In our current work, we have established a novel approach in the synthesis of a new adsorbent by using choline chloride and urea (DES)/orthophosphoric acid (H₃PO₄) as our activating agent and palm kernel shell (PKS) as our precursor. The resulting activated carbon (DES/H₃PO₄-6002:3) was used to adsorb Pb(II) from aqueous solution. Characterization of DES-H₃PO₄-6002:3 by nitrogen adsorption/desorption isotherm measurements, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA) demonstrated good micropores structure and high surface area that makes DES/H₃PO₄-600 2:3 a suitable alternative for liquid phase adsorption. The fundamental batch experiment of DES/H₃PO₄-600 2:3 was investigated by different parameters (such as concentration, pH, temperature and absorbent dose). The results obtained indicated that Langmuir model and pseudo-second-order equation best fit the data, indicating that the adsorption was controlled by chemical reaction and monolayer uptake. In addition, the fabrication of DES/H₃PO₄ AC exhibits good potential for Pb(II) ions uptake, including its high adsorption capacity (97.1 mg/g) and good recyclability. The future potential of this works lies in the identification of alternatives to environmental benign synthesis AC and reuse of Pb(II) ion–laden biosorbent after heavy metal uptake.

Activated carbons were synthesized by thermochemical treatment of palm kernel shells (AC-PKS) and modified with ethylenediaminetetraacetic acid (AC-EDTA). The developed products were characterized by the surface area, porosity, and pH of point zero charge and were used for removal of Pb(II) ions from aqueous solution. The AC-PKS exhibited higher BET surface area (1559.9 m2/g) than the AC-EDTA (1100.7 m2/g). The influence of solution pH, adsorbent dose, initial Pb(II) ion concentration, and temperature on the removal of Pb(II) ions were examined and optimized. The adsorption of Pb(II) on AC-PKS and AC-EDTA fitted the pseudo-second-order kinetics model and the Langmuir model isotherm, respectively. The optimum conditions for sorption of Pb(II) were at the initial Pb(II) concentration of 150 mg/L, dosage 0.35 g (AC-PKS) and 0.25 g (AC-EDTA), and pH 4. Thermodynamic studies showed that the adsorption process was spontaneous and endothermic. The AC-PKS and AC-EDTA both demonstrated high Qmax of 80.6 mg/g and 104 mg/g, respectively, for Pb(II) adsorption. The adsorption data also fitted the Thomas fixed-bed adsorption model.

Biomass-promoting routes for the synthesis of activated carbon (AC) have recently received considerable attention due to the advantages of this method: it is simple, cost-effective, and ecofriendly. This method is also an alternative way to avoid the unsafe practice of waste incineration. We describe the preparation of activated carbon from palm kernel shell (PKS) – an abundant biomass that is available in Africa and Asia. We investigated the effect of process variables such as impregnation ratio (ratio of H3PO4 to PKS) and carbonisation temperature (500–700 °C) on yield, microstructure, morphology, pore structure, and adsorption properties to optimise these parameters. Nitrogen adsorption isotherm analysis indicated that the AC was predominantly microporous in nature. Under optimal conditions, an AC with the highest surface area of 1560 m2/g was obtained. The aqueous adsorption test showed that the AC had significant removal capacity for methylene blue and iodine. The higher iodine value is consistent with the structural properties of the adsorbent, while the lower methylene blue value is consistent with the limited mesopore width. Considering the chemical and surface properties and adsorption properties of the AC produced, PKS has been shown to be an excellent precursor material for AC, thus solving the disposal problems associated with this biomass. Significance: AC significantly promotes adsorption and offers a low-cost and cleaner production method. PKS could serve as a dependable precursor for the synthesis of porous AC. This study provides useful information on how H3PO4-impregnated PKS influences the porosity of the resulting AC. Differences in porosity, yield, and morphology and Brunauer–Emmet–Teller surface area are achievable using AC from PKS.

In this present work, a novel method for synthesis of palm kernel shell activated carbon was established using DES (choline chloride/urea)/H₃PO₄ as the activating agent. The pore characterization, morphology, and adsorption properties of the activated carbons were investigated. The activated carbon samples made from the same feedstock at two pyrolysis temperatures (500 and 600 °C) were compared for their ability to adsorb Pb(II) in aqueous solution. The results demonstrated that the production of the activated carbon and adsorptive properties were significantly influenced by the pyrolysis temperature and the ratio of precursor to activating agent. DES/H₃PO₄ activated carbon (having surface area 1413 m²/g and total pore volume 0.6181 cm³/g) demonstrated good Pb(II) removal. Although all the tested activated carbon samples adsorbed Pb(II) from aqueous solution, they demonstrated different adsorption capabilities according to their various properties. The pyrolysis temperature, however, showed little influence on the activated carbon adsorption of Pb(II) when compared to the impregnation ratio. Their good desorption performance perhaps resulted from the porous structure.