Dyeing of advanced denim fabrics (blend of cotton/bicomponent polyester filaments) using different processes and artificial intelligence method

Denim clothes are the must-have items of clothing around the world. This kind of fabrics is evolving with the increasing consumer demand in order to keep its place as a versatile article. In this context, this paper contributes to the development and dyeing of a new blend fabric made of cotton fibers and bicomponent polyester filaments (PET/PTT). A comparative study between the mechanical and thermal properties of this fabric and conventional fabrics has confirmed the great interest to use bicomponent (PET/PTT) filaments in the manufacture of denim fabrics; these bicomponent filaments allow to give to wearer the desired elasticity and comfort. For dyeing (cotton/bicomponent polyester filaments) blend fabric, three different processes, using reactive and disperse dyes, were tested and analyzed. These dyeing processes are: two-baths/two-phases, one-bath/two-phases, and one-bath/one-phase processes. In addition, in order to obtain uniform shades between cotton fibers dyed with reactive dyes and bicomponent polyester filaments dyed with disperse dyes, an ant colony algorithm was elaborated to predict the optimal dye recipes. By observing obtained results, the developed algorithm is very effective; it allows to find the combination of reactive dyes necessary to achieve the same shade obtained by the disperse dyes with very small color differences between the two components and without having to make corrections mainly for the one-bath/two-phases process. Indeed, dyeing using the two processes (two baths/two phases and one bath/two phases) presents the best values of color yield (K/S) with almost similar results (ΔECMC(2:1) <  < 1). For the one-bath/one-phase process, it presents less significant results; We can observe ΔECMC(2:1) greater than 1 in certain shades. This is due to the strongly pH value (basic pH of 11) of reactive dyeing.

Environmentally friendly dyeing of wool and silk fabrics with natural colorant of turnsole (Chrozophora tinctoria L.)

With the increasing demand for environmentally friendly dyes, natural dye has become an attractive option replacing toxic synthetic dyes. Within the framework of this research, the natural dye of Chrozophora tinctoria L. was extracted using the microwave-assisted extraction method under different operating conditions. The influence of different factors influencing the extraction process (such as pH, extraction time, and microwave power) on the extraction efficiency was investigated by means of a multilevel three-factor design. The suggested model has a high coefficient of determination, indicating high predictability and good approximation. Optimal microwave extraction process conditions were obtained at a value of microwave power equal to 650 W, at a pH of 5 during a period of 3 min. Dyed wool and silk fabrics showed very good washing and light fastness properties.

Chemical composition, antifungal and antibiofilm activities of essential oils from Glycyrrhiza foetida (Desf.) growing in Tunisia

This study was designated to investigate the chemical composition, the antifungal activity and antibiofilm properties of Glycyrrhiza foetida (Desf.) growing in Tunisia and recognized for its pharmacological and therapeutic effects. The chemical analysis of essential oil samples prepared via hydrodistillation of the aerial parts was performed by gas chromatography-mass spectrometry (GC-MS). Moreover, the antifungal activity of G. foetida essential oil was developed against three dermatophyte strains, two molds and Candida spp. yeasts using the broth microdilution assay. According to the percentages, the main constituents are δ-cadinene (13.9%), (E)-caryophyllene (13.2%) and γ-cadinene (8.3%). The efficiency of the essential oil in inhibiting Candida albicans biofilms formation was also evaluated in terms of inhibitory percentages. The results showed that C. albicans and Microsporum canis were the most sensitive to G. foetida essential oil with a complete inhibition at 0.4 and 0.2 mg ml^-1 , respectively. Candida albicans biofilm development was reduced by 80% by the volatile oil at a concentration of 0.8 mg ml^-1 . The essential oil of G. foetida has a promising role in the control of fungal agents with medical interest and in inhibition of Candida biofilm development.

