Thermoplastic composite material based on blending of municipal sludge and carbon conversion product and preparation method of thermoplastic composite material

Abstract

The invention discloses a thermoplastic composite material based on blending of municipal sludge and a carbon conversion product and a preparation method thereof, and belongs to the technical field of resources and environments. The invention aims to solve the problems of low utilization rate of municipal sludge and rice husks and high product conversion difficulty in the prior art. The thermoplastic composite material based on municipal sludge and carbon conversion product blending is prepared from mixed powder, a thermoplastic high-molecular polymer, an auxiliary agent and a pigment, the mixed powder is composed of sludge powder, modified sludge carbon and agricultural waste, the sludge powder is formed by drying municipal sludge, and the modified sludge carbon is formed by drying, high-temperature pyrolysis and chemical modification of the municipal sludge. Inorganic matters in the sludge provide filling strength; the modified sludge carbon increases pores, provides a physical structure and chemical properties which are easy to adsorb, and increases the strength; the agricultural waste assists the dispersion of the sludge powder. According to the invention, cyclic utilization of waste resources is realized, and waste is turned into wealth.

Description

Technical Field

[0001] The invention belongs to the technical field of resources and environment, and specifically relates to a method for preparing a thermoplastic composite material based on the blending of municipal sludge and carbon conversion products. Background Art

[0002] Municipal sludge is solid waste discharged from municipal sewage treatment facilities. Its form is affected by the moisture content and is solid or semi-solid. It contains a large number of microbial cells, pathogens and pollutants. The output of municipal sludge is huge, accounting for about 0.05-1% of sewage COD. If it is disposed of arbitrarily without treatment, it will cause serious soil, water and air pollution and pose a risk to human health. In order to solve the problem of municipal sludge treatment and disposal, a number of corresponding technologies have been developed, such as incineration, composting and sanitary landfill, to achieve the goals of sludge reduction, stabilization and harmlessness. However, in the current mainstream sludge treatment and disposal technologies, it is difficult to achieve synergy between energy consumption, secondary pollution and treatment effect. Generally speaking, sludge treatment accounts for more than 50% of the total cost of sewage treatment. If the cost of municipal sludge treatment and disposal can be reduced, the total cost of sewage treatment will be effectively reduced while achieving efficient sewage treatment, achieving energy saving and consumption reduction.

[0003] The resource utilization of municipal sludge mainly includes reuse in building materials, agriculture, energy and other fields, which has high requirements for the level of equipment and facilities, the level of economic development of the location and the technical level of operators. At present, the harmless disposal rate of sludge in my country has reached 73.5%, while the resource utilization rate is less than 30%. Expanding the types of resource conversion technologies and application fields of municipal surplus sludge is the main way to improve the resource utilization rate of sludge.

[0004] The organic matter content in municipal sludge is usually 40% to 80%, mainly in the form of microbial cells. The reasonable recovery or utilization of organic matter components is the core issue in sludge resource technology. Microplastics refer to plastic particles with a diameter of less than 5 mm. Their sources include the aging and decomposition of large plastics, microbeads for daily and industrial use, etc., and are widely present in sewage. Among them, in the sewage treatment process, most of the microplastics are collected in municipal sludge and enter the subsequent process with the treatment and disposal of sludge. The sewage treatment process has a high removal effect on microplastics in sewage, reaching more than 90%. Microplastics in sewage treatment plants are intercepted in large quantities in sludge through various processes. These microplastics enriched in sludge will change their occurrence form and transfer in time and space with the treatment and disposal of sludge, and enter a variety of environments and media. In particular, pathogens and pollutants contained in the sludge itself will be loaded on microplastics when they coexist with microplastics, superimposing ecological risks. How to take into account the treatment of microplastics in the resource utilization of sludge has not received effective attention in the field of sludge resource utilization.

[0005] Rice husk refers to the outer shell of rice grains, which is agricultural waste removed during the rice milling process. Usually, straw-type agricultural waste can be converted into biogas, feed, and fuel. However, due to the morphological characteristics of rice husks, such as fine particles, sharp edges, and loose stacking, their feasibility as a resource is limited. Expanding the scope of resource utilization of rice husks is a technical difficulty in related fields.

