SE506142C2 - Cationic tannin and its use in wastewater purification - Google Patents

Abstract

Cationic tannin comprises a tannin-contg. conifer bark extract, crosslinked before cationisation with a glycidyl trimethyl ammonium chloride, an N-(3-chloro -2-hydroxypropyl) trimethyl ammonium chloride or a dimethylamine reagent. Process pref. comprises crosslinking with HCHO or epichlorohydrin. The flocculant compsn. pref. also contains an inorganic coagulant, and a high-mol. cationic, anionic or neutral linear polymer. USE/ADVANTAGE - As flocculant in purificn. of waste water contain the cationic tannin. Flocculation efficiency is improved, and active flocculants are obtd. from low-tannin fractions. (In)organic cpds., e.g. organo-Cl cpds. in bleaching waste water, and N- and P-contg. foodstuffs, are flocculated.

Description

506 10 15 20 25 30 35 BNSDOCIÜ: 142 2 cationic flocculants from aqueous extracts of conifer tree barks ", Forest Products Research Society, 40th Annual Meeting, 22. - 26.6.1986, Washington, USA, summary 8; and publication Seppänen R., Mäkelä A. and Pulkkinen E., tree bark extracts and lignins as flocculant for “Use of cationic derivatives of wastewater treatment ", Kemian Päivät 5. - 6.l1.l986, 1986).

Previously, however, cationic has not been used Helsinki, abstract 6.26, Chemistry-Chemistry ll, tannins for flocculation of colloidal substances in runoff water and for the precipitation of fractions containing organic chlorine from wastewater from bleaching ning.

In this invention it is shown that the bark extract cationization method and flocculation effect further can be significantly improved. Also by factions, containing a lot of non-tannins, it has been surprising could probably produce effective flocculants.

The invention thus relates to cationic tannins, which are characterized by the tannin content The bark extract from conifers has been cross-linked before ionization with a glycidyltrimethylammonium chloride or N- (3-chloro-2-hydroxypropyl) trimethylammonium chloride reagent. Thanks to the crosslinking, they are improved the flocculating ability of the cationic tannins is considerable.

By means of cationic tannins according to the invention obtained by modifying the spruce and pine bark extracts, cheap polycations, which neutralize the negative charges of the pollutant particles and flocks of inorganic and organic compounds, such as organic. chlorine compounds in wastewater from bleaching as well as additional business associations containing nitrogen and phosphorus from wastewater. Even small differences in is clearly stated 'in laboratory tests (vessel test or flocculation effect 10 15 20 25 30 BNSDOCID: 506 142 3 test, which is performed with a photometric dispersion analysis (PDA), when e.g. cellulose serves as a colloidal reference). microcrystalline silica or In large- processes for wastewater treatment, they state the effect of cationic bark extracts in removing containing colloidal solids and from i.a. in sedimentation, associations, organic chlorine wastewater from bleaching, flotation and concentration of sludge (water drainage).

In this invention, spruce and pine bark extracts have straight cationized with the following epoxyammonium fl and chlorohydrinammonium salt reagents: In NaOH tannin-on + cH2-cncn2N * (cn3) 3c1 'slow \O/ glycildyltrimethylammonium chloride t 1 -ocn cncn N * ca cl ' ann n za 2 (373 hrs GTAK reagent Na0H fast Nacl + uzo + _ çH2çHCH2N (CH3) 3Cl + NaOH JM Cl OH so N (3-chloro-2-hydroxypropyl) trimethylammonium chloride GTAK-HCl reagent (chlorohydrin reagent) u ..

Aminomethylation of tannins with formaldehyde and dimethylamine is also possible (Tappi publication Vol. 61, No. 5, May 1978). The invention shows further that TW ” The GTAX reagent and the GTAK-HCL reagent 5Û6 142 10 15 20 25 30 35 BNSDOCID: 4 sticks to the bark extract with a large yield (approx. 90%).

This from the reagents, and substantially improves the reduces the amount of by-products, which originate costs per active product.

If the tannin content of the bark extract is high, it can crosslinked before etherification (cationization) with a small amount of formaldehyde and a very effective flocculating cationic tannin is obtained. About bark extracts re-crosslinked with epichlorohydrin before cationization. can also be obtained from the bark extract, which contains very non-tannins, or its fraction (Stias- ny-tal e.g. 40) produce an effective flocculant.

