Nowadays, very coarse wool fibers are considered waste biomass and are discarded at random or burned. Therefore, it is of actual interest to valorize coarse wool fibers as utile products. In this sense, we report herein an environmentally-friendly process for the preparation of a new material based on oxidized wool fibers and designed for efficient adsorption of heavy metals from wastewater. The morphology and the structure of the obtained product were characterized by scanning electron microscopy (SEM) coupled with an X-ray energy-dispersive module (EDX) and by Fourier-transform infrared spectroscopy (FTIR). Likewise, the performances of the oxidized wool fibers for the adsorption of heavy metal cations (Cu²⁺, Cd²⁺, Pb²⁺) from aqueous solutions were tested. The adsorption kinetics data were analyzed by applying the pseudo-first-order (PFO) and pseudo-second-order (PSO) kinetic models. The equilibrium of the adsorption process was investigated by using the Freundlich and Langmuir isotherm models. According to the Langmuir isotherms registered at 300 K, the maximum adsorption capacities of the oxidized wool were found to increase from Cu²⁺ (9.41 mg/g) and Cd²⁺ (10.42 mg/g) to Pb²⁺ (30.71 mg/g). Consequently, the removal efficiency of metal ions was found to vary in the range of 96.8–99.7%. The thermodynamic parameters (e.g., enthalpy, entropy, and Gibbs free energy) were calculated and discussed.

This study reports a simple and low-cost method for water purification using recyclable natural fibers (coarse wool fibers) as column-filling media for adsorption in the dynamic mode. As an instance of a dissolved organic pollutant, a cationic dye (basic blue 9, BB9) was assayed. According to the Langmuir isotherm (recorded at 300 K), the calculated maximum adsorption capacity of the fibrous material was found to be 24.86 mg/g for the retention of BB9. Response surface methodology (RSM) was employed for the design of experiments and the model-based optimization of the adsorption process performed in the dynamic regime (fixed-bed column). The optimal conditions provided by RSM indicated an adsorbent column height of H = 13.5 cm and a feed flow rate of F_v = 3 mL/min; these operating parameters ensured a color removal efficiency of 92.56% after 240 min of contact time. The recorded breakthrough curve under the optimal conditions was further interpolated using five quantitative mathematical models (Adams–Bohart, Thomas, Yoon–Nelson, Yan, and Clark) to assess the dynamic behaviors in the fixed-bed column. The best goodness-of-fit was achieved for the Thomas and Yoon–Nelson models. Thus, the coarse wool fibers used in a fixed bed demonstrated a relevant efficiency in the removal of cationic organic pollutants from contaminated water.

We report herein the synthesis and characterization of a new nanostructured composite (Wool- Fe 3 O 4 -Polysiloxane) aimed to be applied as a magnetic adsorbent for oil spill cleanup. The synthesized composite was characterized by the physical–chemical instrumental techniques (XRD, FTIR, SEM-EDX, and VSM). The hysteresis loops from the VSM measurement disclosed a magnetic saturation value of M S = 5 . 47 emu/g that was sufficient to induce magnetic properties to the composite material. The produced magnetic adsorbent showing hydrophobic properties was successfully tested for the sorption of petroleum products. Kinetic data of oily liquids retention and dripping were modeled by using the exponential and hyperbolic regression equations with three parameters. The hyperbolic kinetic model suggested higher maximal sorption capacity at time zero ( t = 0 ), that is, 14.486, 12.896, and 3.501 g/g, for motor oils 15W, 5W, and n -dodecane, respectively. The advanced recovery (80–92%) of retained oils from the spent sorbent was done by centrifugation.

Hydrogen peroxide is a compound that plays an important role in the biochemical processes of living organisms and found in a large spectrum of applications from chemistry and soft material processing to cosmetics and medicine. It is present in natural waters and contributes to their purification through reactive radical species. Starting from these considerations, an attempt was made to explain the morphological changes and the properties of the fibrous material achieved by means of the reactions with the reactive radical species that appear following the disproportionation process of the hydrogen peroxide. The influence of different factors, such as temperature, pH, the presence or absence of catalysts, etc. on the complex mechanisms by which morphological changes occur in the wool fibrous materials is discussed by corroborating old and new results collected by different investigation techniques. The reports on hydrogen peroxide involvement in wool processing are summarized and new materials based either on wool waste or on keratin subproducts are described. Request access from your librarian to read this chapter's full text.