Eco-friendly synthesis of clay-chitosan composite for efficient removal of alizarin red S dye from wastewater: A comprehensive experimental and theoretical investigation.

Alizarin Red S (ARS) is commonly utilized for dyeing in textile industry. The dye represents a refractory pollutant in the aquatic environment unless properly treated. To tackle this pollutant, the applicability of chitosan-clay composite (3C) for the ARS removal from textile wastewater was studied. Characterization studies were conducted on the synthesized adsorbent using Fourier transformation infrared (FT-IR), X-ray diffraction (XRD), and energy dispersive X-ray (EDX) techniques. Optimized parameters such as adsorbent's dosage, pH, reaction time, and initial concentrations were tested in a batch system. Additionally, density functional theory (DFT) was calculated to understand the adsorption mechanism and the role of benzene rings and oxygen atoms in the ARS as electron donors. At the same initial concentration of 30 mg/L and optimized conditions of 50 mg of dose, pH 2, and 10 min of reaction time, about 86% of ARS removal was achieved using the composite. The pseudo-second-order kinetic was applicable to model a reasonable fitness of the adsorption reaction, while the Temkin model was representative to simulate the reaction with a maximum adsorption capacity of 44.39 mg/g. This result was higher than magnetic chitosan (40.12 mg/g), or pure chitosan (42.48 mg/g). With ΔH = 27.22 kJ/mol and ΔG<0, the data implied the endothermic and spontaneous nature of the adsorption process. Overall, this implies that the clay-chitosan composite is promising to remove target dye from contaminated wastewater.

A Comprehensive Review of Polysaccharide-Based Hydrogels as Promising Biomaterials.

Polysaccharides have emerged as a promising material for hydrogel preparation due to their biocompatibility, biodegradability, and low cost. This review focuses on polysaccharide-based hydrogels' synthesis, characterization, and applications. The various synthetic methods used to prepare polysaccharide-based hydrogels are discussed. The characterization techniques are also highlighted to evaluate the physical and chemical properties of polysaccharide-based hydrogels. Finally, the applications of SAPs in various fields are discussed, along with their potential benefits and limitations. Due to environmental concerns, this review shows a growing interest in developing bio-sourced hydrogels made from natural materials such as polysaccharides. SAPs have many beneficial properties, including good mechanical and morphological properties, thermal stability, biocompatibility, biodegradability, non-toxicity, abundance, economic viability, and good swelling ability. However, some challenges remain to be overcome, such as limiting the formulation complexity of some SAPs and establishing a general protocol for calculating their water absorption and retention capacity. Furthermore, the development of SAPs requires a multidisciplinary approach and research should focus on improving their synthesis, modification, and characterization as well as exploring their potential applications. Biocompatibility, biodegradation, and the regulatory approval pathway of SAPs should be carefully evaluated to ensure their safety and efficacy.

Composites with alginate beads: A novel design of nano-adsorbents impregnation for large-scale continuous flow wastewater treatment pilots.

The sorption capacity of cadmium (Cd (II)) on three new generated nanocomposite beads sodium alginate (SA) based; SA-Clay (SA-C) beads, SA-Phosphate (SA-P) beads, and SA- Activated Charcoal (SA-Ch) beads was investigated in a batch scale, then a continuous flow reactor. The highest adsorption capacity (137 mg/g) was obtained for SA-Ch using 1000 mg/L of initial Cd (II). The isotherm results showed that the adsorption equilibrium is compatible with the Langmuir isotherm and the sorption capacity of SA-Nano-adsorbent beads is very high. The models used for representing kinetic data was given that the removal of Cd (II) be well-fitted by second-order reaction kinetics. For the fixed bed column treatment, the maximum breakthrough times were 30, 38, and 48  h respectively for the SA-C, SA-P, and SA-Ch. According to the obtained results, it was concluded that SA-Nano-adsorbent bead is an excellent designed material as a nanocomposite for cadmium elimination from wastewater in a continuous treatment process.