The cationic tannins produced. belongs to group of cationic polymers, if. whose effect one know that they alone or together with inorganic coagulants adhere to the surface of negatively charged particles. particles in the wastewater, neutralizes the negative charge and thus precipitates the colloidal solid the substance in the wastewater. If you want to increase the flock the size of the particles neutralized by cat- ionic tannin, is added to the finely divided flock a cationic, anionic or neutral linear polymer high molecular weight, its long flexible modulus toy chains connect the pollutant particles bundles that settle well.

An object of the invention is that in a certain use situation find a combination dose, in which cationic tannin acts as a neutralizer and a high molecular weight linear polymer acts as crosslinker, as well as examine the relative amount of such a two-component dose and its method of administration for obtaining the best flocculation results.

The cationic polyelectrolytes and the cationic the flocculating effect of the ionic tannins can be compared among themselves with pre-test. During vessel testing, it precipitates 10 15 20 25 30 35 BNSDOCID: sus 342 5 in different whereby the lowest residual colloids large flocculant doses, dispersions (silica, cellulose) in a series of clearances, after the precipitation dimensioned, indicates the optimal flocculation dose in ratio 'to the dispersion used. When applied of vessel tests on wastewater, it is often impossible to do so measure the turbidity. On the other hand, the chemical oxygen supply (con), during a series of clearances, phosphorus or the amount of organic chlorine as these have been estimated at correspondingly, dose. Tests performed with PDA indicates the relative size of the flock and also durability, if the test is performed at different speeds The PDA test becomes especially valuable, then applied to wastewater. The wastewater is titrated in the vessel of the device with a flocculant or coaglant and optimal called. solution with a certain concentration, man. notes at what dose the flocculation begins, which, the the optimal dose is and how the flocculation strength 'can affected with a crosslinking polymer. f In addition to the colloidal fraction of the wastewater can also the organic acid salts it contains precipitated with sufficiently large doses of cationic tannin. In this case, the flocculant or coagulant consumption is often too great to be beneficial, why one can consider utilizing the precipitating agent from the sludge. W The invention is described by the following examples.

Example 1 A This example shows in detail, how to from tannin in a hot water extract of spruce bark (Stiasny- number 84) ether, the production and flocculation effect of which with a GTAK reagent obtains a cationic timeras.

Table 1 shows the initial situation for cat- ionization. äs 506 10 15 20 25 30 35 BNSDOCID: 142 6 Table 1 Preparation of cationic tannin with a GTAK reagent Gram Vàt Torr Mol Molförh.

Hot water extract of spruce bark Stiasny-tal 84, ts. 47.5% 653 310 GTAK reagent, M 151.64 Activity 70% Dry matter 79% 454 317.8 2.10 l 100% epoxide 40.9 (non-epoxide) NaOH, M 40.01 15 0.37 0.18 Remarkable in the initial situation is a high dry matter content (61, 8%) and a NaOH molar overdose in relative to the GTAK reagents. Reagents are low from Raisio Oy.

With respect to the etherification, it was homogenized aqueous tannin (ts. 47.5%) in a mixture Baker-Perkins type screw (volume about one liter), var- after the reactor solid NaOH was added and this mixture at room temperature for 2 hours. Then added the reagents and mixing were continued at room temperature.

The flocculation capacity of samples taken from the reaction the mixture in a vessel dispersion in a silica dispersion (270 mg / 600 ml) were tested after 14, 17, 40 and 52 hours. mar. The reaction was stopped by neutralizing the reaction mixture with 2 M hydrochloric acid. The results is shown in Figure 1. The results are given as. percentage 10 15 20 25 30 35 BNSDOCID: 506 1342 7 (% RTD) and flocc- the land dose is given as a percentage of the weight of the silica. cloud units of formazin Figure 1 shows that the cationization has carried out completely at room temperature for 40 hours.

The sample of the crude product thus obtained was diluted and ultrafiltered through a Diaflo YM2 film (Ami- con Corp., exclusion limit 1000). The purified and dry The product contained 4.4% nitrogen (determined according to The Kjeldahl procedure).

