or buried in the soil, the flocculant gradually decomposes and improves soil fertility. It is useful for In contrast, conventional synthetic organic polymer flocculants with carbon main chains are difficult to decompose in soil, are not useful for soil fertilization, and may even cause pollution problems if they remain in the soil. .

This PN-based polymer flocculant can be made into various types of flocculants by changing the types of side chains,
That is, it can be a cationic flocculant, an anionic flocculant, a nonionic flocculant, or an amphoteric flocculant, but in this respect it is roughly the same as the case of known organic polymer flocculants having a carbon main chain. .

(6) PN polymers containing amine groups, quaternary ammonium groups, imine groups, etc. as side chains are cationic flocculants, and PN polymers containing carboxyl groups, carboxylate groups, etc. PN polymers that are anionic flocculants and have hydroxyl groups, acrylamide groups, methacrylamide groups, etc. are nonionic flocculants, and PN polymers that have amino acid groups, etc.
The system polymer is an amphoteric flocculant.

These PN-based polymers are represented by the following formula, for example.

In the above formula, R is an organic group, Rc■ is a cation-containing group, R
AO represents an anion-containing group. As in the case of known polymer flocculants having a carbon-based main chain, n is a fairly large number. In the case of the above-mentioned known polymer flocculants, the molecular weight is often described in the literature instead of the value of n, so in the present invention as well, when expressed in terms of molecular weight, the molecular weight of this PN polymer is generally 100,000 or more. , preferably 30,000,000 or more (see reference side below). In addition, in the above formula, the description of the counterpart ion of each ion is omitted to simplify the description.

In addition to flocculants that have a structure in which original active groups such as cationic groups, anionic groups, nonionic groups, etc. are individually bonded, flocculants that have both cationic or anionic groups and nonionic groups, and cationic or anionic groups. It is also possible to easily obtain a flocculant having multiple properties, such as a flocculant having both a hydrophobic bonding group and a hydrophobic bonding group or a hydrogen bonding group, and this is also one of the major features of the present invention.

There are many PN-based polymer flocculants that can be used in the present invention, some of which are shown below. Cationic; fINP(OCH2CH2N■・Me3・Xe)2−)
MotNP(OCH2CH2N-Me2)29G NP(
OCH2CH2NH-Me)2-)+NP(OCH2C
H2NH2)29(9) -E-NP(NHCH2CH2N-Me2)2-)(-
NP(NHCH2CH2NH-Me)2-)moNP(N
HCH2CH2NH2)2-37NP(NH2) 2-
) moNP (NHCH3) 2→ and the above unit and another unit e.g. moNP
-(0R)2→ or a copolymer with NP(OROH)2 The above unit and a further unit such as (-
Copolymer or terpolymer with NP (-Cl2)2-).

Anionic system: MoNP (OCH000-) -) 2 2n MoNP (QC6H4Coo -) 2+ (E-NP(
SCH2Coo )2-)(-NP(OC6H4S05
-)2-).

t18) -F: NPCCI-ILCOO)2]2-1+NP[
0C8H4(COO-)2] → and the above unit and f
A copolymer of li, uni, and t.

Nonionic monoNP mo 0(CH2CH20+H]2→i n +NP+OC■(2COO(CH2CH20+H)2→
7NP -(NH(CH2CH20-) H)2-)-
E-NPMoNHCH2C00 (CH2CH20+H]2
→t n and a copolymer of the above units, t and other units O Amphoteric system.

moNP(NHCH2COO-)2-).

(-NI) (NHCH2CH2COO-)29゜NP
(N(CH3)CH2COO-)2-).

Seven NP[NHCH(COO-)・CH2CH2C00-
]]2-3-MoNPNHCH2CO3-) 2U and a copolymer of the above-mentioned u,=,t and other uni,t.

