Environment-friendly composite hydrogel beads based on carboxymethyl cellulose (CMC), alginate (Alg) and graphene oxide (GO) were synthesized by an ionotropic gelation technique and studied as an efficient adsorbent for methylene blue (MB). The chemical structure and surface morphology of the prepared hydrogel beads were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential thermal analysis (DTA) and point of zero charge (pH_pzc). A hybrid response surface methodology integrated Box–Behnken design (RSM-BBD) was successfully developed to model, simulate, and optimize the biosorption process. The synergistic effects between three critical independent variables including adsorbent dose (0.3–0.7 g), pH of the MB solution (6.5–9.5) and initial MB concentration (15–45 mg L⁻¹) on the MB adsorption capacity (mg g⁻¹) and removal efficiency (%) were statistically studied and optimized. The performance of the RSM-BBD method was found to be very impressive and efficient. Results proved that the adsorption process follows a polynomial quadratic model since high regression parameters were obtained (R²-value = 99.8% and adjusted R²-value = 99.3%). Analysis of variance (ANOVA) further confirms the validity of the suggested model. The optimal conditions for 96.22 ± 2.96% MB removal were predicted to be 0.6 g of CMC-Alg/GO hydrogel beads, MB concentration of 15 mg L⁻¹ and pH of 9.5 within 120 min. The adsorption equilibrium is better described by the Freundlich isotherm, indicating that physisorption is the rate controlling mechanism. The MB adsorption process was thermodynamically spontaneous and endothermic. A reusability study revealed that the prepared adsorbent is readily reusable. The adsorbent still maintains its ability to adsorb MB for up to four cycles. Results reported in this study demonstrated that CMC-Alg/GO hydrogel beads are an effective, promising and recyclable adsorbent for the removal of MB from aqueous solutions.

This study focuses on the design of highly hydrophobic polyester fabrics (PET) coated with organophilic graphene nanosheets (G-ODA) through a simple, cost-effective and scalable coating method.

In this work, a bifunctional nanohybrid silver/zinc oxide material (Ag/ZnO) has been synthesized by a rapid route using sodium alginate simultaneously as a sacrificial template and silver reducing agent. The obtained samples were characterized by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), solid diffuse reflectance and liquid state UV-visible spectroscopy (DRS, UV-visible), and nitrogen adsorption–desorption analysis (BET–BJH). The XRD patterns showed that the Ag/ZnO sample is composed of a hexagonal zinc oxide structure with cubic metallic silver (Ag°). SEM micrographs exhibited a porous structure which was confirmed by BET–BJH methods to be mesoporous. The Ag/ZnO material was used as a nanocatalyst in the conversion of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) as well as an antibacterial agent against Escherichia coli and Staphylococcus aureus. It was found that an efficient 4-NP reduction to 4-AP in the presence of NaBH₄ shows a rate constant of 0.418 min⁻¹ under ultrasonic energy and 0.316 min⁻¹ without ultrasonic energy. Both the catalysis reaction and antibacterial activity analysis were conducted in water solution and showed a synergetic effect of metallic silver loading.

The present study focuses on the design of new nanocomposite films using bio-based thermoplastic polyurethane (TPU) as a polymer matrix and long chain amine functionalized reduced graphene oxide (G-ODA) as a nanofiller. G-ODA was successfully prepared via chemical grafting of octadecylamine and fully characterized by various physicochemical techniques. Dispersion experiments showed that the synthesized organophilic graphene could be easily dispersed in several organic solvents and forms a stable and homogeneous colloidal suspension. G-ODA was incorporated at different loadings (0.1, 0.3, 0.5 and 0.7 wt%) into the polyurethane (PU) matrix to prepare uniformly dispersed G-ODA based PU nanocomposites. The designated nanocomposites resulted in achieving enhanced thermal stabilities as well as excellent mechanical properties compared to the neat PU. Mechanical performance studies show a tremendous enhancement of the tensile strength (2.08 to 5.48 MPa) along with an increment of the tensile modulus (37.19 to 122.83 MPa), the elongation at break (9.67 to 28.91%) and the toughness (13.75 to 124.44 MJ m⁻³). In addition, the designed nanocomposites demonstrate limited moisture and water uptake, reduced permeability and enhanced surface hydrophobicity.