U.S. patent application number 11/910987 was filed with the patent office on 2008-08-14 for chlorine dioxide treatment compositions and processes.
This patent application is currently assigned to Novozymes A/S. Invention is credited to Kim Bloomfield, Henrik Lund, Hui Xu.
Application Number | 20080190573 11/910987 |
Document ID | / |
Family ID | 37452302 |
Filed Date | 2008-08-14 |
United States Patent
Application |
20080190573 |
Kind Code |
A1 |
Xu; Hui ; et al. |
August 14, 2008 |
Chlorine Dioxide Treatment Compositions and Processes
Abstract
The present invention relates to methods and compositions for
chlorine dioxide delignification and/or bleaching processes by
reacting pulp with chlorine dioxide and a peroxidase and/or a
laccase.
Inventors: |
Xu; Hui; (Wake Forest,
NC) ; Bloomfield; Kim; (Raleigh, NC) ; Lund;
Henrik; (Vaerlose, DK) |
Correspondence
Address: |
NOVOZYMES NORTH AMERICA, INC.
500 FIFTH AVENUE, SUITE 1600
NEW YORK
NY
10110
US
|
Assignee: |
Novozymes A/S
Bagsvaerd
NC
Novozymes North America , INC.
Franklinton
|
Family ID: |
37452302 |
Appl. No.: |
11/910987 |
Filed: |
May 4, 2005 |
PCT Filed: |
May 4, 2005 |
PCT NO: |
PCT/US05/15577 |
371 Date: |
November 27, 2007 |
Current U.S.
Class: |
162/73 |
Current CPC
Class: |
D21C 9/14 20130101; D21H
11/04 20130101; D21C 3/18 20130101; D21H 17/005 20130101; C02F
3/342 20130101; D21H 17/675 20130101; D21H 17/74 20130101; C02F
2103/28 20130101; C02F 1/76 20130101; D21C 5/005 20130101 |
Class at
Publication: |
162/73 |
International
Class: |
D21C 3/18 20060101
D21C003/18; D21C 9/14 20060101 D21C009/14 |
Claims
1. A method for delignifying and/or bleaching of a pulp, comprising
reacting pulp, chlorine dioxide and a peroxidase.
2. The method of claim 1, wherein the peroxidase is a
haloperoxidase
3. The method of claim 1, further comprising reacting the pulp with
a laccase.
4. The method of claim 2, wherein the haloperoxidase is a chloride
peroxidase.
5. The method of claim 1, wherein the peroxidase is a Coprinus
peroxidase, a Bacillus peroxidase, a soy bean peroxidase or a
horseradish peroxidase.
6. The method of claim 4, wherein the chloride peroxidase is a
Curvularia inaequalis peroxidase or Curvularia verruculosa
peroxideas.
7. A method for treating wastewater and/or sludge, comprising
reacting wastewater and/or sludge, chlorine dioxide and a
peroxidase.
8. The method of claim 7, wherein the peroxidase is a
haloperoxidase.
9. The method of claim 7, further comprising reacting wastewater
and/or sludge with a laccase.
10. The method of claim 8, wherein the haloperoxidase is a chloride
peroxidase.
11. The method of claim 8, wherein the peroxidase is a Coprinus
peroxidase, a Bacillus peroxidase, a soy bean peroxidase or a
horseradish peroxidase.
12. The method of claim 10, wherein the chloride peroxidase is a
Curvularia inaequalis peroxidase or Curvularia verruculosa
peroxidase.
13. A method for delignifying and/or bleaching of a pulp,
comprising reacting pulp, chlorine dioxide and a laccase.
14. The method of claim 13, wherein the laccase is a Tramates,
Coprinus or Myceliophthora laccase.
15. The method of claim 13, further comprising reacting the pulp
with a peroxidase.
16. The method of claim 15, wherein the peroxidase is a
haloperoxidase
17. The method of claim 16, wherein the haloperoxidase is a
chloride peroxidase.
18. A method for treating wastewater and/or sludge, comprising
reacting wastewater and/or sludge, chlorine dioxide and a
laccase.
19. The method of claim 18, wherein the laccase is a Tramates,
Coprinus or Myceliophthora laccase.
20. The method of claim 13, further comprising reacting the
wastewater and/or sludge with a peroxidase.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to methods and compositions
for improving chlorine dioxide treatment processes, such as, pulp
delignification and bleaching processes.
