Adsorption of phosphate and cadmium on iron (oxyhydr)oxides: A comparative study on ferrihydrite, goethite, and hematite

Gas–Liquid Reactions to Synthesize Positively Charged Fe3O4 Nanoparticles on Polyurethane Sponge for Stable and Recyclable Adsorbents for the Removal of Phosphate from Water

“…Meanwhile, there is no Fe−P precipitation, meaning that electrostatic or physical adsorption has occurred. 70 Therefore, according to the above results, the reaction mechanism of Fe 3 O 4 nanoparticles accompanied by coordination can be depicted as follows: 35 − was also adsorbed by electrostatic attraction with (Fe-TEA) + . Thus, one can infer a better adsorption performance for GL-Fe 3 O 4 -TEA because of more adsorption sites (Figure 9).…”

“…Therefore, according to the above results, the reaction mechanism of Fe 3 O 4 nanoparticles accompanied by coordination can be depicted as follows: FeCl 3 /FeCl 2 are hydrolyzed to Fe–OH, while portions of Fe 3+ /Fe 2+ are coordinated with TEA to form (Fe-TEA) + Cl – , which preserve the positive charge. On the basis of the above mechanism combined with the established phosphate adsorption mechanism on Fe 3 O 4 , the phosphate adsorption models on GL-Fe 3 O 4 -TEA could include three types of interaction (electrostatic attraction with and without H + and ion exchange with OH – ) Fe − OH + normalH 2 PO 4 − = Fe ( H 2 PO 4 ) + OH − Cl ··· Fe − TEA + normalH 2 PO 4 − = ( H 2 PO 4 ) · · · ( Fe − TEA ) + Cl − Fe − OH + normalH + + normalH 2 PO 4 − = Fe − OH 2 ··· normalH 2 PO 4 …”

“…Iron oxide nanoparticles are some of the most widely studied materials for phosphate removal. , The most often used approaches for the synthesis of iron oxide nanoparticles include coprecipitation, electrospinning, gas-phase synthesis, hydrothermal method, membrane emulsification, microemulsion, microwave-assisted synthesis, sol–gel method, and ultrasonic-assisted methods . The interest in these sorbents originates from their amphoteric characteristics, chemical stability, and cost-effective synthesis.…”

Characteristics of the Properties of Absodan Plus Sorbent and Its Ability to Remove Phosphates and Chromates from Aqueous Solutions

“…However, they are more advanced materials that require special reagents to produce. It is also a mineral that effectively adsorbs phosphates by surface complexation and precipitation [ 78 , 79 , 80 ]. As shown in Table 8 diatomite coated by hydrous iron oxide and metallic iron/iron oxides are characterized by a significant increase in the adsorption capacity of phosphates and chromates [ 27 , 28 ].…”

Oxalate promoted iron dissolution of hematite via proton coupled electron transfer

“…Hematite is one of the most abundant iron (oxyhydr)oxide minerals in soils, rocks and crust. [32][33][34] And the {001} facet of hematite possesses a relatively low surface energy that makes it one of the most exposed and naturally growing surfaces for natural hematite, [35][36][37] and widely studied in geochemical and environmental sciences. [38][39][40][41][42][43] Moreover, its atomic structure and properties have been extensively studied both experimentally and theoretically, which are the preconditions to clarify the mechanism of oxalate promoted iron dissolution.…”