Waste Cotton-Derived Fiber-Based Thermoelectric Aerogel for Wearable and Self-Powered Temperature-Compression Strain Dual-Parameter Sensing

The rapid development of the global economy and population growth are accompanied by the production of numerous waste textiles.This leads to a waste of limited resources and serious environmental pollution problems caused by improper disposal.The rational recycling of wasted textiles and their transformation into high-value-added emerging products,such as smart wearable devices,is fascinating.Here,we propose a novel roadmap for turning waste cotton fabrics into three-dimensional elastic fiber-based thermoelectric aerogels by a one-step lyophilization process with decoupled self-powered temperature-compression strain dual-parameter sensing properties.The thermoelectric aerogel exhibits a fast compression response time of 0.2 s,a relatively high Seebeck coefficient of 43μV·K^(-1),and an ultralow thermal conductivity of less than 0.04 W·m^(-1)·K^(-1).The cross-linking of trimethoxy(methyl)silane(MTMS)and cellulose endowed the aerogel with excellent elasticity,allowing it to be used as a compressive strain sensor for guessing games and facial expression recognition.In addition,based on the thermoelectric effect,the aerogel can perform temperature detection and differentiation in self-powered mode with the output thermal voltage as the stimulus signal.Furthermore,the wearable system,prepared by connecting the aerogel-prepared array device with a wireless transmission module,allows for temperature alerts in a mobile phone application without signal interference due to the compressive strains generated during gripping.Hence,our strategy is significant for reducing global environmental pollution and provides a revelatory path for transforming waste textiles into high-value-added smart wearable devices.

The addition of microbes for treating textile wastewater

Some strains and culture of bacteria which are able to decolorize dyes and degrade polyvinyl alcohol(PVA) were isolated and selected. A pilot scale facultative anaerobic-aerobic biological process was applied for treatment of textile wastewater containing dyes and PVA. Activated carbon adsorption was used as a tertiary treatment stage, and residual sludge from clarifier returned to the anaerobic reactor again. The pilot test were carried out with two systems. One was inoculated by acclimated sludge, and the another was adding the mixed culture of dye-decoloring and PVA-degrading bacteria for forming biological films, the latter was observed to be more effective than the former. The test has run normally for ten months with a COD loading of 2.13 kg/m3/day, a BOD5 loading of 0.34 kg/m3/day in anaerobic reactor; a COD loading of 1.71 kg/m3/day, a BOD5 loading 0.44 kg/m3/day in aerobic reactor. The pollutants removal efficiency by adding microbes was about 20% higher than that by acclimated sludge. The average removal efficiency of COD stood about 92%, BOD5 97%, PVA 90% and decolorization 80%. The other parameters of effluent quality are also satisfactory.

Analysis of Post-Consumer Solid Textile Waste Management among Households in Oyo State of Nigeria

This research work viewed issues relating to post-consumers’ solid textile waste management among households from a sociological perspective. The study was carried out in Oyo state of Nigeria. It specifically identified sources of post-consumer solid textiles waste, assessed waste management practices in the study area and, examined knowledge of respondent’s on impact of post-consumers solid textile waste on the environment. Eight Local Government Areas were randomly selected from the state and, multistage random sampling procedure was applied in selecting 880 households for the study. Solid wastes generated by each of this household were collected twice a week. Sensitive and micro-census calibrated scale machine and weighing balance was employed in taking weight of the sorted textile wastes. Calibrated cylinder of radius 10 cm and height 40 cm was used in taking volume of the shredded waste. Mean value of post-consumer solid textile waste generated by individual was 0.11 kg ± 0.08, of volume 354 cm3 per day. Major identified waste disposal systems practiced by the respondents were open land surface dumping and open air burning. The respondents (100%) strongly agreed that, wastes are often discards indiscriminately in the street by individuals. Level of awareness on danger created by poor waste disposal system among 78% of the respondents was low. None of the respondents have training on waste management neither is there any accessible training center in the studied area. Part of procedures to solve environmental problems can be by raising levels of awareness of individual household’s, markets and institutional sectors on danger posed by poor handling of textile wastes to life and the environment, and be trained on waste management techniques. A functional and practically ideal waste management scheme should be established by the various organs of government mostly at the Local Government Area levels, and some investors could also be encouraged in instituting such schemes. Research institutes in the country should develop appropriate technologies and trainings on waste management. Apart from salvaging the environment, such schemes will also provide job to cushion poverty mitigation in Nigeria.

