JP2012166118A - Water treating flocculant and water treating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water treating flocculant having excellent flocculation and insolubilization performance of contaminant and to provide a water treating method using the water treating flocculant.SOLUTION: The water treating flocculant is composed of an alkali solution of a phenol resin obtained by adding aldehydes to the alkali solution of a novolak type phenol resin, which is obtained by reaction of phenols and aldehydes in the presence of an acid catalyst, to perform a resol type secondary reaction. The water treating flocculant is characterized in that the phenols include methyl phenols such as cresol. The water treating method has a flocculation treatment step of adding the water treating flocculant to water to be treated and then adding an inorganic flocculant thereto and a membrane separation treatment step of carrying out membrane separation treatment of flocculation-treated water obtained at the flocculation treatment step.

Description

  The present invention relates to a water treatment flocculant comprising an alkaline solution of a phenolic resin and a water treatment method using the water treatment flocculant. Specifically, methylphenols such as cresol are used as essential components as phenolic raw material phenols, and phenolic resins obtained by condensation with aldehydes in the presence of an acid catalyst are used as an alkaline solution, and aldehydes are added. A water treatment flocculant comprising an alkaline solution of a phenolic resin that has undergone a resol type secondary reaction, and water to be subjected to membrane separation treatment after adding the water treatment flocculant and the inorganic flocculant to the water to be treated. The present invention relates to a water treatment method that is particularly effective for water treatment using reverse osmosis (RO) membrane separation treatment.

In this specification, “phenols” refers to phenol, cresol, naphthol, and other organic compounds having a hydroxy group on an aromatic ring, and “phenolic resin” refers to various phenols. This refers to a resin obtained by addition condensation reaction with aldehydes. “Phenol resin” is obtained by addition condensation reaction between phenol and aldehydes using phenol as a raw material phenol in such a phenolic resin. The term “methylphenol resin” refers to a phenolic resin in which phenols containing methylphenols such as cresol, xylenol and trimethylphenol as essential components are used as raw phenols. Addition condensation of phenols containing aldehydes with aldehydes Refers to resins obtained by response, further as "cresol resin", in such a phenolic resin, using a cresol as a raw material phenol, it refers to a resin obtained by addition condensation reaction of a cresol with an aldehyde.
Accordingly, “phenolic resin” includes “phenolic resin”, “methylphenolic resin” and “cresol resin”.

  The novolac type phenolic resin is called a bakelite resin after the inventor, and was used as a plastic tableware in the old days, and then made use of its excellent heat resistance, insulation and mechanical strength, and fire resistance of molds, etc. As a heat-resistant material, recently, it has been widely used as a raw material resin for electronic materials.

  The novolak-type phenol resin is obtained by adding less than 1 mol of formaldehyde to 1 mol of phenol and subjecting it to an addition condensation reaction in the presence of an acidic catalyst. The structure is a structure in which one phenol ring is two-dimensionally connected in terms of reaction principle by a methylene bond formed by addition condensation reaction of formaldehyde.

  Since the novolak type phenolic resin does not contain a reactive methylol group, a curing agent such as hexamethylenetetramine and an auxiliary material suitable for the application are mixed and heated to a temperature higher than the melting point of the resin to be softened and subjected to predetermined molding. At the same time, a thermosetting reaction is performed to obtain a resin product. The resin after the curing reaction has high heat resistance (deformation resistance when heated, resistance to thermal decomposition), and this supports various uses of the resin.

On the other hand, as a water treatment agent, a solution obtained by dissolving a novolak type phenol resin in an alkaline solution is a paint recovery / removal agent in circulating water for washing away excess paint in an automobile painting booth (Kurita Kogyo Co., Ltd., trade name “Kuristack B310”). ]).
However, this is a treatment agent at a level that can be applied to circulating water at the painting booth, and cannot be used as a water treatment flocculant that satisfies the clarity that can be discharged into public water areas. Absent.

The reason for this is that when a novolac-type phenol resin alkaline solution is used for wastewater flocculation treatment, it contains a large amount of components that remain dissolved in water without flocculation, and this remains in the treated water. Treated water has a higher total organic carbon (TOC) than water, resulting in an increase in COD _Mn .

The component remaining in the treated water without agglomeration is a phenol dinuclear having a molecular weight of 1000 or less, in particular, having a molecular weight of slightly over 200 in which two phenol skeletons are connected by a methylene bond.
In addition, in the thermosetting resin which is the original use of the novolak type phenol resin, and its curing step, these components react as components of the cured resin, and there is no particular trouble.

  However, such a low molecular weight component does not participate in the aggregation during the aggregation process, and at the same time, remains in the treated water to become a new pollutant component. In the membrane separation process such as RO membrane, a new membrane contaminant Therefore, in use as a water treatment flocculant, it is necessary to sufficiently reduce such low molecular weight components.

  In order to solve this problem, the present applicant has studied to reduce the low molecular weight component and increase the weight average molecular weight in the phenolic resin, and has previously filed a patent application for an improved water treatment flocculant (special feature). Application 2010-81078, hereinafter referred to as “prior application”).

  The phenolic resin contained in the water treatment flocculant of the prior application is a novolac type phenolic resin obtained by reacting phenols and aldehydes in the presence of an acid catalyst, and then reducing inconvenient low molecular weight components. In order to increase the weight average molecular weight, an appropriate amount of aldehydes are added, and a resol type secondary reaction is performed in the presence of an alkali catalyst. In particular, raw water during membrane separation processing such as RO membranes is performed. It is useful as a pretreatment flocculant.

  On the other hand, the inventors of the present invention have been researching methods for removing membrane contaminants brought in from raw water by membrane separation treatment such as RO membranes. The present inventors have found that it is effective in coagulating and removing pollutants and improves MFF, which is an indicator of the degree of RO membrane contamination in treated water.

The membrane contaminant is a neutral polysaccharide, which is a part of the polysaccharide that is generally metabolized by microorganisms and algae. Polysaccharides are present in large amounts in wastewater biologically treated water, and even in environmental water, particularly in water with algae, such as lakes and ponds. A polysaccharide is a polymer substance having a very large molecular weight of about 1 million to 10 million. In membrane separation treatment such as RO membrane, membrane feed water (in this specification, “membrane feed water” is membrane separation). If it is present even in a trace amount, it concentrates and stays on the membrane surface without spreading, adheres to the membrane, contaminates it, and inhibits the membrane filtration function.
An acidic polysaccharide having a carboxyl group that occupies most of the polysaccharide is easy to aggregate and remove because the carboxyl group reacts with the metal cation of the inorganic flocculant. There are no reaction sites and it remains in the flocculated water.

  Neutral polysaccharides remaining in the agglomerated treated water have a very high molecular weight as described above, even as a trace amount of about 0.1 mg / L or less. Was demanded.

The MFF (MF factor or MF fouling factor) is the RO membrane feed water as in the FI (fouling index) defined in JIS K3802 and the SDI (silt density index) defined in ASTM D4189. It has been proposed as an index representing the degree of clarity (contamination level).
These are all measured using a microfiltration (MF) membrane having a pore diameter of 0.45 μm.