Acidic and alkaline deep eutectic solvents pre-treatment to produce high aspect ratio microfibrillated cellulose

This study highlights the microfibrillation potential of three deep eutectic solvents (DES) composed of betaine hydrochloride-urea, choline chloride-urea and choline chloride-monoethanolamine. Cellulose fibres (eucalyptus and cotton) were first treated in DES (100 °C for 4 h) and then ground with an ultra-fine grinder to produce microfibrillated cellulose (MFC). DES pre-treatment especially betaine hydrochloride-urea system has significantly improved the microfibrillation process with reduced energy consumption comparable to that of enzymatic treatment (reference pre-treatment). Long and thin microfibril bundles (widths around 50 nm) and individualised microfibrils (widths between 5 and 10 nm) were obtained. MFC gels and nanopapers were characterised using several techniques. Nanopapers produced from DES treated MFC showed good mechanical properties with Young's modulus higher than 10 GPa. In addition, they exhibited higher quality index (between 73 and 76) than those produced from enzymatic hydrolysis (quality index around 68). DES pre-treatment is a promising way to produce MFC with high aspect ratio.

Kinetics study of dyeing bicomponent polyester textiles (PET/PTT) using environmentally friendly carriers

The biobased carriers o-vanillin, p-vanillin, and coumarin, can be used to dye poly(ethylene terephthalate)/poly(trimethylene terephthalate) (PET/PTT) bicomponent filaments at low temperature without affecting their excellent elasticity and elastic recovery. These ecological carriers, which are free from any toxic product, present an effective solution for obtaining an ecological and economical dyeing process. This paper presents a study of the effects of the kinetics when dyeing bicomponent (PET/PTT) filaments with three disperse dyes having different molecular weights at 100 °C (upon adding ecological carriers) and at a high temperature (130 °C). The physicochemical characterization of bicomponent filaments was done using several techniques, such as SEM, BET and DSC, before carrying out a modelling study. Different models (pseudo first-order, pseudo second-order, Elovich, and intra-particle diffusion models) were used to identify an acceptable dyeing mechanism. The dyeing rate constants, the half dyeing times, and the rise time coefficients were then determined and analyzed. The results of this work explain the adsorption mechanism during the dyeing process of bicomponent (PET/PTT) filaments using ecological carriers and provide an experimental foundation for future research.

The biobased carriers o-vanillin, p-vanillin, and coumarin, can be used to dye poly(ethylene terephthalate)/poly(trimethylene terephthalate) bicomponent filaments at low temperature without affecting their excellent elasticity and elastic recovery.

Ecological and cleaner process for dyeing bicomponent polyester filaments (PET/PTT) using ecological carriers: analysis of dyeing performance

Thanks to their excellent properties, bicomponent filaments, in particular, polyethylene terephthalate (PET)/polytrimethylene terephthalate (PTT) are more and more used in stretchable clothing. Despite the researchers' efforts, the dyeing of these filaments still presents several problems which should be resolved. Manufacturers must choose between dyeing polyester under pressure at high temperatures (close to 130 °C) to have less toxic and cheaper textile effluents and/or dyeing at low temperatures (not exceeding 100 °C) which needs the use of toxic carriers. This paper presents a new opportunity and the feasibility of dyeing bicomponent polyester filaments using an economic and clean process at a temperature equal to 100 °C and by replacing toxic carriers by ecological ones. Three kinds of ecological carriers, namely o-Vanillin, p-Vanillin and Coumarin, are used to improve the dyeing performance of bicomponent filaments with three disperse dyes having different molecular weights. They were compared to three conventional ones largely used in industry. The effect of each carrier on dyeing performance (dye bath exhaustion, color strength and CIELab coordinates) was then investigated. The obtained results prove that ecofriendly carriers constitute a good solution to replace the toxic ones and allow to obtain the same, or even better dyeing performance and fastness properties.

Chemical Composition and Antioxidant Activity of Essential Oils and Hexane Extract of Onopordum arenarium from Tunisia

In the present study, volatile oils from Onopordum arenarium fresh flowers and stems were obtained by hydrodistillation and the non-polar aerial part hexane extract was prepared using a Soxhlet apparatus. The constituents of different organs were identified for the first time by gas chromatography equipped with flame ionization detector and gas chromatography coupled to mass spectrometry. A total of 29 and 25 compounds were identified constituting over 91.6 and 89.2% of the whole constituents from flower and stem volatile oils, respectively. Both organs were constituted mainly of long-chain hydrocarbons (23.3-36.4%) followed by oxygenated long-chain hydrocarbons (31.5-33.8%) and oxygenated monoterpenes (14.4-6.6%). The major identified compound was palmitic acid [25.5% in O. arenarium flower essential oil (EO) and 28.7% in the stem EO]. Eighteen compounds representing 80.7% of the whole constituents were identified in the n-hexane extract, which was characterized by high amounts of triterpenoids (39.6%) and dominated by lupeol acetate (19.2%) and β-amyrin acetate (10.1%). Moreover, all extracts were evaluated for antioxidant potential using 1,1-diphenyl-2-picrylhydrazyl radical assay. The obtained results demonstrated that the EOs and the hexane extract could be a new source of natural potentially bioactive molecules.

