Iron-Based Water Treatment Residuals: Phase, Physicochemical Characterization, and Textural Properties

Abstract

Groundwater treatment residuals (GWTRs) are safe waste materials generated during drinking water treatment. GWTRs are mainly deposited in landfills, but the preferred solution should be reused or utilized for some components. To ensure proper sludge management, it is important to provide quality, chemical composition, and texture characteristics of GWTRs. Therefore, in this study, we aimed to investigate and compare the features of GWTRs collected from four water treatment plants. GWTRs were characterized by X-ray diffraction (XRD); scanning electron microscopy (SEM) with energy dispersion spectroscopy (EDS); Fourier transform infrared spectroscopy (FTIR); thermogravimetric, differential thermogravimetric, and differential thermal analysis (TG, DTG, and DTA, respectively); X-ray fluorescence (XRF); inductively coupled plasma optical emission spectrometry (ICP-OEP); specific surface area (SBET) measurement; and determination of the isoelectric point (pHIEP). According to the results, GWTRs are poor crystalline materials that are predominantly composed of ferrihydrite with minor calcite and quartz admixture. They formed heterogeneously mixed particles with irregular shapes. They were mainly composed of iron oxides (32–55%), silica (4–28%), calcium oxide (4–17%), and manganese oxides (0.3–4.0%). They were found to be mesoporous with a large specific surface area. Due to their composition and texture characteristics, GWTRs demonstrate good adsorption properties toward different compounds such as heavy metals and metalloids.

Efficient Adsorption of Tl(I) from Aqueous Solutions Using Al and Fe-Based Water Treatment Residuals

“…Figure 8 shows FTIR spectra used to evaluate functional group differences between Fe-WTR and Al-WTR before and after adsorption. The blank group (before adsorption) shows -OH stretching vibration peaks (3440 cm −1 ) [87,88], -OH bending vibration peaks (1640 cm −1 ) [54], and Al/Fe-O stretching vibration peaks (470 and 536 cm −1 ) on the WTR surface [89][90][91]. In addition, the peaks at 1040 and 1080 cm −1 correspond to Al-OH bending vibrations [92,93].…”

Application of modified water treatment residuals in water and wastewater treatment: A review

“…This high Fe content is due to the Fe based coagulants used in the water treatment process [ 36 ]. Likus et al [ 97 ] also reported high Fe content (32–56%) in groundwater treatment residuals.…”

Moringa oleifera leaf as a natural water purifier and causes decontamination of fecal-coliform bacteria

“…Although these coagulants are effective in reducing the particle and organic hindrances; however, they may be non-cost effective and harmful; in addition, they need special store and handling requirements (Yamaguchi et al, 2021). The previous study conducted by Likus et al, (2021) reported that the coagulants may also cause secondary water problems, such as residual iron and aluminum species, as well as harmful synthetic polymers in the treated water. All the chemicals used in water purification are costly, thus the use of native products such as plant extracts for clarification and purification of drinking water in the underdeveloped nations is an urgent need (Delelegn et al, 2018;Yamaguchi et al, 2021).…”