Specifically, MFF is measured as follows.
500 ml of sample water is filtered under a reduced pressure of 66 kPa (500 mmHg) using a filter made of nitrocellulose having a pore diameter of 0.45 μm and 47 mmφ manufactured by Millipore, and the filtration time T1 is measured. Further, 500 ml of sample water is similarly filtered, and the filtration time T2 is measured.
MFF is indicated by T2 / T1, and for example, distilled water or RO membrane permeate without membrane contaminants, T1 and T2 are almost equal, and MFF is 1.00.
The appropriate value of MFF as RO membrane supply water is 1.10 or less, preferably 1.05 or less.
If even a small amount of neutral polysaccharide is present, the viscosity due to being a polymer, and part of it adheres to the membrane, resulting in permeation resistance and filtration inhibition of the MF membrane, resulting in a large MFF and evaluation as RO membrane supply water Will be bad.

Japanese Patent Application No. 2010-081078

Examples of the raw material phenols used in the production of the novolak type phenolic resin shown in the prior application include phenol and other phenols, but in the examples, only those using phenol are listed. .
The present invention relates to a water treatment flocculant that is superior in water flocculation and insolubilization performance of pollutants than a water treatment flocculant comprising an alkaline solution of a phenolic resin disclosed in the prior application, and a water treatment using this water treatment flocculant. It is an object to provide a method.

  In order to solve the above-mentioned problems, the present inventors have further considered and studied the following water treatment flocculant.

  That is, the water treatment flocculant of the prior application has the characteristic of specifically aggregating and insolubilizing neutral polysaccharides and nonionic surfactants, which are pollutants that cannot be aggregated with inorganic flocculants. This characteristic is that, firstly, the phenolic resin has a binding force presumed to be a hydrogen bond with the pollutant, and secondly, the phenolic hydroxyl group dissociated by the alkali becomes non-dissociated under neutrality. It was thought that the property of becoming water-insoluble itself was exhibited.

Here, if the phenols of the phenolic resin are methylphenols such as cresol, xylenol, and trimethylphenol in which one or more methyl groups are introduced into the phenol, the hydrophobicity of the resin can be improved. It was considered that water insolubility increased further and the ability of the pollutant to agglomerate and insolubilize was increased, and verification using cresol and xylenol as raw materials was conducted.
As a result, as shown in Examples and Comparative Examples described later, an alkaline solution of a phenol resin (phenolic resin using phenol as a raw material phenol) subjected to a resol type secondary reaction having a weight average molecular weight of 13,000, Methylphenol resin having undergone a resol type secondary reaction having a weight average molecular weight of 16000 and 14000, which is approximately the same molecular weight (phenol resin using cresol as raw phenol and cresol and xylenol as raw phenols) 33 (phenolic resin used at a molar ratio) with an alkaline solution of methylphenolic resin having an MFF improvement effect about 1.4 times that of phenolic resin with the same amount of phenolic resin conversion. Confirmed.
In addition, even an alkaline solution of a cresol resin having a weight average molecular weight of 4900, which is not subjected to a resol type secondary reaction, has an MFF improving effect equal to or higher than that of a resol type secondary reaction phenol resin having a weight average molecular weight of 13,000, and a methyl group is introduced. The cresol skeleton was confirmed to be superior to the phenol skeleton.

  The present invention has been achieved on the basis of such findings, and the gist thereof is as follows.

[1] Phenol obtained by adding an aldehyde to an alkaline solution of a novolak-type phenolic resin obtained by reacting a phenol with an aldehyde in the presence of an acid catalyst and performing a resol-type secondary reaction. A water treatment flocculant comprising an alkaline solution of a resin, wherein the phenols contain methylphenols.

[2] The water treatment flocculant according to [1], wherein the methylphenol is cresol.

[3] In [1] or [2], the phenolic resin obtained by performing the resol-type secondary reaction has a weight average molecular weight of 10,000 or more and a content of low molecular weight components having a molecular weight of 1,000 or less of 20%. % Water treatment flocculant characterized by being less than or equal to%.

[4] In a water treatment method comprising a flocculation treatment step of adding a flocculant to the water to be treated and a membrane separation treatment step of membrane separation treatment of the flocculation water in the flocculation treatment step, the flocculation treatment step comprises: A water treatment method comprising adding an inorganic flocculant after adding the water treatment flocculant according to any one of [1] to [3] to water.

An alkaline solution of a phenolic resin obtained by performing a resol type secondary reaction on a novolak-type phenolic resin is generally an agglomeration of water, such as a nonionic surfactant or an uncharged neutral polysaccharide. It is possible to efficiently agglomerate and remove pollutants that cannot be treated with the inorganic flocculant alone used in the treatment, and the problem of contamination of the contaminated components in the treated water is also reduced.
In particular, among these phenolic resins, methylphenols are used as raw material phenols, methylphenolic resins condensed with aldehydes under an acid catalyst are made into an alkaline solution, and aldehydes are added to add resole type 2 The water treatment flocculant of the present invention consisting of an alkaline solution of methylphenol resin subjected to the next reaction uses a phenol as a raw material phenol of a phenolic resin, and is compared with a water treatment flocculant prepared in the same manner. The improvement effect of the pollution index MFF is about 1.4 times. Moreover, the residual rate of the residual resin that becomes secondary contamination is as small as the water treatment flocculant made of an alkaline solution of phenol resin using phenol as the raw material phenols, and the pretreatment flocculant of the membrane supply water such as RO membrane As such, you can expect excellent functionality.

  The water treatment flocculant of the present invention is particularly effective for the aggregation treatment as a pretreatment step of the membrane separation treatment step such as RO membrane separation treatment, and improves the water membrane contamination index MFF used for the membrane separation treatment, A decrease in permeation flux of a membrane such as an RO membrane can be prevented, and a stable and efficient membrane separation process can be performed over a long period of time.

  Therefore, according to the water treatment method of the present invention for membrane separation treatment of the flocculated water using the water treatment flocculant of the present invention, stable and efficient treatment can be continuously performed over a long period of time. .

It is a graph which shows the relationship between a MFF index | exponent and MFF. It is a graph which shows the relationship between the water processing flocculant addition amount of the phenol resin conversion of Example II-1,2 and Comparative Example II-1,2 and a MFF index | exponent. It is a graph which shows the relationship between the amount of water treatment flocculant addition of the phenol-type resin conversion of Example III-1 and Comparative Example III-1, and an MFF index. It is a graph which shows the relationship between the amount of water treatment flocculant addition of the phenol-type resin conversion of Example IV-1 and Comparative Example IV-1 and 2, and an MFF index.

  Hereinafter, embodiments of the present invention will be described in detail.

  In the present invention, the molecular weight or the weight average molecular weight is a value measured by a GPC method (gel permeation chromatography method) and calculated using a standard polystyrene calibration curve.

