Poly(vinyl chloride)-supported triazoles grafted onto calix[4]arene for chromium ions extraction

A new suitable material was synthesized using click reaction between dialkynyl-p-tert-butylcalix[4]arene and poly(vinyl chloride) azide (PVC-N3). This novel dialkynyl-p-tert-butylcalix[4]arene with triazole groups grafted onto PVC polymer (PVC-0.75CX[4]) has an excellent extraction capability for chromium ions from aqueous solutions. It shows a unique ability to extract chromium (VI) ions from aqueous solutions, thanks to the soft cavity, the presence of π-triazole rings and hydrogen bonds. Cr (VI) ion sorption capacity is 95.5% at pH = 3.

Adsorption of phosphate ions from aqueous solutions by layered magnesium and aluminum double hydroxide obtained by solid-phase synthesis

A layered double hydroxide of magnesium and aluminum was obtained by solid-phase synthesis.It was found that it has a predominantly mesoporous structure with cylindrical and wedge-shaped pores, as well as a specific surface area of 50 m2/g. The process of phosphate ion sorption by a synthesized sample is studied. Processing of experimental data on the Freundlich and Langmuir sorption equations showed that the process is described fairly accurately by the Langmuir monomolecular adsorption equation. The capacity of the adsorption monolayer of the synthesized sample with respect to the РО43--ion and the adsorption equilibrium constant are calculated.

Poly (Amidehydrazide) Hydrogel Particles for Removal of Cu2+ and Cd2+ Ions from Water

Poly(amidoamine)s (PAMAM) are very effective in the removal of heavy metal ions from water due to their abundant amine and amide functional groups, which have a high binding ability to heavy metal ions. We synthesized a new class of hyperbranched poly(amidehydrazide) (PAMH) hydrogel particles from dihydrazides and N,N′-methylenebisacrylamide (MBA) monomer by using the A2 + B4 polycondensation reaction in an inverse suspension polymerization process. In Cd2+ and Cu2+ ion sorption tests, the synthesized dihydrazide-based PAMH hydrogel particles exhibited sorption capacities of 85 mg/g for copper and 47 mg/g for cadmium. Interestingly, the PAMH showed only a 10% decrease in sorption ability in an acidic condition (pH = 4) compared to the diamine-based hyperbranched PAMAM, which showed a ~90% decrease in sorption ability at pH of 4. In addition, PAMH hydrogel particles remove trace amounts of copper (0.67 ppm) and cadmium (0.5 ppm) in water, below the detection limit.

Studies on the Mechanism of Cu(II) Ion Sorption on Purolite S 940 and Purolite S 950

The aim of the presented research was to investigate the mechanism of sorption of Cu(II) ions on the commercially available Purolite S 940 and Purolite S 950 chelating ion exchangers with the aminophosphonic functional groups. In order to understand better the sorption mechanism, the beads were cut with an ultramicrotome before and after the Cu(II) ion sorption process. The cut beads were examined by scanning electron microscopy (SEM) with an EDX detector. The performed linear profiles of the elemental composition allowed us to examine the depth with which the sorbed metal penetrates into. For further investigations concerning the mechanism of the sorption process, the Fourier transform infrared spectroscopy (FTIR) analysis using the attenuated total reflectance (ATR) technique and the X-ray photoelectron spectroscopy (XPS) methods have been used. The comparison of FTIR and XPS spectra before and after the sorption of Cu(II) ions showed that free electron pairs from nitrogen and oxygen in the aminophosphonic functional groups participate in the process of copper ion sorption. In addition, the microscopic studies suggested that the process of ion exchange between Na(I) ions and sorbed Cu(II) ions takes place on the Purolite S 940 and Purolite S 950. This study concerning the in-depth understanding the of Cu(II) sorption mechanism, using modern analytical tools and research methods could be very useful for its further modifications leading to the improvement of the process efficiency.