Sand/Polyethyleneimine Composites with Enhanced Sorption/Desorption Properties toward Pollutants

Abstract

The direct deposition of polyethyleneimine (PEI), a weak polycation with a large content of amino groups, onto sand fractions with different sizes (F70, F100, F200, and F355), resulted in versatile core-shell sorbents for water cleaning. Herein, PEI and the weak polyanion poly(acrylic acid) (PAA) were directly precipitated as an nonstoichiometric polyelectrolyte complex ([PEI]:[PAA] = 2:1) onto a sand surface followed by cross-linking with glutaraldehyde (GA) at three molar ratios ([CHO]:[amine] = 1:10; 1:5; 1:1 = r). Non-crosslinked polyelectrolyte chains were washed out in strongly basic (pH 14) and acidic (pH 0) media. The sand/PEI-GA composites were evaluated to determine the organic shell stability using swelling experiments and X-ray photoelectron spectroscopy. The sorbed/desorbed amount of two model pollutants (copper ions and bromocresol green) in column experiments depended on the sand fraction size and cross-linking degree of the PEI shell. The maximum recorded values, after five loading/release cycles of pollutant species onto F70/PEI-GAr, F100/PEI-GAr, F200/PEI-GAr, and F355/PEI-GAr, were situated between the 0.7–5.5 mg Cu2+/mL column and 3.7–15 mg BCG/mL column. Sand/PEI-GAr composites could act as promising sorbents, low-cost and eco-friendly, which could be applied for water purification procedures.

Versatile Zwitterionic Beads for Heavy Metal Ion Removal from Aqueous Media and Soils by Sorption and Catalysis Processes

“…For cleaning water, both synthetic and natural polymers are attractive. They can be employed as membrane coatings, flocculants, or for the low-cost production of various sorbents for pollutants like fibers, hydrogels, resins, or core–shell particles. – The synthetic ionic exchange resins are synthetic polymers that takes advantage of the properties of forming chelates with HMIs and exchanges them with nonharmful hydrogen ions. ,,– They are reusable and highly stable in alkaline or acidic solutions. Column laboratory studies, which are considered preliminary to implementing a larger scale solution, are recommended for improving HMI sorption efficiency under real application conditions.…”