CN102206363B - Preparation method and application of crosslinked starch, polycaprolactone and polylactic acid mixture - Google Patents
Preparation method and application of crosslinked starch, polycaprolactone and polylactic acid mixture Download PDFInfo
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- CN102206363B CN102206363B CN2011100925704A CN201110092570A CN102206363B CN 102206363 B CN102206363 B CN 102206363B CN 2011100925704 A CN2011100925704 A CN 2011100925704A CN 201110092570 A CN201110092570 A CN 201110092570A CN 102206363 B CN102206363 B CN 102206363B
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Abstract
The invention discloses a preparation method and application of a crosslinked starch, polycaprolactone and polylactic acid mixture, which belongs to the technical field of environment protection. The preparation method comprises the following steps of: adding auxiliary agents such as a plasticizing agent and the like into crosslinked starch, polycaprolactone and polylactic acid which serve as raw materials; stirring and mixing uniformly; extruding by using a double-screw extruder at a time; and pelleting to obtain a product. The crosslinked starch, polycaprolactone and polylactic acid mixture can be simultaneously used as a denitrification carbon source and a biomembrane carrier during water treatment, overcomes the defect that the adding amount of the carbon source is difficult to regulate and control in the conventional denitrification process, and has higher adaptability to inflow water dissolved oxygen concentration and pH; simultaneously, low-cost starch is added into the mixed carbon source, so that denitrification cost is reduced.
Description
Technical field
The invention belongs to environmental protection technical field, be specifically related to preparation method and the application of a kind of cross-linking starch, polycaprolactone and polylactic acid blend.
Background technology
Cut the operational management of dirty control source, enhanced sewage treatment plant along with strict enforcement, with the water pollution problems that occurs take low organic contamination, higher nitrogen as discharge characteristics.Reach the water outlet of one-level A standard as the ecological water supplement of water surrounding such as sewage work, derive from confluxing of rainwash in rainy season face source, city etc.If the low-pollution water that this class exceeds standard take nitrate nitrogen as main total nitrogen directly confluxes into lake, reservoir without further processing, may cause body eutrophication, produce serious eco-catastrophe.In China's various places groundwater pollution, nitrate also is main contamination index, and the trend that increases the weight of is year by year arranged.Therefore, the removal of nitrate has important practical significance.
How the nitrate nitrogen in the removal water of economical and efficient is a bottleneck problem of water pollution control always.Common liquid carbon source biological denitrification denitrification process has an inborn defective: carbon-nitrogen ratio is difficult to control, exists to add excessive danger.For this reason, someone adopts water-insoluble solid-state biodegradable polymers as carbon source and the biomembranous carrier of denitrifying bacteria denitrogenation, has effectively avoided the excessive problem that causes polluted water that adds of carbon source.The denitrifying solid carbon source of solid phase that is used for of having studied at present has certain defective, and lower such as the denitrification rate of the material (wheat straw, cotton etc.) of rich cellulose, the DOC in the initial operating stage water outlet, colourity, total plate count etc. are generally higher; And the denitrification cost of the polymkeric substance of bacterium and synthetic (PHB, PCL etc.) is high, does not also possess at present economic serviceability.For this reason, develop the solid carbon source that possesses technology and economic feasibility and become the key that limits this technology popularization application.
Starch is the good polymeric carbohydrate of a kind of biodegradability, contains a large amount of hydroxyls on its molecule, thereby its intermolecular Hyarogen-bonding is strong, causes the second-order transition temperature of starch to be higher than decomposition temperature, is difficult for processing.The simultaneously existence of these hydroxyls is also so that esterification, etherificate and the reaction such as crosslinked can occur in starch, therefore can utilize the various reactions of hydroxyl to prepare required treated starch.Starch is because its good reactivity worth and lower cost, thereby received increasing concern aspect bio-degradable plastics.Can be mainly with the degradable synthetic materials of starch blending polyvinyl alcohol (PVA), poly butyric ester (PHB), poly-hydroxyl valerate (PHV), PHB-PHV multipolymer, polycaprolactone (PCL) etc.Cross-linking starch is a kind of important treated starch, is two ehter bonds or ester bond that the polynary functional group of the alcoholic extract hydroxyl group of starch and linking agent forms.The consistency of increase that can be suitable after starch is crosslinked itself and degradable synthetic materials, linking agent commonly used has epoxy chloropropane etc.Research before mainly concentrates on the degradable plastics field, and the report of the blend of the cross-linking starch for preparing for the denitrification purposes and degradable synthetic materials is not also arranged at present.
