Hydrothermal Treatment of Wool Fibers with Tetrabutyl Titanate and Chitosan

In order to improve the dye depth of TiO₂-modified wool fibers, chitosan is incorporated with tetrabutyl titanate in preparing the nanosized TiO₂ particles, which are loaded on the surfaces of wool fibers, during hydrothermal process. The TiO₂ coated wool fibers are subsequently dyed with Lansol Blue 3G. The structural changes of wool fibers before and after treatments are characterized by several techniques, such as field emission scanning electron microscope, energy-dispersive X-ray, transmission electron microscope, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, thermal gravimetric analysis, and diffuse reflectance spectrum. The properties of tensile, antibacterial activity, yellowness and whiteness indices, dye uptake, K/S value, color fastness to washing, rubbing, and artificial light are also compared. It is found that the as-prepared TiO₂ particles with pure anatase phase are easy to agglomerate because of the introduction of chitosan. Meanwhile, the aggregated particles are deposited on the surface of wool fibers via a simple hydrothermal route. Compared with the original wool fibers, the thermal behaviors of the TiO₂ coated wool fibers change slightly. The performances of UV protection, antibacterial activity, dyeing depth, and color fastness to wet rubbing and artificial light are improved to some degree. However, the tensile properties of wool fibers decrease but not too much.     

Microstructure and adhesive properties of TiO2 coating on PU and PVC leathers

Titanium dioxide (TiO₂) films were deposited onto polyurethane (PU) and polyvinyl chloride (PVC) leather by magnetron sputtering, respectively. The crystal structure of the prepared film was studied using X-ray diffraction (XRD) and the surface morphology of the TiO₂ films was investigated by scanning electron microscopy (SEM) and atomic force microscope (AFM). The SEM and AFM observations revealed that the surface roughness of the substrates was an extremely important influencing factor on the morphology of the TiO₂ films. Moreover, a calculation formulation on the weight loss of per peeling force was proposed to determine the bonding strength between the TiO₂ films and the substrates. It was found that the adhesive performance of the TiO₂ nanofilms coating on PVC leather was better than that on the substrate of the PU leather.     

Al2O3负载ZnO催化臭氧氧化处理造纸废水的研究

将ZnO负载在Al₂O₃上,制备用于催化臭氧降解造纸废水中有机物的催化剂(Al₂O₃@ZnO);采用场发射扫描电子显微镜(SEM)和X射线衍射仪(XRD)对Al₂O₃@ZnO催化剂进行物相分析;研究了造纸废水的初始pH值、反应时间和催化剂用量对Al₂O₃@ZnO催化臭氧氧化处理造纸废水效果的影响;并进行了自由基捕集剂叔丁醇实验,以探讨降解造纸废水中有机物的主要因素。结果表明,本研究成功制备了具有良好催化性能的Al₂O₃@ZnO催化剂;在造纸废水初始pH值为11、催化剂用量为2.0 g/L、反应时间为60 min的条件下,Al₂O₃@ZnO催化剂对造纸废水中COD_Cr的去除率可达到84.6%,与单独使用臭氧氧化方法相比,COD_Cr去除率明显提高,且COD_Cr的动力...     

Study on the properties of woolen fabric treated with chitosan/TiO2 sol

In order to improve the color yield and color fastness to light, woolen fabrics were treated with chitosan and TiO₂ sol at first, and then dyed using C.I. Acid Blue 7 dye. The woolen fabric samples before and after treatment were investigated by means of scanning electron microscope and energy dispersive spectroscopy, thermal analysis, and Fourier transform infrared spectroscopy. The reflectance spectrum, color yield K/S value and color fastness to light were also measured. The results show that compared with the untreated woolen fabric, the thermal stability of woolen fabric treated with chitosan/TiO₂ sol is improved. The protection against ultraviolet radiation, color yield K/S value, and color fastness to light are also improved.     

