Desorption of copper ions from the polyamine-functionalized adsorbents: Behaviors and mechanisms

Abstract

This paper is aiming at analyzing the desorption performance of the four polyamine-functionalized adsorbents after copper ion adsorption, with nitric acid as the desorption agent. The four adsorbents (namely, P-EDA, P-DETA, P-TETA and P-TEPA) studied were immobilized with ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetramine (TETA) and tetraethylenepentamine (TEPA), respectively. Nitric acid concentration, ionic strength, and solid-to-liquid (S/L) ratio were taken into consideration as the influencing factors on the desorption performance. The findings showed that higher desorption efficiency had no necessary connection with the higher concentration of nitric acid, and the highest desorption efficiency was realized for P-EDA and P-DETA at 0.10 mmol/L, and for P-TETA and P-TEPA at 0.25 mmol/L, in the nitric acid concentration range of 0.01-2.00 mmol/L studied. In addition, Ionic strength showed obvious influence on the desorption efficiency, and higher ionic strength resulted in significant lower desorption efficiency. Different S/L ratios studied showed almost no differences on the desorption efficiency. The copper ion desorption kinetics, best described by the Elovich model, was discovered to be very fast that more than 85% of the desorption efficiency was attained within 2 min. A slight decrease in Cu ion adsorption capacity was found through ten cycles of adsorption-desorption-regeneration for all the four adsorbents.

Copper-Binding Properties of Polyethylenimine–Silica Nanocomposite Particles

“…The first two peaks correspond to Cu-bound amines 78,84 and protonated amines with a shift of binding energy of 0.7− 0.9 eV and an increase of the atomic ratio of the protonated amines (A/B ≈ 2:1) in comparison with pristine material. The increase in the binding energy of amines in Cu-loaded materials is similar to that observed in the study on copper adsorption by aminated poly(glycidyl methacrylate) 86 and could be explained by the chelation of copper by amines, 73 which increased the binding energy of the corresponding nitrogen electrons. 83 The increase in the atomic ratio of the protonated amines after binding of copper reflects the decrease of pH to 3−4 during this reaction, while pristine materials have a natural pH around 9, not allowing a high rate of protonation.…”

“…83 The increase in the atomic ratio of the protonated amines after binding of copper reflects the decrease of pH to 3−4 during this reaction, while pristine materials have a natural pH around 9, not allowing a high rate of protonation. The third peak corresponds to nitrates, 73,78,86 which are counterions for Cu 2+ ions in the present study and were electrostatically adsorbed to the PEI network. Observed changes in the XPS scans for the composites and microgels before and after the introduction of copper confirm that the formation of Cu−amine complexes is the key process underlying the copper-binding capabilities of both the PEI microgel and PEI−silica composite.…”

“…For pristine composites (Figure 6D), two peaks N 1s-A (∼398.5 eV) and N 1s-B (∼400.3 eV) with atomic ratio A/B ≈ 10:1 were detected, which are assigned to neutral amines and protonated amines, respectively. 73,78,84,86 After binding of copper, the N 1s spectra showed three peaks: N 1s-A (∼399.3 eV), N 1s-B (∼401.1 eV), and N 1s-C (∼406.4 eV) (Figure 6E). The first two peaks correspond to Cu-bound amines 78,84 and protonated amines with a shift of binding energy of 0.7− 0.9 eV and an increase of the atomic ratio of the protonated amines (A/B ≈ 2:1) in comparison with pristine material.…”

Agricultural waste of sugarcane bagasse as efficient adsorbent for lead and nickel removal from untreated wastewater: Biosorption, equilibrium isotherms, kinetics and desorption studies

“…for the removal of heavy metals from wastewater through conventional methods (membrane filtration; solvent extraction, ion exchange, reverse osmosis, oxidation, chemical precipitation, etc.). However, these methods have many shortcomings of generation of toxic chemical sludge, incomplete metal removal, low efficiency, requirement of high energy and high reagent [ [13] , [14] , [15] ]. Hence, new cost effective, safe and economic tools are recommended to reduce the limitations of the conventional methods.…”

“…Biosorption is an alternative, favourable and effective tool highly recommended for the removal of heavy metal ions from waste water because of its many advantages of low operation cost, eco-friendly, minimal or no toxic sludge generation, short operating time, easy to prepare, no supplementary nutrient required, possibility of metal recovery and availability [ 13 , 14 ]. Numerous biomass-based adsorbents from biological (fungi, algae, yeast and bacteria) and agricultural origin (rice husk, saw dust, banana peels, corn cob, orange peel, sawdust, sugarcane bagasse, etc.…”