Summary of the invention
The object of the present invention is to provide the preparation method of a kind of cross-linking starch, polycaprolactone and polylactic acid blend.
The cross-linking starch, polycaprolactone and the polylactic acid blend that provide to prepare are provided hang down C/N than the application of the denitrogenation aspect of azotate pollution water as the carrier that carbon source and the microbial film of biological denitrification adheres to.
The preparation method of a kind of cross-linking starch, polycaprolactone and polylactic acid blend is characterized in that, carries out in accordance with the following steps:
(1) starch is crosslinked: add starch, water and sodium-chlor in reactor, under mechanical stirring, transfer pH to 9.5 with the sodium hydroxide solution of 0.5mol/L, slowly add epoxy chloropropane after being warming up to 50 ℃, under the constant temperature behind the reaction 8h, filter, wash, dry, obtain cross-linking starch;
(2) preparation of cross-linking starch, polycaprolactone and polylactic acid blend: after cross-linking starch, starch, polycaprolactone, poly(lactic acid), glycerine, water, wood powder and silane coupling agent stirred, in twin screw extruder in 120～175 ℃ of extruding pelletizations.
The mass ratio of the used starch of step (1), water, sodium-chlor, sodium hydroxide solution and epoxy chloropropane is: 10: 30: 0.7: 0.7: 0.8.
The mass ratio of the used cross-linking starch of step (2), starch, polycaprolactone, poly(lactic acid), glycerine, water, wood powder and silane coupling agent is: (0-60): (0-60): (0-70): (0-50): (0-20): (4-20): (0-10): (0-2).
Described starch is one or more the mixing in W-Gum, potato starch, the tapioca (flour).
The molecular weight of described polycaprolactone is 40000～100000; The molecular weight of poly(lactic acid) is 40000～80000; The particle diameter of wood powder is 200～400 orders.
Described silane coupling agent is one or more the mixing among KH-550, KH-560 and the KH-570.
Cross-linking starch, polycaprolactone and polylactic acid blend be the application aspect the nitrate in removing low C/N water.
Intentionally effect of the present invention: 1, the present invention has added cheap reproducible cross-linking starch, so that greatly reduce with the denitrogenation cost of this blend.2, blend provided by the invention has the characteristics that start time is short, denitrification rate fast and the variation of DO and pH is had very strong adaptive faculty as the denitrification solid carbon source time, and all components all can be degradable, can not bring secondary pollution to environment.3, blend provided by the invention can be used for the denitrogenation processing of low C/N surface water, underground water and effluent of municipal sewage plant as the denitrification solid carbon source time.4, water-insoluble blend provided by the invention not only serves as the required carbon source of denitrification but also as biomembranous carrier, overcome and use the uppity shortcoming of carbon source dosage in the traditional liquid carbon source biological denitrification process, has advantages of simple to operate.
Description of drawings
Fig. 1 is the process flow diagram that blend that the present invention prepares is applied to denitrogenation of waste water;
Among the figure, 1-inlet flume, 2-peristaltic pump, 3-constant temperature water tank, 4-reactor, 5-effluent trough.
Embodiment
Below in conjunction with the drawings and specific embodiments the present invention is described further; be pointed out that following examples can not be interpreted as limiting the scope of the invention, the person skilled in the art of this area foregoing according to the present invention still belongs to protection scope of the present invention to some nonessential improvement and the adjustment that the present invention makes.
Embodiment 1
The preparation method of cross-linking starch, polycaprolactone and polylactic acid blend, carry out in accordance with the following steps:
(1) starch is crosslinked: add 10g starch, 30g water and 0.7g sodium-chlor in reactor, sodium hydroxide solution (adding 0.7g) with 0.5mol/L under mechanical stirring is transferred pH to 9.5, slowly add the 0.8g epoxy chloropropane after being warming up to 50 ℃, after reacting 8h under the constant temperature, filter, wash, dry, obtain cross-linking starch;
(2) preparation of cross-linking starch, polycaprolactone and polylactic acid blend: after the crosslinked W-Gum of 35g, 25g polycaprolactone (molecular weight 60000), 25g poly(lactic acid) (molecular weight 40000), 11g glycerine, 4g water stirred, in twin screw extruder in 120～175 ℃ of extruding pelletizations.
