A review: a comparison of different adsorbents for removal of Cr (VI), Cd (II) and Ni (II)

Abstract

A review of the studies dealing with the removal of chromium, cadmium, and nickel ions with different adsorbents published in the literature between 2014 and 2018 is given in tabular form, along with the adsorption conditions, adsorption isotherm, and kinetic models applied by the authors to model the experimental data and adsorption capacities. The review focuses on the efficiency of ion removal.

Adsorption of cadmium ion from water using activated carbon produced from palm kernel shell

“…This suggests that the higher the dosage of adsorbents in the solution, the more sites available for exchangeable ions up to the point of saturation. It also shows that after the saturation point, only part of the active sites are occupied by Cd 2+ , leading to a lower % adsorption 22 .…”

Poly(2-vinylpyridine)/MCM-41 Composites with Micropores and Switchable Mesopores for the Removal of Cr(VI)

“…Among Cr­(VI) pollution treatment technologies, − the adsorption technique possesses wider application potentials due to its low cost, high efficiency, simple process, and good regeneration ability. Carbon-based materials, natural mineral materials, mesoporous silica, organic framework materials, and biomass materials were used to trap Cr­(VI) in solution and exhibited excellent removal capacity. − Compared with other materials, mesoporous silica materials exhibit good capture to Cr­(VI) based on its high surface area and porosity, low cost, simple preparation, and easy surface modification. − Organics (ethylenediamine, pyrene, etc. ), polymers (polyethyleneimine, polyamidoamine, etc.…”