The situation of intercepted alien pests from imported hides in Hebei during 2013-2014 was systematically analyzed. The results showed that 163 batches of alien pests were intercepted, including 2 batches of quarantin...The situation of intercepted alien pests from imported hides in Hebei during 2013-2014 was systematically analyzed. The results showed that 163 batches of alien pests were intercepted, including 2 batches of quarantine weeds and they both were Italian cocklebur. According to the statistics of original countries, the intercepted hides from 21 countries all had alien pests, in which Australia was the largest number of batches and species of alien pests. The analysis results showed that there was severe risk in the imported hides carrying alien pests, thus to effectively prevent the invasion of alien pests to our country, several quarantine measures should be taken in the future, such as enhancing the quarantine inspection in ports, and promoting the personnel ability of interception and species identification of alien pests.展开更多
A category of chromium (Cr)-containing fertilizers is represented by the fertilizers deriving from byproducts of tanning process. Their use is widespread because of their good agronomic response due to the high conten...A category of chromium (Cr)-containing fertilizers is represented by the fertilizers deriving from byproducts of tanning process. Their use is widespread because of their good agronomic response due to the high content of slow release or- ganic nitrogen (N) and carbon (C). They do not represent an environmental hazard because only the non-toxic form of Cr(III) is present. Productive processes may involve chemical, enzymatic or thermal hydrolysis. The final product is characterized by different contents of peptides and free amino acids depending on the type of hydrolysis. Legislation concerning Cr-containing fertilizers is controversial because often do not consider any scientific evidences;nevertheless, the European Union, the United States and countries as Italy, do not set the restriction to Cr(III) and generally only the presence of the toxic form, Cr(VI), is limited. Depending on its two main oxidation forms, Cr issue has been studied for many years. Several authors confirmed that Cr(VI) is carcinogenic, while Cr(III) is an essential trace element in human and animal diet. In soil Cr(III) has low mobility, whereas Cr(VI) is highly water soluble. However Cr(VI) in soil is quickly reduced to Cr(III);on the contrary oxidation of Cr(III) to Cr(VI) is rarely possible because particular conditions must occur. Only a very small fraction of Cr in soil is available to plant uptake and its translocation in edible parts is limited because it is immobilized in roots as Cr(III). Therefore risks of environmental pollution using these fertilizers are negligible;on the contrary they have positive environmental and agronomical effects. The aim of this review is to deal with the category of the organic fertilizers containing Cr derived from tannery processes focusing on its chemical, productive, legislative, environmental and agronomical aspects. Special attention is given to the ambiguous issue of Cr briefly summarizing the most important studies of the last forty years.展开更多
Donkey hides are used in a form of Traditional Chinese medicine called ejiao, the demand for ejiao is currently so high the global donkey population is currently in decline. Africa’s donkey population is considered a...Donkey hides are used in a form of Traditional Chinese medicine called ejiao, the demand for ejiao is currently so high the global donkey population is currently in decline. Africa’s donkey population is considered a key source for the trade, with Kenya being highlighted as being particularly affected. In Kenya donkeys play a vital contribution to people’s livelihoods;this study aimed to explore the potential impact of the donkey hide trade on small holder farmer’s livelihoods. The study was conducted in five counties in Kenya;data was collected using household survey questionnaires, focus group discussions and key informant interviews. When household survey participants (n = 421) were asked if the number of donkeys in their herd had decreased within the last two years 34.2% (n = 144) reported a decrease, of those 43.8% (n = 63) reported the selling of donkeys as the primary cause of reduction in herd size. Increased money spent on the transportation of farm produce, water and firewood was the most frequently reported effect of the loss of donkeys (62.5%, n = 263). Some focus group discussion participants said that they had previously sold their donkeys to raise money for school fees, likewise 43% (n = 97) of focus group discussion participants said that they would sell their donkeys to pay medical bills. Results from the study suggest that small holder farmers are choosing to sell their donkeys for an instant boost in income, but long-term this is unlikely to be a sustainable livelihood option.展开更多