Calculation of reagent yield 6 In 100 g of ultrafiltered cationic bark extract found man: ' 4.4 --- = 0.3134 x 151.64 = 47.66 g GTAK reagent 14 and 52.34 g of tannin.

Thus, some of the GTAK reagents have bound to the tannin: 0.3l43 x 310.0 = 88.6% 52.34 Flocculation test left Vascular testing was performed in a device (with 6 (Phipps & Bird) and acting as a colloidal dispersion microcrystalline silica (Min-U-Sil 5, Pennsylvania nia Glass and Sand Corp.), of which 1,800 g were slurried in 4 liters of water at a pH of 4.0 - 4, in one hour. The precipitants were added under rapid bonding. in an 800 ml decanter glass with 600 ml of silica (270 mg of silica) and mixed successively according to following: 20 min at a speed of ss rpm, 2: 6 min at a speed of 30 rpm, after which the sediment des i 30 min. The residual turbidities were measured with eäç fl ach which had been taken 2 cm below the liquid surface. The results are shown in Figure 2. turbidometer from sample of 25 now, Figure 2 shows that cationic tannin, which purified by ultrafiltration, precipitates colloidal silica 506 10 15 20 25 30 35 BNSDOCID: 142 8 significantly more efficient than a commercial cationic lymer (Fennopol 194 K, Kemira Oy). In tests with photo- metric dispersion analyzer (PDA 2000, Rank Broth- ers Ltd) has a cuvette connected with a 3 mmzs hose to a 1.5 liter reaction vessel with an engine re (blade mixer) equipped with a tachometer (stroposcope). The sample for the cuvette was taken from the the bottom of the vessel, to which the distance was 15 cm. 12000 Variopres peristaltic pump. The printing took place with The flow rate was regulated with an LKB a printer. Sensitivity was regulated with a PDA-2000 analyzer (Gatin RMS, DC), so no pre- resistance was needed. The flow rate at all ratios were 1.22 ml / min.

Test conditions: Silica: 450 mg / 1,000 ml Microcrystalline cellulose: 450 mg / 1,000 ml pH: 4.0 - 4.1 Mixture at start: 65 rpm Mixture under test: 65 rpm Flow: 1.22 ml / min Analyzer sensitivity: RMS 1.07 Filter on DS 5.4 Limit on Determination of the optimal dose with a dispersion analysis analyzer (PDA) The PDA prints it on the printer's horizontal axis time elapsed from the injection of the flocculant dose. On the vertical axis can be the relative flock size read (in volts). The optimal dose has, in relative flock size and at the rate at which it achieved, a maximum. On the basis of Table 2, it is obtained optimal dose of cationic tannin, i.e. 0.058% off silica, when the relative flock size is 3.95 V and the flock growth rate is 9.22 volts / min. 10 15 20 25 30 35 BNSDOCID: 506 4 2 Table 2 PDA determination of the optimal dose of cationic tannin 1 relation to colloidal silica Dosage Relative Flock Growth- % silica flock size velocity volts / min (volt) 0.023 1.35 0.75 0.029 2.65 3.55 0.035 3.10 6.15 0.046 3.55 8.55 0.058 3.95 9.22 0.070 3.95 5.56 0.081 2.95 3.70 ___-__________________-_________-_ ~ __________-__ It is noted that the optimal dose obtained held with PDA (0.058% of silica) is greater than the corresponding dose obtained by vascular test (0.035-fa of silica).

Example 2 This example describes tests in which tannin, obtained from spruce bark by hot water extraction, tvarbunaits with fomalaenyd before cationiserišššan.

The results show that thanks to the crosslinking sjlulïker the optimal flocculation dose of the corresponding tannin in relation to colloidal silica and flock strength increases.

The example is based on a bark extractor content of soluble tannins is lower than in the bark used in Example 1 (Stiasny figures '70 resp. 84). The bark extract is first crosslinked with formaldehyde and then cationized with a GTAK reagent. ¿Í (a) Determination of the gelatin of the bark extract 506 10 15 20 25 30 Bwsoocno; 142 10 sensitivity was performed first determination.