BACKGROUND
[0002] Chlorine dioxide is one of the most widely used
delignification/bleaching agents in the pulp and paper industry,
providing a high-quality, low-cost delignification and bleaching
process. Chlorine dioxide treatment is superior to chlorine
bleaching processes in that it virtually eliminates all dioxin
discharges into the environment, and has accordingly, helped pulp
and paper manufactures to employ environmentally friendly processes
and to meet environmental requirements. Accordingly, the use of
chlorine dioxide treatment is increasing and most pulp and paper
mills now have at least one chlorine dioxide delignification or
bleaching stage. Chlorine dioxide treatment has also been used to
treat wastewater, sludge and other process streams.
[0003] During the chlorine dioxide treatment processes some of the
chlorine dioxide is converted to chlorate and chlorite, which
decreases the efficiency of the chlorine dioxide treatment. Methods
have been proposed to improve the efficiency of the chlorine
dioxide treatment process by reducing chlorate and chlorite
formation. Seger et al., Chiang, Tappi J., 1992, 75(7):174-180, for
example, discloses a two step high-pH and low-pH process, which is
believed to reduce the formation of chlorate at the higher pH and
chlorite becomes reactive in the low-pH step. Joncourt et al.,
International Symp. Wood Pulping Chemistry, Montreal, Jun. 9-12,
1997, discloses the use of iron to regenerate chlorine dioxide from
chlorite. Jiang et al, U.S. Pat. No. 6,235,154, discloses process
for improving chlorine dioxide delignification or bleaching by
regenerate chlorine dioxide from the chlorite using
formaldehyde.
[0004] New compositions and methods are needed to improve the
efficiency and effectiveness of chlorine dioxide treatment,
including, chlorine dioxide delignification and bleaching
processes.
SUMMARY OF THE INVENTION
[0005] The present invention relates to methods and compositions
for chlorine dioxide delignification and/or bleaching processes by
reacting pulp with chlorine dioxide and a peroxidase and/or a
laccase. In accordance with the present invention, a peroxidase
and/or a laccase is/are added to a chlorine dioxide delignification
and/or bleaching step. Although not limited to any one theory of
operation, the addition of a peroxidase and/or a laccase to a
chlorine dioxide treating composition is believed to result in the
regeneration of chlorine dioxide from chlorite, resulting in
improved delignification and/or brightening during bleaching of
pulp.
[0006] The present invention relates to methods and compositions
for chlorine dioxide treatment of wastewater, sludge or any other
process stream. In accordance with the present invention, a
peroxidase and/or a laccase is added to a chlorine dioxide
treatment step to improve the chlorine dioxide treatment
process.
DETAILED DESCRIPTION
[0007] A "peroxidase" means a peroxidase (E.C.1.11.1.7) and/or a
haloperoxidase, such, as, preferably, a chloride peroxidase
(E.C.1.11.1.10). Preferably, the peroxidase is an acid stable
peroxidase.
[0008] Peroxidases may be obtained from any suitable source, such
as, e.g., from plants (e.g., a soy bean or horseradish peroxidase)
and from microorganisms (fungi and bacteria, such as, e.g., the
peroxidase may be obtained from a strain of Coprinus, e.g., C.
cinerius or C. macrorhizus, or of Bacillus, e.g. B. pumilu). Some
preferred fungal sources include strains belonging to the
subdivision Deuteromycotina, class Hyphomycetes, e.g., Fusarium,
Humicola, Tricoderma, Myrothecium, Verticillum, Arthromyces,
Caldariomyces, Ulocladium, Embellisia, Cladosporium or Dreschlera,
in particular, Fusarium oxysporum (DSM 2672), Humicola insolens,
Trichoderma resii, Myrothecium verrucana (IFO 6113), Verticillum
alboatrum, Verticillum dahlie, Arthromyces ramosus (FERM P-7754),
Caldariomyces fumago, Ulocladium chartarum, Embellisia alli or
Dreschlera halodes. Other preferred fungal sources include strains
belonging to the subdivision Basidiomycotina, class Basidiomycetes,
e.g., Coprinus, Phanerochaete, Coriolus or Trametes, in particular
Coprinus cinereus f. microsporus (IFO 8371), Coprinus macrorhizus,
Phanerochaete chrysosporium (e.g., NA-12) or Coriolus versicolor
(e.g., PR4 28-A). Further preferred fungal sources include strains
belonging to the subdivision Zygomycotina, class Mycoraceae, e.g.,
Rhizopus or Mucor, in particular, Mucor hiemalis.