[0006] In summary, sludge resource utilization can take into account both energy consumption and conversion to useful products, and is a more promising technical solution for municipal residual sludge. However, existing sludge resource utilization technologies have high requirements for equipment, technology, economy and personnel quality. How to explore new sludge resource utilization technologies with lower equipment requirements, simpler operation procedures and richer application scenarios is the focus of research and application in this field. Resource utilization technology that takes into account both municipal sludge and agricultural rice husk waste is of great significance for solving the current treatment and disposal problems of municipal and agricultural solid waste and reasonably improving their economic benefits. It is also an exploration of new quality productivity to promote comprehensive resource utilization. Summary of the invention

[0007] In order to solve the problems of low utilization rate of existing municipal sludge and rice husks and great difficulty in product conversion, the present invention proposes a method for preparing a thermoplastic composite material based on the blending of municipal sludge and carbon conversion products.

[0008] The thermoplastic composite material based on the blending of municipal sludge and carbon conversion products of the present invention is prepared from mixed powder, thermoplastic high molecular polymer, auxiliary agent and pigment; wherein, by weight, the mixed powder is 10-55 parts; the thermoplastic high molecular polymer is 45-87 parts, the auxiliary agent is 3-14 parts, and the pigment is 0-5 parts; the mixed powder is composed of sludge powder, modified sludge carbon and agricultural waste, the sludge powder is 1-48 parts, the modified sludge carbon is 1-30 parts, and the agricultural waste is 1-35 parts; the sludge powder is prepared by drying municipal sludge; the modified sludge carbon is prepared by drying, high-temperature pyrolysis and chemical modification of municipal sludge to increase oxidative functional groups and acid anhydrides.

[0009] The present invention provides a method for preparing a thermoplastic composite material based on a mixture of municipal sludge and carbon conversion products, characterized in that the method is carried out according to the following steps:

[0010] 1. Preparation of sludge powder

[0011] The municipal sludge is dried to inactivate microorganisms and pathogens in the sludge, and the dried sludge is crushed to 100-200 mesh to obtain sludge powder;

[0012] The drying process is drying at 100-120°C for 3h;

[0013] The water content of the municipal sludge is 30-99%;

[0014] 2. Preparation of modified sludge charcoal

[0015] Under nitrogen protection, the sludge powder is pyrolyzed at a temperature of 500-750°C for 2-3 hours to generate sludge carbon powder; the sludge carbon powder is mixed with concentrated sulfuric acid at 0°C, and potassium permanganate is added, and stirred at 20-40°C for 1-2 hours; deionized water is added and stirred at 60-95°C for 10 minutes, and hydrogen peroxide is added dropwise until the reaction liquid turns yellow; the solid product is taken out, and washed with distilled water until the pH is 6.5-7, and finally dried to obtain modified sludge carbon;

[0016] The ratio of the mass of the sludge charcoal powder to the volume of concentrated sulfuric acid is 3 g:100 mL;

[0017] The mass ratio of the sludge charcoal powder to potassium permanganate is 3:13;

[0018] The ratio of the mass of the sludge carbon powder to the volume of deionized water is 3 g:60 mL;

[0019] The drying temperature is 20°C to 80°C;

[0020] 3. Drying the rice husk after husking the rice grains, and crushing it into 100-200 meshes with a grinder to obtain agricultural waste;

[0021] 4. mixing the sludge powder, modified sludge charcoal and agricultural waste to obtain mixed powder;

[0022] 5. Add lubricant to the mixed powder and mix for 10 minutes. When there are two or more lubricants, the interval between adding two lubricants is 3 minutes;

[0023] 6. Add the compatibilizer to the mixture obtained in step 5 and mix for 5 minutes;

[0024] 7. Add the thermoplastic polymer and pigment to the mixture obtained in step 6 and mix for 5 minutes;

[0025] 8. Granulate the mixture obtained in step 7 at 100-190° C. to obtain thermoplastic composite masterbatch.

[0026] The beneficial effects of the present invention are:

[0027] The present invention converts organic matter in municipal sludge into carbon in the modified sludge carbon preparation process and uses it for the preparation of thermoplastic composite materials. Microplastics contained in the sludge are mixed with thermoplastic polymers and heated to remelt the sludge microplastics to increase the connection with the plastic material. The inorganic matter in the sludge provides filling strength. The oxidized functional groups and acid anhydrides added by chemical modification in the modified sludge carbon preparation process provide chemical properties that are easy to adsorb, and the pores are increased to provide a physical structure that is easy to adsorb. The surface of the modified sludge carbon adsorbs polymer molecular chains to form a network structure. The addition of the modified municipal sludge carbon induces crystallization when the thermoplastic polymer material is deformed by force, thereby promoting interface bonding and increasing strength. The present invention realizes the recycling of municipal sludge waste.