Animal hide chew is mainly hand crafted at home and abroad.This paper designed an automatic production equipment of animal hide chew.The equipment achieved the whole process automation from chicken breast smashing(mea...Animal hide chew is mainly hand crafted at home and abroad.This paper designed an automatic production equipment of animal hide chew.The equipment achieved the whole process automation from chicken breast smashing(meat grinding and feeding equipment),extrusion,tearing cowhide strip,rolling,wrapping chicken breast,cutting to strips,weighing and drying to packaging through automated production line,which saved a lot of manpower and material resources and leads to uniform and stable product quality.展开更多
CHINA has recently deployed unmanned drones to detect the levels of air pollution in northern areas of the country, to aid an inspection on the enforcement of environmental protection laws, according to a statement fr...CHINA has recently deployed unmanned drones to detect the levels of air pollution in northern areas of the country, to aid an inspection on the enforcement of environmental protection laws, according to a statement from the country＇s Ministry of Environmental Protection.展开更多
New Yorkbased Human Rights Watch re cently released its annual World Human Rights Report, in which it habitually points an accusing finger at other countnes＂ human nglats records. As a Chinese scholar of human right...New Yorkbased Human Rights Watch re cently released its annual World Human Rights Report, in which it habitually points an accusing finger at other countnes＂ human nglats records. As a Chinese scholar of human rights studies, I have to express my observations about the report＇s allegations against China. First, the report still takes an outdated and biased approach to judge human rights records and makes comments that are beyond reality. For instance, it continues to claim that China＇s household registration, or hukou, system, denies migrant workers＇ children the chance of a decent education. However, a regulation introduced in 2003 already allows the children of migrant workers to receive nineyear compulsory education in cities where their parents work.展开更多
Steganography has been used to prevent unauthorized access to private information during transmission.It is the scheme of securing sensitive information by concealing it within carriers such as digital images,videos,a...Steganography has been used to prevent unauthorized access to private information during transmission.It is the scheme of securing sensitive information by concealing it within carriers such as digital images,videos,audio,or text.Current steganography methods are working by assigning a cover le then embed the payload within it by making some modications,creating the stego-le.However,the left traces that are caused by these modications will make steganalysis algorithms easily detect the hidden payload.Aiming to solve this issue,a novel,highly robust steganography method based on hacking anti-shoplifting systems has proposed to hide data within clothes.The anti-Shoplifting system is an anti-theft security system that protects goods and products,leaving the store in an illegal way(i.e.,without paying for them).The proposed method works by modifying the default anti-shoplifting system by changing its built-in soft RFID(radio-frequency identication)tags sewn in clothes into NFC(Near Field Communication)tags.These NFC tags are smart tags that can communicate with NFC-Enabled smart-phones using NDEF(NFC Data Exchange Format).NDEF is one of the advancements added to RFID technology by NFC,which allows the data exchange.Every NDEF message has one/more NDEF records that contain record type,a unique ID,a length,and a payload of data that contains the secret message content that can be any type of data that ts in a byte stream.Based on NDEF and NFC-enabled smart-phones,the proposed method will take the secret message from the sender,make use of his NFC-enabled smart-phone to communicate with the NFC tag,then hide the secret message within the NDEF’s payload of the NFC tag stuck in clothes.Finally,to evaluate the proposed method,it has been compared with default(digital)steganography weak points.Such as time,lockable,robustness,attacks,capacity,and a few more points.The results and comparisons showed that the proposed method is more efcient than default(digital)steganography and has many advantages.展开更多