[Water treatment flocculant]
The water treatment flocculant of the present invention is a resol type secondary reaction in which an aldehyde is added to an alkali solution of a novolak type phenol resin obtained by reacting a phenol with an aldehyde in the presence of an acid catalyst. Is a water treatment flocculant made of an alkaline solution of a phenolic resin obtained by performing the step, wherein the phenols contain methylphenols.

  In the present invention, the novolac-type phenolic resin used as a raw material for the resol-type secondary reaction is subjected to an addition condensation reaction of phenols and aldehydes in the presence of an acidic catalyst in a reaction kettle according to a conventional method. In addition, it is produced by dehydration and removal of unreacted phenols under reduced pressure.

  In the present invention, methylphenols such as cresol, xylenol, and trimethylphenol are essential components as raw material phenols used in the production of the novolak-type phenolic resin.

As cresol, any of o, m, and p can be used, and a mixture of two or more of these may be used. Further, each isomer of xylenol and 2,3,5-trimethylphenol can be used. Further, as the raw material phenols, methylphenols such as cresol may be mainly used and other phenols may be mixed and used. In this case, as other phenols, for example, phenol, ethylphenols of o, m, and p, isomers of diethylphenol, alkylphenols such as 2,3,5-triethylphenol, and naphthols of α and β And polyaromatic phenols such as bisphenol A, bisphenol F, bisphenol S, pyrogallol, resorcin, catechol, and the like, and hydroquinone, but are not limited thereto. These other phenols may be used individually by 1 type, and 2 or more types may be mixed and used for them.
In addition, when these other phenols are used together with methylphenols, in order to effectively obtain the effects of the present invention by using methylphenols as raw material phenols, 50% by weight or more in raw material phenols, particularly 70 to 100% by weight is preferably methylphenols such as cresol, xylenol and trimethylphenol.

On the other hand, examples of aldehydes include formaldehyde, paraformaldehyde, acetaldehyde, propylaldehyde, benzaldehyde, salicylaldehyde, glyoxal, and the like, but are not limited thereto. These aldehydes may be used individually by 1 type, and may mix and use 2 or more types.
Among these, practical substances are formaldehyde and paraformaldehyde.

  Acid catalysts for producing novolak-type methylphenol resins include inorganic acids such as hydrochloric acid, sulfuric acid, and phosphoric acid, organic acids such as oxalic acid, acetic acid, citric acid, tartaric acid, benzoic acid, and paratoluenesulfonic acid, zinc acetate And organic acid salts such as zinc borate, but are not limited thereto. These acid catalysts may be used alone or in combination of two or more.

In the present invention, there is no limitation on the melting point of the novolac-type methylphenol resin used as the raw material for the resol-type secondary reaction, but usually the raw material phenols mainly composed of methylphenols such as cresol is 60 to 135 ° C. .
In the novolak-type methylphenol resin having the same composition, the higher the melting point, the higher the molecular weight of the raw novolak-type methylphenol resin, and the higher the molecular weight of the resin after the resol-type secondary reaction. The agglomeration effect is also improved.
In the present invention, the upper limit of the melting point of the raw novolak type methylphenol resin is not limited, but when the melting point exceeds 130 ° C., the softening / flowing temperature becomes approximately 160 ° C. or higher, and the novolac type methyl phenol resin in the reaction kettle Local temperature greatly exceeds 200 ° C. For this reason, the resin is decomposed or burnt, and a stable quality product cannot be obtained. Further, since the melt viscosity becomes too high, there arises a problem that the removal becomes industrially difficult. Therefore, it is preferable that the melting point of the raw novolak-type methylphenol resin for the resol-type secondary reaction is about 100 to 130 ° C.

  In the present invention, the molecular weight of the novolac-type methylphenol resin used as a raw material for the resol-type secondary reaction is not limited, but the resin having a higher molecular weight is not involved in aggregation after the completion of the secondary reaction. This is preferable because the content of low molecular weight components that remain in the agglomerated treated water and contaminate the treated water is reduced. For this reason, it is preferable that the novolak-type methylphenol-type resin to be used is 1000 or more in weight average molecular weight, and it is especially preferable that it is 2000 or more. Although there is no restriction | limiting in the upper limit of the molecular weight of a novolak-type methylphenol-type resin, Usually, it is about 8000 in a weight average molecular weight.

  In such a novolak type methylphenol resin, even if the resin has a weight average molecular weight of about 2000 or more, the phenolic binuclear having a molecular weight of over 200 remaining in the treated water is 5% by weight or more, and the molecular weight is 624. The total of 15% by weight or more of the following low molecular weight components that are not involved in aggregation and may remain in the agglomerated treated water. For example, in the case of a novolac cresol resin using cresol and formaldehyde as raw materials, a cresol dinuclear body having a molecular weight of slightly over 200 is generally contained in an amount of about 5 to 10% by weight, and a low molecular weight component having a molecular weight of 624 or less. In general, it is generally contained in an amount of about 15 to 30% by weight, and low molecular weight components having a molecular weight of 1000 or less are contained in a total of about 20 to 40% by weight.

In the present invention, such a novolac type methylphenol resin is first made into an alkaline solution.
Solvents that dissolve the novolac-type methylphenol resin include one or more of alkali metal or alkaline earth metal hydroxides such as sodium hydroxide, potassium hydroxide, calcium hydroxide, and barium hydroxide. An aqueous solution is mentioned, and this simultaneously serves as an alkali catalyst for the resol type secondary reaction in the next step.

  In addition, alcohols such as methanol, ethanol, propanol, butanol, ethylene glycol, ketones such as acetone, methyl ethyl ketone, methyl amyl ketone, and methyl isobutyl ketone, cell solves such as methyl cellosolve, ethyl cellosolve, and butyl cellosolve And sorbitol esters, methyl carbitol, ethyl carbitol, ethyl carbitol acetate and other carbitols and carbitol esters, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, ethyl lactate, butyl acetate and the like Such as triethylamine, trimethylamine, DBU (1,8-diazabicyclo [5.4.0] undec-7-ene), DBN (1,5-diaza). Basic solvents to dissolve the organic base cyclo [4.3.0] non-5-ene), etc. may also be used as an alkaline solution which also serves as an alkaline catalyst resole secondary reaction.

There is no particular restriction on the pH of the alkali solution of the novolak-type methylphenol resin, but if the pH is too low, the solubility of the novolak-type methylphenol resin is poor, and if it is too high, the added alkaline substance is wasted. It is preferably about pH 11-13.
The resin concentration in the alkali solution of the novolak-type methylphenol resin is not particularly limited, but if the concentration is too high, the solution viscosity increases, and the uniformity of the secondary reaction in which aldehydes are added is maintained. , It is inconvenient to handle the pump injection of the final product, etc. If it is too low, there will be a decrease in production efficiency, packing of the final product, and an increase in transportation costs, so 5 to 50% by weight, especially about 10 to 25% by weight It is preferable that

  As the aldehyde to be added to the alkali solution of the novolak-type methylphenol resin for the resol-type secondary reaction, the same aldehydes as the above-mentioned novolak-type methylphenol-based resin raw material may be used alone or in combination. Two or more kinds can be mixed and used. Among these, formaldehyde and paraformaldehyde are particularly practical, but are not limited thereto.

