Utilization of industrial waste as a novel adsorbent: Mono/competitive adsorption of chromium(VI) and nickel(II) using diatomite waste modified by EDTA

Abstract

The adsorption of Cr(VI) and Ni(II) using ethylenediaminetetraacetic acidmodified diatomite waste (EDTA-DW) as an adsorbent in single and binary systems was investigated. The EDTA-DW was characterized using various analytical techniques, including Fourier transform infrared spectroscopy, thermogravimetric analysis, Brunauer-Emmett-Teller measurements, X-ray diffraction, scanning electron microscopy and energy-dispersive spectrometry.The adsorption experiment was conducted by varying pH, adsorbent dosage, initial concentration and temperature. In the single system, the sorption data for Cr(VI) fitted the Langmuir isotherm, but the Ni(II) adsorption data fitted well the Freundlich isotherm. The maximum sorption capacity of Cr(VI) and Ni(II) was 2.9 mg g −1 at pH = 3 and 3.64 mg g −1 at pH = 8, respectively. The kinetic data for both Cr(VI) and Ni(II) followed well the pseudo-second-order kinetic model in single and binary systems. Meanwhile, the extended Langmuir and extended Freundlich multicomponent isotherm models were found to fit the competitive adsorption data for Cr(VI) and Ni(II). In addition, in the binary system, the existence of Ni(II) hindered the adsorption of Cr(VI), but the presence of Cr(VI) enhanced the removal of Ni(II). This study provides some realistic and valid data about the usage of modified diatomite waste for the removal of metal ions.

Environmental Applications of Diatomite Minerals in Removing Heavy Metals from Water

“…Industrial waste diatomite from brewery has been used as material for removal of Cr(VI) and Ni(II) from aqueous solution as well. 89 The authors found that functional groups grafted onto diatomite chelated with metal species in aqueous solution and the removal mechanisms were shown in Figure 11.…”

Characterization and Use of Agroindustrial by-Products in the Removal of Metal Ions in Aqueous Solution

“…On the other hand, the Ni (II) ions behave differently from those of Cr (VI), while their adsorption percentage was lower using the three adsorbents, which could be explained due to the selectivity of the active sites by of Nickel ions [32]. It could also be due to the formation of soluble hydroxylated metal complexes understudy at pH 6, which compete with the active sites of the biomaterial surface and decrease the net concentration of Ni (II) in the solution, causing a decrease in the motive force to boosts the process of mass transfer from the solution to the adsorbent, and as a consequence, ion retention is reduced [11].…”

“…Thus, the African palm bagasse, which had the highest porous surface according to the SEM and BET analysis, is the one with the highest percentage of removal of this ion. Also, at pH 2 the surface of the adsorbent tends to protonate to a greater extent, which is why the adsorption of Cr (VI) ions is more effective [32].…”

Removal of heavy metals from binary and multicomponent adsorption systems using various adsorbents – a systematic review

“…The elimination of Ni(II) and Cr(VI) from mono-and bisolutes sorption media by modied diatomite waste as an adsorbent were performed in batch mode. 135 In the mono-solute medium, the sorption data of Cr(VI) and Ni(II) achieved by the adsorbent was accurately represented by the Langmuir and Freundlich models. At a solution pH of 3.00 and 8.00, maximum uptake efficiencies of 3.64 and 2.90 mg g −1 for Ni(II) and Cr(VI) were attained.…”