This paper presented an approach to hide secret speech information in code excited linear prediction (CELP)-based speech coding scheme by adopting the analysis-by-synthesis (ABS)-based algorithm of speech information ...This paper presented an approach to hide secret speech information in code excited linear prediction (CELP)-based speech coding scheme by adopting the analysis-by-synthesis (ABS)-based algorithm of speech information hiding and extracting for the purpose of secure speech communication. The secret speech is coded in 2.4 Kb/s mixed excitation linear prediction (MELP), which is embedded in CELP type public speech. The ABS algorithm adopts speech synthesizer in speech coder. Speech embedding and coding are synchronous, i.e. a fusion of speech information data of public and secret. The experiment of embedding 2.4 Kb/s MELP secret speech in G.728 scheme coded public speech transmitted via public switched telephone network (PSTN) shows that the proposed approach satisfies the requirements of information hiding, meets the secure communication speech quality constraints, and achieves high hiding capacity of average 3.2 Kb/s with an excellent speech quality and complicating speakers’ recognition.展开更多
Calcium homeostasis is crucial for muscle contractilityMuscle cells are critically dependent on calcium homeostasis. Without having the right amount of calcium ions just on the spot and coordinated in between muscle c...Calcium homeostasis is crucial for muscle contractilityMuscle cells are critically dependent on calcium homeostasis. Without having the right amount of calcium ions just on the spot and coordinated in between muscle cells, no contraction can take place. Therefore, calcium homeostasis is one of the critical regulatory mechanisms in all muscle cells, including skeletal muscle and heart [1,2]. Ca2＋ adenosine triphosphatase the relaxation of muscle cells Sarco-endoplasmic reticulum （SERCA） is responsible for by pumping Ca2＋ into the sarcoplasmic reticulum （SR） .展开更多
In this study,collagen hydrolysates were prepared by autoclaving or its combination with enzymolysis.After it,the digestion pattern and antioxidant activity were estimated in vitro gastrointestinal digestion.Three MW(...In this study,collagen hydrolysates were prepared by autoclaving or its combination with enzymolysis.After it,the digestion pattern and antioxidant activity were estimated in vitro gastrointestinal digestion.Three MW(HMW-CH,10-100 kDa;MMW-CH,1-10 kDa;LMW-CH,<1 kDa)of collagen hydrolysates were obtained.After digestion,MW of these samples decreased to some extent,while their total MW composition still show a similar tendency to the undigested samples,i.e.HMW-CH>MMW-CH>LMW-CH.From gastric to intestinal phase,DPPH radical scavenging of HMW-CH increased from 5.45%to 35.19%.However,MMW-CH and LMW-CH increased from 47.35%to 52.90%and 49.84%-64.40%in the gastric phase,and then decreased to 27.94%and 21.69%in the intestinal phase,respectively.Meantime,the reducing power of these samples was lower in the gastric phase,but increased within 15 min of intestinal phase.After,the differences decreased and the final was LMW-CH(1.030)>MMW-CH(0.914)>HMW-CH(0.872).These results indicate that the lower the MW,the higher the antioxidant activity.In addition,the binding mode of them to tannins was analyzed by thermody-namic parameters.The results suggest that the main mode of interaction between HMW-CH and MMW-CH and tannins was hydrogen bonding,whereas LMW-CH and tannin was hydrophobic.Overall,these results are helpful for us to better understand absorption process of collagen hydrolysates and provide some theoretical and technological support for collagen consumed in food and medicine.展开更多
Hide collagen of animals is used to prepare adsorbent material and its adsorption properties to tannins are investigated. It is indicated that the collagen fibres has excellent adsorption selectivity and high adsorpti...Hide collagen of animals is used to prepare adsorbent material and its adsorption properties to tannins are investigated. It is indicated that the collagen fibres has excellent adsorption selectivity and high adsorption capacity to tannins. The adsorption rate of tannins is more than 90% whilst less than 10% of functional components are retained by the adsorbent. The adsorption mechanism of tannins onto hide collagen fibres is hydrogen-bonding association. Freundlich model can be used to describe the adsorption isotherms, and the pseudo-second-order rate model can be used to describe adsorption kinetics.展开更多