[0028] The agricultural waste of the present invention is mixed with sludge powder to assist the dispersion of the sludge powder. The lignin, cellulose and hemicellulose in the agricultural waste also supplement the strength of the thermoplastic composite. Therefore, the present invention also realizes the recycling of agricultural waste resources, solves the problem of agricultural waste stacking, and turns waste into treasure. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Heavy metal leaching amount of the thermoplastic composite materials prepared in Examples 1 to 5. DETAILED DESCRIPTION

[0030] The technical solution of the present invention is not limited to the specific implementation modes listed below, but also includes any reasonable combination of the specific implementation modes.

[0031] Specific implementation method one: In this implementation method, the thermoplastic composite material based on the blending of municipal sludge and carbon conversion products is prepared from mixed powder, thermoplastic polymer, additives and pigments; wherein, the mixed powder is 10 to 55 parts by mass; the thermoplastic polymer is 45 to 87 parts, the additive is 3 to 14 parts, and the pigment is 0 to 5 parts; the mixed powder is composed of sludge powder, modified sludge charcoal and agricultural waste, the sludge powder is 1 to 48 parts, the modified sludge charcoal is 1 to 30 parts, and the agricultural waste is 1 to 35 parts; the sludge powder is made by drying municipal sludge; the modified sludge charcoal is made by drying, high-temperature pyrolysis and chemical modification of municipal sludge to increase oxidative functional groups and acid anhydrides.

[0032] This embodiment has the following beneficial effects:

[0033] In this embodiment, organic matter in municipal sludge is converted into carbon in the modified sludge carbon preparation process and used for the preparation of thermoplastic composite materials. Microplastics contained in the sludge are mixed with thermoplastic polymers and heated to increase the connection with plastic materials. Inorganic matter in the sludge provides filling strength. The oxidized functional groups and acid anhydrides added by chemical modification in the modified sludge carbon preparation process provide chemical properties that are easy to adsorb, and the increased pores provide a physical structure that is easy to adsorb. The surface of the modified sludge carbon adsorbs polymer molecular chains to form a network structure. The addition of modified municipal sludge carbon induces crystallization when the thermoplastic polymer material is deformed by force, thereby promoting interface bonding and increasing strength. This embodiment realizes the recycling of municipal sludge waste.

[0034] In this embodiment, agricultural waste is mixed with sludge powder to assist the dispersion of the sludge powder. The lignin, cellulose and hemicellulose in the agricultural waste also supplement the strength of the thermoplastic composite. Therefore, this embodiment also realizes the recycling of agricultural waste resources, solves the problem of agricultural waste stacking, and turns waste into treasure.

[0035] Specific implementation method 2: This implementation method is different from specific implementation method 1 in that the municipal sludge is one or more of primary sedimentation tank sludge, secondary sedimentation tank sludge, dewatered sludge, dried sludge, granular sludge, anaerobic digestion sludge, and residues of sludge reduction technology based on micro-animal predation.

[0036] Specific implementation method three: This implementation method is different from specific implementation methods one or two in that the agricultural waste is rice husks obtained after shelling rice grains.

[0037] Specific implementation method 4: This implementation method is different from any one of specific implementation methods 1 to 3 in that: the thermoplastic polymer is one or more of HDPE, LDPE, PE, PP, and PVC.

[0038] Specific implementation method five: This implementation method is different from specific implementation methods one to four in that: the auxiliary agent is composed of a lubricant and a compatibilizer; the lubricant in the auxiliary agent is 0.1 to 6 parts, and the compatibilizer is the balance.

[0039] Specific implementation method six: This implementation method is different from any of specific implementation methods one to five in that: the lubricant is one or more of paraffin, fatty acid amide, fatty acid ester, fatty acid, low molecular weight PE, and low molecular weight PP; the molecular weight of low molecular weight PE is 500-5000, and the molecular weight of low molecular weight PP is 3000-4000.

