Due to industrial growth and its impact on the environment, the increasing amount of industrial waste requires a comprehensive approach aligned with the principles of sustainable development. The main goals are not only to preserve natural resources but also to encourage innovation in the reuse of waste materials. In an attempt to reduce the problems regarding waste disposal and wastewater treatment in the textile industry, fibrous textile waste was used as a starting material to obtain carbon adsorbents for the removal of pollutants from wastewater. Waste cotton and mixed yarns, mainly consisting of polysaccharide cellulose, were hydrothermally carbonized and activated with KOH to convert them into efficient carbon adsorbents for heavy metal removal from water. Characterization of carbonized material showed that after activation, an increase in specific surface area (up to 872 m²/g) and content of surface oxygen groups (6.04 mmol/g) leads to a higher affinity towards heavy metal ions, especially lead ions, and high adsorption capacity of 19.98 mg/g obtained for activated cotton yarns. The results of this research represent a contribution to the reduction of waste materials by modifying them into adsorbents, while the regeneration of adsorbents is an example of the practical application of polysaccharide-based materials in the purification of wastewater containing various heavy metal ions.

The study was aimed at determining the most suitable irrigation schedule program for hemp grown for fibers by using evaporation from the free water surface (E_o), measured by a Class A pan and related crop plant coefficient (K_c). The experiment, carried out in Vojvodina, a northern part of the Republic of Serbia, included three irrigation regimes: I₁, I₂, and I₃ corresponding, respectively, to daily evaporation from an open water surface (E_o), two interrow spacings: RS₁ (12.5 cm) and RS₂ (25 cm), and topped (T) and not topped (NT) variants. The K_c values used for the calculation of daily evapotranspiration (ET_d) were 0.42 for April and May and 1.00 (I₁), 0.80 (I₂), and 0.60 (I₃) from June to the harvest. In addition, the nonirrigated (I_o) control variant was also included in the trial. The dioecious fiber hemp variety Marina was used for the trials. Irrigation was carried out by a drip irrigation system and was scheduled based on the water budget method. It started when readily available water (RAW) in the soil layer of 0.4 m was completely depleted by the plants. In the first year of the study, irrigation did not influence the yield of hemp fiber, but in the second one, the best result was achieved for the irrigation variant I₁. Interrow spacing did not have a statistically significant effect on both the hemp fiber yield and the quality. The topping of plants significantly decreased the yield of hemp, and it is not recommended when the hemp is cultivated for fibers. The quality of the hemp fibers was not influenced by irrigation, inter-row spacing, and topping. The rate of hemp evapotranspiration was in an interval of 312 mm (ET_a) to 520 mm (ET_m). The highest values of IWUE and ETWUE in both years and the bark yield in the first year were detected for the I₃ irrigation variant, which suggested that the crop plant coefficient (K_c) of 0.6 could be recommended for the correction of E_o values in the calculation of the daily evapotranspiration of hemp (ET_d) from June to August. The yield response factor (K_y) with values of 0.22 and 0.60 for the total growing season reveals that, in rainy years, hemp for fiber production could be grown without irrigation in the temperate climate of the Vojvodina region. However, such years are rare. Without doubt, irrigation of fiber hemp is recommended in the mentioned region in order to obtain high yields of good quality product.

Waste hemp and flax fibers, and cotton and cotton/polyester yarns, available in large quantities from the textile industry, were used as cheap and effective sorbents for the removal of methylene blue from wastewater. Waste fibers and yarns were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, iodine sorption, water retention, and point of zero charge, as well as through the determination of crystallinity index and degree of surface crystallinity. The adsorption of methylene blue was optimized by examining the influence of contact time, initial concentration, temperature, and pH value. It was found that the more ordered structure of cotton and cotton/polyester yarns leads to lower adsorption capacities and better agreement with pseudo-second order kinetic and Langmuir isotherm model, while the more heterogeneous structure of flax and hemp fibers shows higher capacities for methylene blue adsorption, better described by the pseudo-first order kinetic and Freundlich isotherm model. Based on the obtained results, waste lignocellulosic fibers and yarns can be used for the discoloration of wastewater, thereby solving the problem of waste generated in the textile industry.

In an attempt to reuse fibrous textile waste and, at the same time, to address dye pollution in textile wastewater, waste cotton-based yarn was utilized as a cheap and sustainable adsorbent, as well as a row material for carbon adsorbent production. Unmodified yarn and cotton-based carbon adsorbents were used as adsorbents for dye removal from water. Cotton and cotton/polyester yarn samples underwent thermal modification through carbonization followed by chemical activation with KOH. Various techniques, including scanning electron microscopy, Fourier transform infrared spectroscopy, nitrogen adsorption–desorption isotherms, and surface charge determination, were employed to analyze the morphological and surface characteristics of the cotton-based adsorbents. Adsorption properties were evaluated by testing the removal of selected cationic and anionic dyes from water. The impact of temperature, initial pH and concentration of the dye solution, and contact time on adsorption were investigated, and experimentally obtained data were analyzed using theoretical models. While carbonization alone did not significantly enhance adsorption properties, activated samples exhibited high efficacy in removing both cationic and anionic dyes from water. Despite the negative influence of the polyester component in the carbon precursor on the efficiency of activated samples in removing methyl orange, the results indicated that activated cotton and cotton/polyester yarn could be used to prepare highly efficient adsorbents for the rapid removal of methylene blue from real wastewater samples.