Leather is a collagen-based biomass prepared from raw skins or hides by a series of unit operations, in which the unhairing and fiber opening are extremely important operations. However, the conventional Na2S/Ca(OH)2 ...Leather is a collagen-based biomass prepared from raw skins or hides by a series of unit operations, in which the unhairing and fiber opening are extremely important operations. However, the conventional Na2S/Ca(OH)2 system used in unhairing and fiber opening has given rise to the pollution to the environment. It is necessary to develop substitute technology for the Na2S/Ca(OH)2. In the present study, 1-allyl-3-methylimidazolium chloride ([AMIm]Cl) was used to cooperate with dispase for cycle unhairing and one-pot beamhouse to recycle waste bovine hides and com-pared with conventional processing. During those processes, the mechanism of [AMIm]Cl-dispase synergistic unhair-ing and collagen fibers opening were studied. Besides, plant hazard, organic matter and [AMIm]Cl of wastewater from [AMIm]Cl-dispase process were respectively investigated and separated to evaluate the environmental and economic benefits of the [AMIm]Cl-dispase process. As a result, enzyme activity after unhairing by [AMIm]Cl-diapase system for using 5 times is higher than that by KCl-dispase system, and needs lower unhairing time, which is because of rapid penetration of [AMIm]Cl-dispase solution in bovine hides. For this reason, the tensile strength and elastic modulus of tanned leather from [AMIm]Cl-dispase process are higher than those from the KCl-diapase and conventional pro-cesses, and its hydrothermal shrinkage temperature is comparable to that of the conventional one. Because of the 58.13% lower wastewater discharge (WD), 66.60% lower total solids (TS), 97.23% lower ammonia nitrogen (NH3-N), non-toxic wastewater and organic matter recovery in wastewater are reached from [AMIm]Cl-dispase process, which is expected to be an alternative to the conventional process to reduce environmental pollution and realize the sustainable development of technology for leather manufacturing.展开更多
The application and mechanism study of microwave irradiation in traditional industries have attracted considerable attention owing to the unique thermal and athermal effects that could lead to unexpected benefits in h...The application and mechanism study of microwave irradiation in traditional industries have attracted considerable attention owing to the unique thermal and athermal effects that could lead to unexpected benefits in high-efficiency and clean production.Herein,we report the investigation of the aluminum tanning under microwave irradiation upon using hide powder and skin pieces,respectively,as simulants of real hide or skin.The aluminum tanning process and the tanned products under microwave heating(MWH)were studied and compared with those of conventional water bath heating(WBH)as the controls.For the tanning system of hide powder,the tanning effluents were analyzed in terms of pH,conductivity,dielectric constant and aluminum content,and the tanned powder was investigated by differential scanning calorimetry(DSC),thermogravimetric(TG)analysis,and FT-IR spectroscopy.For the skin piece system,the pH and aluminum content of tanning effluents were also determined,and at the same time,DSC,TG,SEM,FT-IR and shrinkage temperature were used to illustrate the actions of microwaves on the structure and properties of the tanned pieces.The results show that aluminum reactivity in the penetration and binding process of collagen fibers in hide powder and skin pieces improved using microwave treatment.The residual aluminum content was greatly reduced by microwave heating action,and the increased amount of aluminum with evener distribution was observed in the tanned products.Microwave irradiation also resulted in the tanned products with better thermal stability and thermal decomposition resistance.This work further promotes application of microwave treatments for aluminumbased tanning in leather industry.展开更多
基金Supported by the Scientific Research Project of Hebei Entry-Exit Inspection and Quarantine Bureau(HE2013K030)~~
文摘The situation of intercepted alien pests from imported hides in Hebei during 2013-2014 was systematically analyzed. The results showed that 163 batches of alien pests were intercepted, including 2 batches of quarantine weeds and they both were Italian cocklebur. According to the statistics of original countries, the intercepted hides from 21 countries all had alien pests, in which Australia was the largest number of batches and species of alien pests. The analysis results showed that there was severe risk in the imported hides carrying alien pests, thus to effectively prevent the invasion of alien pests to our country, several quarantine measures should be taken in the future, such as enhancing the quarantine inspection in ports, and promoting the personnel ability of interception and species identification of alien pests.
