China 
Africa 
Explore chapters and articles related to this topic
Soil
Published in Stanley E. Manahan, Environmental Chemistry, 2022
Orthophosphate is most available to plants at pH values near neutrality. It is believed that in relatively acidic soils, orthophosphate ions are precipitated or sorbed by species of Al(III) and Fe(III). In alkaline soils, orthophosphate may react with calcium carbonate to form relatively insoluble hydroxyapatite: 3HPO42-+5CaCO3(s)+2H2O→Ca5(PO4)3(OH)(s)+5HCO3-+OH-
Phosphorus
Published in Robert H. Kadlec, Treatment Marshes for Runoff and Polishing, 2019
Wetland science has evolved to focus on categories of phosphorus compounds that are defined by methods of analysis (Table 10.1). In every case, the analytical result is reported as the elemental phosphorus content of the category. The most reactive forms are the dissolved phosphates, which change hydration in response to pH. The most common species are mono- and dibasic phosphates, which dominate at all typical wetland pH values (4 < pH < 9) (Morel and Hering, 1993). The generic term used for these inorganic phosphate ions is orthophosphate, (PO4-P). The molybdate analytical test nominally finds this form of phosphorus, but has been shown to also detect exchangeable phosphorus and colloidally bound phosphorus in eutrophic wetlands (Hens and Merckx, 2002).
A review of the application of iron oxides for phosphorus removal and recovery from wastewater
Published in Critical Reviews in Environmental Science and Technology, 2023
Shi-Xu Wang, Yun-Xin Huang, Qi-Fan Wu, Wei Yao, Yao-Yao Lu, Bao-Cheng Huang, Ren-Cun Jin
In previous studies, various adsorbents with different active components (e.g., La, Ce, Al, Fe) have been fabricated and used (Almeida et al., 2020; He et al., 2021; Kim et al., 2008; Liu et al., 2022a). Among them, iron (Fe) has gained increased attentions for using in wastewater treatment due to its low economic price and abundance in the Earth’s crust. Depending on the environmental conditions, iron can form various oxides, which can be found in a wide range of natural environments including soils, rocks, lakes, rivers, seafloor, air, and living organisms (Huang et al., 2021). Iron oxides are widely involved in various processes that occur in ecosystems, making their manipulation key for the control of phosphate concentrations in aqueous environments. Due to the high affinity of iron oxides for orthophosphate, they have been widely used for phosphorus adsorption and removal. Also, the adsorption performance of iron oxides has long-term stability and they are not easy to release the adsorbed phosphate ions, so they are more reliable in long-term application and treatment of water bodies with high phosphorus load (Bjerrum & Canfield, 2002; Wang et al., 2023; Zhang et al., 2022).
Phosphorus pollution control using waste-based adsorbents: Material synthesis, modification, and sustainability
Published in Critical Reviews in Environmental Science and Technology, 2022
Hongxu Zhou, Andrew J. Margenot, Yunkai Li, Buchun Si, Tengfei Wang, Yanyan Zhang, Shiyang Li, Rabin Bhattarai
Phosphorus occurs in waters as different forms, notably soluble forms (e.g., <0.45 μm filter) and particulate forms (e.g., retained on a 0.45 μm filter). Reactive P refers to orthophosphate or more operationally molybdate reactive P (MRP), which reflects the widespread use of molybdate in orthophosphate colorimetry (Bernhart & Wreath, 1955; Fiske & Subbarow, 1925; Kitson & Mellon, 1944). The nonreactive P fraction, also known as condensed or acid hydrolyzable P (AHP) or organic P (OP), includes inorganic polyphosphates (metaphosphates and di-, tri-, and tetra-polyphosphates) (American Public Health Association (APHA) et al., 2012). Among them, it is widely accepted that the orthophosphate is the key compound responsible for eutrophication and can exist in water as four different species: H3PO4, H2PO4−, HPO42−, and PO43−, depending on pH conditions (Kumar et al., 2019). Therefore, orthophosphate is the priority compound for P removal from water and subsequent recovery of P-rich products. Nonetheless, recent studies also show the necessity to remove and recover several types of non-orthophosphates (Lei et al., 2020; Venkiteshwaran et al., 2018).
Rubber wastewater treatment using UV, ozone, and UV/ozone and its effluent potency for microalgae Spirulina platensis cultivation medium
Published in Cogent Engineering, 2020
Hadiyanto Hadiyanto, Marcelinus Christwardana, Detian Indah Pratiwi, Silviana Silviana, Muhammad Syarifudin, Adian Khoironi
It has been known that there are two forms of phosphorus in the wastewater; the dissolved form and the particulate form. Orthophosphate, the primary form of dissolved phosphorus reacts with excess water and forms phosphoric acid. When the pH of the wastewater drops, phosphoric acid starts to exist in the wastewater. In our study, the pH decreased from 5.2 to 4.65, and it was illustrated in Figure 3(d).