ES2430248B2 - Process for the preparation of immobilized peat - Google Patents

Abstract

Process for obtaining a bioadsorbent consisting of peat or peat-like material immobilized in calcium alginate spheres, intended for water treatment, the use of peat (or any other plant material with similar characteristics to peat) immobilized in spheres of calcium alginate is an alternative to other more expensive products such as ion exchange resins or more difficult to handle as active carbon for the treatment of contaminated water. Emphasize that peat is an environmentally friendly, biodegradable product and that after its immobilization it can be easily handled for use in water treatment.

Description

   Process for the preparation of a bioadsorbent based on peat or material analog to immobilized peat

Technical sector

The product obtained is of immediate application in companies related to obtaining peat or with those companies dedicated to obtaining fertilizers in the form of biodegraded plant matter with similar characteristics to peat, since it would be necessary to obtain a new line of product, with great application in the treatment of water with a high load of colored compounds, such as water from the wine industry or the textile sector.

State of the Art

Both national companies and large international conglomerates compete in the race to develop environmentally friendly products. Many industries such as those belonging to the textile sector, the paper industry, consume huge volumes of water and as a result generate a large amount of water contaminated with colored compounds, most often highly phytotoxic, such as vinasses from of the wine industries (paradelo et al., 2009). Other colored compounds can also be highly carcinogenic and affect aquatic ecosystems (O'Neill et al., 1999; Vandevivere et al., 1998). In addition, some colored compounds are noticeable at concentrations less than 1ppm, generating undesirable visual impact (Robinson et al., 2001; Banat et al. "1996). The colored compounds are highly hydrophilic because they are frequently found in wastewater. (Pearce et al., 2003; Robinson et al., 2001.) The concentration of these compounds in industrial effluents is increasingly more restrictive, so it is necessary to find new environmentally friendly products, easily handling and low cost that allow the elimination of this type of compounds Many colored compounds are recalcitrant, non-biodegradable and stable to light, heat as well as oxidizing agents so you have to look for different alternatives for disposal. It is the most commonly used basic operation for the treatment of wastewater with a high content of colored compounds.In most of these processes it is used iza immobilized active carbon, which although it has been considered by the American Environmental Protection Agency as one of the best products in the market for water treatment, this presents a high cost, the search for low-cost alternative adsorbents being necessary . The use of immobilized peat in the treatment of contaminated water with colored compounds constitutes an innovative technique that is environmentally friendly and can replace other more expensive and more difficult to handle adsorbents, such as activated carbon, in the treatment of contaminated water with colored compounds In addition, peat, unlike active carbon, does not need to be subjected to the activation process (Anjaneyulu al., 2005). Peat is a natural compound of lignocellulosic nature, which contains lignin, cellulose and humic and fulvic acids. It also has a polar character, so it has a high adsorption capacity of metals and polar compounds. The adsorption capacity of peat has been demonstrated by numerous researchers. Peat has been tested primarily as an adsorbent of colored metals and compounds in water treatment (Allen 2004; Ho and MacKay, 1998; Ho and Mackay 2003; Sun and Yaog, 2003; Ramakrishna aod Viraraghavan "1997; Poots et al., 1976; Paradelo et al., 2009), although its direct use has several disadvantages such as the increase of particles in the water and its difficult handling, so it is interesting to look for new forms of presentation of this product that can facilitate its application in the water treatment Sun and Yang (2003) proposed the use of resin mixed with peat, by oxidizing the peat and mixing it with polyvinyl alcohol and formaldehyde with an adsorption capacity of 400-350ng / g depending on the dye used Jeffers et al., 1991 investigated the immobilization of peat, using polysulfone and N, N-dimethylphonnamide for the removal of heavy metals from cotaminated waters.In this process the immo vilization of the peat in calcium alginate spheres, a biodegradable material widely used in the immobilization of microbial cells, with which, it is intended to obtain an adsorbent with a broad spectrum of application in the treatment of highly colored wastewater.