Adsorption of nitrate, phosphate, nickel and lead on soils: Risk of groundwater contamination

Agricultural activities pose a significant risk of groundwater pollution. Indeed, fertilizers and treated wastewater used for irrigation are, in part, responsible for the deterioration of groundwater and surface water quality. In some cases, soil may provide a protective barrier against this pollution, but this depends on the nature of the soil and the contaminant. This work presents the effect of the soil clay content on the retention of four different pollutants in order to evaluate the risk they represent for the groundwater. These contaminants are generated by two main agricultural activities: 1/soil fertilization with phosphate and nitrate fertilizers and 2/irrigation with treated wastewater in which heavy metals such as nickel and lead are persistent. Firstly, the characterization of the sand and clay used in this work was performed and showed a cation exchange capacity of 1.24 and 25 meq/100 g, a specific surface area of 0.12 and 67.98 m²/g and a percentage of organic matter of 0.15 and 2% for sand and clay, respectively. The retention isotherms on all pollutants and the Langmuir, Freundlich, Freundlich-Langmuir, Hill and Koble-Corrigan models were applied. All experimental isotherms have been successfully adjusted using the Koble-Corrigan expression. The amounts of nitrates, phosphates, nickel and lead retained by the sandy soil, for an initial pollutant concentration equal to 1 meq/L, were evaluated at 0.29, 3.89, 5.97 and 8.56 μeq/g respectively. In contact with a soil containing 30% clay, the adsorbed amounts were estimated at 3.55, 15.00, 6.97 and 8.79 μeq/g for nitrates, phosphates, nickel and lead, respectively. These results mean that the pollutants that pose the greatest risk of groundwater contamination when carried by water through sandy soil are classified as follows lead < nickel < phosphate < nitrate while for a clayey soil, the classification becomes as follows: phosphates < lead < nickel < nitrate.

Chemical Constituents of the Aerial Parts ofDaucus carotasubsp.hispidusGrowing in Tunisia

Three known polyol menthane monoterpenoids, namely, (4 R)-1- p-menthen-6,8-diol (1), (4 R)-1- p-menthen-4,7-diol (2), and (1 R,2 R,4 R)- p-menthane-1,2,4-triol (3), and 6 known phenolics (4-9), in addition to β-sitosterol 3- O-glucoside (10), were isolated from the aerial parts of Daucus carota subsp. hispidus (Ball) Heywood (Family: Apiaceae) growing in Tunisia. The structures of the isolated compounds were established depending upon the spectroscopic techniques including one and two-dimensional nuclear magnetic resonance (1D, and 2D NMR) and high resolution mass spectroscopy (HRMS). The absolute configuration of the compounds 1 to 3 was determined using experimental circular dichroism (CD) for the first time. Compounds 1 to 3 were reported for the first time from this plant. Compounds 1 to 3 exhibited no antimicrobial and antioxidant activity using superoxide dismutase-like activities. Compounds 2 and 3 exhibited weak activity, while 1 showed negative cytotoxic activity against human mouth squamous carcinoma (HSC-2) and human cervical cells (HeLa) cancer cells.

Calculation of gyrotropy coefficients in media with low-pitch helical structures

Chiral smectic liquid crystals are known for their huge optical activity due to the precession of the anisotropic dielectric tensor around the helicoidal axis. For an oblique direction of the propagating wave, the helix acts as a grating which splits an incident beam in different directions as long as the pitch is not too small with respect to the light wavelength. When the pitch of the helix is smaller than the wavelength, the effect of the helix is a renormalization of the gyrotropic coefficients (g_{⊥} and g_{∥}) of the resulting uniaxial medium. We report here on a method to compute these coefficients in that limit. Resolution of the Maxwell equations, using a perturbative approach, gives expressions for g_{⊥} and g_{∥} as a power development of the ratio (p/λ). The various terms of these developments coincide with the approximate expressions of these coefficients known in the literature.

