Phosphate removal using modified Bayoxide® E33 adsorption media

Abstract

The adsorption of phosphate onto modified Bayoxide® E33 (E33) and underlying mechanisms were comparatively investigated by batch kinetics, sorption isotherms, rapid small-scale column tests, and material characterization. Synthesis of modified E33 was conducted by the addition of manganese and silver nanoparticles on the surface of the goethite (α-FeOOH)-based E33. Upon successful adsorbent synthesis, the materials were characterized using SEM, TEM, XRD, EDX, HR-TEM, and BET surface area analysis. The adsorption kinetics is described by a fast initial adsorption stage followed by a slow adsorption stage, complying with pseudo second-order kinetics and Elovich kinetics. Sorption isotherms revealed that the equilibrium capacity of one of the modified adsorbents (E33/AgII) exceeded that of unmodified E33 likely due to its increased BET surface area. Column experiments confirmed the results for adsorption kinetics and equilibrium of phosphate sorption onto E33 and modified E33. This suggests that media modification has the potential to improve phosphate removal properties.

The mechanisms of conventional pollutants adsorption by modified granular steel slag

“…Thermally modified GSS had the highest pH value in deionized water (Fig. 5), indicating that there were a large number of free hydroxyl groups in the solution, due to the complex reaction of Ca 2+ and Mg 2+ with water [17,30]. However, the pH did not change significantly in phosphates solution, either.…”

“…The original GSS had a phosphates adsorption capacity of 2.33 mg/g, and the main mechanisms of phosphates removal by GSS were chemical precipitation and ligand exchange [14,22,28]. The main mechanism of chemical precipitation was that Ca 2+ , Fe 2+ , Al 3+ hydrolyzed from GSS reacted with phosphates to form Ca-P and other precipitations [27,[29][30][31]. The main equations are as follows:…”

“…The fitting results of the isothermal adsorption model were shown in Table S3. Langmuir model was more suitable for the adsorption process of phosphates by the GSS, which indicated that the single layer adsorption occurred at a specifically uniform location [30].…”

Removal of phosphate and nitrate ions aqueous using strontium magnetic graphene oxide nanocomposite: Isotherms, kinetics, and thermodynamics studies

“…Phosphates are commonly used as fertilizers and also present in detergents, baking powder, toothpaste, cured meat, evaporated milk, soft drinks, processed cheese, pharmaceuticals, and water softeners . Not only have increasing phosphate ions brought concern about several human disease it causes, it has also drawn a profound attention toward its effects on eutrophication . Consequently, WHO set the maximum level of phosphate ions in drinking water 50 μg/L.…”

Enhanced phosphate removal under an electric field via multiple mechanisms on MgAl-LDHs/AC composite electrode

“…Numerous adsorbents have been investigated for selective phosphate removal through specific (via inner-sphere complexation) and nonspecific interactions (via electrostatic affinity/outer-sphere complexation) of phosphate with the functional groups of the adsorbents [8]; these adsorbents include lanthanum oxide and hydroxide [9][10][11], iron oxides and hydroxides [12,13], magnesium oxide and hydroxide [14,15], aluminum hydroxides [16], and cobalt-containing spinel oxides [17], and Bayoxide® E33 [18]. Among them, layered double hydroxide (LDH) is one of the most widely used options and phosphate contained LDHs recently shows potential application in slow release phosphate fertilizer [19][20][21].…”