[0009] Some preferred bacterial peroxidase sources include strains
of the order Actinomycetales, e.g., Streptomyces spheroides (ATTC
23965), Streptomyces thermoviolaceus (IFO 12382) or
Streptoverticillum verticillium ssp. verticillium. Other preferred
bacterial sources include Bacillus pumillus (ATCC 12905), Bacillus
stearothermophilus, Rhodobacter sphaeroides, Rhodomonas palustri,
Streptococcus lactis, Pseudomonas purrocinia (ATCC 15958) or
Pseudomonas fluorescens (NRRL B-11).
[0010] Haloperoxidases may be obtained form any suitable source.
Haloperoxidases, for example, have been isolated from various
organisms, including mammals, marine animals, plants, algae, a
lichen, fungi and bacteria (for reference see Biochimica et
Biophysica Acta 1161, 1993, pp. 249-256). Suitable
choloroperoxidases include the chloroperoxidase obtained from the
fungus Curvularia inaequalis (see SWISS-PROT:P49053), the
chloroperoxidase obtained from the fungus Curvularia verruculosa
(see WO 97/04102) and the chloroperoxidases disclosed in Svendsen
et al, U.S. Pat. No. 6,372,465.
[0011] Laccases (EC 1.10.3.2) may be obtained from any suitable
sources, such as, from a genus selected from the group consisting
of Aspergillus, Botrytis, Collybia, Fomes, Lentinus,
Myceliophthora, Neurospora, Pleurotus, Podospora, Polyporus,
Scytalidium, Trametes, and Rhizoctonia. In a more preferred
embodiment, the laccase is obtained from a species selected from
the group consisting of Humicola brevis var. thermoidea, Humicola
brevispora, Humicola grisea var. thermoidea, Humicola insolens, and
Humicola lanuginosa (also known as Thermomyces lanuginosus),
Myceliophthora thermophila, Myceliophthora vellerea, Polyporus
pinsitus, Scytalidium thermophila, Scytalidium indonesiacum, and
Torula thermophila. The laccase may be obtained from other species
of Scytalidium, such as Scytalidium acidophilum, Scytalidium album,
Scytalidium aurantiacum, Scytalidium circinatum, Scytalidium
flaveobrunneum, Scytalidium hyalinum, Scytalidium lignicola, and
Scytalidium uredinicolum. Rhizoctonia solani and Coprinus cinereus.
The laccase may be obtained from other species of Polyporus, such
as Polyporus zonatus, Polyporus alveolaris, Polyporus arcularius,
Polyporus australiensis, Polyporus badius, Polyporus biformis,
Polyporus brumalis, Polyporus ciliatus, Polyporus colensoi,
Polyporus eucalyptorum, Polyporus meridionalis, Polyporus varius,
Polyporus palustris, Polyporus rhizophilus, Polyporus rugulosus,
Polyporus squamosus, Polyporus tuberaster, and Polyporus
tumulosus.
[0012] A "chlorine dioxide treatment" means any chloride dioxide
treatment process, such as, for example, chlorine dioxide treatment
stages used in pulp and paper mills and chlorine dioxide treatment
of wastewater and/or sludge, for example, plant wastewater or
ordinary household sewage or wastewater.
[0013] Typically chlorine dioxide treatment is applied in a pulp
and paper mills in delignification and pulp bleaching processes.
Any suitable pulp may be treated, although preferably, the pulp is
a lingocellulosic pulp. The pulp may be treated with other
delignification and/or bleaching agents prior to, during or
following the chlorine dioxide treatment, such as, e.g., oxygen
delignification, peroxide treatment, and enzyme treatment
processes.
[0014] The chlorine dioxide used in the treatment process may be
generated by any suitable method. However, because chlorine dioxide
is unstable as a gas and can only stored as a solution, it is
usually generated on-site, e.g., at the pulp mill. Once in
solution, however, chlorine dioxide is fairly stable.
[0015] Chlorine dioxide is generally added in amounts effective to
treat the pulp or process waters (e.g., waste water), as are known
in the art.
[0016] Typically, chlorine dioxide treatment of pulp is carried out
at a temperature from about 40 to 80.degree. C. for a period of
about 15 to 120 min. The effectiveness of the chlorine dioxide
depends in part on pH, and is maximized at a pH of about 2 to 4.