Embodiment 2
The preparation method of cross-linking starch, polycaprolactone and polylactic acid blend, carry out in accordance with the following steps:
(1) starch is crosslinked: add 10g starch, 30g water and 0.7g sodium-chlor in reactor, sodium hydroxide solution (adding 0.7g) with 0.5mol/L under mechanical stirring is transferred pH to 9.5, slowly add the 0.8g epoxy chloropropane after being warming up to 50 ℃, after reacting 8h under the constant temperature, filter, wash, dry, obtain cross-linking starch;
(2) preparation of cross-linking starch, polycaprolactone and polylactic acid blend: after 46g crosslinked cassava starch, 14g polycaprolactone (molecular weight 40000), 14g poly(lactic acid) (molecular weight 80000), 15g glycerine, 5g water 5g wood powder and 1g KH-560 silane coupling agent stirred, in twin screw extruder in 120～175 ℃ of extruding pelletizations.
Embodiment 3
The preparation method of cross-linking starch, polycaprolactone and polylactic acid blend, carry out in accordance with the following steps:
(1) starch is crosslinked: add 10g starch, 30g water and 0.7g sodium-chlor in reactor, sodium hydroxide solution (adding 0.7g) with 0.5mol/L under mechanical stirring is transferred pH to 9.5, slowly add the 0.8g epoxy chloropropane after being warming up to 50 ℃, after reacting 8h under the constant temperature, filter, wash, dry, obtain cross-linking starch;
(2) preparation of cross-linking starch, polycaprolactone and polylactic acid blend: after the crosslinked W-Gum of 23.04g, 23.04g W-Gum, 14.11g polycaprolactone (molecular weight 40000), 14.11g poly(lactic acid) (molecular weight 80000), 14.81g glycerine, 4.94g water, 4.95g wood powder and 1g KH-560 silane coupling agent stirred, in twin screw extruder in 155 ℃ of extruding pelletizations.
Embodiment 4
The preparation method of cross-linking starch, polycaprolactone and polylactic acid blend, carry out in accordance with the following steps:
(1) starch is crosslinked: add 10g starch, 30g water and 0.7g sodium-chlor in reactor, sodium hydroxide solution (adding 0.7g) with 0.5mol/L under mechanical stirring is transferred pH to 9.5, slowly add the 0.8g epoxy chloropropane after being warming up to 50 ℃, after reacting 8h under the constant temperature, filter, wash, dry, obtain cross-linking starch;
(2) preparation of cross-linking starch, polycaprolactone and polylactic acid blend: after the crosslinked W-Gum of 48g, 25g polycaprolactone (molecular weight 80000), 15g glycerine, 5g water, 5g wood powder and 2g KH-570 silane coupling agent stirred, in twin screw extruder in 120～175 ℃ of extruding pelletizations.
Embodiment 5
The preparation method of cross-linking starch, polycaprolactone and polylactic acid blend, carry out in accordance with the following steps:
(1) starch is crosslinked: add 10g starch, 30g water and 0.7g sodium-chlor in reactor, sodium hydroxide solution (adding 0.7g) with 0.5mol/L under mechanical stirring is transferred pH to 9.5, slowly add the 0.8g epoxy chloropropane after being warming up to 50 ℃, after reacting 8h under the constant temperature, filter, wash, dry, obtain cross-linking starch;
(2) preparation of cross-linking starch, polycaprolactone and polylactic acid blend: after the crosslinked W-Gum of 46.08g, 28.22g polycaprolactone (molecular weight 80000), 14.81g glycerine, 4.94g water, 4.95g wood powder and 1g KH-570 silane coupling agent stirred, in twin screw extruder in 130 ℃ of extruding pelletizations.
The denitrification of embodiment 6 cross-linking starchs, polycaprolactone and polylactic acid blend is used
1, the biofilm of denitrifying microorganism.Reactor is packed bed pattern (Fig. 1), and the blend particle (particle diameter 0.4cm) for preparing is filled in the reactor 4, and packing height is 2/3rds of reactor 4, the upflowing water inlet.With the active sludge of sewage disposal plant aeration tank, denitrifying microorganism is tamed, take constant temperature water tank 3 control acclimation temperatures as 25～30 ℃.Behind the denitrification effect stability, domestication finishes.
2, denitrification denitrogenation.After domestication finishes, the normal operation of beginning reactor 4, the temperature of constant temperature water tank 3 is 25～30 ℃ during operation.At first will contain the former water of nitrate (being contained in inlet flume 1) and pump into reactor 4 by peristaltic pump 2, contain the former water of nitrate enters packed bed from water tank flow velocity with peristaltic pump 2 controls, guarantee that certain residence time is effectively carried out anti-nitration reaction.Under the effect of the denitrifying microorganism in packed bed of the nitrate nitrogen in the former water, progressively be reduced to nitrogen, discharge by venting port, the water after the processing enters effluent trough 5.