Visualization of the Motion of Textiles through a Waste Water Pump at Different Operating Points

In this paper,?the motion of textiles through a waste water pump is studied by aid of vision technologies. The steel volute of a commercial pump is replaced with a similar volute made in acrylic glass, which allows recording the motion of textiles inside the pump. Recordings are made at four different operating points to investigate the influence of rotational speed of the impeller and flow?rate on the passage of textiles through the pump. The experiments show that the textiles flow rapidly through the pump when the pump is operated near the best efficient point for both high and low impeller speed. The textiles tend to stay inside the pump when the pump is operated at part load for both low and high impeller speed.?At?low impeller speed,?the textiles often stick to the tongue in the pump casing. At higher impeller speed,?the textiles flow multiple rounds in the volute. For fail-safe operation,?it is recommended not to operate waste water pumps far away from the best efficiency point.

Minimization of Air Consumption and Potential Savings of Textile Denim Fabric Manufacturing Process

One of the most important aspects of Bangladesh’s textile industry is denim. Bangladesh now has a new opportunity thanks to the global demand for denim among fashion industry professionals. Entrepreneurs from Bangladesh provide denim products to well-known international merchants all over the world. The worldwide denim market is predicted to expand by roughly 8% through the year 2020. We must raise the standard of denim if we are to keep up with the expanding industry. In contrast to projectile and rapier systems, air-jet weaving machines nowadays can weave practically all types of yarns without any issues and at higher rates. Due to this, air-jet looms are an excellent substitute for other weft insertion techniques. This kind of device still has one significant flaw, though, and that is the enormous power consumption brought on by the creation of compressed air. Researchers and manufacturers of air-jet looms have therefore worked very hard to find a solution to this issue and achieve a huge reduction in air consumption without compromising loom performance or fabric quality. Therefore, the purpose of this project is to look into ways to decrease air consumption and reduce auxiliary selvedge waste without any decrease in loom performance and fabric quality on existing air-jet weaving looms which reduce the manufacturing costs with process improvement. Just updating the air pressure allowed a weaving mill to reduce air usage by 11 cfm. So, with just almost no cost, a company with 100 looms could save $0.15 M each year, on compressed air. Two new methods for decreasing process costs on air jet looms have also been developed by this project work.

Converting textile waste into value-added chemicals:An integrated bio-refinery process

The rate of textile waste generation worldwide has increased dramatically due to a rise in clothing consumption and production.Here,conversion of cotton-based,colored cotton-based,and blended cotton-polyethylene terephthalate(PET)textile waste materials into value-added chemicals(bioethanol,sorbitol,lactic acid,terephthalic acid(TPA),and ethylene glycol(EG))via enzymatic hydrolysis and fermentation was investigated.In order to enhance the efficiency of enzymatic saccharification,effective pretreatment methods for each type of textile waste were developed,respectively.A high glucose yield of 99.1%was obtained from white cotton-based textile waste after NaOH pretreatment.Furthermore,the digestibility of the cellulose in colored cotton-based textile wastes was increased 1.38e1.75 times because of the removal of dye materials by HPAC-NaOH pretreatment.The blended cotton
PET samples showed good hydrolysis efficiency following PET removal via NaOHeethanol pretreatment,with a glucose yield of 92.49%.The sugar content produced via enzymatic hydrolysis was then converted into key platform chemicals(bioethanol,sorbitol,and lactic acid)via fermentation or hydrogenation.The maximum ethanol yield was achieved with the white T-shirt sample(537 mL/kg substrate),which was 3.2,2.1,and 2.6 times higher than those obtained with rice straw,pine wood,and oak wood,respectively.Glucose was selectively converted into sorbitol and LA at a yield of 70%and 83.67%,respectively.TPA and EG were produced from blended cotton
PET via NaOHeethanol pretreatment.The integrated biorefinery process proposed here demonstrates significant potential for valorization of textile waste.