The PN-based polymer used in the present invention is a phosphonitrile dichloride polymer ÷ PNCI2-) in which the chlorine atom or a part thereof is substituted with an anionic group, a nonionic group, a cationic group, or an amphoteric group; These groups are compared with a hydrophobic bonding group or a hydrogen bonding group. The synthesis method for this polymer is to perform ring-opening polymerization of cyclic triphosphonitrile hexachloride (PNCI2) 3 to produce a linear phosphonitrile cyclolide polymer 4PNC12+, which is then substituted with a desired group, or to There is a method in which triphosphonitrile hexachloride is substituted in advance with a desired group, and then this is subjected to ring-opening polymerization to obtain the desired polymer.

In any case, one starting material is cyclic triphosphonitrile hexachloride, which is usually obtained by reacting phosphorus pentachloride and ammonium chloride in a solvent, followed by purification. Further, cyclic tetraphosphonitrile octachloride (PNCI2) 4 is often used as a starting material alone or in combination with cyclic triphosphonitrile hexachloride.

Note that many other synthesis methods have also been proposed.

The above cyclic triphosphonitrile hexachloride is 2
Ring-opening polymerization occurs when heated to a temperature of 50-350°C. To give one example, this cyclic triphosphonitrile hexachloride is placed in a glass tube, evacuated, then argon or nitrogen gas is introduced, the tube is sealed, and heated to polymerize it. A phosphonitrile dichloride polymer is obtained. The obtained polymer is separated and purified using a solvent such as tetrahydrofuran (THF), and the polymer obtained from the soluble portion is the desired polymer without crosslinking. The chlorine atoms in this polymer have very high reactivity. Esterification reactions, amination reactions, Friedel-Krach reactions, etc. are easily carried out, and these reactions can be used to add compounds having anionic groups, cationic groups, or nonionic groups, or cationic groups to the polymer (13). By reacting with a compound having a group and an anion group, and/or a compound having another group, a PN polymer having a desired substituent group can be obtained.

When carrying out a flocculation operation or an offshore operation using the PN-based polymer, conventional equipment can be used, and special equipment is generally unnecessary. The flocculant is advantageously used in the form of a dilute water-resistant liquid (or suspension in water), and can be used, for example, in the form of a 01-1% aqueous solution. It should be noted here that the present flocculant should be dissolved immediately before use, and storage in the form of an aqueous solution should be avoided. The amount of the present flocculant to be used varies depending on the type of suspension, concentration, PI3 temperature of the liquid, and other conditions, but can be easily determined by a simple preliminary test. The description of the examples below may also serve as a guideline for determining the usage amount in individual cases. This flocculant may be used together with other flocculants.

The above-mentioned PN-based polymer can be used advantageously in various fields depending on the type of the known organic polymer (14) as in the case of the flocculant, and moreover, it has the unique properties as described above. For example, cationic flocculants can be used for organic colloidal suspensions, flocculation of ionic organic compounds, dewatering of sludge, promotion of filtration, etc. For example, cationic flocculants can be used for urban sewage treatment, floor treatment, paper mill wastewater treatment,・nirufu 0
This flocculant can be advantageously used for factory wastewater treatment, removal of sodium alkylbenzene sulfonate, dyeing factory wastewater treatment, etc. (to promote flocculation and filtration in C).

In view of the above characteristics of the present flocculant, it goes without saying that it can be used very advantageously in activated sludge methods and the like.

Anionic flocculants can be used to promote the precipitation of positively charged heavy metal oxides, to prevent the agglomeration of proteins and other suspended substances, and for example, to separate red mud in alumina factories, to remove impurities during the production of caustic soda, to fish and livestock meat, etc. It can be used for the recovery of edible granular heavy white matter from wastewater after water rinsing, treatment of raw tap water, recovery of metal ions, etc.

Nonionic flocculants can be used for the flocculation of relatively coarse particle suspensions, such as flocculation of powdered mineral substances, purification of blast furnace gas cleaning wastewater in steel plants, and asbestos in asbestos and slate factories.
1F water treatment, promotion of sedimentation of clay, coagulation of impurities during phosphoric acid production, removal of impurities during zinc smelting, promotion of precipitation of magnesium hydroxide during magnia production, removal of impurities during caustic soda production, oil content in petrochemical plants It can be used for the separation and removal of suspended solids, wastewater treatment at the Lube factory, wastewater treatment at paper mills, wastewater treatment at emulsion paint manufacturing factories, suspended solids aggregation at civil engineering construction sites, etc.