  The amount of aldehyde added to the alkali solution of the novolak-type methylphenol resin is not particularly limited. However, if the amount added is too small, the decrease in low molecular weight components including binuclear compounds is insufficient. , Phenolic resin obtained by resol type secondary reaction (hereinafter referred to as “secondary reaction phenolic resin”, the one using phenol as raw material phenol is “secondary reaction phenol resin”, and methylphenol as raw material phenols (In some cases, a secondary reaction methylphenol resin is sometimes used as an essential component). On the other hand, if the amount is too large, crosslinking of the resulting secondary reaction methylphenol resin proceeds, resulting in insolubilization and solidification. The appropriate amount of aldehydes varies depending on the content of low molecular weight components having a molecular weight of 1000 or less including dinuclear compounds in the raw novolac type methylphenol resin and the kind of phenols to be composed. It becomes 0.1-0.4 mol per mol of phenol skeletons in the phenolic resin. However, in practice, a preliminary test is performed in advance to confirm the relationship between the amount of aldehyde added and the melting point of the secondary reaction methylphenol resin, and based on the results, the secondary reaction methylphenol resin having a desired melting point is obtained. It is preferable to determine the addition amount so that is obtained.

  The resol type secondary reaction method is not particularly limited. For example, a novolak type methylphenol resin having a predetermined resin concentration and pH in a reaction facility having a stirrer, a steam blowing facility, a refluxing device, and a temperature control mechanism. The alkali solution is heated to a predetermined temperature, for example, about 40 to 70 ° C. by steam blowing, and then aldehydes are added, and the temperature is maintained at 80 to 100 ° C. for 1 to 12 hours while maintaining the temperature. Perform a resol-type reaction.

  After completion of the reaction, the reaction solution is cooled to obtain an alkaline solution of the secondary reaction methylphenol resin. This secondary reaction methylphenol-based resin has a low content of low-molecular-weight components having a molecular weight of 1000 or less including a phenolic binuclear compound and a weight average molecular weight higher than that of the raw material novolac-type methylphenol-based resin. Secondary reaction methylphenol resin.

  The resin concentration, pH, aldehyde addition amount, reaction temperature and reaction time in the secondary reaction are not limited at all, and are appropriately set so as to obtain a secondary reaction methylphenol resin having a desired melting point. Is done.

  In the present invention, the melting point of the secondary reaction methylphenol resin thus obtained is 130 to 220 ° C, preferably 150 to 205 ° C.

In the present invention, the weight average molecular weight of the secondary reaction methylphenol resin is preferably 5,000 or more, and more preferably 10,000 or more. On the other hand, when the weight average molecular weight exceeds 50,000, some molecules having a molecular weight of 1 million or more are formed, the viscosity is high, and further crosslinking occurs over time, so that insoluble matter is likely to be generated. The weight average molecular weight of the phenolic resin is preferably 50000 or less, particularly preferably 30000 or less.
The weight average molecular weight of the secondary reaction methylphenol resin may be about 2 to 7 times the weight average molecular weight of the novolac type methylphenol resin before the reaction, that is, the raw material of the resol type secondary reaction. preferable.

In addition, the content of low molecular weight components having a molecular weight of about 1000 or less, including binuclear compounds, is reduced in this secondary reaction methylphenol resin relative to the novolak type methylphenol resin that is a raw material for the resol type secondary reaction. When used in the water agglomeration treatment, the agglomerated water that is preferable as the feed water for the membrane separation treatment can be obtained in which the amount of unaggregated matter remaining on the agglomeration water side is remarkably reduced and TOC and COD _Mn are remarkably reduced.

  In the secondary reaction phenolic resin (secondary reaction methylphenolic resin) according to the present invention obtained using methylphenols as raw material phenols, due to the increase in hydrophobicity due to the use of methylphenols as raw material phenols Compared with the secondary reaction phenol resin obtained by using phenol as the raw material phenols, the molecular weight region of the resin remaining in the agglomerated treated water without agglomeration shifts to the low molecular weight side. For this reason, the secondary reaction methylphenol resin according to the present invention obtained using methylphenols as the raw material phenols has a molecular weight of 1000 compared with the secondary reaction phenolic resin obtained using phenol as the raw material phenols. The allowable value of the content of the following low molecular weight components is high, and this value may be about 20% by weight or less, preferably 15% by weight or less.

  The alkaline solution of methylphenol resin obtained by this resol type secondary reaction is a liquid that can be pumped, and the manufactured product can be used as it is as a water treatment flocculant.

  In addition, the melting point measurement sample preparation method, the melting point measurement method, the molecular weight measurement sample preparation method, the molecular weight measurement method and the like of the secondary reaction phenolic resin or the novolak type phenolic resin which is a raw material of the resol type secondary reaction in the present invention are as follows. It is as follows.

<Method for preparing melting point measurement sample>
The alkaline solution of the secondary reaction phenolic resin is diluted with ion-exchanged water so that the resin concentration is 1% by weight or less, and is sufficiently stirred with a stirrer or the like, and about 1N hydrochloric acid is added dropwise to adjust the pH to 5 Adjust to less than. The resin precipitated by this operation was No. After filtering with 5A filter paper, it is washed twice with ion-exchanged water, and this precipitated resin is transferred to another filter paper to thoroughly remove moisture.
The resin from which moisture has been cut is vacuum dried overnight at room temperature, or dried for several days until weight loss is eliminated by a desiccator.
In addition, about the novolak-type phenol-type resin which is a raw material of a resol type | mold secondary reaction which does not perform a secondary reaction, after making it an alkaline solution, a sample is prepared again by the said method.

<Measuring method of melting point>
Measurement is performed using a differential scanning calorimeter (DSC) manufactured by SII Nanotechnology.
2 mg of a sample is put on a DSC measuring device, the temperature is raised at 10 ° C./min, a line of heat flow (Heat Flow / mW) is obtained with respect to the temperature rise on the horizontal axis, and the top temperature of the endothermic peak is taken as the melting point.
In the present invention, the melting points of the novolac type phenolic resin and the secondary reaction phenolic resin are values measured by the sample preparation method and the melting point measurement method described above.

<Molecular weight measurement sample preparation method>
In order to perform molecular weight measurement including fractionation, the removal of alkali metal ions and the removal of water from the alkaline solution of the secondary reaction phenolic resin can be carried out without causing the low molecular weight component containing the phenol dinuclear in the resin to flow out. There is a need to do.
Therefore, first, the alkaline solution of the secondary reaction phenolic resin is diluted to a resin concentration of about 0.1% by weight (1000 mg / L), put into a dialysis membrane apparatus, and then the phenol group that has been dissociated in advance is not dissociated. The amount of hydrochloric acid for neutralization necessary for this is determined, and this is added to the solution in the dialysis membrane device before dialysis. The contents after completion of dialysis are concentrated and dried at a low temperature of about 40 ° C. in a vacuum flask with the entire amount including the deposits.
This is vacuum-dried at room temperature and dissolved in the above-mentioned tetrahydrofuran to obtain a molecular weight measurement sample containing a fraction.
Note that the novolac phenolic resin, which is a raw material prior to the resol type secondary reaction, is also subjected to the same operation to share error factors such as a shift in measured values that may occur in the pretreatment.