Gelatinization time test 30 g of one (Stiasny number 70) was dissolved in 100 ml of water, which contained held 3.36 g of NaOH. 45.1 g of this solution (contains 10.4 g of extract) cross-linked with 1.5 ml of 37% formaldehyde at 50%: in a Tecan gelatinization timer gelatinization time hot water extract of spruce bark (GT 3 disc diameter 14 mm). The gelatinization time was 138 min. Before the gelatinization contained 22.3% dry extract. The amount of NaOH calculated on dry the extract was 11.5% and the content of CH 2 O per dry extract was 0.178 mol / 100 g. solution Table 3 Crosslinking and cationization of hot water spruce bark extract __________________________________-____________ Gram Wet Dry Mol Crosslinking 50 ° C / 30 h Alkali solution of hot water the extract of spruce bark (Stiasny-tal 70) 50 16.7 Organic part 15.0 NaOH 1.67 0.042 CH 2 O 37% 1.24 0.46 The solution contained 11.1% NaOH of the dry extract and 0.103 mol CH 2 O / 100 g bark extract. 10 15 20 25 30 35 BNSDOCID: _______________________.-_______ - ______________ Etherification 50 ° C / 20 h Reagent GTAK (M 151.64) Dry matter of the reagent was 79% and it contained 66.2% epoxide 19.1 15.1 12.6 0.083 (100% epoxide) A sample of the crude product was filtered through a Diaflo YM2 exclusion limit M 1000), whereby 3.9% nitrogen was found in the purified product.

(Amicon Corp., Calculation of reagent yield In 100 g of ultrafiltered: cationic bark extract found man ” 3.9 = 0.2786 x 151.64 = 42.25 g GTAK reagent 14 and 57.75 g of bark extract.

Thus, the GTAK reagent has bound to the tannin: 0.279 mol N 15 g bark extract x = 757.75 g bark extract 0.083 mol reagent 0.279 x 15 % = 87.3% 57.75 x 0.083 b) In a second test, the bark extract is cross-linked with 0.154 moles of formaldehyde per 100 g of tannin and brought then reacting with the GTAK reagent at SOWZ for 3 hours in a Berghoff autoclave, the purified product 506 142 10 15 20 25 BNSDOCID: 12 the nitrogen content of the product was 3.5%. In a reference test, the cationization without crosslinking was carried out in the same the nitrogen content of the purified product was 3.6%.

Table 4 The effect of crosslinking on the cationic tannins molecular weight distribution in the gel filtration chromatogram Molecular mass Cationized ---------------------------------- tannin 10 000 5 OOU 3 OO0 1 500 1 000 Non- cross-linked 36 56 68 82 89 Tvärbundet 50 66 74 84 89 (0.13 mol CH 2 O / 100 g) A gel filtration procedure has been described in the publication Forss K., Kokkonen R. and Sàgfors P- E., ‘Determination of molar mass distribution of lig- nins by gel permeation chromatography ", 1989, Ameri- can Chemical Society, Symposium Series 397, chapter 9, 125 - 133. The gel consisted of Sephadex G-50 and the eluent of 0.5 M NaOH.

The improvement of each crosslinking is shown in Table 5. flocculation effect please 10 15 20 25 30 35 BNSDOCID: 50613142 13 Table 5 Effect of tannin crosslinking cationic ether prepared therefrom precipitate silica in a vessel test (CH 2 O) on a ability to _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ - _ _ _ _ _ _ _ _ _ _ _ - _ _ _ _ _ _ _ _ _ ççp-n Degree of crosslinking Dosage, Relative mol CH 2 O / 100 g% of flock size % N silica 100 rpm 0 3.6 0.17 - 0.20 1.2 0.154 3.5 0.07 - 0.11 2.8 Example 3 This example further describes the effect of the tannin's CHZO crosslinking on the flocculation effect of the cationic ether prepared therefrom.

The starting standard is the same as in Example 1 (Stiasny-tal 84). In the crosslinking phase, the wet 278.7 g (ts. 43.3%), the dry bark being the extract was 120.7 g, calculated on which 0.6% formaldehyde was used (0.0153 mol Cl-I20 / 100 g bar region). CH 2 O was added as a 37% aqueous solution and NaOH as an S M solution, until the reaction mixture The pH was 12. flat grinding piston 'by letting after the power mixture the reaction mixture is allowed to stand at room temperature for 2 hours and then for 45% I4 hours. _ “Fi To the crosslinked mixture was added a ionization reagent (GTAK, ts. 70%, active substance 60%) 80.19 g (0.529 mol calculated as active substance) and. the reaction mixture was homogenized with a. ef- fencing mixer (Braun). The mixture was left for 2 hours 20 ° C and 22 hours at 40 ° C.