Explanation of the invention.

1: Brief explanation of the invention It is proposed to obtain a product consisting of peat (spongy and light mass in which the plant components that originated it are still appreciated) or organic fertilizer, immobilized in calcium alginate spheres, for the treatment of wastewater containing colored compounds or metals, as an alternative product to other more expensive or difficult to handle such as active carbon. The procedure for obtaining this product is specified in:

one.

Dry the peat or organic fertilizer until moisture less than 4% is obtained, to

facilitate grinding In any case, the humidity of the

peat, at the time of phonulating the sodium alginate solution.

II.

Grind the peat or organic fertilizer to a particle size of less than 0.4 mm.

III.

Mix between 0.5-2% peat with 1-5% sodium alginate.

IV.

Add the above mixture to a calcium chloride solution between 0.05-0.9 M,

pumping

with a constant flow rate of the formation of spheres of

more or less homogeneous calcium alginate, which will contain peat or fertilizer

organic and also forming sodium chloride.

V.

Obtain the peat or immobilized organic fertilizer after filtering the solution of

sodium chloride from the previous step and containing the peat or organic fertilizer

immobilized in calcium alginate spheres.

SAW.

Wash the immobilized peat with hot water

VII.

Store the peat or immobilized organic fertilizer in a chloride solution

0.051-0.9 M sodium for conservation.

2: Detailed explanation of the invention

This invention is based on obtaining organic peat or fertilizer immobilized in calcium alginate spheres for the treatment of colored waters. For this, it is important to use the appropriate amount of peat or organic fertilizer, sodium alginate and calcium chloride that allows the correct immobilization of the peat or organic fertilizer and subsequent adsorption of the colored compounds on the immobilized substrate.

2.1 Peat conditioning

Before immobilizing the peat or organic fertilizer it is important to remove moisture from it. drying it in the air until obtaining a percentage of humidity that allows its grinding. Subsequently it is necessary to homogenize the peat or organic fertilizer, grinding it until obtaining a particle size of less than 0.4 nun.

2.2 Peat composition

Commercial peat has been used with the following composition:

pH (CaCI,

5.0-6.5

Salt content (KCI) gil.

<3 ~ O

200-450 mWl NitTÓ ~ eno (N)

Fertilizer content (soluble nutrients)

200-500 rng! L Phosphate (P, O,)

300-550 rng! L Potassium oxide (K, D)

Basic content

Peat, Perlite, Agrosil, lime and nutrients

2.3 Mobilization of peat

10 To immobilize the peat it was mixed with different solutions of 15% sodium alginate. Afterwards the mixture was added dropwise using a Masterflex pump to a calcium chloride solution between 0.051-0.9 M. The peat immobilization process was carried out at room temperature.

15 2.4 Storage of immobilized peat Once the peat has been immobilized, it is washed with water and stored in 0.9 M sodium chloride.

Example of embodiment of the invention For the immobilization of the peat or organic fertilizer 3 essential components are needed:

to.

peat or organic fertilizer

b.

sodium alginate

C.

calcium chloride

25 Strategy carried out to obtain the conditions of immobilized peat

The optimal conditions of the immobilization of the peat were obtained by carrying out an incomplete factorial design where the independent variables evaluated were the peat concentration (XI); the concentration of sodium alginate (X2) and the concentration of calcium chloride (Xl), while the dependent variables evaluated were the decrease in absorbance at 620 nm (YI), 520 nm (Y2), 420 nm (Y3) and 280 nm (y,), color intensity (/ '5), color hue (Y6), color intensity (Y7), color brightness L (y,), a' (y,), b '(YIO ), e "b (YII) and the color tone H .. (YI21-Table 1 shows the independent variables studied, as well as the range of

35 study used. For the statistical analysis of the data, the statistical program STAT BASIC was used, where the independent variables were entered in a coded way to facilitate the analysis of the same at the time of knowing which of them is more significant. On the other hand, Table 2 shows the experimental results obtained. After the statistical treatment of the data it has been observed that the variables

40 most influential independents in the range studied are Xl and X) that correspond to the percentage of peat and calcium chloride concentration respectively, the amount of sodium alginate being the least influential variable in the production of immobilized peat. In addition, Table 3 and Table 4 show the statistical coefficients obtained after the treatment of the data which, after being substituted in equation 1, allows the calculation of the dependent variables for whatever the value of the independent variables in the study range settled down.

