Removal of aluminum from alkaline aqueous solution by adsorption on Degussa P25 TiO₂ and vermiculite concrete‐supported ferric oxyhydroxide

Abstract

The current investigation on aluminum adsorption from an aqueous solution originated from the need to implement a water treatment technology that would decrease the prohibitive aluminum concentrations in the groundwater of the Khibiny Alkaline Massif (Kola Peninsula), which is limiting the use of this water source as a source for the household water supply in the area. TiO2 and vermiculite concrete‐supported ferric oxyhydroxide (VC) were used as adsorbents to remove aluminum from the alkaline aqueous solution, considering the water‐specific natural conditions of the Khibiny aquifer. The effects of pH, initial aluminum concentration, contact time, adsorbent dose, and ions present in Khibiny groundwater were investigated. The results showed that the adsorption kinetics followed the pseudo‐second order model, and the equilibrium data were described well by Langmuir and Freundlich isotherm models. The aluminum adsorption on TiO2 exhibited a dramatically higher adsorption rate compared to VC; the adsorption equilibrium was reached in 30 and 240 minutes, respectively, while the maximum TiO2 and VC adsorption capacities were similar and had values of 6.85 and 6.75 mg g−1 as the results of laboratory tests revealed. It was shown that when these two adsorbents worked jointly the capacity reached 8.28 mg g−1 within 60 minutes at pH 9.0. No apparent significant effects on aluminum removal by adsorbents tested in the presence of SO42−, NO3−, and Cl− were observed. The obtained outcomes identify a possible approach and reliable foundation for water treatment technology to solve the problem of elevated aluminum concentrations in the household water of the Khibiny Alkaline Massif area as well as within other locations where the solution of this problem can improve living conditions or industrial technologies.

Photocatalytic degradation of oily waste and phenol from a local South Africa oil refinery wastewater using response methodology

“…The average grain size of the nanoparticles was estimated by using the x-ray line augmentation technique together with the Scherrer (2) [48][49][50] . The estimated size for the anatase (110) and rutile (101) respectively were about 23 nm and 39 nm, which was close to what has been reported 50,51 . The estimated particle size and crystal structure signify scattering rising from large crystals produce Bragg peaks as a function of the reflection angle [48][49][50][51] .…”

“…The estimated size for the anatase (110) and rutile (101) respectively were about 23 nm and 39 nm, which was close to what has been reported 50,51 . The estimated particle size and crystal structure signify scattering rising from large crystals produce Bragg peaks as a function of the reflection angle [48][49][50][51] . Figure 3 presents the SEM image (a and b) of the TiO 2 nanoparticle morphology before and after the experiment, as well as the EDS image (c).…”

“…Likewise, the estimated smaller and larger particle size appears to be about 23 and 39 nm respectively 47,48 . This suggest that the smaller particles are the anatase whereas the larger particles are rutile as established by other authors [47][48][49][50][51] . Figure 4 shows the EDS peaks (a) with its corresponding elemental distribution (b) deposited on the photocatalyst slurry.…”

“…Also, the broad diffraction peak at 2θ = 15-25° in the XRD (Fig. 1) might also be the amorphous silica layer 48,51 . This is likely to rapture an amount of the TiO 2 photocatalyst reactive site from oxidation and might suppress the photocatalytic efficiency 48,50,52 .…”

“…3c) signifies agglomeration occurrence during mineralization 50,51 . From the EDS image (a-peaks; b-table), it was certain the chemical composition in the wastewater can suppress the TiO 2 photocatalyst 51,52 . The appreciable increasing order of compounds presence were as follows:…”