Antiproliferative metabolites from the Northern African endemic plant Daucus virgatus (Apiaceae)

Chemical analysis of the dichloromethane fraction obtained from aerial parts of the Northern African endemic plant Daucus virgatus led to the isolation of three previously undescribed sesquiterpenoids, namely the daucane vaginatin B, a eudesmane and the elemane elemavirgolide, along with five known metabolites. The structures of these compounds were determined by a detailed MS and NMR analysis and they were evaluated for antiproliferative activity against three human cell lines, A375 (melanoma), MCF-7 (breast adenocarcinoma), and HACAT (keratinocyte). The phytoalexin 6-methoxymellein revealed a previously unreported antiproliferative activity, while the eudesmane and the elemane derivatives exhibited a selective activity (SI = 11.1 and 3.3, respectively) against melanoma tumor cell lines.

Fatty acids from high rate algal pond's microalgal biomass and osmotic stress effects

The extraction of oil from a wild microalgae biomass collected from a domestic wastewater treatment facility's high rate algal pond (HRAP) was investigated. An experiment plan was used to determine the most efficient extraction method, the optimal temperature, time and solvent system based on total lipids yield. Microwave-assisted extraction was the most efficient method whether in n-hexane or in a mixture of chloroform/methanol compared to Soxhlet, homogenization, and ultrasounds assisted extractions. This same wild biomass was cultivated in a photobioreactor (PBR) and the effect of osmotic stress was studied. The lipids extraction yield after 3days of stress increased by more than four folds without any significant loss of biomass, however, the quality of extracted total lipids in terms of saturated, monounsaturated and polyunsaturated fatty acids was not affected by salinity change in the culture medium.

Microalgae from domestic wastewater facility's high rate algal pond: Lipids extraction, characterization and biodiesel production

In this study, the harvesting of a biomass from a high rate algal pond (HRAP) of a real-scale domestic wastewater treatment facility and its potential as a biomaterial for the production of biodiesel were investigated. Increasing the medium pH to 12 induced high flocculation efficiency of up to 96% of the biomass through both sweep flocculation and charge neutralization. Lipids extracted by ultrasounds from this biomass contained around 70% of fatty acids, with palmitic and stearic acids being the most abundant. The extract obtained by supercritical CO2 contained 86% of fatty acids. Both conventional solvents extracts contained only around 10% of unsaturated fats, whereas supercritical CO2 extract contained more than 40% of unsaturated fatty acids. This same biomass was also subject to direct extractive-transesterification in a microwave reactor to produce fatty acid methyl esters, also known as, raw biodiesel.

Sorption of paracetamol onto biomaterials

Pharmaceutical residues released into the environment are posing more and more public health problems. It is worthwhile to study the retention of pharmaceuticals residues by adsorption on solid supports. Batch sorption experiments are intended to identify the adsorption isotherms of the pharmaceutically active ingredient on the biomaterials. The results obtained in this study have shown that the retention possibilities of these compounds by bio-adsorbents (clay and sand) are not significant. The negligible sorption for these media is explained by the low hydrophobicity of paracetamol (Log K(ow) = 0.46). The retention of paracetamol on the dehydrated sewage sludge and on Posidonia oceanica showed a relatively significant adsorption with a maximal quantity of 0.956 mg g(-1) and 1.638 mg g(-1) for the dehydrate sludge and P. oceanica, respectively. On the other hand, the study of paracetamol retention on the powdered activated carbon showed a high adsorption capacity of about 515.27 mg g(-1). Isotherm data show a good fit with Langmuir's model. An infrared analysis is carried out. It shows identical bands before and after adsorption, with some modifications.

Nonlinear modelisation of heavy metal removal from aqueous solution using Ulva lactuca algae

After extensive analysis, Ulva lactuca dried algae, collected from the Monastir coastal zone, was proven to be successful as an adsorbent for the removal of certain inorganic pollutants. The main objective of this study was the nonlinear modeling of heavy metal removal from an aqueous solution, using a freely available and well analyzed biomaterial, as well as the evaluation of its efficacy on various metal ion sorptions. Although relatively low specific surface area, compared to more conventional adsorbents, the selected biomaterial displays very interesting retention capacities when used with aqueous inorganic pollutants. The pseudo, first and second-order kinetic models were used to investigate the kinetic retention mechanism. Assuming the nonlinear form, the results indicate that the retention mechanism is diffusion controlled. Concerning the heavy metal uptake capacity, it was found that the selected biomaterial has a retention capacity of 67 mg g(-1) of Ni(II), 112 mg g(-1) of Cu(II), 127 mg g(-1) of Cd(II) and 230 mg g(-1) of Pb(II).