Application examples 1
The reactor specification is: 20cm * 100cm (diameter * height).In packed bed reactor, add cross-linking starch, polycaprolactone and the polylactic acid blend of embodiment 1 as carbon source and biofilm carrier.Processed former water is the tap water of Kunming, adds NaNO
3Regulate NO
3-N concentration is 50mg/L, carries out under the following conditions denitrogenation processing:
Hydraulic detention time: 2 hours
Temperature: 30 ℃
pH：7.5
Former water DO:6.0mg/L
Water quality is as shown in table 1 after processing.
Water-quality ratio is before and after treatment for table 1
Application examples 2
The reactor specification is: 20cm * 100cm (diameter * height).In packed bed reactor, add cross-linking starch, polycaprolactone and the polylactic acid blend of embodiment 2 as carbon source and biofilm carrier.Processed former water is the tap water of Kunming, adds NaNO
3Regulate NO
3-N concentration is 25mg/L, carries out under the following conditions denitrogenation processing:
Hydraulic detention time: 1 hour
Temperature: 25 ℃
pH：7.5
Former water DO:5.5mg/L
Water quality is as shown in table 2 after processing.
Water-quality ratio is before and after treatment for table 2
Claims (5)
1. the preparation method of a cross-linking starch, polycaprolactone and polylactic acid blend is characterized in that, carries out in accordance with the following steps:
(1) starch is crosslinked: add starch, water and sodium-chlor in reactor, under mechanical stirring, transfer pH to 9.5 with the sodium hydroxide solution of 0.5 mol/L, slowly add epoxy chloropropane after being warming up to 50 ℃, under the constant temperature behind reaction 8 h, filter, wash, dry, obtain cross-linking starch; Wherein the mass ratio of starch, water, sodium-chlor, sodium hydroxide solution and epoxy chloropropane is: 10:30:0.7:0.7:0.8;
(2) preparation of cross-linking starch, polycaprolactone and polylactic acid blend: after cross-linking starch, starch, polycaprolactone, poly(lactic acid), glycerine, water, wood powder and silane coupling agent stirred, in twin screw extruder in 120～160 ℃ of extruding pelletizations; Wherein the mass ratio of cross-linking starch, starch, polycaprolactone, poly(lactic acid), glycerine, water, wood powder and silane coupling agent is: 23.04:23.04:14.11:14.11:14.81:4.94:4.95:1.
2. the preparation method of described a kind of cross-linking starch, polycaprolactone and polylactic acid blend according to claim 1 is characterized in that, described starch is one or more the mixing in W-Gum, potato starch, the tapioca (flour).
3. the preparation method of described a kind of cross-linking starch, polycaprolactone and polylactic acid blend according to claim 1 is characterized in that, the molecular weight of described polycaprolactone is 40000～100000; The molecular weight of poly(lactic acid) is 40000～80000; The particle diameter of wood powder is 200～400 orders.
4. the preparation method of described a kind of cross-linking starch, polycaprolactone and polylactic acid blend according to claim 1 is characterized in that, described silane coupling agent is one or more the mixing among KH-550, KH-560 and the KH-570.
5. arbitrary blend of the preparation method of the described a kind of cross-linking starch of claim 1-4, polycaprolactone and polylactic acid blend preparation application aspect the nitrate in removing low C/N water.
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| CN102212259B (en) * | 2011-05-04 | 2013-07-31 | 北京大学 | Starch and polycaprolactone blend and preparation method and application thereof |
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| CN103408129B (en) * | 2013-08-19 | 2015-12-23 | 中国水产科学研究院渔业机械仪器研究所 | Degradable biological affinity water treatment filling and preparation method thereof |
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| WO2021253144A1 (en) * | 2020-06-15 | 2021-12-23 | 温州蓝宝科技有限公司 | Novel solid carbon source and preparation method therefor |
| CN113583466A (en) * | 2021-07-22 | 2021-11-02 | 湖北嘉鑫环保新材料科技有限公司 | Moderate cross-linked starch biodegradable plastic and preparation method thereof |
| CN114229992B (en) * | 2021-12-16 | 2022-10-28 | 广州市天河区林和粤财技术服务中心 | Preparation of composite modified carrier and sewage treatment method |
| CN115259371A (en) * | 2022-08-24 | 2022-11-01 | 温州市工业科学研究院 | Pretreatment method of mushroom bran for preparing carbon source |
| CN117209074B (en) * | 2023-11-08 | 2024-03-08 | 广州市豫泉净水材料有限公司 | Preparation process of composite carbon source |
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