[0040] Specific embodiment seven: This embodiment differs from any one of specific embodiments one to six in that: the compatibilizer is one or more of maleic anhydride grafted HDPE, maleic anhydride grafted LDPE, maleic anhydride grafted PE, maleic anhydride grafted PP, and maleic anhydride grafted SEBS.

[0041] Specific implementation eight: This implementation differs from any one of specific implementations one to seven in that: the pigment is one or more of carbon black, cobalt diacetate, copper powder, and modified sludge charcoal.

[0042] Specific embodiment 9: This embodiment is based on the preparation method of the thermoplastic composite material blended with municipal sludge and carbon conversion products, characterized in that the method is carried out according to the following steps:

[0043] 1. Preparation of sludge powder

[0044] The municipal sludge is dried to inactivate microorganisms and pathogens in the sludge, and the dried sludge is crushed to 100-200 mesh to obtain sludge powder;

[0045] The drying process is drying at 100-120°C for 3h;

[0046] The water content of the municipal sludge is 30-99%;

[0047] 2. Preparation of modified sludge charcoal

[0048] Under nitrogen protection, the sludge powder is pyrolyzed at a temperature of 500-750°C for 2-3 hours to generate sludge carbon powder; the sludge carbon powder is mixed with concentrated sulfuric acid at 0°C, and potassium permanganate is added, and stirred at 20-40°C for 1-2 hours; deionized water is added and stirred at 60-95°C for 10 minutes, and hydrogen peroxide is added dropwise until the reaction liquid turns yellow; the solid product is taken out, and washed with distilled water until the pH is 6.5-7, and finally dried to obtain modified sludge carbon;

[0049] The ratio of the mass of the sludge charcoal powder to the volume of concentrated sulfuric acid is 3 g:100 mL;

[0050] The mass ratio of the sludge charcoal powder to potassium permanganate is 3:13;

[0051] The ratio of the mass of the sludge carbon powder to the volume of deionized water is 3 g:60 mL;

[0052] The drying temperature is 20-80°C;

[0053] 3. Drying the rice husk after husking the rice grains, and crushing it into 100-200 meshes with a grinder to obtain agricultural waste;

[0054] 4. mixing the sludge powder, modified sludge charcoal and agricultural waste to obtain mixed powder;

[0055] 5. Add lubricant to the mixed powder and mix for 10 minutes. When there are two or more lubricants, the interval between adding two lubricants is 3 minutes;

[0056] 6. Add the compatibilizer to the mixture obtained in step 5 and mix for 5 minutes;

[0057] 7. Add the thermoplastic polymer and pigment to the mixture obtained in step 6 and mix for 5 minutes;

[0058] 8. Granulate the mixture obtained in step 7 at 100-190° C. to obtain thermoplastic composite masterbatch.

[0059] In this embodiment, organic matter in municipal sludge is converted into carbon in the modified sludge carbon preparation process and used for the preparation of thermoplastic composite materials. Microplastics contained in the sludge are mixed with thermoplastic polymers and heated to increase the connection with plastic materials. Inorganic matter in the sludge provides filling strength. The oxidized functional groups and acid anhydrides added by chemical modification in the modified sludge carbon preparation process provide chemical properties that are easy to adsorb, and the increased pores provide a physical structure that is easy to adsorb. The surface of the modified sludge carbon adsorbs polymer molecular chains to form a network structure. The addition of modified municipal sludge carbon induces crystallization when the thermoplastic polymer material is deformed by force, thereby promoting interface bonding and increasing strength. This embodiment realizes the recycling of municipal sludge waste.

[0060] In this embodiment, agricultural waste is mixed with sludge powder to assist the dispersion of the sludge powder. The lignin, cellulose and hemicellulose in the agricultural waste also supplement the strength of the thermoplastic composite. Therefore, this embodiment also realizes the recycling of agricultural waste resources, solves the problem of agricultural waste stacking, and turns waste into treasure.

[0061] Specific implementation method ten: This implementation method is different from specific implementation method nine in that: the mass fraction of the concentrated sulfuric acid in step 2 is 85-98%; the mass fraction of the hydrogen peroxide is 30%.

