Adsorbent from Textile Waste for Removal of Textile Reactive Dye from Water – Equilibrium Adsorption and Kinetics

The removal of textile reactive dye from an aqueous solution on a new adsorbent prepared from waste cotton knitted fabric was investigated in this study. Waste cotton textile, used for the production of adsorbents, is a by-product of the cutting of stacked parts of cotton knitwear planned for the production of women’s T-shirts. The degree of efficiency of a paper pattern determines the amount of collected waste. The qualitative and quantitative characterization of the new adsorbent showed carbon and oxygen to be dominant in the chemical composition. A longer contact time means a greater amount of dye on the adsorbent, i.e. the dye concentration in the solution decreases with the duration of the adsorption process. The percentage of removed dye decreases with an increase in the initial dye concentration in the solution. However, the actual amount of adsorbed dye increases as the initial dye concentration increases. The results for equilibrium adsorption show that the Langmuir isotherm can be used for the interpretation of reactive dye adsorption on a new adsorbent. The pseudo-first order model can be fully used to describe the kinetics of dye adsorption on an adsorbent, with respect to valid results for statistical indicators. Based on the results, it can be concluded that the new adsorbent obtained from waste textiles has the potential to remove textile reactive dye from aqueous solutions.

Possibility of Using Cotton Knitted Fabric Waste in Concrete

The use of waste and recycled materials in the construction industry, especially in concrete production, is becoming increasingly popular. The production of cotton underwear generates a certain amount of knitted fabric waste. This study was conducted to investigate the possibility of using cotton knitted fabric waste (CKFW) in concrete and to explore its potential application in the construction industry. The aim of the study is not only to reduce the waste but also to add positive properties to the concrete. A total of 4 mixes were prepared for testing purposes. CKFW were cut into small pieces of size about 6-8 cm x 2 cm. The addition of CKFW was a substitute for aggregates and replaced 0, 2.5, 5 and 10% of the total volume of aggregates in the concrete mix to make the concrete lighter. All mixes have the same amount of cement, water and superplasticizer. The knitted waste was saturated in water before mixing with other concrete components. The properties of the fresh mix were determined by slump method. The dynamic modulus of elasticity, flexural strength and compressive strength were tested on 28 days old concrete specimens. The σ-δ diagram is also presented. It was found that specimens with CKFW have better flexural strength and higher ductility but lower compressive strength than the reference concrete mix. The mix with the highest percentage of CKFW reduced the compressive strength by 28%, while the specimens with lower percentage of CKFW increased the flexural strength by 20% compared to the reference mix. The capillary water absorption capacity of concrete is closely related to its durability. The water absorption by capillarity was measured after 2, 4, 8, 15, 30, 45, 60 min, and 4 and 24 h. The increase in the amount of water absorbed was found to be higher than that of the reference mix. It was related to the percentage increase in the knitted waste and the values obtained ranged from 3.3 to 5.6% of the mass of the dry sample. The largest reduction in concrete density was 3.8% compared to the reference mix. Based on the obtained results, recommendations for further tests are given.

Surface functionalization of greige cotton knitted fabric through plasma and cationization for dyeing with reactive and acid dyes

Dyeing cotton fabrics with anionic dyes produces high effluent loads and requires a considerable amount of water and energy due to the electrostatic repulsion with cellulose. Therefore, several approaches have been researched to increase the efficacy of cotton dyeing. One is the cationization, which adds cationic sites to the cellulose. Another is the treatment of the cotton surface with plasma. In this paper, the combination of both techniques was investigated. Two commercially available cationic agents were used: 3-chloro-2-hydroxypropyl trimethyl ammonium chloride (CHPTAC) and poly[bis(2-chloroethyl) ether-alt-1,3-bis[3-(dimethylamino)propyl]urea] quaternized, a novel cationic agent also known as Polyquaternium2 (P42). The plasma treatment was performed using a dielectric barrier discharge atmospheric plasma facility, helium was used as seed gas and 1.5 % of oxygen was injected. The cationization and plasma treatment were performed on greige cotton fabric, an innovative and sustainable approach that eliminates conventional scouring and bleaching processes. The cationic and plasma treated samples were dyed using Reactive Red 195 and Acid Blue 260 dyes. The effect of the treatments was evaluated by different characterization techniques such as X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and atomic force microscopy (AFM). The plasma treatment slightly increased the light fastness for some samples, but the cationization tends to prevail over the plasma treatment. The best results were attributed to the samples pretreated by CHPTAC, which presented the highest K/S and lowest unlevelness for samples dyed with reactive and acid dyes. CHPTAC is the most common cationic agent for textiles, but its industrial use is limited due to safety criticisms. The combination between plasma and P42 resulted in the same color strength as the conventional reactive dyeing. Therefore, this approach offers a safer alternative to the conventional cationization process.

Thermal comfort properties of cotton/spandex single jersey knitted fabric

Knitted fabrics are characterized by comfort compared to woven fabrics due to their high extensibility and airpermeability, but they have lower dimensional stability after repeated washing especially single jersey knitted fabric(SJKF). Therefore, the spandex (Lycra) core-spun yarns are used to maintain the dimensions of knitted fabrics duringuse and after repeated stresses. In this study, nine elastic SJKF samples were produced at three levels of loop lengthand spandex percent using yarn linear density 30/1 Ne. For comparison, three 100% cotton knitted samples wereproduced with the same levels of loop length and yarn count. The dimensional and thermal comfort properties of thelong-stretch samples were compared with the short-stretch cotton knitted fabric. The thermal comfort properties (thermalconductivity, resistance, absorptivity, and water vapour permeability), air permeability, and dimensional properties weremeasured and compared to 100% cotton samples. The results showed that the stitch density, fabric density, fabricthickness, and thermal resistance increased, whereas the air, water vapour permeability, and spirality angle decreasedin cotton/spandex samples.

Comparison of the Effects of the Cationization of Raw, Bio- and Alkali-Scoured Cotton Knitted Fabric with Different Surface Charge Density

Modification of cotton with 3-chloro-2-hydroxypropyltrimethylammonium chloride (CHPTAC) has been studied extensively and can be operated by means of exhaustion, cold pad-batch, and continuous and pad-steam methods. Most of the research addresses the cationization of cotton fabric after bleaching or mercerization, or during the mercerization process. In our studies, we performed a comparison of the cationization effects on raw, enzymatic, and alkali-scoured cotton knitted fabrics applying CHPTAC according to the exhaustion method. The charge density of the cotton surface was measured using a Muetek Particle Charge Detector and a “back titration” method with polyelectrolytes. These results were compared with the nitrogen content in the samples, K/S measurements of tested samples after dyeing with anionic dye (Acid Yellow 194), and other physicochemical parameters such as weight loss, whiteness, and wettability.