Migration of titanium dioxide from PET/TiO2 composite film for polymer-laminated steel

PET/TiO₂ composite film is the most widely used film for polymer-laminated steel, and the migration of TiO₂ is very important for the safety evaluation of its packaged food. Microwave digestion, wet digestion and dry ashing were used for pretreatment of composite film to determine the content of TiO₂ in composite film. Migration tests were carried out at 40°C, 60°C and 80°C 4% using acetic acid and 50% ethanol as the acid and ester food simulants. The migration amount of TiO₂ was determined by inductively coupled plasma optical emission spectrometry (ICP-OES). With increasing temperature and time, the migration of TiO₂ increased. In 4% acetic acid, the migration amount of TiO₂ at 40°C for 10 days was 1.88 mg kg^?1 and the migration amount at 80°C for 8 h was 3.32 mg kg^?1, indicating that the effect of temperature on migration was more obvious. Under the same conditions, the migration amount of TiO₂ in 4% acetic acid was greater than in 50% ethanol. X-ray diffraction (XRD), scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimeter (DSC) were used to analyse the crystal structure, morphology, chemical groups and thermal properties of the film before and after the migration tests. The results showed that filmTiO₂ had a stable rutile type crystal structure and it was almost uniformly distributed. PET and TiO₂ were combined with strong chemical bonds. After TiO₂ migration, the crystallinity and the glass transition temperature (Tg) of the film decreased, but the change of melting temperature (Tm) was not obvious.     

稻草低温p-TsOH制浆性能研究

对稻草进行对甲苯磺酸(p-TsOH)一步法制浆和两步法制浆,并与碱法制浆进行对比,探讨了p-TsOH法制浆的可行性。结果表明,与碱法稻草浆相比,p-TsOH稻草浆的得率更高,成纸的松厚度及强度更好;p-TsOH两步法制浆可以进一步提高木质素脱除率,且浆料纤维断裂少,平均纤维长度更长。其中,稀碱-p-TsOH两步法制浆(N-P45T70t60)比p-TsOH一步法制浆(P45T70t60)的木质素脱除率高12.7个百分点,成纸的抗张指数和耐破指数分别高4.52 N·m/g和0.653 kPa·m~2/g,耐破指数与碱法稻草浆成纸相当。     

纳米TiO2光催化氧化技术在造纸废水处理中的应用

TiO2光催化氧化是一种新兴的高效水处理技术，其在处理废水中的难降解毒性有机污染物等方面具有广阔的应用前景。文章介绍了纳米TiO2光催化氧化技术的原理、影响因素及其在制浆造纸废水处理方面的研究进展，并对存在的问题作了探讨。     

Proteases pretreatment on wool to enhance durable antimicrobial and UV protection with nano TiO2 and polycarboxylic acids using RSM

In this research, protease pretreated wool fabric (PWF) was treated with butane tetra carboxylic acid (BTCA), citric acid (CA), and nano TiO₂ (NTO) to produce fabric with enhanced durable antimicrobial and ultraviolet (UV) protection properties. However, treatment of proteases enzymatic wool with NTO/CA/BTCA has not been informed. The NTO particles were stabilized on the enzymatic wool surface using CA/BTCA cross-linking agents. In order to create optimum UV protection (UP) based on (ΔE^?) and bacteria reduction against gram-positive and gram-negative bacteria, the appropriate models were obtained based on Design-Expert software. The roles of CA, BTCA, and NTO concentrations in UP and antimicrobial properties of the PWF were investigated using response surface methodology. Overall, the protease pretreatment of the wool fabrics made the improvement of the antimicrobial activity against Staphylococcus aureus and Escherichia coli bacteria, and also caused the remarkable enhancement of UP properties as compared with control samples. Also, reflectance spectra analyses (200–400?nm) and scanning electron microscopy were employed to confirm the NTO particles on the pretreated wool surface.     

