Characterization and Arsenic Adsorption Behaviors of Water Treatment Residuals from Waterworks for Iron and Manganese Removal

Abstract

Water treatment residuals (WTRs), obtained from a groundwater treatment plant for biological iron and manganese removal, were investigated and used as adsorbents for arsenic removal. The surface morphology and structural features of the WTRs were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Brunauner–Emmett–Teller analysis (BET). Laboratory experiments were also carried out to test the adsorption capability and adaptability of WTRs on both As (III) and As (V) removal from the water. The results showed that the WTRs were mainly amorphous and had a large specific surface area of 253.152 m2/g. The maximum adsorption capacities, evaluated using the Langmuir isotherm equation, were 36.53 mg/g and 40.37 mg/g for As (III) and As (V), respectively. The pseudo-second-order model fitted the kinetic data better, with R2 more than 0.99 for both As (III) and As (V). The removal of As (V) decreased with the increase in pH, especially when the pH was above 9, whereas for As (III), the removal effectiveness almost remained constant at both acidic and neutral pHs. H2PO4− and SiO32− could strongly inhibit arsenic adsorption onto the WTRs, and the effect of other ions was little.

Bentonite-composite polyvinyl alcohol/alginate hydrogel beads: Preparation, characterization and their use as arsenic removal devices

“…Normally there are three stages during the adsorption processes in porous media (Zeng et al, 2019), in the case of samples PVA50/Alg50/Bent30 and PVA75/Alg25/Bent30 a similar result was obtained. In the first two hours, the first stage occurs where the adsorbate diffuses towards the adsorbent surface.…”

Synthesis of Fe3O4@mZrO2-Re (Re = Y/La/Ce) by Using Uniform Design, Surface Response Methodology, and Orthogonal Design & Its Application for As3+ and As5+ Removal

“…Therefore, the adsorption kinetics of As 3+ and As 5+ from solution by the adsorbent Fe 3 O 4 @mZrO 2 -Re (Re = Y/La/Ce) is more suitably designated by the Pseudo-second-order reaction kinetic model, where rate of reaction depended directly on the square of the concentration of the reactants remaining in the solution [ 48 ]. Many other researchers suggested that adsorption kinetics of Magnetic nanomaterials are supporting the Pseudo-second order Kinetics, and our results are also favoring the 2nd order kinetic model [ 49 , 50 , 51 ].…”

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

“…Previous studies have shown that iron oxides can be simply formed by the oxidation of Fe 2+ in natural water. However, due to the presence of other ions such as silica, calcium, or manganese, as well as organic matter in groundwater, the process of crystallization is constricted [ 35 , 36 ], which is demonstrated by the results of this study. Despite the high content of iron oxides, as demonstrated by XRF analysis, it was an amorphous form of iron compounds.…”

“…GWTRs-1 and 3 displayed a type II isotherm with a type H3 hysteresis loop ( Figure 4 ). This suits a mesoporous character with the construction of slit-shaped pores originating from the stacking of crystal particles [ 64 , 65 ], whereas GWTRs-2 and 3 had a composite of type IV isotherms with hysteresis loop of type H3, having adsorption curve characteristics of typical mesoporous material [ 36 ]. Table 3 shows the results of S BET and porosity analysis.…”