Adsorption of lead(II) from aqueous solution using a poly(ethyleneimine)‐functionalized organic–inorganic hybrid silica prepared by hydrothermal‐assisted surface grafting method

Abstract

The poly(ethyleneimine) (PEI)-functionalized organic-inorganic hybrid silica was prepared by a hydrothermal-assisted surface grafting technique. Static adsorption experiment results showed that PEI-functionalized hybrid silica had high static adsorption capacity of 68.1 mg g À1 , which was 1.3 times as much as that of the sorbents by conventional heating method. PEI-functionalized hybrid silica displayed stable adsorption ability for Pb(II) ions in the range of pH 4-8. An equilibrium state was reached within 30 min. Freundlich and Langmuir adsorption isotherm models were used to fit the equilibrium data, and it was found that the Langmuir adsorption model provided good fit. Kinetic studies indicated that the adsorption followed a pseudo-second-order model. Various thermodynamic parameters, such as ΔG o , ΔH o and ΔS o , were evaluated with results indicating that this system was a spontaneous and endothermic process. The results indicated that PEIfunctionalized hybrid silica could be employed as an effective material for the adsorption of Pb(II) ions from aqueous solutions.

Adsorptive removal of biophenols from olive mill wastewaters (OMW) by activated carbon: mass transfer, equilibrium and kinetic studies

“…As depicted in Table , the adsorption efficiency of phenolic compounds increases in the ranges 40.9% to 45.1% for AC1, 38.8% to 42.6% for AC2, and 34.2% to 38.4% for AC3 adsorbent when increasing the temperature from 298.2 to 318.2 K. This suggests that the interaction of adsorbate and adsorbent is endothermic in the nature. The temperature dependence of adsorption process is associated with changes in several thermodynamic parameters such as standard Gibbs energy (Δ G 0 ), enthalpy (Δ H 0 ), and entropy (Δ S 0 ) of adsorption, which can be calculated from the following equations where K C is the equilibrium constant defined as the ratio of the amount of phenols adsorbed onto the adsorbent ( C AC ) to the concentration of phenols in the aqueous phase ( C e ).…”

Influence of process parameters on sorption capacity of microwave activated biosorbents for urea recovery from human urine: a comparative study

“…Recently, low‐cost precursors have been the focus of researchers' worldwide . Precursors from wastes and agricultural by‐products such as almond shells, bamboo, cactus leaves, coir pith, grape waste, hazelnut, Indian rosewood sawdust, jute fiber, oil palm fiber, olive cake and stones, orange waste, mango kernel, bagasse fly ash, pine needles, rice husk, rubber seed coat, sawdust, walnut, wheat bran and wool have shown potential for removal of organic and inorganic contaminants …”