Ag掺杂TiO2光催化剂的制备及其处理造纸废水研究

采用溶胶-凝胶法制备Ag掺杂TiO_2(Ag-TiO_2)光催化剂,采用X射线衍射仪(XRD)、紫外-可见分光光度计(UV-vis)、扫描电子显微镜(SEM)、能谱仪(EDS)对所制备Ag-TiO_2光催化剂进行表征,并用该光催化剂处理中段造纸废水,以降低造纸废水的COD_(Cr)和色度。探讨了Ag掺杂量、造纸废水初始pH值、光催化剂用量和光照时间对处理效果的影响。结果表明,Ag掺杂后TiO_2的结晶度下降,Ag-TiO_2的禁带宽度随Ag掺杂量的增大而减小。废水处理结果表明,当造纸废水初始p H值为6、光催化剂用量为0.6 g/L、Ag掺杂量为3%时,Ag-TiO_2光催化效果最佳,光照12 h后,造纸废水的色度和COD_(Cr)去除率分别达到100%和81.3%。     

N掺杂TiO2纳米管阵列膜光催化剂制备及其处理造纸废水的研究

本研究通过阳极氧化技术制备了N掺杂TiO_2纳米管阵列膜光催化剂,用于光催化处理造纸废水中的有机物。采用场发射扫描电子显微镜(FESEM)、X射线衍射仪(XRD)和紫外可见分光光度计(UV-Vis)对光催化剂表面形貌和化学组成等特征进行了表征。结果表明,当阳极氧化电压为40 V时,TiO_2纳米管阵列膜具有高度有序的形貌,其孔径和纳米管长度达到一个最佳状态;该TiO_2光催化剂的晶型为锐钛矿型,且从UV-Vis的结果来看,其吸收带边发生了明显的红移,对光有很强的吸收能力。将制备的光催化剂用于光催化造纸废水,当光催化剂用量为2.5 g/L,光照时间为60 min时,COD_(Cr)去除率达到80.1%,色度去除率达到90.2%。     

改性TiO2的制备及其在壁纸中的应用研究

以纳米TiO_2 (P25)为改性对象,通过简单的一步水热法制备了具有可见光催化活性的N掺杂改性P25光催化剂 (N-P25),借助X射线衍射仪、紫外-可见光谱仪和扫描电子显微镜对N-P25的结构进行表征;再将其涂布于壁纸上,通过对壁纸物理性能和光催化降解甲醛性能的综合对比选择最佳涂布工艺。结果表明,N-P25仍为混晶结构,但对可见光的响应得到提升。在最佳涂布工艺条件下,N-P25涂布量1. 5g/m~2的壁纸在日光灯照射6 h后,对甲醛的降解率可达87%;且对不同初始浓度甲醛的光催化降解符合LH一级反应动力学规律。     

纳米TiO2胶体光催化-磁絮凝回收深度处理造纸废水

以纳米TiO₂(Nano-TiO₂)为光催剂、Fe₃O₄/SiO₂(FS)为磁性絮凝剂,提出了一种通过调节p H值来实现Nano-TiO₂磁絮凝回收及解絮凝释放的回收再利用系统;研究了FS/Nano-TiO₂质量比和相同质量比下Nano-TiO₂浓度对系统絮凝性能的影响,考察了造纸废水预处理方式对Nano-TiO₂光催化-磁絮凝回收循环光降解性能的影响。结果表明,FS/Nano-TiO₂质量比越大或相同质量比下Nano-TiO₂浓度越高,两者形成的FS/Nano-TiO₂絮凝体的沉降速率越快,越有利于Nano-TiO₂的磁絮凝回收;经浓度为0.6 g/L Nano-TiO₂絮凝处理后的造纸废水(SBR-T)在光催化降解180 min后,其COD_Cr、固体悬浮物、...     