文摘A category of chromium (Cr)-containing fertilizers is represented by the fertilizers deriving from byproducts of tanning process. Their use is widespread because of their good agronomic response due to the high content of slow release or- ganic nitrogen (N) and carbon (C). They do not represent an environmental hazard because only the non-toxic form of Cr(III) is present. Productive processes may involve chemical, enzymatic or thermal hydrolysis. The final product is characterized by different contents of peptides and free amino acids depending on the type of hydrolysis. Legislation concerning Cr-containing fertilizers is controversial because often do not consider any scientific evidences;nevertheless, the European Union, the United States and countries as Italy, do not set the restriction to Cr(III) and generally only the presence of the toxic form, Cr(VI), is limited. Depending on its two main oxidation forms, Cr issue has been studied for many years. Several authors confirmed that Cr(VI) is carcinogenic, while Cr(III) is an essential trace element in human and animal diet. In soil Cr(III) has low mobility, whereas Cr(VI) is highly water soluble. However Cr(VI) in soil is quickly reduced to Cr(III);on the contrary oxidation of Cr(III) to Cr(VI) is rarely possible because particular conditions must occur. Only a very small fraction of Cr in soil is available to plant uptake and its translocation in edible parts is limited because it is immobilized in roots as Cr(III). Therefore risks of environmental pollution using these fertilizers are negligible;on the contrary they have positive environmental and agronomical effects. The aim of this review is to deal with the category of the organic fertilizers containing Cr derived from tannery processes focusing on its chemical, productive, legislative, environmental and agronomical aspects. Special attention is given to the ambiguous issue of Cr briefly summarizing the most important studies of the last forty years.
文摘Donkey hides are used in a form of Traditional Chinese medicine called ejiao, the demand for ejiao is currently so high the global donkey population is currently in decline. Africa’s donkey population is considered a key source for the trade, with Kenya being highlighted as being particularly affected. In Kenya donkeys play a vital contribution to people’s livelihoods;this study aimed to explore the potential impact of the donkey hide trade on small holder farmer’s livelihoods. The study was conducted in five counties in Kenya;data was collected using household survey questionnaires, focus group discussions and key informant interviews. When household survey participants (n = 421) were asked if the number of donkeys in their herd had decreased within the last two years 34.2% (n = 144) reported a decrease, of those 43.8% (n = 63) reported the selling of donkeys as the primary cause of reduction in herd size. Increased money spent on the transportation of farm produce, water and firewood was the most frequently reported effect of the loss of donkeys (62.5%, n = 263). Some focus group discussion participants said that they had previously sold their donkeys to raise money for school fees, likewise 43% (n = 97) of focus group discussion participants said that they would sell their donkeys to pay medical bills. Results from the study suggest that small holder farmers are choosing to sell their donkeys for an instant boost in income, but long-term this is unlikely to be a sustainable livelihood option.
基金Supported by Basic Scientific Research Project of Wenzhou City(N20220026).
文摘Animal hide chew is mainly hand crafted at home and abroad.This paper designed an automatic production equipment of animal hide chew.The equipment achieved the whole process automation from chicken breast smashing(meat grinding and feeding equipment),extrusion,tearing cowhide strip,rolling,wrapping chicken breast,cutting to strips,weighing and drying to packaging through automated production line,which saved a lot of manpower and material resources and leads to uniform and stable product quality.
文摘CHINA has recently deployed unmanned drones to detect the levels of air pollution in northern areas of the country, to aid an inspection on the enforcement of environmental protection laws, according to a statement from the country＇s Ministry of Environmental Protection.
文摘New Yorkbased Human Rights Watch re cently released its annual World Human Rights Report, in which it habitually points an accusing finger at other countnes＂ human nglats records. As a Chinese scholar of human rights studies, I have to express my observations about the report＇s allegations against China. First, the report still takes an outdated and biased approach to judge human rights records and makes comments that are beyond reality. For instance, it continues to claim that China＇s household registration, or hukou, system, denies migrant workers＇ children the chance of a decent education. However, a regulation introduced in 2003 already allows the children of migrant workers to receive nineyear compulsory education in cities where their parents work.
