Developing green and functional adsorbents for the removal of inorganic pollutants from industrial wastewater is still a great challenge. Activated carbons (ACs) are promising eco-friendly materials for adsorption applications. This study reports on the preparation and functionalization of AC and its application for fluoride removal from water. Activated carbon was prepared from date stems, and the material was employed as a support for different modifications such as incorporation of Al(OH)₃, in situ dispersion of aluminum particles (Al⁰) and grafting of 3-(aminopropyl)triethoxysilane (APTES). The resulting functional adsorbents were fully characterized by Fourier transform infrared spectroscopy, scanning electronic microscopy, energy dispersive X-ray fluorescence, X-ray diffraction, differential scanning calorimetry and zeta potential analysis. The results evidenced successful surface modifications. All adsorbents had affinity for the removal of fluoride ions (F⁻). The highest F⁻ removal rate was up to 20 mg g⁻¹ for AC-Al(OH)₃. Removal of fluoride ions obeyed Langmuir isotherms and a second-order kinetic model, and reached 99% uptake. The AC-Al(OH)₃ adsorbent was successfully used to treat a groundwater solution contaminated by fluoride ions. These results open an interesting avenue for developing eco-friendly functionalized AC for adsorption applications.

The successful removal of fluoride from water in dynamic mode with an innovative material was achieved. The maximum adsorption capacity in the column was 41.84 mg g ⁻¹ at 7.5 mL min ⁻¹ .

This study reports on the synthesis, immobilization, and stabilization of iron (Fe) particles in activated carbon (AC) from date stem material for the heterogeneous Fenton-like removal of hazardous pollutants from water. AC-Fe was synthesized through a simple and sustainable chemical reaction using and resulting in an environmentally friendly material (AC-Fe). X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray analyses (EDX) were used to characterize the synthesized samples. XRD, FTIR and XPS results showed the successful incorporation of iron particles onto AC. SEM images indicated smooth surfaces with clearly visible Fe particles. Compared to pure AC, AC-Fe showed higher degradation rates of toluidine blue O (TBO) dye. The effects of the initial pH and TBO and H₂O₂ concentrations on TBO degradation were investigated. The AC-Fe catalyst proved highly efficient in the Fenton-like degradation of TBO (50 ppm), with the removal of up to 99% in 3 min. This catalyst was used efficiently for up to four repeated cycles. The improved catalytic activity of AC-Fe was related to Fe particles for the generation of HO•. These results prove that date stems—a waste product from agriculture—are a suitable precursor for preparing an appropriate AC and catalyst and for eliminating dyes from an aqueous solution by a heterogeneous Fenton-like reaction. The above results open an interesting avenue for the development of functional green catalysts based on AC-Fe for pollution removal.

The increasing environmental threat posed by dye-contaminated wastewater, particularly from textile industries, calls for the development of effective and economically viable treatment solutions. Adsorption has emerged as a promising method due to its straightforward application, enhanced efficiency, and economic feasibility. In this study, an industrial by-product from sweet almond oil extraction (sweet almond, SA) was chemically modified with hydrogen peroxide (H₂O₂) to produce an innovative adsorbent material, noted SA-OH, for the removal of Basic Blue 41 (BB41) dye from aqueous solutions. The SA and SA-OH materials were characterized using scanning electron microscopy/energy-dispersive spectroscopy (SEM/EDS), Fourier transform infrared spectroscopy (FTIR), and Brunauer–Emmett–Teller (BET) to investigate their morphological and surface properties. The operational parameters affecting BB41 removal, including solution pH, adsorbent dosage, and initial dye concentration, were optimized using central composite design (CCD) within the framework of the response surface methodology (RSM). Isotherm and kinetic models were applied to describe the biosorption behavior. The results indicated a substantial improvement in the adsorption capacity of SA-OH compared to untreated SA, demonstrating the potential of SA-OH as an effective, cost-efficient, and environmentally sustainable adsorbent for industrial wastewater treatment. To the best of our knowledge, this is the first study reporting the use of hydrogen peroxide-modified sweet almond waste for BB41 dye removal.