[0062] Example 1

[0063] The method for preparing a thermoplastic composite material based on the blending of municipal sludge and carbon conversion products in this embodiment is carried out according to the following steps:

[0064] 1. Preparation of sludge powder

[0065] The municipal sludge is dried to inactivate microorganisms and pathogens in the sludge, and the dried sludge is crushed to 100 mesh to obtain sludge powder;

[0066] The drying process is drying at 120°C for 3h;

[0067] The municipal sludge is dewatered sludge, and the water content (mass fraction) of the municipal sludge is 81%;

[0068] 2. Preparation of modified sludge charcoal

[0069] Under nitrogen protection, the sludge powder was pyrolyzed at 650°C for 2h to generate sludge charcoal powder; 3g of sludge charcoal powder was mixed with 100mL of concentrated sulfuric acid at 0°C, and the mass fraction of concentrated sulfuric acid was 98%; 13g of potassium permanganate was added and stirred at 30°C for 1h; deionized water was added and stirred at 80°C for 10min, and 30% hydrogen peroxide was added dropwise until the reaction liquid turned yellow; the solid product was taken out and washed with distilled water to a pH of 7, and finally dried at 50°C to obtain modified sludge charcoal;

[0070] 3. Drying the rice husk after husking the rice grains, and crushing it into 100 meshes with a grinder to obtain agricultural waste;

[0071] 4. Mix 11.7 parts of sludge powder, 5.2 parts of modified sludge charcoal, and 9.1 parts of agricultural waste to obtain a mixed powder;

[0072] 5. Add 1.5 parts of stearic acid lubricant and 0.5 parts of paraffin lubricant to the mixed powder and mix for 10 minutes. The interval between adding the two lubricants is 3 minutes.

[0073] 6. Add 2 parts of maleic anhydride grafted PP compatibilizer to the mixture obtained in step 5 and mix for 5 minutes;

[0074] 7. Add 70 parts of thermoplastic polymer to the mixture obtained in step 6 and mix for 5 minutes; the thermoplastic polymer is PP;

[0075] 8. Granulate the mixture obtained in step 7 at 170° C. to obtain thermoplastic composite masterbatch.

[0076] The thermoplastic composite material masterbatch prepared in this embodiment was injected into the mold of an injection molding machine to prepare a thermoplastic composite material. The bending strength of the thermoplastic composite material was 36.7 MPa, which was 6.1% higher than that of PP.

[0077] Example 2

[0078] The method for preparing a thermoplastic composite material based on the blending of municipal sludge and carbon conversion products in this embodiment is carried out according to the following steps:

[0079] 1. Preparation of sludge powder

[0080] The municipal sludge is dried to inactivate microorganisms and pathogens in the sludge, and the dried sludge is crushed to 100 mesh to obtain sludge powder;

[0081] The drying process is drying at 120°C for 3h;

[0082] The municipal sludge is dewatered sludge and granular sludge, with a dry weight ratio of 1:1; the moisture content of the dewatered sludge is 78%, and the moisture content of the granular sludge is 92%;

[0083] Dewatered sludge, wherein the water content of the municipal sludge is 81%;

[0084] 2. Preparation of modified sludge charcoal

[0085] Under nitrogen protection, the sludge powder was pyrolyzed at 750°C for 2h to generate sludge charcoal powder; 3g of sludge charcoal powder was mixed with 100mL of concentrated sulfuric acid at 0°C, and the mass fraction of concentrated sulfuric acid was 92%; 13g of potassium permanganate was added and stirred at 30°C for 1h; deionized water was added and stirred at 80°C for 10min, and 30% hydrogen peroxide was added dropwise until the reaction liquid turned yellow; the solid product was taken out and washed with distilled water to a pH of 7, and finally dried at 50°C to obtain modified sludge charcoal;

[0086] 3. Drying the rice husk after husking the rice grains, and crushing it into 100 meshes with a grinder to obtain agricultural waste;

[0087] 4. Mix 14.2 parts of sludge powder, 10.7 parts of modified sludge charcoal, and 10.6 parts of agricultural waste to obtain a mixed powder;

[0088] 5. Add 2 parts of stearic acid lubricant to the mixed powder and mix for 10 minutes;

[0089] 6. Add 2.5 parts of maleic anhydride grafted PE compatibilizer to the mixture obtained in step 5 and mix for 5 minutes;

[0090] 7. Add 60 parts of thermoplastic polymer to the mixture obtained in step 6 and mix for 5 minutes; the thermoplastic polymer is PE;

[0091] 8. Granulate the mixture obtained in step 7 at 130° C. to obtain thermoplastic composite masterbatch.