Use of titanium dioxide (TiO2) photocatalysts as alternative means for Listeria monocytogenes biofilm disinfection in food processing

The aim of this work was to study the photocatalytic activity of titanium dioxide (TiO₂) against Listeria monocytogenes bacterial biofilm. Different TiO₂ nanostructured thin films were deposited on surfaces such as stainless steel and glass using the doctor-blade technique. All the surfaces were placed in test tubes containing Brain Heart (BH) broth and inoculated with L. monocytogenes. Test tubes were then incubated for 10 days at 16 °C in order to allow biofilm development. After biofilm formation, the surfaces were illuminated by ultraviolet A light (UVA; wavelength of 315-400 nm). The quantification of biofilms was performed using the bead vortexing method, followed by agar plating and/or by conductance measurements (via the metabolic activity of biofilm cells). The presence of the TiO₂ nanoparticles resulted in a fastest log-reduction of bacterial biofilm compared to the control test. The biofilm of L. monocytogenes for the glass nanoparticle 1 (glass surface modified by 16% w/v TiO₂) was found to have decreased by 3 log CFU/cm² after 90 min irradiation by UVA. The use of TiO₂ nanostructured photocatalysts as alternative means of disinfecting contaminated surfaces presents an intriguing case, which by further development may provide potent disinfecting solutions. Surface modification using nanostructured titania and UV irradiation is an innovative combination to enhance food safety and economizing time and money.     

响应面法优化O3/H2O2组合工艺处理制浆中段废水的研究

本研究为提高臭氧（O₃）氧化处理制浆中段废水的COD去除率,以广西某造纸厂制浆中段废水为研究对象,采用O₃/H₂O₂组合工艺对其进行高级氧化处理。分别探究了废水初始pH值、O₃用量、H₂O₂用量、反应时间和搅拌速度等影响因素对废水色度和COD去除效果的影响。为提高最优工艺参数的精确度,对O₃/H₂O₂组合工艺参数进行响应面优化法分析。结果表明,在废水初始pH值=8、H₂O₂用量为1.0 mL/L、O₃用量为480 mg/L的工艺条件下,废水色度为85.7倍,色度去除率为99.3%;COD_Cr达208.2 mg/L,COD_Cr去除率为84.5%。     

Optimization of wool mothproofing with nano TiO2 using statistical analysis

Wool, with excellent characteristics, has the problem of being fed on by the moth. Until now several chemicals have been introduced for mothproofing with some limitations. In this research, an optimized mothproofing of wool has been proposed with nano TiO₂ and citric acid by using Design-Expert software. Mothproofing was statistically investigated by measuring wool weight loss during feeding by the larvae of carpet beetle, Anthrenus verbasci. The analysis of variance was applied to obtain the optimum conditions for mothproofing. The damage intensity of wool fabrics was also observed with a digital camera. Further, the dyeing properties of the treated wool fabrics were examined through evaluating exhaustion of CI Acid Blue 113. Finally, the wool fabrics treated with optimized concentration of CA and 1.2% TiO₂ nanoparticles indicated the best protection against moths.     

低聚木糖作为牺牲剂在光催化产氢中的应用

目前光催化产氢的研究主要集中于修饰和改性半导体材料来提高其光催化产氢性能。在光催化分解水产氢过程中需要添加牺牲剂甲醇来消耗掉光生空穴,牺牲剂是影响半导体光催化剂产氢性能的一个重要因素。本研究选择可再生生物质低聚木糖作为牺牲剂,探讨了其光催化产氢性能,并与常用牺牲剂甲醇进行了光催化产氢性能比较。结果表明,未负载贵金属Pt时,半导体材料TiO2和C3N4进行光催化产氢时未检测到氢气。负载质量分数1%的Pt后,半导体材料Pt-TiO2和Pt-C3N4可以作为光催化剂进行产氢,经过24 h的光催化反应,基于催化剂质量,以甲醇为牺牲剂时分别产出4298. 3μmol/g和356. 5μmol/g的氢气,以低聚木糖为牺牲剂时分别产出3054. 5μmol/g和495. 6μmol/g的氢气。低聚木糖可以作为光催化产氢的牺牲剂,尤其用作Pt-C3N4的牺牲剂时,产氢性能优于甲醇。     

