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The presence of poisonous Pb(II) ions in water resources has raised global health concerns. Herein, the adsorption performance of accordion‐like Ti3CN MXene for Pb(II) ions was investigated for the first time. Batch experiments were carried out by varying modifications, pH values, initial Pb(II) concentrations, adsorption time and temperatures. The results prove that the alkalized‐Ti3CN shows enhanced adsorption performance. Although the temperature effect is insignificant, the Pb(II) adsorption is strongly pH‐dependent. The maximum Pb(II) adsorption capacity of alkalized −Ti3CN is about 2.5 times higher than that of activated carbon. The adsorption ratio of Pb(II) is up to 96.6 %. The adsorption capacity increases with increasing the initial concentration of Pb(II). The alkalized‐Ti3CN adsorbs Pb(II) very quickly and the adsorption equilibrium is nearly achieved within 70 minutes. The adsorption follows the quasi‐second‐order kinetic model as well as the Langmuir model, and is mainly controlled by chemical adsorption. It is preliminarily concluded that Pb(II) replaces Na(I) of the −ONa functional groups on the alkalized‐Ti3CN surfaces. This study proves the alkalized‐Ti3CN MXene has potential application for the purification treatment of wastewater contaminated with Pb(II) ions. [ABSTRACT FROM AUTHOR]

BACKGROUND: Pb(II)‐containing wastewater causes serious pollution in our daily life. Adsorption is the technique most often used to remove heavy metals from aqueous solution. For improving the removal efficiency of Pb(II) ions from aqueous solution, adsorbent materials and the functionalization method of the adsorbent need to be further studied. RESULTS: A novel Schiff's base functionalized bio‐material (DAS2‐AT) with two tridentate coordinated units was synthesized by the reaction of 2‐acetylthiophene and modified dialdehyde starch (DAS‐NH2) for the adsorption of Pb(II) ions from aqueous solution. Experimental results demonstrated that the DAS2‐AT exhibited high adsorption capacity and selectivity towards Pb(II), and the maximum adsorption capacity was up to 203 mg g−1. The adsorption isotherms and kinetic of Pb(II) ions on the DAS2‐AT were correlated well with the Langmuir isotherm model and Pseudo‐second‐order model. Moreover, thermodynamic analysis indicated that the adsorption process is spontaneous and endothermic. Desorption and regeneration experiments indicated that DAS2‐AT has good reusability. Besides that, the adsorbent displayed good affinity of DAS2‐AT towards Pb(II) ion in the presence of Cr(VI), Zn(II), and Ni(II) ions. CONCLUSION: The bio‐adsorbent (DAS2‐AT) displayed good adsorption performance to remove Pb(II) ions from aqueous solution. DAS2‐AT gave a potential application as a low‐cost and effective adsorbent. © 2021 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

This study reports on the adsorption characteristics of Pb(II) ions from aqueous solutions using ZnCl-activated date ( Phoenix dactylifera) bead (ADB) carbon with respect to change in adsorbent dosage, initial pH, contact time, initial concentration, and temperature of the solution. Kinetic studies of the data showed that the adsorption follows the pseudo-second-order kinetic model. Thermodynamic parameters, enthalpy change (Δ H° = 55.11 kJ/mol), entropy change (Δ S° = − 0.193 kJ/mol/K), and Gibbs free energy change (Δ G°) were also calculated for the uptake of Pb(II) ions. These parameters show that adsorption on the surface of ADB was feasible, spontaneous in nature, and endothermic between temperatures of 298.2 and 318.2 K. The equilibrium data better fitted the Langmuir and Freundlich isotherm models than the D-R adsorption isotherm model for studying the adsorption behavior of Pb(II) onto the ADB carbon. It could be observed that the maximum adsorption capacity of ADB was 76.92 mg/g at 318.2 K and pH 6.5. The results of this study suggested that the pseudo-second order kinetic model can be used extensively to describe the adsorption of Pb onto ZnCl activated date bead carbon over the range of studied parameter, as it has the best correlation coefficient and Chi-squared test for the obtained data. [ABSTRACT FROM AUTHOR]