Because the pH of pulp streams and other process waters are
typically more basic, acid may be added to the treatment water to
reduce the pH. In some processes, the pH of the process water may
be controlled by applying excess amounts of chlorine dioxide.
[0017] The peroxidase and/or laccase is/are applied directly to the
chlorine dioxide process stream in an amount effective to improve
the chlorine dioxide treatment process, as exemplified below. The
peroxidase and/or laccase may be applied as part of the chlorine
dioxide solution, a part of a filtrate used to prepare the process
water (e.g. delignification or bleaching liquour), in the recycled
process water, and/or by a separate addition.
[0018] The peroxidase and/or laccase are applied in an amount
effective to improve the chlorine dioxide treatment process, such
as, as measured by improved pulp delignification and/or improved
pulp bleaching. An example of an effective amount of a peroxidase
is 0.005 mg-10 g/L of process water, more preferably 0.01-1000 mg/L
of process water, and most preferably 0.05-500 mg/L of process
water. In regard to pulp applications, such effective amount of a
peroxidase will include 0.01 g-20 kg/ton of pulp, more preferably
0.1 g-5 kg/ton of pulp, and most preferably 1 g-2 kg/ton of pulp.
An example of an effective amount of a laccase is 0.005 mg-10 g/L
of process water, more preferably 0.01-1000 mg/L of process water,
and most preferably 0.05-500 mg/L of process water. In regard to
pulp applications, such effective amount of a laccase will include
0.01 g-20 kg/ton, more preferably 0.1 g-5 kg/ton, and most
preferably 1 g-2 kg/ton. The peroxidases and laccases are
preferably selected based their compatibility with the process
conditions for the pulp treatment or waste water/sludge treatment,
e.g., pH optimum, temperature optimum, acid stability.
[0019] Although the invention herein has been described with
reference to particular embodiments, it is to be understood that
these embodiments are merely illustrative of the principles and
applications of the present invention. It is therefore to be
understood that numerous modifications may be made to the
illustrative embodiments and that other arrangements may be devised
without departing from the spirit and scope of the present
invention as defined by the appended claims.
EXAMPLES
Example 1
[0020] 160 mg of NaCIO.sub.2 was dissolved in 100 mL of DI water.
10 mL aliquots of the NaClO.sub.2 solution were added to different
test tubes. 20 uL of acetic acid were added to each tube and the pH
was adjusted to about 3.5. Then 100 uL of enzyme was added to the
solution. After 30 min of incubation at ambient temperature, the
solution was diluted 3 times by DI water. ClO.sub.2 formation was
detected by UV absorbency at 360 nm. It is evident that all of the
enzymes can generate ClO.sub.2 to some extent under the conditions
used in this experiment.
TABLE-US-00001 TABLE 1 Enzymatic Chlorine Dioxide Generation
Absorbency No. Sample at 360 nm 1 Control 0.155 2 Peroxidase from
Coprinus cinereus 0.764 (Novozymes) 3 Haloperoxidase from
Curvularia verruculosa 0.168 (Novozymes) 4 Laccase from Trametes
villosa 0.802 (Novozymes) 5 Laccase from Coprinus cinereus 0.190
(Novozymes) 6 Laccase from Myceliophthora thermophila 0.197
(Novozymes) 7 Chloroperoxidase from Caldariomyces fumago 0.393
(Sigma, C-0278)
Example 2
[0021] 5 g (o.d. dry) of unbleached kraft pulp was added to each
beaker and diluted to about 5% consistency. The pulp was adjusted
to various pH by 2N H.sub.2SO.sub.4. 10 mL of 11.3/L of NaClO.sub.2
was added to each beaker. 500 ul of peroxidase (Coprinus cinereus
peroxidase, Novozymes) was added to the solution and the beaker was
incubated at 60.degree. C. for 1 hr. After bleaching, the pulp was
rinsed with DI water and handsheets were made and tested for
brightness. Brightness was tested according to Tappi standard
(T452). It is clear the peroxidase improved pulp brightness in all
the pH range.
TABLE-US-00002 pH Sample Brightness 3 Control 50.4 3 Peroxidase
51.4 4 Control 46.8 4 Peroxidase 47.3 5 Control 43.3 5 Peroxidase
44.2 6 Control 42.8 6 Peroxidase 45.0
* * * * *