Table 2 also shows the e2 values obtained for each row of the dependent variables studied, which shows how much the experimental results deviate from 105 predicted by the model. It is seen that in all cases

10 obtain values of `` 'greater than 0.95 (except for Y6 which obtains a' 'of 0.86). After the study of the data, it is deduced that low concentrations of sodium alginate, as well as high concentrations of sodium chloride and intermediate conditions of peat in the studied range lead to good results in the elimination of colored compounds from the vinasses.

15 Example of embodiment of the invention It is based on 0.5-2% organic peat or fertilizer and 1-5% sodium alginate, which are mixed and dropped dropwise in a 0.051 calcium chloride solution -0.9 M forming calcium alginate spheres containing peat or organic fertilizer (Figure

20 1). To study the effectiveness of immobilized peat in removing colored wastewater compounds, vinasses from the wine industry with a strong color load were used and contacted with immobilized peat. Figure 2 shows a photo of the vinasses before treatment with the

25 bioadsorbent (left tube) and after treatment with the bioadsorbent (right tube). Adsorption experiments were performed in batch with an irunobilized peat ratio: 1: 1 vinaza; at room temperature and with a stirring of 75 rpm. Samples were taken at different times (1h, 6h and 24h). The dependent variables analyzed to assess the effectiveness of the process were based on

30 measurements with a spectrophotometer at different wavelengths: 620, 520 and 420 from which different color indices can be calculated and 280 that accounts for the amount of phenolic compounds that can be in a water of this nature. Color measurements were also taken using a Color Analysis program that incorporates the Jasco V -650 photometer spectrum and obtaining different parameters

35 based on the CIELAB method; that determine the charge of colored compounds that have a problem water (L-, a-, b ·, e · ab • Hab)

Table S shows the values of the dependent variables evaluated in the

initial vinasse, as well as the results obtained after the treatment of these vinasses with

immobilized peat elaborated in intermediate conditions of the studied range, which

40 can be considered as optimal (1.25% peat, 1% alginate; 0.9M calcium chloride).

Figure 2 shows the color reduction achieved under these conditions of

bioadsorbent formulation.

References

45 AHen, S.J., Mckay, G., Porter, J.F. (2004). Adsorption isothenn models for basic dye adsorption by peat in single and binary component systems. J Co // oid Interface Sci. 280 (2), 322-333.

Anjaneyulu, Y., Sreedhara Chary, N., Samue1 Suman Raj, D. (2005). Decolourization of

industrial effluents -Available methods and emerging technologies -A review. Rev.

Environ. Sci. Biotechnol. 4 (4), 245-273.

Banat, I.M., Nigam, P., Singh, D., Marchant, R. (1996). Microbial decolorization of

textile-dye-containing effluents: A review. Bioresour Technol 58 (3), 217-227.

Ho, Y.S., McKay, G. (1998). Kinetic model for lead (11) surprise on to pea !. Adsorpt. Sci. Technol. 16 (4), 243-255.

Bousher, A., Shen, X., Edyvean, R.G.J. (1997). Removal of colored organic maUer by

adsorption onto low-cost waste materials. Water Res. 31 (8), 2084-2092.

Ho, Y.S., McKay, G. (2003). Sorption of dyes and copper ions onto biosorbents. Biochem process. 38 (7), 1047-1061.