Textile waste-an opportunity as well as a threat

Clothing and textiles are very challenging to recycle due to the fact that they are nearly always a blend of fibres from different types of polymers.There are some promising early indications that new green solvents including CyreneTM and TMO as well as some simple ionic liquids can be used to aid recycling of complex fabrics by selective dissolution of one of the component polymers.A viable process for the future valorisation of many waste fabrics should be designed to maximise the creation of valuable product streams while also minimising any waste.

Study on textile waste generation in the undifferentiated municipal solid waste stream in Guimarães,Portugal

Guimarães is a middle sized city and municipality located in northern Portugal.The municipality has committed to reducing the annual amount of undifferentiated municipal solid waste(MSW)from 371 kg/capita in 2021 to 120 kg/capita by 2030 under the Zero Waste Cities Certification process.In the municipality of Guimarães,one of the constant fractions of MSW composition is textile waste(TW),which the revised EU Waste Framework Directive requires separate collection by 1 January 2025.Therefore,two indicators of TW generation were analysed to identify waste collection routes with a high level of textile waste generation for the priority implementation of separate collection:TW composition in the undifferentiated MSW stream and TW generation per capita.Basic statistical analysis methods were used to process the source data of TW composition in the undifferentiated MSW stream.Cluster analysis was applied to the data set on TW generation per capita,considering the area typology(urban,rural or mixed)of collection routes.It was considered that 39%of the industrial sector of Guimarães consists of textile and clothing production and represents small-and medium-sized enterprises,which can affect TW generation in the undifferentiated MSW stream.Causal-comparative research was used to define the correlation between TW generation per capita and the economic activity of the textile and clothing industry in the municipality.As a result,applying a multi-disciplinary approach,a project of the Textile Waste Generation Map was presented.

基于迁移学习的棉/毛纤维自动识别方法

针对纺织品废料中织物纤维手工分类存在效率低、主观性强等问题,提出了一种小样本条件下纺织品废料中棉/毛纤维的自动识别方法。首先使用扫描电子显微镜,对已有的棉/毛纤维进行拍照,形成小样本棉/毛纤维图像集;然后分别加载4种经ImageNet数据集训练过的模型进行迁移学习,保留或部分微调模型的网络参数,并基于小样本图像集进行训练和验证,生成棉/毛纤维的分类模型;最后基于准确率、精确率和召回率评价指标,对各种分类模型进行对比测试,选出最优分类模型,实现棉/毛纤维的自动识别。经过实验发现ResNetXt50模型在模型训练过程中取得了最高的精确率,其值为97.33%。对测试集进行测试,结果显示通过微调后的4种分类模型中,ResNet50和ResNetXt50的测试准确率可达99.537%,验证了方法的有效性。

废旧涤纶纺织品回收BHET聚合及再生切片纺丝性能研究

为实现废旧涤纶纺织品的产业化循环利用,在前期小试研究的基础上,以公斤级废旧涤纶纺织品为原料,通过乙二醇(EG)蒸气脱色、EG醇解、回收对苯二甲酸乙二醇酯(BHET)纯化及缩聚制得百克级再生聚对苯二甲酸乙二醇酯(PET)切片,并对再生PET切片进行模拟熔融纺丝,研究了回收BHET的纯度及色度、再生PET切片的结构及性能、再生PET初生纤维的性能。结果表明:回收BHET的纯度为98.69%、色度L值为99.46,其品质优于市售石油基BHET;由回收BHET聚合制备的再生PET的特性黏数为0.681 dL/g,端羧基含量为15 mol/t,色度L值为89.59、a值为-1.82、b值为2.99,各项指标均达到纤维级切片国家标准要求;制备的再生PET初生纤维的断裂强度为0.78 cN/dtex、断裂模量为0.42 cN/dtex、断裂伸长率为182.98%,与石油基PET初生纤维的断裂强度、断裂模量及断裂伸长率相当;本回收方法为实现废旧涤纶纺织品“纤维到纤维”的化学法循环利用提供了可行新途径。

