Chromium and nickel metal ions removal from contaminated water using Nigerian bentonite clay

Abstract

In this work bentonite clay was characterized and investigated for the adsorption of chromium and nickel metal ions from aqueous solution. The clay calcined at 650 °C was characterized for physical, chemical and textural properties. Nickel sulphate hexahydrate (NiSO4.6H2O) and chromium tri oxide (Cr2O3) solutions were used as metal model compounds to evaluate the adsorption efficiency of the clay in a batch mode. The initial metal ions concentration range from 10 to 50 mg/L and the maximum removal efficiency was 99.40% for Cr (III) and 71.50% for Ni (II) metal ions. Langmuir and Freundlich models were utilized for the analysis of adsorption equilibrium isotherm. The experimental data fitted well into Freundlich model for Cr (III) with regression coefficient (R2) of 0.996 and the Langmuir model for Ni (II) having R2 value 0.994. The Pseudo second order kinetic model fitted well for both chromium and nickel and their adsorption from single metal solutions followed the order Cr > Ni. Highlight The local clay has not been reported in any scholarly journal or publication. Theremoval of nickel and chromium using this clay has been found effective. The dataobtained will form a baseline for references and learning purposes.

Adsorptive Removal of Chromium (VI) Ions from Aqueous Solution by Banana Pseudo Stem Adsorbent

“…At 600 ppm, the removal efficiency of Cr (VI) decreases as insufficient availability of active sites, thus causing the saturation of the adsorbent's surface at equilibrium. Similar initial Cr (VI) concentration effects on removal trends were observed for absorbents prepared from iron-based solid waste and bentonite clay by Qi et al (2023) and Jock et al (2021), respectively.…”

“…Cr (VI) ions removal was drastically increased by 35.0% with the increase in initial concentration from 100 ppm to 300 ppm. This observation might be caused by the adsorbent surface having a large number of active sites available, which would increase the Cr (VI) adsorption (Jock et al, 2021). The percentage removal continued to increase by 6.4% at 400 ppm and thereafter achieved the highest removal of 88.4% at 500 ppm.…”

The Improvement of Natural Thai Bentonite Modified with Cationic Surfactants on Hexavalent Chromium Adsorption from an Aqueous Solution

“…These results confirm that neither Cr(III) nor Cr(VI) significantly changed the valency state after adsorption with NTB and MTBs. A previous study reported that the forms of Cr(III) at pH 4.2–12 were Cr 2 O 3 and minor Cr(OH) 3 [58]. These cation forms in the bulk solution were exchangeable with polycations of the bentonite surface, including Ca 2+ , Mg 2+ , Na + , and K + cations [59].…”