Jeffers, T.H., Ferguson, e., Stevenson, H.Q (1991). Mathematically Modeling the

Removal of Heavy Metals from a Wastewater Using Immobilized Biomass. Environ. Yeah

Technol 25,1559-1565.

Lee, y-e., Shin, H-J., Ahn, Y., Shin, M-C., Lee, M., Yang, J-W. (2010). Biodegradation

of diesel by mixed bacteria irnmobilized onto a hybrid support of peat moss and additives: A batch experiment. J. Hazard Mater. 183, 940-944.

O'Neill, e., Hawkes, F.R., Hawkes, D.L., Louren ~ o. N.O., Pinheiro, H.M., Delée. W. (1999). Color in textile effluents -Sources, measurement, discharge consents and

simulation: A review. J Chem. Technol. Biotechnol 74 (1 1), 1009-1018.

Paradelo, R., Moldes, A.B., Barral, M.T. (2009). Treatment of red wine vioasses with

non-conventional substrates for removing colored compounds. Water Sci. Technol. 59

(8), 1585-1592.

Pearce, c.1., Lloyd, J.R., Guthrie, J.T. (2003). The removal of color from textile wastewater using whole bacterial cells: A review. Dyes Pigment 58 (3), 179-196.

Poots, V.J.P., McKay, G., Healy, J.J. (1976). The removal of acid dye from effluent using natural adsorbents.l. Pea! Water Res. 10 (12), 1061-1066.

Ramakrishna, K.R., Viraragbavan, T (1997). Dye removal using low cost adsorbents. Waler Sei. Teehnol 36 (2-3), 189-196. 5

Robioson, T., McMullan, G., Marchant, R., Nigam, P. (2001). Remediation of dyes in textile effluent: A critique! review on current treatment technologies with a proposed altemative. Bioresour Technol 77 (3), 247-255.

10 Sun, Q., Yang, L. (2003). The adsorption of basic dyes from aqueous solution on

modified peat-resin particle. Water Res. 37 (7), 1535-1544.

Vandevivere, P.C., Bianchi, R., Verstraete, W. (1998). Trealment and reuse of wastewater from the textile wet-processing industry: Review of emerging technologies. J.

15 ehem Teehnol Bioteehnol 72 (4), 289-302.

Claims (5)

1. Process for the preparation of a bio-absorbent based on peat or peat-like material mobilized in calcium alginate spheres, characterized by comprising the following stages: 3. Determine the humidity of the peat or peat-like material to calculate the concentration of sodium alginate that the peat solution or peat-like material must contain.

b.

Grind the peat or peat-like material to a particle size smaller than 0.4 mm.

C.

Mix between 0.5-2% dry peat or dry peat analogue material with 1-5% sodium alginate.

d.

Add the previous mixture to a solution of calcium chloride between 0.0510.9 M, pumping at a constant flow rate that allows the formation of calcium alginate spheres, which will contain the peat or peat-like material and also form sodium chloride .

and.

Obtain the peat or immobilized peat-like material after filtering the sodium chloride solution from the previous step and containing the peat or peat-like material immobilized in calcium alginate spheres.

F.

Wash the peat or peat-like material with hot water.

g.

Store the peat or peat-like material in a 0.9 M calcium chloride solution for preservation.

2.

Process for the preparation of a bioadsorbent based on peat or peat-like material immobilized in calcium alginate spheres, according to claim 1, wherein the peat-like material is an organic fertilizer.

3.

Process for the preparation of a peat-based bioadsorbent or peat-like material immobilized in calcium alginate spheres, according to claim 1, wherein the peat-like material is any plant residue that has undergone a degradation process similar to peat.

Four.

The use of a peat-based bioadsorbent or peat-like material immobilized in calcium alginate spheres, according to claims 1-3, as an adsorbent for wastewater treatment.