废旧纺织品脱色简易方法

针对废旧纺织品回收后的脱色处理进行研究。由于废旧纺织品组分复杂多样,染色所用染料也各有不同。研究废旧纺织品中占比较大的涤、纤维素类纤维织物的脱色工艺,采用比较简易的脱色工艺处理,脱色率基本达到80%左右,可以结合后续面料回收利用的途径进行适宜的脱色处理。

一种生成对抗网络半监督回归的废纺样品中羊毛含量的预测方法

针对废旧纺织品回收在线分拣的需求,提出了一种基于生成对抗网络的半监督回归方法,使用少量标记样本和大量未标记样本来训练半监督回归器。半监督回归器由神经网络组成的生成器和由神经网络构成的判别器组成。生成器用于生成尽可能接近实际标记和未标记训练数据集内容的混合样本。鉴别器用于验证生成器生成的样本并预测这些样本的连续标记。生成的网络通过特征匹配损失进行训练,损失函数是鉴别器中间层真实样本的输出与生成样本之间的误差平均值。判别式有两个输出,一个用于预测序列标记,另一个用于确定生成的样本是真样本还是假样本的概率。通过使用传统的无监督生成对抗性网络损失函数和监督回归损失的组合来训练判别式。生成的网络通过特征匹配损失进行训练,损失函数是鉴别器中间层真实样本的输出与生成样本之间的误差平均值。先后收集了400个不同羊毛含量的混纺样品和3000个未知成分的混纺样品。70%的标记和未标记的混合样本被随机选择作为训练集,其余30%的标记样本被用作重复实验的测试集。开展了多个实验进行验证。第一个实验为混纺光谱生成实验,用于验证生成对抗网络能够根据内在规律有效生成混合样本光谱。第二个实验为半监督对抗网络定量分析性能对比实验,对羊毛成分分析模型训练与测试,并将本半监督对抗网络定量分析模型与其他定量模型进行性能对比。第三个实验为现场高羊毛含量混纺细分模型预测对比实验,用羊毛含量在80%到99%之间的混纺样品进行成分分析,并将本文的半监督对抗网络定量分析模型与其他定量模型进行性能对比。第四个实验为中高羊毛含量混纺细分综合模型现场预测实验,用羊毛含量在40%到99%之间的混纺样品训练半监督对抗网络定量分析模型并部署在分拣系统,由操作员进行现场测试数据进行准确率、分析时间等测试。实验结果表明,基于生成对抗网络的半监督回归方法优于PCR、PLSR、SVR、BPNN等模型,该模型的预测R2达到0.964。经过现场反复测试,该模型能快速提取出40%以上羊毛含量的混纺样品。

废旧棉纺织品再生浆绿色制备及性质研究

随着纺织品的生产和消费量日益增加,每年产生数千万吨废旧纺织品。现有废旧纺织品回收技术主要以物理方法为主,再生利用少,产品品质低,亟需发展新型废旧纺织品再生利用方法。本文探讨了以废旧棉纺织品为原料制备再生棉浆纤维的新方法,通过改变再生浆制备工艺实现对再生浆的聚合度、白度等特性高效调控。通过蒸煮制浆等流程,实现对废旧棉纺织品的高效利用及再生浆制备,为缓解原生浆制备过程中的原料短缺等问题提供了新思路。在造纸、纺织、功能纤维制备等领域有广泛应用前景。

