Facile Fabrication of Calcium-Doped Carbon for Efficient Phosphorus Adsorption

Abstract

High phosphorus concentrations mainly result in environmental problems such as agricultural pollution and eutrophication, which have great negative influence on many natural water bodies. In this work, calcium lignosulfonate was employed to produce calcium-doped char at 400 and 800 °C. To compare the phosphorus adsorption behaviors of the two carbon materials, batch adsorption experiments were conducted in a phosphorus microenvironment. The factors including the initial solution pH, phosphorus concentration, and adsorbent amount were considered, and the main characteristics of calcium-doped chars before and after adsorption were assessed. The results revealed that the phosphorus removal processes fitted both the Freundlich and pseudo-second-order-kinetic models. According to the Langmuir model, the maximum adsorption capacities of the two adsorbents obtained at 400 and 800 °C toward phosphorus (50 °C) were 53.22 and 17.77 mg/g adsorbent, respectively. The former was rich in calcium carbonate (CaCO 3 ) and hydroxyl and carboxyl groups, and it mainly served as a precipitant and a chelating agent, while the latter with a high surface area was dominant in P adsorption.

Iron–ozone catalytic oxidation reactive filtration of municipal wastewater at field pilot and full‐scale with high‐efficiency pollutant removal and potential negative CO2e with biochar

“…Modification of BC has been reported to increase P sorption on BC (Bakshi et al, 2021; Jung & Ahn, 2016; Li et al, 2018; Li et al, 2020; Liu et al, 2015; Min et al, 2020; Mood et al, 2020; Wang & Wang, 2019; Zhang et al, 2021). Using Fe for BC modifications is often promoted because Fe is relatively inexpensive and increases the sorption capacity of the BC, making it more suitable for P and micropollutant removal from wastewater (Kearns et al, 2021; Nobaharan et al, 2021; Psaltou et al, 2022).…”

Oyster Shell Modified Tobacco Straw Biochar: Efficient Phosphate Adsorption at Wide Range of pH Values

“…Hydroxyl surface charge density due to the migration of Ca-BC surface protons in solution, the surface charge density changes as the material adsorbs ions from the solution. The pH PZC value of Ca-BC is 3.81 ( Figure 2 b), which indicates electrostatic inhibition effect on phosphate solutions with initial pH varying from 3.81 to 11 [ 1 , 30 ]. It is speculated that when the initial pH is acidic, chemical binding energy plays a dominant role and phosphate adsorption capacity is high.…”

“…Phosphorus (P) is one of the three essential nutrients (N, P, and K), which plays a pivotal role in maintaining crop growth and improving grain yield [ 1 , 2 ]. The sources of phosphorus emission mainly include three aspects: industrial, agricultural, and domestic sources.…”

Reactivity of Fe-amended biochar for phosphorus removal and recycling from wastewater

“…Research on biochars made from traditional carbon-rich biomass feedstock such as forest biomass, plant fibers from agricultural residue, and coconut fibers, indicates that they do not sorb large amounts of P. Several papers have provided methods for modifying the biochars to enhance P sorption [15]. Some of the most common modifications include adding Fe to the biochar [50,52,55] or adding Ca or Mg [60,63,64]. Other more complex modification methods have also been developed to produce magnetic biochars [68][69][70] as well as the AD biochar that was modified by pyrolyzing anaerobic digestate in the presence of ammonia gas to create positively charged amine functional groups that can adsorb P [44].…”

“…To enhance P removal from solution onto biochar, several biochar modifications have been proposed, including Fe [21,[49][50][51][52][53][54][55][56][57], and alkaline earth metals Mg or Ca [58][59][60][61][62][63][64]. Other less common biochar modifications, such as Zr [65,66], polymer modification [40], or creation of a magnetic Fe-doped biochar [67][68][69][70] have also been proposed.…”