ES 2 430 248 Al Table l. Independent and dependent variables used in this study.

a) Independent variables

Variable

Nomenclature Units Variation Range

Peat

T % 0.5-2

Sodium alginate

TO % 1-5

Calcium chloride

C M 0.050-0.900

b) Coded dimensionless independent variables

Variable

Nomenclature Definition Range of variation

Peat

x, (T 1.25) /0.75 (-1.1)

Sodium alginate

x, (A 3) 12 (-1.1)

Calcium chloride

x, (C - Q.475) 10.2125 (-1.1)

e) Dependent variables Variable Nomenclature Units

Decrease in absorbance at 620 om

Y, %

Decrease in absorbance at 520 om

Y, %

Decrease in absorbance at 420 om

Y, %

Decrease in absorbency to 280 om

Y. %

1 = AI2O + As20 (Intensity of color)

Y, nm

T =

A42f) / Year (Hue) Y, nm

le = ~ 2nd + A520 + A420 (Coloring intensity)

Y, nm

L · (Color brightness)

Y. nm

a '(associated with changes in red-green)

Y, nm

b · (associated with changes in yellow-blue)

Y" nm

C · ab (Intensity of color or saturation)

Y" nm

H..b (Color tone)

Y" nm

Table 2. Operational CDs considered in this study (expressed in terms of independent coded variables) and the experimental results obtained from the variables dependent on YI to Y12. Independent Variables Dependent Variables

Exp.

x, o x, -1 x, -1 and, 0.06 and, 0.11 and, 0.17 and, 2.50 and, 0.28 and, 1.62 and, 0.34 and, 92.24 and, 1.25 and "7.82 and "31, 36 Y12 0, 16

2

OR -one 0.04 0, 10 0.16 3, 14 0.26 1.72 0.30 93, 34 1.82 8.71 39.59 0.21

3

OR -one 0.04 0.08 0.13 1.97 0.21 1.54 0.25 94.07 1.22 5.73 17, 16 0.21

or

4 5 6 7 8 9 O -1 -1 -1 -1 -1 1 O O O O O -1 0.04 0.08 0.12 0.07 0.06 0.15 0.09 0.15 0.21 0, 10 0.11 0.25 0.13 0.2 1 0.28 0, 15 0.17 0.33 2.71 2.80 3.3 1 1.87 2.47 3.35 0.22 0.3 7 0.49 0.25 0.28 0.58 1.57 1.37 1.3 6 1.59 1.57 1.3 3 0.26 0.45 0.6 1 0.31 0.33 0.73 94.07 88.99 85.4 1 92.79 92.21 82.46 2.26 3.39 3.94 0.48 1.66 4.3 5 6.55 8.98 10.57 6.23 7.3 8 11.03 24.01 46.07 63.62 19.52 28.61 70.29 0.33 0.36 0.36 0.08 0.22 0.3 8 tT1 w IV ... w O IV ... 00>

10

-one OR 0.04 0, 11 0.16 2.64 0.27 1.41 0.31 92.51 3.56 7.43 33.94 0.45

eleven

OR -one 0.05 0.10 0.16 2.21 0.26 1.69 0.31 93.00 0.93 7.69 30.00 0.12

12

OR 0.10 0, 15 0.2 1 1.98 0.36 1.45 0.46 89.04 1.38 7.48 28.93 0.18

13

OR OR OR 0.07 0, 11 0.17 2.27 0.28 1.57 0.36 9 1.58 1.90 7.4 1 29.25 0.25

14

OR OR OR 0.06 0.10 0, 18 2.29 0.28 1.70 0.34 92.51 1.88 7.70 31.37 0.24

fifteen

OR OR OR 0.07 0, 13 0.19 2.26 0.32 1.47 0.39 90.65 1.91 7.98 33.66 0.23

r '