<Molecular weight fractionation / molecular weight measurement method>
The molecular weight is measured by gel permeation chromatography (hereinafter referred to as GPC).
Elution is performed by developing the tetrahydrofuran solution of the secondary reaction phenolic resin described above at a flow rate of 0.8 mL / min and a temperature of 40 ° C. using HLC8022 made by TOSOH as a chromatography column and tetrahydrofuran as a solvent. Resin detection is performed by refractive index and ultraviolet absorption, and the wavelength having a maximum absorption is 254 nm. The detector uses RI-8020 and UV-8020 manufactured by TOSOH.
This result is applied to a calibration curve using a polystyrene standard substance with a clear molecular weight, and the molecular weight fraction and the molecular weight of the fractionated resin component and its content are tested.
The content of the low molecular weight component is calculated from the area ratio (%) with respect to the whole resin by the GPC molecular weight distribution curve.
In the present invention, the weight average molecular weight of the phenolic resin, the molecular weight of the low molecular weight component, and the content thereof are values obtained by the above-described sample preparation method and molecular weight fractionation / molecular weight measurement method.

The water treatment flocculant of the present invention is a secondary reaction methylphenol obtained by carrying out a resol type secondary reaction of a novolak type methylphenol resin containing methylphenol as an essential component as a raw material phenol as described above. The resin concentration is preferably 10 to 25% by weight and the pH is preferably about 11 to 13.
Since this water treatment flocculant has a small amount of low molecular weight components remaining on the treated water side regardless of aggregation, the water treatment and waste water coagulation treatment, particularly membrane separation treatment, especially as a pretreatment step of RO membrane separation treatment. It is effective as a water treatment flocculant used in

[Water treatment method]
In the water treatment method of the present invention, the water to be treated is agglomerated, and this agglomerated water is subjected to membrane separation treatment. After the water treatment flocculant of the present invention is added in the agglomeration treatment of the water to be treated, In addition, an inorganic flocculant is added.

  The target substance for which the water treatment flocculant of the present invention exerts its flocculating effect is incapable of being treated with inorganic flocculants represented by ordinary aluminum salts such as polyaluminum chloride (PAC) and iron salts such as ferric chloride. It is a non-ionic surfactant, a neutral polysaccharide that has no or very little anionic property.

  In the RO membrane separation treatment, neutral polysaccharides that cannot be removed by pretreatment aggregation with a normal inorganic flocculant remain, contaminating the RO membrane and reducing its permeation flux. In the field, the water treatment flocculant and the water treatment method of the present invention are effectively applied.

  When the water treatment flocculant of the present invention is used for such a flocculation treatment, the amount of the water treatment flocculant added to the water to be treated is appropriately determined depending on the quality of the water to be treated and the intended flocculation effect, and is inorganic. Although it depends on whether the coagulant is used or not, it is generally the same amount as the nonionic surfactant or neutral polysaccharide that is the target of aggregation of the water treatment coagulant of the present invention. For example, RO membrane separation treatment, etc. When used in the pretreatment step of the membrane separation treatment step, the addition amount in terms of phenolic resin is preferably 0.1 to 5.0 mg / L, particularly about 0.3 to 2.0 mg / L.

  In addition, when the water treatment flocculant of the present invention is used for agglomeration treatment as a pretreatment step of membrane separation treatment using an RO membrane, an ultrafiltration membrane, a microfiltration membrane or the like, it is inorganic together with the water treatment flocculant of the present invention It is preferable to use a coagulant together.

  The inorganic flocculant used in combination is not particularly limited, but aluminum-based flocculants such as polyaluminum chloride (PAC), aluminum sulfate, aluminum chloride, ferric chloride, ferric sulfate, polyferric sulfate, etc. These iron-based flocculants may be used, and these may be used alone or in combination of two or more.

  The amount of the inorganic flocculant added varies depending on the quality of the water to be treated and the intended quality of the treated water, but when the water to be treated is industrial water and is used in the pretreatment step of the membrane separation step, it is usually 20 to 100 mg / When the water to be treated is primary treated water of wastewater such as biologically treated water and used for the pretreatment step of the membrane separation step, it is usually about 100 to 700 mg / L.

  When the water treatment flocculant of the present invention is used in combination with an inorganic flocculant to perform a flocculant treatment as a pretreatment of the membrane separation treatment, the water flocculant of the present invention is first added to the water to be treated, and then the inorganic flocculant is added. Added. Specifically, the water treatment flocculant of the present invention is added to the water to be treated and allowed to react for 1 minute or longer, and then the inorganic flocculant is added and about 3 to 10 minutes with rapid stirring, and further 3 with slow stirring. React for about 10 minutes, and the resulting flocculation treatment liquid is subjected to primary solid-liquid separation with a precipitation tank, a pressure levitation device, etc., and further subjected to secondary solid-liquid separation with a gravity filtration device, and the separated water is subjected to membrane separation treatment. It is preferable to use feed water.

When the water treatment flocculant of the present invention and the inorganic flocculant are added to the water to be treated at the same time, or when the inorganic flocculant is added at a location close to the addition position of the water treatment flocculant of the present invention, As a result of the direct reaction with the inorganic flocculant, the effect of adding the phenolic resin cannot be obtained, and the required amount of the drug added to compensate for the amount consumed by the reaction increases.
In addition, when the water treatment flocculant of the present invention is added after the inorganic flocculant, the water to be treated is a phenolic resin except when the water is high salt-containing water having an electric conductivity of 1000 mS / m or more such as seawater. Remains in an unaggregated state, becomes a membrane separation inhibitor, and deteriorates MFF.

Hereinafter, the present invention will be described more specifically with reference to examples.
In the following, “%” represents “% by weight”.

  In the following, the melting point measured in accordance with the above-mentioned <Melting point measurement method> for the sample prepared in accordance with the above-mentioned <Melting point measurement sample preparation method> is simply referred to as “melting point”, and the resin catalog value or the sample resin The melting point measured without being dissolved in the alkaline solution is referred to as “original resin melting point”.

[Production of secondary reaction phenolic resin alkaline solution]
Resietop PS-6945 and PS-4991 manufactured by Gunei Chemical Industry Co., Ltd. were used as raw material resins for the examples. PS-6945 is a novolak cresol resin obtained by addition condensation of cresol and formaldehyde in the presence of an acid catalyst, and PS-4991 is similarly subjected to addition condensation with a molar ratio of cresol and xylenol of 67/33. The novolac-type cresol / xylenol resin thus obtained has the following melting point, weight average molecular weight, low molecular weight component content, and the like.