Ampholytic flocculants (Jl) can be used in the same fields of use as known water-soluble protein type flocculants (eg gelatin).

A flocculant having a hydrophobic bonding group or a hydrogen bonding group in addition to a cationic active group, a nonionic active group, an anionic active group, an amphoteric active group can enhance its effectiveness and expand the field of use.

Since the agglomerated product obtained as described above generally contains a considerable amount of water, it is preferable to subject it to a dehydration operation.

Dehydration can be carried out according to a conventional method, for example, after dehydration with a centrifuge, hot air drying can be carried out. When it is in the form of a dry powder, it is convenient to store and transport, and it is also easy to apply on-site.

It is also possible to mix other substances such as fertilizers, soil, organic wastes (eg sawdust), pesticides, etc. before, during or after the dewatering and drying of the agglomerated product.

Field application can be carried out according to conventional methods, for example, according to the same application methods as in the case of fertilizer application, soil application, etc.

Of course, it should not be used if it contains harmful heavy metals or inorganic or organic compounds.

Reference example] Polyphosphonitrile nochloride (PNCI, +
Poly[bis(
Methylimino)phosphacene is a known polymer compound, and can be represented by the following formula (17). This is a little unstable underwater,
Decomposes in water within approximately 30 days.

The following aggregation experiment was conducted using the imino compound (A) (molecular weight approximately 550,000).

Finely powdered kaolin was suspended in water, left to stand overnight, a portion that did not settle was collected, and the flocculant compound (A) was added in the form of a 1% aqueous solution, followed by thorough stirring and mixing.

Examine the clear liquid after 20 minutes to find a substantially clear supernatant (
The minimum required amount of flocculant necessary to obtain a turbidity of 100% (18) (18) turbidity of 10% liquid) was investigated. In this case, the required amount of humidity is 5.1 p.
It was pm. On the other hand, in the case of aluminum sulfate, which is a control sample, the minimum required amount is 189 ppm, and the minimum required amount of a commercially available cationic organic polymer flocculant is 13 ppm.
It was ppm.

Reference Example 2 (The method of reacting -PNC12÷ with an alcohol to obtain a fully substituted ester is well known. Using choline chloride as the monohydric alcohol, this known reaction produces an ester (B) of the following formula. was produced.The molecular weight was approximately 450.0
00° Since this ester (B) contained a quaternary ammonium group, it could be used as a cationic flocculant.

The sewage water containing various suspended organic and inorganic substances was collected for several hours, and the portion that did not settle was collected and placed in a sedimentation tube, and a flocculant was added thereto. By varying the amount of flocculant,
Find out the minimum amount of flocculant needed to obtain a clear liquid after 1 minute. The results of this experiment were as follows.

*Commercial product X: A flocculant that is a cationized modified product of polyacrylamide.

Reference example 3 Polyphosphonitrile dichloride 4PNC12÷0 and O
The esterification reaction itself, which is a reaction with an H group-containing compound, is known. Glycolic acid HOC as an OH group-containing compound
The above-mentioned known reaction was carried out using the sodium salt of H2COOH to produce a carboxylic acid group-containing compound (C) of the following formula. The molecular weight of compound (C) was 340,000.

A longitudinal experiment was conducted using this compound (C) as an anionic flocculant.

A 5% suspension of iron oxide in water was prepared and placed in a settling tube, and a flocculant was added in the form of a 1% aqueous solution of IOl)Pm.

The sediment volume was measured after 5 hours. The result of this experiment (21
) The results are shown in the table below.

Flocculant compound (C) Sodium lyacrylate (commercial product) 23 Reference N4 Cyclic phosphonitrile chloride (mixture of hexachloride and octachloride (PNCI2), 4) 25
Heating to 0-300℃ to carry out ring-opening polymerization to form a chain polymer +P
NCI, + was obtained.