[0092] The thermoplastic composite material masterbatch prepared in this embodiment was injected into the mold of an injection molding machine to prepare a thermoplastic composite material. The flexural strength of the thermoplastic composite material was 36.3 Mpa, which was increased by 58.5% compared with PE.

[0093] Example 3

[0094] The method for preparing a thermoplastic composite material based on the blending of municipal sludge and carbon conversion products in this embodiment is carried out according to the following steps:

[0095] 1. Preparation of sludge powder

[0096] The municipal sludge is dried to inactivate microorganisms and pathogens in the sludge, and the dried sludge is crushed to 100 mesh to obtain sludge powder;

[0097] The drying process is drying at 120°C for 3h;

[0098] The municipal sludge is the residue of sludge reduction technology based on micro-animal predation, and its water content is 95%; the water content of the municipal sludge is 95%; the micro-animals are worms, and aquatic oligochaete micro-animals, namely worms, are used to prey on municipal surplus sludge, and the sludge residue remaining after predation is the residue of sludge reduction technology.

[0099] 2. Preparation of modified sludge charcoal

[0100] Under nitrogen protection, the sludge powder was pyrolyzed at 550°C for 3h to generate sludge charcoal powder; 3g of sludge charcoal powder was mixed with 100mL of concentrated sulfuric acid at 0°C, and the mass fraction of concentrated sulfuric acid was 98%; 13g of potassium permanganate was added and stirred at 30°C for 1h; deionized water was added and stirred at 80°C for 10min, and 30% hydrogen peroxide was added dropwise until the reaction liquid turned yellow; the solid product was taken out and washed with distilled water to a pH of 7, and finally dried at 50°C to obtain modified sludge charcoal;

[0101] 3. Drying the rice husk after husking the rice grains, and crushing it into 100 meshes with a grinder to obtain agricultural waste;

[0102] 4. Mix 18.9 parts of sludge powder, 8.4 parts of modified sludge charcoal, and 14.7 parts of agricultural waste to obtain a mixed powder;

[0103] 5. Add 3 parts of stearic acid lubricant and 1 part of paraffin lubricant to the mixed powder and mix for 10 minutes. The interval between adding the two lubricants is 3 minutes;

[0104] 6. Add 4 parts of maleic anhydride grafted PP compatibilizer to the mixture obtained in step 5 and mix for 5 minutes;

[0105] 7. Add 50 parts of thermoplastic polymer to the mixture obtained in step 6 and mix for 5 minutes; the thermoplastic polymer is PP;

[0106] 8. Granulate the mixture obtained in step 7 at 170° C. to obtain thermoplastic composite masterbatch.

[0107] The thermoplastic composite material masterbatch prepared in this embodiment was injected into the mold of an injection molding machine to prepare a thermoplastic composite material. The bending strength of the thermoplastic composite material was 38.2 MPa, which was increased by 10.4% compared with PP.

[0108] Example 4

[0109] The method for preparing a thermoplastic composite material based on the blending of municipal sludge and carbon conversion products in this embodiment is carried out according to the following steps:

[0110] 1. Preparation of sludge powder

[0111] The municipal sludge is dried to inactivate microorganisms and pathogens in the sludge, and the dried sludge is crushed to 100 mesh to obtain sludge powder;

[0112] The drying process is drying at 120°C for 3h;

[0113] The municipal sludge is granular sludge; the water content of the municipal sludge is 91%;

[0114] 2. Preparation of modified sludge charcoal

[0115] Under nitrogen protection, the sludge powder was pyrolyzed at 700°C for 2h to generate sludge charcoal powder; 3g of sludge charcoal powder was mixed with 100mL of concentrated sulfuric acid at 0°C, and the mass fraction of concentrated sulfuric acid was 98%; 13g of potassium permanganate was added and stirred at 30°C for 1h; deionized water was added and stirred at 80°C for 10min, and 30% hydrogen peroxide was added dropwise until the reaction solution turned yellow; the solid product was taken out and washed with distilled water to a pH of 7, and finally dried at 50°C to obtain modified sludge charcoal;

[0116] 3. Drying the rice husk after husking the rice grains, and crushing it into 100 meshes with a grinder to obtain agricultural waste;

[0117] 4. mixing 12 parts of sludge powder, 12 parts of modified sludge charcoal, and 16 parts of agricultural waste to obtain a mixed powder;