  Moreover, Gunei Chemical Industry Co., Ltd. resin top PSM-6358 was used as raw material resin for a comparative example. This product is a novolac type phenol resin obtained by addition condensation of phenol and formaldehyde in the presence of an acid catalyst, and its melting point, weight average molecular weight, low molecular weight component content, etc. are as follows.

  The main uses of these PS-6945, PS-4991 and PSM-6358 are for electronic materials and are not used as water treatment flocculants.

<Example I-1>
In a beaker, 41 g of PS-6945, 7.4 g of caustic soda corresponding to 18% of the amount of resin and 150 g of ion-exchanged water were added and dissolved by stirring with a magnetic stirrer. Finally, ion-exchanged water was added, and PS- 200 g of an alkaline solution containing 20.5% of 6945 was obtained.
Add 100 g of PS-6945 alkaline solution to a 200 ml Erlenmeyer flask with a stopper, warm to about 60 ° C., and then add 2.4 g of 37% formaldehyde solution diluted with an appropriate amount of ion-exchanged water. A nitrogen gas blowing tube and a thermometer were attached to the stopper, and a resol-type formaldehyde addition condensation reaction was allowed to proceed for 8 hours at a liquid temperature of 85 ° C. with an oil bath (resol-type secondary reaction).
Thereafter, this was cooled, ion exchange water (ion exchange water for concentration adjustment) was added to make the total amount 132 g, the low molecular weight component content including cresol dinuclear body was reduced, and the high melting point with increased weight average molecular weight Secondary reaction cresol resin alkali solution (cresol resin content: 16%, hereinafter referred to as “the present invention synthetic product A”) was obtained.

<Example I-2>
In a beaker, 41 g of PS-4991, 7.4 g of caustic soda corresponding to 18% of the resin amount and 150 g of ion-exchanged water were added and dissolved by stirring with a magnetic stirrer. Finally, ion-exchanged water was added, and PS- 200 g of an alkaline solution containing 20.5% of 4991 was obtained.
Add 100 g of the PS-4991 alkaline solution to a 200 ml Erlenmeyer flask with a stopper, heat to about 60 ° C., and then add 3.4 g of 37% formaldehyde solution diluted with an appropriate amount of ion-exchanged water. A nitrogen gas blowing tube and a thermometer were attached to the stopper, and a resol-type formaldehyde addition condensation reaction was allowed to proceed for 8 hours at a liquid temperature of 85 ° C. with an oil bath (resol-type secondary reaction).
Then, this was cooled, ion exchange water (ion exchange water for concentration adjustment) was added to make the total amount 132 g, the content of low molecular weight components including methylphenol dinuclear was reduced, and the weight average molecular weight was increased. A secondary reaction methylphenol resin alkali solution having a melting point (methylphenol resin content: 16%, hereinafter referred to as “the synthetic product B of the present invention”) was obtained.

<Comparative Example I-1>
In a beaker, 41 g of PSM-6358, 8.2 g of caustic soda corresponding to 20% of the amount of resin and 150 g of ion-exchanged water were added, and stirred and dissolved with a magnetic stirrer. Finally, ion-exchanged water was added, and PSM-6358 was added. 200 g of an alkaline solution containing 20.5% was obtained.
Add 100 g of the PSM-6358 alkaline solution to a 200 ml Erlenmeyer flask with a stopper, heat to about 60 ° C., and then add 4.4 g of 37% formaldehyde solution diluted with an appropriate amount of ion-exchanged water. A nitrogen gas blowing tube and a thermometer were attached to the stopper, and a resol-type formaldehyde addition condensation reaction was allowed to proceed for 8 hours at a liquid temperature of 85 ° C. with an oil bath (resol-type secondary reaction).
This was cooled, and ion-exchanged water for concentration adjustment was added to make the total amount 132 g, and the secondary reaction phenol resin alkaline solution (phenol resin) in which the low molecular weight content including the phenol dinuclear substance was reduced and the weight average molecular weight was increased. Content: 16%, hereinafter referred to as “Comparative Synthetic Product C”).

<Comparative Example I-2>
In Example I-1, a resol-type secondary reaction was not carried out, and a comparative preparation D was prepared by adding ion-exchanged water to an alkaline solution of resin raw material PS-6945 and diluting to a resin concentration of 16%.

[Measurement of melting point, molecular weight and low molecular weight component content]
For the synthetic products A and B of the present invention, the comparative synthetic product C and the comparative preparation product D, molecular weight fractionation was carried out by the above-described method, respectively, and binuclear and low molecular weight component contents were tested. The results are shown in Table 2. Indicated.
The melting point was measured by the method described above, and the results are shown in Table 2.
In addition, about the monomer (phenols), it analyzed separately by JISK-6910-7.22.

The weight average molecular weight of Example I-1 (Inventive Synthetic Product A) is 16000, Example I-2 (Inventive Synthetic Product B) is 14,000, and the Weight Average Molecular Weight of Comparative Example I-1 (Comparative Synthetic Product C) Is almost the same level as 13,000.
In addition, in Example I-1 (the present synthetic product A), the weight average molecular weight is 4900 to 16000 and 3.3 as compared with Comparative Example I-2 (Comparative Adjustment Product D) that does not undergo the resol type secondary reaction. Has doubled. Further, in Example I-2 (the present invention synthetic product B), the weight average molecular weight is increased from 2500 to 14000, which is 5.6 times as compared with PS-4911, which is not subjected to the resol type secondary reaction.
The low molecular weight component content is 9.7% for the synthetic product A of the present invention and 12.6% for the synthetic product B of the present invention, with a total molecular weight of 1000 or less in terms of polystyrene, more than 6.9% of the comparative synthetic product C, In particular, the component having a molecular weight of 280 or less remains much more than that of the comparative synthetic product C. However, when compared with the comparative preparation D and PS-4991 that do not perform the resol type secondary reaction, the total of the polystyrene equivalent molecular weight of 1000 or less is synthesized according to the present invention. It is greatly reduced from 26.8% to 9.7% in the product A and from 40.6% to 12.6% in the synthetic product B of the present invention.
In addition, the melting point of the synthetic product A of Example I-1 at 205 ° C. is higher than the melting point of the comparative synthetic product C of Comparative Example I-1 at 180 ° C. Moreover, it has risen from 110 to 135 ° C. of Comparative Adjustment Product D of Comparative Example I-2 in which no resol type secondary reaction is performed. Similarly, the synthetic product B of Example I-2 also has a melting point rising from 100 to 120 ° C. to 195 ° C. in the resol type secondary reaction.
Note that the range of the melting points of PS-6945 (Comparison adjustment product D) and PS-4991 indicates that the heat absorption temperature range of the chart is broad.