文摘Steganography has been used to prevent unauthorized access to private information during transmission.It is the scheme of securing sensitive information by concealing it within carriers such as digital images,videos,audio,or text.Current steganography methods are working by assigning a cover le then embed the payload within it by making some modications,creating the stego-le.However,the left traces that are caused by these modications will make steganalysis algorithms easily detect the hidden payload.Aiming to solve this issue,a novel,highly robust steganography method based on hacking anti-shoplifting systems has proposed to hide data within clothes.The anti-Shoplifting system is an anti-theft security system that protects goods and products,leaving the store in an illegal way(i.e.,without paying for them).The proposed method works by modifying the default anti-shoplifting system by changing its built-in soft RFID(radio-frequency identication)tags sewn in clothes into NFC(Near Field Communication)tags.These NFC tags are smart tags that can communicate with NFC-Enabled smart-phones using NDEF(NFC Data Exchange Format).NDEF is one of the advancements added to RFID technology by NFC,which allows the data exchange.Every NDEF message has one/more NDEF records that contain record type,a unique ID,a length,and a payload of data that contains the secret message content that can be any type of data that ts in a byte stream.Based on NDEF and NFC-enabled smart-phones,the proposed method will take the secret message from the sender,make use of his NFC-enabled smart-phone to communicate with the NFC tag,then hide the secret message within the NDEF’s payload of the NFC tag stuck in clothes.Finally,to evaluate the proposed method,it has been compared with default(digital)steganography weak points.Such as time,lockable,robustness,attacks,capacity,and a few more points.The results and comparisons showed that the proposed method is more efcient than default(digital)steganography and has many advantages.
文摘This paper presented an approach to hide secret speech information in code excited linear prediction (CELP)-based speech coding scheme by adopting the analysis-by-synthesis (ABS)-based algorithm of speech information hiding and extracting for the purpose of secure speech communication. The secret speech is coded in 2.4 Kb/s mixed excitation linear prediction (MELP), which is embedded in CELP type public speech. The ABS algorithm adopts speech synthesizer in speech coder. Speech embedding and coding are synchronous, i.e. a fusion of speech information data of public and secret. The experiment of embedding 2.4 Kb/s MELP secret speech in G.728 scheme coded public speech transmitted via public switched telephone network (PSTN) shows that the proposed approach satisfies the requirements of information hiding, meets the secure communication speech quality constraints, and achieves high hiding capacity of average 3.2 Kb/s with an excellent speech quality and complicating speakers’ recognition.
基金supported by the German Centre for Cardiovascular Research (DZHK) and the German Ministry of Education and Research (BMBF)
文摘Calcium homeostasis is crucial for muscle contractilityMuscle cells are critically dependent on calcium homeostasis. Without having the right amount of calcium ions just on the spot and coordinated in between muscle cells, no contraction can take place. Therefore, calcium homeostasis is one of the critical regulatory mechanisms in all muscle cells, including skeletal muscle and heart [1,2]. Ca2＋ adenosine triphosphatase the relaxation of muscle cells Sarco-endoplasmic reticulum （SERCA） is responsible for by pumping Ca2＋ into the sarcoplasmic reticulum （SR） .
基金supported by the National Nature Science Foundation of China(32172249)the Research Innovation Project for Post-graduate Students of Tianjin,China(No.2022BKY136).
文摘In this study,collagen hydrolysates were prepared by autoclaving or its combination with enzymolysis.After it,the digestion pattern and antioxidant activity were estimated in vitro gastrointestinal digestion.Three MW(HMW-CH,10-100 kDa;MMW-CH,1-10 kDa;LMW-CH,<1 kDa)of collagen hydrolysates were obtained.After digestion,MW of these samples decreased to some extent,while their total MW composition still show a similar tendency to the undigested samples,i.e.HMW-CH>MMW-CH>LMW-CH.From gastric to intestinal phase,DPPH radical scavenging of HMW-CH increased from 5.45%to 35.19%.However,MMW-CH and LMW-CH increased from 47.35%to 52.90%and 49.84%-64.40%in the gastric phase,and then decreased to 27.94%and 21.69%in the intestinal phase,respectively.Meantime,the reducing power of these samples was lower in the gastric phase,but increased within 15 min of intestinal phase.After,the differences decreased and the final was LMW-CH(1.030)>MMW-CH(0.914)>HMW-CH(0.872).These results indicate that the lower the MW,the higher the antioxidant activity.In addition,the binding mode of them to tannins was analyzed by thermody-namic parameters.The results suggest that the main mode of interaction between HMW-CH and MMW-CH and tannins was hydrogen bonding,whereas LMW-CH and tannin was hydrophobic.Overall,these results are helpful for us to better understand absorption process of collagen hydrolysates and provide some theoretical and technological support for collagen consumed in food and medicine.