Olive mill wastewater treatment in a membrane bioreactor: process stability and fouling aspects

An external ceramic membrane bioreactor was used to carry out an experimental study of process stability and fouling aspects for olive mill wastewater (OMW) treatment. Three diluted OMW solutions were used to continuously feed the reactor. An acclimated biomass was employed and the process stability was followed on the basis of the permeate quality and some operating parameters (pressure, temperature, mass flow and dissolved oxygen). Several backpulse combinations were tested to determine the best filtration and backwash time. It appeared that a short backpulse duration was sufficient and that the behaviour, in terms of the permeate flux versus time, stabilized. In terms of increased permeate flux, the effect of the backpulsing depended on the nature of the solution. This improvement was limited, but, in the long-term, backpulsing makes it possible to maintain a constant permeate flux over a period of several days.

Extension of the Hamaneh-Taylor model using the macroscopic polarization for the description of chiral smectic liquid crystals

Chiral smectic liquid crystals exhibit a series of phases, including ferroelectric, antiferroelectric, and ferrielectric commensurate structures as well as an incommensurate Sm-Calpha* phase. We carried out an extension of the phenomenological model recently presented by Hamaneh and Taylor based on the distorted-clock model. The salient feature of this model is that it links the appearance of phases to a spontaneous microscopic twist: i.e., an increment alpha of the azimuthal angle from layer to layer. The balance between this twist and an orientational order parameter J gives the effective phase. We introduce a second orientational order parameter I , which physical meaning comes from the macroscopic polarization; the effect of an applied electric is also studied. We derive phase diagrams and correlate them to our experimental results under field showing the sequence of phases versus temperature and electric field in some compounds.

Vat dye sorption onto crude dehydrated sewage sludge

In this work, sewage sludge is used as a textile dye adsorbent. A sample of crude dehydrated sewage sludge issued from an urban wastewater treatment plant (high-rate aeration, activated sludge process, Sahline, Tunisia) is utilized for vat dye retention. The main objective of this work is to evaluate the "efficiency" of the crude material on vat dye sorption. However, no treatment to modify any of the adsorbent properties was considered. Although the relatively low specific surface area (about 3.2m(2)g(-1)) compared to more conventional adsorbents, the used material shows very interesting retention capacities when used with water pollutants. The pseudo, first and second order kinetic models have been used to investigate the retention mechanism. When linearized, the pseudo-second order fit, for the both used dyes, in a better way the obtained experimental results than the pseudo-first order kinetic model. For equilibrium dye uptake amount it is found that the used material has a capacity (Langmuir Freundlich monolayer) of 73.1mg/g to fix the VAT RED 10 and 58.7 mg/g to fix the VAT ORANGE 11.

The anaerobic treatment of sewage and granule formation in upflow anaerobic sludge blanket reactor

The granulation process was examined using synthetic wastewater containing glucose in a 1 liter laboratory upflow anaerobic sludge blanket (UASB) reactor. The anaerobic biotransformation of glucose was investigated during the granulation process. Anaerobic unacclimated sludge and glucose were used as seed and primary substrate, respectively. Massive initial granules were developed after three months of start-up. The effect of operational parameters such as influent glucose concentrations, pH, Volatile Fatty Acids (VFA) were also considered during granulation. The presence of a large concentration of sulphate in the sludge of a mesophilic (37 degrees C+/-1 degrees C) UASB reactor treating sewage resulted in severe process disturbance, with a complete inhibition of the propionate-degrading ability of the sludge. Severe inhibition of acetate removal was also observed, with concentrations of propionic acid and acetic acid in the reactor effluent of 1.72% and 18.88%, respectively. Hydrogen sulfide (H2S) is formed from the anaerobic decomposition of organic matter containing sulfate by sulfate-reducing bacteria. This gas is toxic at rate exceeding 2% tolerable by a reactor. The result shows the rate of hydrogen sulfide production was 3.8 %.