[MFF evaluation]
[1] Highly polluted organisms described later, which are biologically treated water containing a large amount of neutral polysaccharides that are membrane pollutants, using the above-described synthetic products A and B of the present invention, comparative synthetic product C, and comparative preparation D Similarly to treated water and [2] medium-polluted biological treated water, as well as [3] lake-based industrial water described below, which is industrial water with water source from lakes and marshes, where neutral polysaccharides from algal metabolic production exist. The MFF of the treated water that had been subjected to agglomeration treatment and filtration treatment was measured indoors, and the optimization effect as membrane supply water was evaluated.

  The methods for the aggregation test, filtration treatment, MFF measurement, and evaluation are as follows.

{Aggregation test: Jar test}
For the jar test, a jar tester manufactured by Miyamoto Seisakusho was used, and 1100 ml of sample raw water was subjected to agglomeration treatment according to the following procedure.
(1) Under rapid stirring at 150 rpm, a predetermined amount of the phenolic resin alkaline solutions of the synthetic products A and B of the present invention, the comparative synthetic product C, and the comparative preparation product D were added and reacted for 5 minutes.
(2) Next, after the inorganic flocculant addition reaction, acid is added so as to have a predetermined pH, followed by addition of a predetermined amount of the inorganic flocculant, followed by 150 rpm rapid stirring for 7 minutes and 50 rpm slow stirring for 8 minutes. went.

{Filtration treatment}
The treated agglomerated water is allowed to stand for about 15 to 30 minutes to precipitate the aggregate, and The whole amount was filtered with 5A filter paper to obtain 1000 ml or more of filtered water.

{MFF measurement}
(1) 500 ml of the filtered water was filtered under a reduced pressure of 66 kPa (500 mmHg) using a nitrocellulose filter having a pore diameter of 0.45 μm and 47 mmφ manufactured by Millipore, and the filtration time T1 was measured.
(2) Another 500 mg / L filtered water was filtered in the same manner, and the filtration time T2 was measured.
(3) MFF is indicated by T2 / T1, and for example, distilled water or RO membrane permeate without membrane contaminants, T1 and T2 are almost equal, and MFF is 1.00.
The appropriate value of MFF as reverse osmosis (RO) membrane feed water is 1.10 or less, preferably 1.05 or less.
On the other hand, MFF inappropriate as reverse osmosis (RO) membrane feed water is 1.2 or 1.3 or more.

{Evaluation of MFF}
The MFF index calculated from MFF was used for evaluation.
The MFF index is calculated by log (1 / (MFF-1.00), and the relationship with MFF is as shown in FIG.

The reasons for evaluation with the MFF index are as follows (1) to (3).
(1) The addition amount of the water treatment flocculant and the MFF improving function of the present invention and the comparative example are statistically significant with a linear regression equation and a correlation coefficient of 0.9 or more, and a clear numerical comparison can be made.
(2) The range of MFF 1.01 to 1.10 can be evaluated by enlarging the display numerical value difference because the difference in display numerical values is small although the effect difference is actually large.
(3) In order to understand the effect visually, a larger number is better.

[Evaluation of aggregated residual resin concentration]
The low molecular weight component in the phenolic resin not only does not contribute to the aggregation of the pollutant, but also remains in the treated water and becomes a new film contaminant, so it is desirable that the amount is smaller.
Moreover, when using it for the organic matter of a waste_water _| drain, and COD _Mn reduction accompanying this, it is naturally desirable that there are few parts which remain | _{survive in} treated water.
The novolak-type phenolic resin dissolved in water exhibits ultraviolet (UV) absorption due to the C═C double bond accompanying the hydroxybenzene ring, and its maximum absorption wavelength is 280 nm.
On the other hand, the novolak-type phenolic resin, which is the target of aggregation treatment, has no double bond and does not participate in UV absorption regardless of whether or not it is removed. At the same time, it participates in UV absorption present in the target raw water. Since it hardly contributes to the removal of organic substances (presumed to be humic substances having a molecular weight of about 5000 or less), the resin residual amount was estimated from the increase in UV absorbance at a wavelength of 280 nm as follows.

<Method for estimating residual resin amount>
(1) For each flocculated water, the difference between the absorbance (UV ₂₈₀ ) of a 50 mm cell of light having a wavelength of 280 nm when treated with an inorganic flocculant only (reference example below) and the UV ₂₈₀ of the examples and comparative examples Obtain (ΔUV ₂₈₀ : minus if lower than the reference example).
(2) ΔUV ₂₈₀ is divided by UV ₂₈₀ (B) when 1 mg / L of the present synthetic product A, comparative synthetic product C, and comparative adjustment product D is present in terms of phenolic resin, and the residual concentration is determined. At this time, the absolute value of the minus maximum value of ΔUV ₂₈₀ of all data (for example, 0.002 in Table 3) is added to ΔUV ₂₈₀ .
Residual resin equivalent concentration = (ΔUV ₂₈₀ +0.002) / B
B values are the present synthetic product A: 0.085, the present synthetic product B: 0.085, the comparative synthetic product C: 0.098, and the comparative adjustment product D: 0.083.
(3) Next, the residual resin equivalent concentration was divided by the added resin concentration, and the residual ratio with respect to the additive resin concentration (water treatment flocculant additive concentration in terms of phenolic resin) was determined.
Why plus 0.002 in (2) is a small amount, the DerutaUV ₂₈₀ for removing _{UV 280} construction material phenolic resin is present in the raw water is negative. Therefore, the maximum value of the negative absolute value is added to cancel out the negative that is impossible in principle.
For these reasons, the residual resin equivalent concentrations in Tables 3 to 5 below cannot be said to be accurate. Moreover, since there are so many errors that there are few addition amounts of the water treatment flocculant of phenol type resin conversion, numerical description of the resin residual rate was avoided under the low addition amount conditions.

[1] Highly polluted biological treated water Treated water that has been subjected to biological treatment, including up to denitrification, for liquid crystal manufacturing process wastewater is further subjected to coagulation treatment with polyiron sulfate, followed by RO membrane separation treatment and wastewater recovery. Biologically treated water from factory F was evaluated as raw water.
At the F factory, 440 mg / L of polyferric sulfate (PFS) is added to this biologically treated water, agglomeration treatment is performed at pH 4.8, and primary solid-liquid separation is performed by pressurized flotation. However, the MFF of the membrane feed water is 1.3 or more, which is poor. Even if the amount of PFS is increased, the MFF 1.3 is cut for the raw water used for the evaluation. I couldn't.
According to the above-mentioned method of <flocculation test: jar test>, the synthetic water product A, the comparative synthetic product C, and the comparative preparation product D are added to the raw water in amounts shown in Table 3 as addition amounts in terms of phenolic resin. After that, 440 mg / L of PFS was added to perform aggregation treatment. The aggregation pH was 4.8.
The obtained flocculated water was filtered according to the above-mentioned <filtration treatment>, and then MFF was measured and evaluated according to <MFF measurement> and <MFF evaluation>.
Further, according to the above [Evaluation of Aggregated Residual Resin Concentration], the residual resin equivalent concentration and the resin residual ratio were obtained.
These results are shown in Table 3.
Moreover, the relationship between the amount of water treatment flocculant added in terms of phenolic resin and the MFF index is shown in FIG.
In addition, Example II-1 and Example II-2 are examples of the present invention using the synthetic product A and the synthetic product B of the present invention, respectively. Comparative Examples II-1 and II-2 are respectively It is a comparative example using comparative synthetic product C and comparative adjustment product D, and Reference Example II does not use these but adds only PFS.