文摘Hide collagen of animals is used to prepare adsorbent material and its adsorption properties to tannins are investigated. It is indicated that the collagen fibres has excellent adsorption selectivity and high adsorption capacity to tannins. The adsorption rate of tannins is more than 90% whilst less than 10% of functional components are retained by the adsorbent. The adsorption mechanism of tannins onto hide collagen fibres is hydrogen-bonding association. Freundlich model can be used to describe the adsorption isotherms, and the pseudo-second-order rate model can be used to describe adsorption kinetics.
基金National Natural Science Foundation of China(No.51673177)National Key R&D Program of China(No.2017YFB0308500).
文摘Leather is a collagen-based biomass prepared from raw skins or hides by a series of unit operations, in which the unhairing and fiber opening are extremely important operations. However, the conventional Na2S/Ca(OH)2 system used in unhairing and fiber opening has given rise to the pollution to the environment. It is necessary to develop substitute technology for the Na2S/Ca(OH)2. In the present study, 1-allyl-3-methylimidazolium chloride ([AMIm]Cl) was used to cooperate with dispase for cycle unhairing and one-pot beamhouse to recycle waste bovine hides and com-pared with conventional processing. During those processes, the mechanism of [AMIm]Cl-dispase synergistic unhair-ing and collagen fibers opening were studied. Besides, plant hazard, organic matter and [AMIm]Cl of wastewater from [AMIm]Cl-dispase process were respectively investigated and separated to evaluate the environmental and economic benefits of the [AMIm]Cl-dispase process. As a result, enzyme activity after unhairing by [AMIm]Cl-diapase system for using 5 times is higher than that by KCl-dispase system, and needs lower unhairing time, which is because of rapid penetration of [AMIm]Cl-dispase solution in bovine hides. For this reason, the tensile strength and elastic modulus of tanned leather from [AMIm]Cl-dispase process are higher than those from the KCl-diapase and conventional pro-cesses, and its hydrothermal shrinkage temperature is comparable to that of the conventional one. Because of the 58.13% lower wastewater discharge (WD), 66.60% lower total solids (TS), 97.23% lower ammonia nitrogen (NH3-N), non-toxic wastewater and organic matter recovery in wastewater are reached from [AMIm]Cl-dispase process, which is expected to be an alternative to the conventional process to reduce environmental pollution and realize the sustainable development of technology for leather manufacturing.
基金Financial support from the National Natural Science Foundation(No.21576171)the Science&Technology Department of Sichuan Province(No.2018HH0038)is gratefully acknowledgedfunded by the Innovation Training Program for college students of Sichuan University(C2020107809).
文摘The application and mechanism study of microwave irradiation in traditional industries have attracted considerable attention owing to the unique thermal and athermal effects that could lead to unexpected benefits in high-efficiency and clean production.Herein,we report the investigation of the aluminum tanning under microwave irradiation upon using hide powder and skin pieces,respectively,as simulants of real hide or skin.The aluminum tanning process and the tanned products under microwave heating(MWH)were studied and compared with those of conventional water bath heating(WBH)as the controls.For the tanning system of hide powder,the tanning effluents were analyzed in terms of pH,conductivity,dielectric constant and aluminum content,and the tanned powder was investigated by differential scanning calorimetry(DSC),thermogravimetric(TG)analysis,and FT-IR spectroscopy.For the skin piece system,the pH and aluminum content of tanning effluents were also determined,and at the same time,DSC,TG,SEM,FT-IR and shrinkage temperature were used to illustrate the actions of microwaves on the structure and properties of the tanned pieces.The results show that aluminum reactivity in the penetration and binding process of collagen fibers in hide powder and skin pieces improved using microwave treatment.The residual aluminum content was greatly reduced by microwave heating action,and the increased amount of aluminum with evener distribution was observed in the tanned products.Microwave irradiation also resulted in the tanned products with better thermal stability and thermal decomposition resistance.This work further promotes application of microwave treatments for aluminumbased tanning in leather industry.