过氧化氢/臭氧-曝气生物滤池深度处理造纸废水生化出水

本研究采用过氧化氢/臭氧-曝气生物滤池组合工艺处理造纸废水生化出水,通过实验确定了优化操作参数,并对组合工艺的处理性能进行了探究。结果表明,组合工艺的优化操作条件为：pH值（7.3~8.4）、过氧化氢/臭氧投加量=113/60 mg/mg、氧化时间25 min、曝气生物滤池水力停留时间2.5 h、曝气生物滤池气水比3∶1。在优化操作条件下,过氧化氢/臭氧氧化后废水的生物处理适宜性显著提高;废水经组合工艺处理后,出水COD_Cr<20 mg/L、色度<10倍,达到企业废水回用水质要求。     

A simple gold plate electrode modified with Gd-doped TiO2 nanoparticles used for determination of trace nitrite in cured food

A simple gold plate electrode (GPE) based on a gadolinium-doped titanium dioxide (Gd/TiO₂) ultrathin film was successfully constructed by using a surface sol-gel technique, and used for the detection of trace amounts of nitrite in cured foods. The Gd/TiO₂ nanoparticles were synthesised and characterised via scanning electron microscopy (SEM) and X-ray diffraction (XRD), indicating that the Gd-doped TiO₂ formed an anatase phase through roasting at 450°C, generating actively interstitial oxygen at the interface of the surface of TiO₂ lattice surrounded by Gd³⁺. The electro-catalytic effect for oxidation of nitrite on the modified electrode was investigated by cyclic voltammetry in 0.10?mol?l^?1 sulfuric acid media solution, showing that the modified electrode exhibited excellent response performance to nitrite with good reproducibility, selectivity and stability. The catalytic peak current was found to be linear with nitrite concentrations in the range of 8.0?×?10^?7 to 4.0?×?10^?4??mol?l^?1, with a detection limit of 5.0?×?10^?7?mol?l^?1 (S/N?=?3). The modified electrode could be used for the determination of nitrite in the cured sausage samples with a satisfactory recovery in the range of 95.5–104%, showing its promising application for food safety monitoring.     

Criteria to define a more relevant reference sample of titanium dioxide in the context of food: a multiscale approach

ABSTRACT

Titanium dioxide (TiO₂) is a transition metal oxide widely used as a white pigment in various applications, including food. Due to the classification of TiO₂ nanoparticles by the International Agency for Research on Cancer as potentially harmful for humans by inhalation, the presence of nanoparticles in food products needed to be confirmed by a set of independent studies. Seven samples of food-grade TiO₂ (E171) were extensively characterised for their size distribution, crystallinity and surface properties by the currently recommended methods. All investigated E171 samples contained a fraction of nanoparticles, however, below the threshold defining the labelling of nanomaterial. On the basis of these results and a statistical analysis, E171 food-grade TiO₂ totally differs from the reference material P25, confirming the few published data on this kind of particle. Therefore, the reference material P25 does not appear to be the most suitable model to study the fate of food-grade TiO₂ in the gastrointestinal tract. The criteria currently to obtain a representative food-grade sample of TiO₂ are the following: (1) crystalline-phase anatase, (2) a powder with an isoelectric point very close to 4.1, (3) a fraction of nanoparticles comprised between 15% and 45%, and (4) a low specific surface area around 10 m² g^–1.     

纳米TiO2复合荧光增白剂的制备及其在纸张中的应用

以4,4-二氨基-2,2-二磺酸二苯乙烯(DSD酸)为母体,三聚氯氰为桥联剂,制备了三嗪氨基二苯乙烯型荧光增白单体(FBs);再将FBs、丙烯酰胺、苯乙烯与改性纳米TiO_2共聚,制得纳米TiO_2复合荧光增白剂(FBs-TiO_2),并将其用于纸张表面涂布。结果表明,FBs-TiO_2成功制备,且稳定性更好;FBs-TiO_2涂布后,纸张白度由67.2%提高到87.2%,抗张强度由3.12 kN/m提高到4.87 kN/m,撕裂指数由13.8 mN·m~2/g提高到17.4 mN·m~2/g,并且紫外光老化48 h后,返黄值由10.40下降到6.66。说明FBs-TiO_2不但能提高纸张白度、抑制纸张返黄,还能有效增强纸张的表面强度和力学性能,是一种性能优异的造纸助剂。