K_(2)CO_(3)/KOH协同醇解废弃涤纶纺织品及其制备再生DMT的研究

废弃涤纶纺织品囤积量逐年上升,而对废弃涤纶纺织品的综合利用回收率却较低。化学法回收中乙二醇醇解-甲醇酯交换法是一种回收废弃涤纶纺织品的方法,然而乙二醇醇解-甲醇酯交换工艺过程中存在对苯二甲酸双羟基乙酯(BHET)单体产率低、低聚物含量高的问题。文章采用K_(2)CO_(3)/KOH协同醇解废弃涤纶纺织品,并结合响应面法优化了醇解工艺参数,通过甲醇酯交换法制得再生对苯二甲酸二甲酯(DMT),研究了K_(2)CO_(3)/KOH协同醇解对乙二醇醇解-甲醇酯交换产物的影响。结果表明,随着KOH添加量的增加,醇解产物中BHET含量呈现先增加后下降的趋势。当KOH的添加量达到2%时,BHET含量达到最高70.2%。同时,优化后的醇解工艺参数为:反应温度210℃、反应时间120 min、K_(2)CO_(3)质量分数2.0%、KOH质量分数2.4%。此时BHET的收率为73.1%;醇解产物与甲醇酯交换得到再生DMT产率为80.1%,通过减压升华纯化后得到再生DMT含量高于99%以上。

基于再生对苯二甲酸二甲酯制备阻燃聚酯纤维

文中以再生对苯二甲酸二甲酯(r-DMT)和乙二醇(EG)为原料、以2-羧乙基苯基次磷酸(CEPPA)为阻燃剂,采取共聚合的策略合成了阻燃再生聚对苯二甲酸乙二醇酯(rFR-PET)切片,并通过熔融纺丝技术制备了83 dtex/36 f规格的阻燃再生聚酯纤维。研究发现,CEPPA的引入使得聚酯的缩聚变得困难,阻燃再生PET相较于未改性的再生PET端羧基含量增大、二甘醇含量降低、亮度L值下降、黄蓝色度b值增大、热稳定性和结晶性下降。通过极限氧指数(LOI)测试和垂直燃烧性能(UL-94)分析得知,再生PET经阻燃改性后,LOI值由22.1%提高至32.7%,UL-94垂直燃烧等级从V-2级提升至V-0级,阻燃性能大幅提升。阻燃再生PET切片可纺性优异,通过熔融纺丝工艺制备的纤维具有良好的力学性能。为利用r-DMT开发下游高值化再生聚酯材料提供了有益参考。

废旧天丝溶解液流变及固化方式的研究

为了探讨废旧天丝溶解液的流变及固化方式,采用HEC来改变废旧天丝溶解液的流变性,制备出质量分数为1%、2%、3%、4%、5%、6%和7%的七种的打印液,通过流变性能测试,得出溶液均具有剪切稀化性。通过单因素试验对打印工艺进行优化,确定优化后的打印工艺为:浆料挤出速度2.0 mm/s,针头移动速度20 mm/s,针头直径0.31 mm。采用直接墨水书写(Direct Ink Writing,简称DIW)技术将制备的七种液体进行打印,通过成形情况确定出较优浓度为4%、5%和6%。采用冷冻干燥、热固化和光固化对打印织物进行固化研究,通过收缩变形、颜色气味确定出最优浓度为6%,并优选热固化和冷冻干燥固化这两种固化方式,对其打印织物的性能进行测试和表征。结果表明,冷冻干燥织物表面有小而尖锐的凸起,截面呈现横向层状结构;热固化织物表面较大而平的突起较冷冻干燥固化方式舒适度更好,截面有均匀致密的竖向片状结构;冷冻干燥固化织物和热固化织物的红外光谱基本一致;与织物脱色前后的X射线图谱比较,两种固化方式的打印织物纤维素Ⅱ型和纤维素Ⅲ型的特征衍射峰转换成了混合晶型的特征峰,且特征峰宽而窄,衍射能力弱;两种固化方式表现出相似的热学性能。