Formaldehyde The crosslinking was performed in a 1.5 liter solidifying effect in the reaction the mixture is already visible at room temperature, but the 506 142 10 15 20 25 30 35 BNSDOCIDI 14 tan solid mass is thinned during the etherification to a viscous liquid. In the neutralized crude product found after ultrafiltration 3.6% nitrogen.

Reagent yield calculated as follows was significantly high: 3.6 = 0.257 x 151.64 = 39.0 g GTAK reagent and 14 100 g - 39.0 g = 61.0 g tannin The GTAK reagent binds to the tannin: 0.257 X 120.7 -----_-- = 95.1%. 61.0 x 0.529 The effect of crosslinking on the flocculation effect Although non-crosslinked cationic tannin contains held 4.4% nitrogen (Example 1) and cross-linked tannin 3.6%, bark extract, so that the flocculation results can be both cationizations have been performed on the same carried among themselves, if the doses are calculated per nitrogen in the cationic tannin. Of the results in clear that crosslinking with reduces the optimal dose in vascular testing and increases it figure 3 formaldehyde appears relative flock size in tests performed in PDA.

Example 4 In this example it is shown that epichlorohydrin binds the hot water extract of spruce bark, which contains contains a lot of non-tannins (Stiasny number 40), whereby the flocculating effect of the cationized product significantly improved thanks to the crosslinking. 2 g of the hot water extract of spruce bark (Stiasny- number 40) dissolved in a strong NaOH solution (0.3 g NaOH and 2 ml H 2 O) were mixed in SOWZ in a glass vessel for approx one hour. The crosslinking was performed by adding (ECH) i the mixing was continued at the same temperature for 10 minutes. 0.1 g of epichlorohydrin reaction vessel and 10 15 20 25 30 35 BNSDOCID: 506 __. 142 15 For cationization was added in the crosslinked reaction mixture 1 g GTAK »reagent (calculated to 100% relative to the epoxy content, 6.7 mol) and the heating continued at 50%! 2.5 hours. Reactive the ion was stopped by neutralizing the mixture with 2 N HCl. The crude product was dried to constant weight 1 SOWZ. A portion of the dry product (1 g) was slurried at room temperature to 160 ml of 94% ethanol, was filtered and the precipitate was washed with diethyl ether and dried to constant weight in a vacuum desiccator.

Purified, with epichlorohydrin crosslinked, cationic granules bark extract was obtained by ethanol washing of 61% of it dry crude product and its nitrogen percentage was 2.6.

Starting situation Gram Gram mmol Molförh.

Bark extract Stiasny-tal 40 2 2 NaOH (40) 0.3, 7.5 7.5 1.12 7 ECB (92.53) 0.1 0.1 1 GTAK (151.64) 1 1.0 6.6 1 HZÛ 2 5.4 3.4 dry matter 63% __________________-_______-___________________ p-g-_ | ___ The starting situation is calculated at 100 g per bark extract: Gram Gram mmol Molförh.

Bark extract Stiasny-tal 40 100 100 NaOH (40) 15 15 0.375 1.14 7 l ECB (92.53) 5 5 0.054 1 0.14 GTAK (l51.64) 50 50 0.330 1 H20 100 270 170 dry matter 63% 506 142 10 15 20 25 30 35 BNSOOCID: 16 Figure 4 shows the effect of the bark extract crosslinking to the capacity of the corresponding cationic ether to precipitate silica (Min-U-Sil-5, silica 150 mg / l) at vessel test. The cationic tannin produced by cross-linked bark extract (nitrogen 2.6%) gave a considerable lower optimal dose than non-crosslinked cationic nin (nitrogen 2.7%).

Example 5 In this example, vessel tests where carbon loid silica acts as a reference agent shown that, then a small amount of Al ”or Fe” salt is added in solution cationic tannin, the cationic the tannin's flocculating ability. This is clear from figure 5.