The above chain polymer was treated with glycol and ethylene oxide to obtain a polymer compound of the following formula.

r99) The molecular weight of this polymer compound (D) is approximately 2,500,00
A flocculation experiment was conducted using the above compound (+) as a nonionic flocculant. Dilute this compound) with water to 01
% aqueous solution.

Clarification treatment of clay wastewater (solid content 0.80%) was carried out. The water temperature was about 20°C, and the pH was about 3.0-4.0. The light transmittance of clear water was examined using a colorimetric tube with a capacity of 100 CC. The experimental results are shown in the table below.

Coagulant Transmittance (%; after 5 minutes) [Product (D) 1 ppmJ + "NNa2CO3 300 pp" 91 1 Nonionic polyacrylamide Example 1 Digested sludge from sewage treatment plant (pH = 7,5; evaporation residue -59
Various flocculants were added to 0%; suspended solids - 5.40%; ignition residue of suspended solids = 625%), stirred gently, and free water separated by sludge flocculation was removed. , dehydration treatment was carried out in a press vacuum p over-dehydration device.

The flocculant used in this experiment and the experimental results are shown in the table below.

(23) Table 1 (25) (24) The dehydrated cake obtained by the coagulation operation using the flocculant (B) (see Table 1) was dried with hot air to obtain a dry product with a moisture content of 20 cm. In addition, a cultivation test was conducted using a control sample obtained in the same manner using a cationized modified polyacrylamide (see Table 1). 20 g of each was added to field soil, left for 2 months, the ground was leveled, Chinese cabbage was sown, and the growth status was observed.

The number of germination after 7 days of sowing was 95 in the case of the present invention, whereas it was 83% in the control. It was .9.

Separately, Sero IJ was planted and the live weight at harvest was measured in m1.
In the case of the present invention, it was 230.9, and in the control, it was 185 g.

Example 2 Drainage from land gravel cleaning work was allowed to stand for 20 hours. The two liquids containing the non-sedimenting portion were treated separately with the anionic flocculant (C) of Reference Example 3 and a known polyacrylamide-based anionic flocculant. Use 1 piece of each flocculant Q′lJ,
respectively] Oppm, and the rate of flocculation and sedimentation of suspended solids using the flocculant of the present invention was about three times the rate when using the control flocculant.

In each case, the resulting precipitate and the precipitate obtained from the first standing were mixed and dried. This was used as soil.

Seedling boxes were filled with each type of soil and used as cultivation beds. After sowing the germinated seed rice, a predetermined cultivation fM of 1% was carried out, and the results were examined after 25 days. Present invention 1/? X Therefore, when the operation was changed, the average plant height was 16.7 cm and the average weight was 25 g, whereas in the control, the average plant height was 12.7 cm.
5 crn, average type ill 1.7,! Example 3 The cationic flocculant (B) described in Reference Example 2 was added in an amount of 5% based on the weight of the waste liquid to the sulfurous acid / Schiff 0 cooking waste liquid, and the mixture was heated to 50°C for 1 hour. 1~ I was confused. The mixture was then allowed to stand, and the resulting precipitate was separated in a furnace, centrifugally dehydrated, and dried with hot air. Separately, prepare a directly dried product of the same waste liquid (control assay). Cultivation tests were conducted by mixing these dried substances into soil.

20% of the dry waste liquid described in Section 2 was mixed into sandy loam soil, and the soil was left in a moist state for two months before cultivation.

After filling the Wagner tubes and adding potash fertilizer to each,
We sowed Kokapu and examined its growth status. The investigation results after 40 days showed that in the case of the present invention, the total weight of the mine was 65 g, 14
3g, while in the control 47g of mines, total army N] O
/Ig.

Claims (1)

[Claims] General formula % Formula % (where R1, R2, R5, and R4 are a cation-containing group, an anion-containing group, a hydrogen-bonding group, a halogen, or an inert organic group, provided that R1, R2, At least one of R5 and R4 is a cation-containing group, an anion-containing group, or a hydrogen-bonding group. , a method for adjusting a plant medium, characterized in that it is used as soil or a soil conditioner.