[0118] 5. Add 3 parts of stearic acid lubricant and 1 part of paraffin lubricant to the mixed powder and mix for 10 minutes. The interval between adding the two lubricants is 3 minutes;

[0119] 6. Add 4 parts of maleic anhydride grafted PP compatibilizer to the mixture obtained in step 5 and mix for 5 minutes;

[0120] 7. Add 52 parts of thermoplastic polymer to the mixture obtained in step 6 and mix for 5 minutes; the thermoplastic polymer is PP;

[0121] 8. Granulate the mixture obtained in step 7 at 170° C. to obtain thermoplastic composite masterbatch.

[0122] The thermoplastic composite material masterbatch prepared in this embodiment was injected into the mold of an injection molding machine to prepare a thermoplastic composite material. The bending strength of the thermoplastic composite material was 38.6 MPa, which was increased by 11.6% compared with PP.

[0123] Example 5

[0124] The method for preparing a thermoplastic composite material based on the blending of municipal sludge and carbon conversion products in this embodiment is carried out according to the following steps:

[0125] 1. Preparation of sludge powder

[0126] The municipal sludge is dried to inactivate microorganisms and pathogens in the sludge, and the dried sludge is crushed to 100 mesh to obtain sludge powder;

[0127] The drying process is drying at 120°C for 3h;

[0128] The municipal sludge is dried sludge; the water content of the municipal sludge is 36%;

[0129] 2. Preparation of modified sludge charcoal

[0130] Under nitrogen protection, the sludge powder was pyrolyzed at 650°C for 2.5h to generate sludge charcoal powder; 3g of sludge charcoal powder was mixed with 100mL of concentrated sulfuric acid at 0°C, and the mass fraction of concentrated sulfuric acid was 95%; 13g of potassium permanganate was added and stirred at 30°C for 1h; deionized water was added and stirred at 80°C for 10min, and 30% hydrogen peroxide was added dropwise until the reaction liquid turned yellow; the solid product was taken out and washed with distilled water to a pH of 7, and finally dried at 50°C to obtain modified sludge charcoal;

[0131] 3. Drying the rice husk after husking the rice grains, and crushing it into 100 meshes with a grinder to obtain agricultural waste;

[0132] 4. mixing 11 parts of sludge powder, 11 parts of modified sludge charcoal, and 15 parts of agricultural waste to obtain a mixed powder;

[0133] 5. Add 2.8 parts of stearic acid lubricant and 0.9 parts of paraffin lubricant to the mixed powder and mix for 10 minutes. The interval between adding the two lubricants is 3 minutes.

[0134] 6. Add 3.5 parts of maleic anhydride grafted PP compatibilizer to the mixture obtained in step 5 and mix for 5 minutes;

[0135] 7. Add 55.8 parts of thermoplastic polymer to the mixture obtained in step 6 and mix for 5 minutes; the thermoplastic polymer is PP;

[0136] 8. Granulate the mixture obtained in step 7 at 170° C. to obtain thermoplastic composite masterbatch.

[0137] The thermoplastic composite material masterbatch prepared in this embodiment was injected into the mold of an injection molding machine to prepare a thermoplastic composite material. The bending strength of the thermoplastic composite material was 37.9 MPa, which was increased by 9.5% compared with PP.

[0138] Figure 1 Figure 1 shows the heavy metal leaching amount of the thermoplastic composite materials prepared in Examples 1 to 5. It can be seen that the heavy metal content of the thermoplastic composite materials prepared in Examples 1 to 5 is at a relatively low level.

Claims

1. A thermoplastic composite material based on a blend of municipal sludge and carbon conversion products, characterized in that: The thermoplastic composite material based on the blending of municipal sludge and carbon conversion products is prepared from mixed powder, thermoplastic polymer, additives and pigments; wherein, by weight, the mixed powder is 10 to 55 parts; the thermoplastic polymer is 45 to 87 parts, the additive is 3 to 14 parts, and the pigment is 0 to 5 parts; the mixed powder is composed of sludge powder, modified sludge carbon and agricultural waste, the sludge powder is 1 to 48 parts, the modified sludge carbon is 1 to 30 parts, and the agricultural waste is 1 to 35 parts; the sludge powder is made by drying municipal sludge; the modified sludge carbon is made by drying, high-temperature pyrolysis and chemical modification of municipal sludge to increase oxidative functional groups and acid anhydrides.