0.93 0.95 0.95 0.99 0.95 0.86 0.95 0.95 0.99 0.96 0.98 0.99

Table 3. Regression coefficients and their statistical error of the variables and, at Y6. y, y, y, p "y, p" y, p "y, p "p" ""

bo

0.07 0.01 ' 0.11 0.00 ' 0.18 0.00 ' 2.27 0.00 0.29 0.00 1.58 0.00

b,

-0.01 0.06 -0.03 0.02 -0.04 0.01 * -0.45 0.00 ' -0.07 0.01 * 0, 10 0.13

bll

0.03 0.04 * 0.04 0.03 0.05 0.01 ' 0.15 0.00 ' 0.09 0.02 ' -0.13 0.17

b,

0.00 0.90 0.01 0.25 0.01 0.07 0.31 0.00 * 0.02 0.13 0.01 0.82 tT1

w

b "

-0.01 0.13 -0.02 0.15 -0.02 0.04 * 0.19 0.00 -0.04 0.08 0.02 0.77 N ...

w

::

or

b,

~ Ol 0.11 -0.02 0.08 -0.03 0.01 * -0.24 0.00 -0.04 0.03 * -0.05 0.35 N ...

00

b "

-0.01 0.26 -0.0 1 0.45 -0.01 0.17 0.12 0.00 -0.02 0.29 0.02 0.81 >

b12

-0.01 0.17 -0.01 0.25 -0.01 0.09 0.02 0.08 -0.02 0.15 0.00 0.96

bu

0.04 0.02 ' 0.05 0.02 ' 0.06 0.01 * 0.12 0.00 0.10 0.01 ' -0.08 0.30

b "

0.00 0.70 0.00 0.66 0.00 0.48 0.02 0.07 0.01 0.58 -0.02 0.79

· Significant coefficient (p> O.OS) Table 4. Regression coefficients and their statistical error of the variables and, at Y12. y, y, y, YIO 1 ', 10 1' ,,, 1 ',,, p "p" y "y" "" b, 0.36 0.00 · 91.58 0.00 · 1.90 0.00 · 7.70 0.00 '31.43 0.00' 0.24 0.00 · b, -0.09 0.01- 2.21 0.02--1.35 0.00 · -1.15 0.01--13.36 0.00 · -0.12 0.00 '0.11 0.02 * -2.95 0.03-0.69 0.000.90 0.03-10.39 0.01 '' 0.03 0.01 b "tT1 b, 0.02 0.21 -0.38 0.36 0.42 0.000.56 0.03-5.22 0.020.04 0.0 1 '"w IV ...

-

0.05 0.08 1.22 0.13 -0.22 0.00 · -0.31 0.18 -2.37 0.18 -0.02 0.04

b "w No IV b, -0.05 0.04-1.08 0.08 0.01 0.25 -1.01 0.01--8.40 0.01 '0.04 0.01 > 0.25 0.63 0.32 -0.04 0.05 -0.19 0.33 -1.03 0.46 0.01 0.27 b "-0.02 -0.04 0.14 0.75 0.25 0.16 0.00 · -0.11 0.52 -2.12 0.20 0.04 0.01 b " bu 0.14 0.01 '-3.50 0.02' 0.31 0.000.85 0.03 '8.82 0.02' 0.00 0.62 bo, 0.01 0.59 -0.27 0.61 0.12 0.00 -0.02 0.91 -0.35 0.78 0.02 0.04 '  · Significant coefficient (p> O.05) Table 5. Values of the dependent variables of the untreated vinasse and the treated vinasse obtained after the treatment with immobilized peat elaborated under the optimal conditions

Parameters

Nomenclature Untreated Vinasse Treated vinegar

Abs 620

Y, 0.42 0.04

Abs S20

Y, 1.03 0.08

Abs uo

Y, 1.05 0.13

Abs 280

Y. 4.49 1.97

Y,

2.08 0.21

T

Y, 1.01 1.54

IC

Y, 2.50 0.25

L '

Y. 49.28 94.07

, to

Y, 29.60 1.22

b '

Y" 23.95 5.73

C'",

Y" 724.88 17.16

H ",

Y" 0.89 0.21