Example 6 This example describes the cationic tannin interaction of the linear cationic polymer on the flocculation of microcrystalline cellulose at vessel test. The results are shown in Figure 6.

The dose of cationic tannin (0.25) selected in this test not only passes the cellulose dispersion, but then in this amount a linear cationic is added polymer (Fennopol K21l, Kemira Oy), achieves residual minimum value in total dose approx the amount 0.13 ppm. In this test, the optimal total dose was 0.38 ppm (cationic tannin (nitrogen 3.9%) and Fennopol K2ll's percentage ratio 66:34).

Example 7 In this test, cationic tannin was added as well a combination, consisting of cationic tannin and an inorganic coagulant (Al-sulphate, Fe-chloride) in which had intended to The vessel test was performed with the running water from a cellulose factory, biologically treated and released in 600 ml was added, the mixture was mixed and sedimented thus was recipients. flocculants wastewater, in which the above 10 BNSDOCID: 506: * '; = 142 17 Solid content, COD, AOX (organic chlorine), dye, solid phosphorus and whole nitrogen after a certain time. were set on the basis of samples taken from a pernatant. The results are presented in Table 6. Of the the results appear i.a. that the amount of phosphate can significantly by adding cationic tannin either alone or with coagulants.

The results also show that the cationic tannin reduces the solubility of aluminum when used as a precipitating agent together with Al-sulphate. 18 506 142 | I. |||. |. || .IIuwl-llul-ILIAII-IIIII ». ||| II..I |. | II ~ I. || I» | I »I | I | I. |. la || III-Il.llfln | lu | l | lullunl | lulu | lucl || l || .l |||| l ~. |||| l .. || ..I - m.Hw ~ .H> \ m> o. ~ w.o @ @ .m m_Hm + @. ~ H ß. ~> @. ~ «@ _M @ @ .mm @ .mß @. «H H.m> w_- H.om m.m ß.mw + wm \ H < -amma o.o @ o ~ w © o_mw H_ ~ m >. «M @ .mm if «. @@ @. ~ @ m.mm m \ @ ~ @ _ ~ @ @_m « m_ ~ @ w.m @ m.øæ Nm @. ~> @ .m> @. @@ >. ~ « m. @ o. «> w.m « æ.mm @.> m m.mm øq @.O" ~. «M m.mm w _ @@ m. @@ o_ø « ~. «« O."" Pmmh || .Inlll-l-IqfßllnllI.'nl.l. || l. | .L || al. | Lzl ||| l ||||| luulnllululn || o «@ \ m.N fi oæ «\ m« A om ~ \ m ~ H m ~ H \ m- OON H ooo mom mmm oøm omw OQN øHHo fi x | wm \ @. «uz pm «Høm | H <\ @.« “z COHÜGC fl QEOX Awm æ m.NHv UwuO fi x | 0m Pmma5ma fi < A »@.« .Zv CHCCMF. PÜX .MSPHDQHMWOHDH fi ÜU GQ CWHH CÜPPG> WQQOH> Ü ÜQHÜCDSÜD PXMHUOAOAHQ ._ .. CÜCE fl fl OHH n fl mxw> m vmømcmmmH> æ mm cmxnm> mæcuwucø fi nmmox mxm fi cßmuoo mn: OO mvwc fl ccmv mxm fl co fi umx pmm 0 A fi wnmß BNsDoc1u

Claims (6)

BNSDOCID: soed142 19 Patent claims: 1. Cationic tannin, characterized in that the tannin-containing bark extract of conifers has been crosslinked before cationization with a glycidyltrimethylammonium chloride, N- (3-chloro-2-hydroxypropyl) trimethylammonium chloride rea or dimethylamine reagene . 2. Cationic tannin according to claim 1, characterized in that formaldehyde is used in the crosslinking. 3. Cationic tannin according to claim 1, characterized in that epichlorohydride is used in the crosslinking. á 4. A composition which can be used as a flocculant in the purification of waste water, characterized in that it contains cationic tannin - according to any one of claims 1-3. 5. A composition according to claim 4, wherein it further contains an inorganic coagulant. 6. A composition according to claim 4 or 5, characterized in that it additionally contains a high molecular weight cationic, anionic or neutral linear polymer.