2. The thermoplastic composite material based on the blend of municipal sludge and carbon conversion products according to claim 1, characterized in that: The municipal sludge is one or more of primary sedimentation tank sludge, secondary sedimentation tank sludge, dewatered sludge, dried sludge, granular sludge, anaerobic digestion sludge, and residues of sludge reduction technology based on micro-animal predation.

3. The thermoplastic composite material based on the blend of municipal sludge and carbon conversion products according to claim 1, characterized in that: The agricultural waste is rice husks obtained after husking rice grains.

4. The thermoplastic composite material based on the blend of municipal sludge and carbon conversion products according to claim 1, characterized in that: The thermoplastic high molecular polymer is one or more of HDPE, LDPE, PE, PP and PVC.

5. The thermoplastic composite material based on the blend of municipal sludge and carbon conversion products according to claim 1, characterized in that: The auxiliary agent is composed of a lubricant and a compatibilizer; the lubricant accounts for 0.1 to 6 parts of the auxiliary agent, and the compatibilizer accounts for the balance.

6. The thermoplastic composite material based on the blend of municipal sludge and carbon conversion products according to claim 5, characterized in that: The lubricant is one or more of paraffin, fatty acid amide, fatty acid ester, fatty acid, low molecular weight PE, and low molecular weight PP; the molecular weight of low molecular weight PE is 500-5000, and the molecular weight of low molecular weight PP is 3000-4000.

7. The thermoplastic composite material based on the blend of municipal sludge and carbon conversion products according to claim 5, characterized in that: The compatibilizer is one or more of maleic anhydride grafted HDPE, maleic anhydride grafted LDPE, maleic anhydride grafted PE, maleic anhydride grafted PP, and maleic anhydride grafted SEBS.

8. The thermoplastic composite material based on the blend of municipal sludge and carbon conversion products according to claim 1, characterized in that: The pigment is one or more of carbon black, cobalt diacetate, copper powder and modified sludge charcoal.

9. The method for preparing a thermoplastic composite material based on a blend of municipal sludge and carbon conversion products according to claim 1, characterized in that: The method proceeds as follows:

1. Preparation of sludge powder The municipal sludge is dried to inactivate microorganisms and pathogens in the sludge, and the dried sludge is crushed to 100-200 mesh to obtain sludge powder; The drying process is drying at 100-120°C for 3h; The water content of the municipal sludge is 30-99%; 2. Preparation of modified sludge charcoal Under nitrogen protection, the sludge powder is pyrolyzed at 500-750°C for 2-3 hours to generate sludge charcoal powder; the sludge charcoal powder is mixed with concentrated sulfuric acid at 0°C, and potassium permanganate is added, and stirred at 20-40°C for 1-2 hours; deionized water is added and stirred at 60-95°C for 10 minutes, and hydrogen peroxide is added dropwise until the reaction liquid turns yellow; The solid product is taken out and washed with distilled water until the pH value is 6.5-7, and finally dried to obtain modified sludge carbon; The ratio of the mass of the sludge charcoal powder to the volume of concentrated sulfuric acid is 3 g:100 mL; The mass ratio of the sludge charcoal powder to potassium permanganate is 3:13; The ratio of the mass of the sludge carbon powder to the volume of deionized water is 3 g:60 mL; The drying temperature is 20-80°C; 3. Drying the rice husk after husking the rice grains, and crushing it into 100-200 meshes with a grinder to obtain agricultural waste; 4. mixing the sludge powder, modified sludge charcoal and agricultural waste to obtain mixed powder; 5. Add lubricant to the mixed powder and mix for 10 minutes. When there are two or more lubricants, the interval between adding two lubricants is 3 minutes; 6. Add the compatibilizer to the mixture obtained in step 5 and mix for 5 minutes; 7. Add the thermoplastic polymer and pigment to the mixture obtained in step 6 and mix for 5 minutes; 8. Granulate the mixture obtained in step 7 at 100-190° C. to obtain thermoplastic composite masterbatch.

10. The method for preparing a thermoplastic composite material based on a blend of municipal sludge and carbon conversion products according to claim 9, characterized in that: The mass fraction of the concentrated sulfuric acid in step 2 is 85-98%; the mass fraction of the hydrogen peroxide is 30%.

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