加速溶剂萃取-固相萃取净化-GC/MS法测定纺织固废中16种多环芳烃

建立了加速溶剂萃取-固相萃取净化-气相色谱-质谱(ASE-SPE-GC/MS)的方法,用于纺织固体废物中16种多环芳烃(PAHs)的定性和定量分析。以丙酮-正己烷(V(丙酮)∶V(正己烷)=1∶1)作为萃取剂,采用L_(9)(3^(4))正交实验法对加速溶剂萃取条件进行选择和优化,提取液经MIP-PAHs固相萃取柱富集和净化,GC/MS进行测定,外标法定量。结果表明:16种PAHs在0.1~5 mg/L范围内线性良好,相关系数为0.9932~0.9998,检出限为0.82~1.95μg/kg,定量限为3.28~7.80μg/kg。在0.1、2、5 mg/L加标水平下,16种PAHs的回收率为73.7%~103.8%,日内相对标准偏差为0.7%~8.2%,日间相对标准偏差为1.4%~9.1%,满足分析检测的要求。ASE-SPE-GC/MS方法操作简便、干扰度低,适用于纺织固体废物中PAHs的检测分析。

废旧涤/棉混纺织物回收再利用研究进展

随着人们生活水平不断提升,服装更换周期缩短,废旧纺织品的处理问题日益凸显。文章针对目前废旧涤/棉混纺织物量大但回收利用率低的现状,主要介绍了此类织物回收再利用的常用方法,详细阐述了醇解法、离子液体法、水热法分离涤棉的研究进展,并对回收利用废旧涤棉纺织品的前景进行了展望。

再生无色聚对苯二甲酸丁二醇酯-co-碳酸丁二醇酯流变性能研究

有色废旧聚酯纺织品经乙二醇(EG)醇解后,与甲醇(MeOH)酯交换并脱色提纯,得到无色对苯二甲酸二甲酯(DMT);DMT再与1,4-丁二醇(BDO)酯交换得到无色对苯二甲酸双羟基丁二醇酯(BHBT);BHBT与碳酸二甲酯(DMC)和BDO酯交换,得到双甲基碳酸丁二醇酯(BMBC),通过缩聚反应制备出再生无色聚对苯二甲酸丁二醇酯-co-碳酸丁二酯(clr-PBCT)共聚酯。采用毛细管流变仪分别对clr-PBCT60和clr-PBCT70的熔融流变性能进行了测试。结果表明:2种clr-PBCT共聚酯的熔体呈现剪切变稀现象,具有非牛顿流体的流动特征;当剪切速率小于1100 s^(-1)时,clr-PBCT60的可纺性要优于clr-PBCT70;二者的非牛顿指数n均小于1,且随着测试温度的提高而增大;其粘流活化能(ΔE_(η))则随剪切速率的增加而减小,且clr-PBCT60共聚酯的ΔE_(η)明显低于clr-PBCT70;当剪切速率小于1100 s^(-1)时,clr-PBCT60样品熔体的结构黏度指数低于clr-PBCT70样品,剪切速率增大时则相反。

基于PCA+KNN和kernal-PCA+KNN算法的废旧纺织物鉴别

该研究采集了15类废旧纺织物的4 998张近红外谱图,以7∶3的比例分为训练集和验证集,并分别采用主成分分析(PCA)与核主成分分析(kernal-PCA)两种不同降维方法对数据进行降维,并选用余弦相似度(cosine)核作为kernal-PCA的最佳核函数,最后分别将PCA和kernal-PCA降维处理后的数据进行k-近邻算法(KNN)训练。结果表明,kernal-PCA+KNN的模型准确率(95.17%)优于PCA+KNN模型的准确率(92.34%)。研究表明,kernal-PCA+KNN算法可以实现15类废旧纺织物识别准确率的提升,为废旧纺织物在线近红外自动分拣提供有力的技术支撑。