The MFF improvement effect of each water treatment flocculant can be determined from the slope of the linear regression equation in FIG. The slope of Example II-1 (invented product A) was 0.649, the slope of Example II-2 (invented product B) was 0.633, and that of Comparative Example II-1 (compared product C). The slope is 0.447, and the slope of Comparative Example II-2 (Comparison Adjustment Product D) is 0.525.
Based on phenol resin comparative example II-1 (comparative synthetic product C), the cresol resin example II-1 (present synthetic product A) was 1.45 times, and the cresol / xylenol resin example. In II-2 (present synthetic product B), it is 1.42 times, clearly showing the superiority of methylphenol-based resin. Moreover, since the numerical value on the low addition amount side of the comparative synthetic product C of the phenol resin is below the regression line, it is shown that the effect of improving the membrane filterability at the low addition amount is weak.
Regarding the resin residual ratio, Example II-1 (present synthetic product A) and Example II-2 (present synthetic product B) were 2% in the same manner as Comparative Example II-1 (comparative synthetic product C). Less residual resin below.
On the other hand, the comparative preparation D of the cresol resin not subjected to the resol type secondary reaction is 1.17 times as effective as the comparative synthetic product C of the phenol resin subjected to the resol type secondary reaction in the MFF index evaluation. The residual rate is clearly about 9%.

[2] Medium-polluted biological treated water The treated water that has undergone biological treatment for liquid crystal production process wastewater is further agglomerated with polyiron sulfate, and then RO membrane separation treatment for wastewater recovery. Evaluation was made using treated water as raw water.
At factory G, 600 mg / L of polyferric sulfate (PFS) is added to biologically treated water, and coagulation treatment is performed at pH 5.0, followed by primary solid-liquid separation by pressurized flotation and two-layer gravity filtration. The filtrated water obtained was used as RO membrane feed water, and the MFF of the membrane feed water was around 1.15, which was a little higher than 1.10, which is a good level as RO membrane feed water.
To this raw water, according to the method of <Coagulation test: Jar test> described above, the synthetic product A of the present invention and the comparative synthetic product C were added in the amounts shown in Table 4 as addition amounts in terms of phenolic resin, and then PFS was added. Aggregation was performed by adding 600 mg / L. The aggregation pH was 5.0.
The obtained flocculated water was filtered according to the above-mentioned <filtration treatment>, and then MFF was measured and evaluated according to <MFF measurement> and <MFF evaluation>.
Further, according to the above [Evaluation of Aggregated Residual Resin Concentration], the residual resin equivalent concentration and the resin residual ratio were obtained.
These results are shown in Table 4.
Moreover, the relationship between the amount of water treatment flocculant added in terms of phenolic resin and the MFF index is shown in FIG.
In addition, Example III-1 is an example of the present invention using the synthetic product A of the present invention, and Comparative Example III-1 is
It is a comparative example using the comparative synthetic product C, and Reference Example III does not use these but adds only PFS.

  As is clear from FIG. 3, the slope of Example III-1 using the synthetic product A of the present invention is 0.431, which is 1.31 compared to 0.294 of Comparative Example III-1 using the comparative synthetic product C. 46 times more effective.

[3] Lake-based industrial water In river-based industrial water, there is little growth of microorganisms such as algae. There are many polysaccharides, and there are inevitably many neutral polysaccharides that cannot be removed by aggregation with an inorganic flocculant. Treatment of organic substances containing acidic polysaccharides that react with PAC using 60 mg / L of polyaluminum chloride (PAC) as an inorganic flocculant using industrial water from Kitaura, Ibaraki Prefecture as the source water under such conditions Was evaluated by an agglutination test at a high pH of 6.2.
In the flocculation treatment using only PAC, the MFF was 1.15, which was a little higher than 1.10 which is a good level as RO membrane supply water.
For this raw water, according to the method of <Coagulation test: Jar test> described above, the present synthetic product A, the present synthetic product B, the comparative synthetic product C, and the comparative adjustment product D are respectively added as phenolic resin equivalents. After adding the amount shown in Table 5, sulfuric acid was added so that the pH after PAC addition was 6.2, and then 60 mg / L of PAC was added for aggregation treatment.
The obtained flocculated water was filtered according to the above-mentioned <filtration treatment>, and then MFF was measured and evaluated according to <MFF measurement> and <MFF evaluation>.
Further, according to the above [Evaluation of Aggregated Residual Resin Concentration], the residual resin equivalent concentration and the resin residual ratio were obtained.
These results are shown in Table 5.
Moreover, the relationship between the amount of water treatment flocculant added in terms of phenolic resin and the MFF index is shown in FIG.
In addition, Example IV-1 is an example of the present invention using the synthetic product A of the present invention, Example VI-2 is an example of the present invention using the synthetic product B of the present invention, Comparative Example IV-1 and Comparative Example IV-2 is a comparative example using comparative synthetic product C and comparative adjustment product D, respectively, and Reference Example IV does not use these but only PAC is added.

As is clear from FIG. 4, the slope of Example IV-1 using the synthetic product A of the present invention is 1.185, and the slope of Example IV-2 using the synthetic product B of the present invention is 1.178. The effect of 1.38 times and 1.37 times is shown with respect to the inclination 0.858 of Comparative Example IV-1 using the synthetic product C, respectively.
In Comparative Example IV-2 using Comparative Adjustment Product D not subjected to the resol type secondary reaction, the slope of 0.881 is similar to that of Comparative Example IV-1 using Comparative Synthetic Product C, and the MFF improvement effect is Although there is a resin residual ratio of about 10%.

Claims (4)

  A phenolic resin obtained by adding an aldehyde to an alkaline solution of a novolak-type phenolic resin obtained by reacting a phenol with an aldehyde in the presence of an acid catalyst and performing a resol-type secondary reaction. A water treatment flocculant comprising an alkaline solution, wherein the phenols contain methylphenols.   The water treatment flocculant according to claim 1, wherein the methylphenol is cresol.   In Claim 1 or 2, the weight average molecular weight of the phenol resin obtained by performing the resol-type secondary reaction is 10,000 or more, and the content of low molecular weight components having a molecular weight of 1,000 or less is 20% by weight or less. Water treatment flocculant characterized by   In a water treatment method comprising a flocculation treatment step of adding a flocculant to the water to be treated and a membrane separation treatment step of membrane separation treatment of the flocculation water in the flocculation treatment step, the flocculation treatment step charges the water to be treated. A water treatment method, which is a step of adding an inorganic flocculant after adding the water treatment flocculant according to any one of Items 1 to 3.

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