Removal of phosphates using eggshells and calcined eggshells in high phosphate solutions

Abstract

This study was conducted to evaluate the phosphate sorption properties of eggshell (ES) and calcined ESs (C-ESs) in a high-concentration phosphate solution. The C-ESs yield decreased rapidly at 900 °C, indicating that the CaCO3 constituting the ES was converted to CaO by the high calcination temperature. The optimum calcination temperature for phosphate removal using C-ES was 900 °C. The actual sorption amount of phosphate by ES and C-ES900 was in agreement with the Langmuir isothermal sorption equation, and the maximum sorption capacities derived from this equation were 178.6 and 270.3 mg/g, respectively. The sorption rate of phosphate by ES and C-ES900 was divided into two stages: an initial fast sorption stage, followed by a slow sorption stage. The sorption of phosphate by ES was dominantly influenced by the initial pH and salt concentration, whereas C-ES900 exhibited a constant sorption capacity regardless of environmental changes. The SEM–EDS and XRD results demonstrated that phosphate was successfully adsorbed on the ES and C-SE900 surfaces. In this study, it was found that the sorption of phosphate by ES occurred via ion exchange and precipitation reactions and that the sorption of phosphate by C-ES900 was dominantly affected by precipitation. Above all, C-ES can be applied as an effective adsorbent for removing high concentrations of phosphate under a wide range of environmental conditions.

On the removal efficiency of copper ions in wastewater using calcined waste eggshells as natural adsorbents

“…Evidence from clinical studies indicates that humans who receive calcium from eggshells have increased bone density, improvements in brittle nails, hair, constipation, and asthma, and even benefit from the removal of radioactive elements 2 , 8 , 9 . The various applications of eggshell materials for recycling include wastewater treatment, antibacterial agents, air quality management, biodiesel fuel, electrochemistry, medicine, and food production 3 , 9 – 14 . The nanocatalytic system for conversion of biomass into advanced material has proven to be a valuable option (such as calcination and catalysis allow the interaction between both components), yet further efforts are required to improve processes so that their manufacturing costs are well-controlled 9 .…”

“…Moreover, removing pollutants from water has been an extremely challenging task, and many research endeavors have focused on at least two formulations, each with advantages and disadvantages 21 . In addition, novel studies in the chemical adsorption field have also included (1) the conversion of titanium gypsum (TiG) into an efficient adsorbent for phosphate recovery 22 ; (2) phenolic compounds—tannins for precipitation of proteins as sludge conditioning 23 ; (3) industrial red mud particle waste used to adsorb Pb 2+ , CD 2+ , and Cu 2+ 24 ; (4) C 2 N and g-C 3 N 4 to separate nitrate and nitrite contaminants from aqueous solutions 25 ; (5) ultrasound combined with seed material facilitates phosphorus recovery from swine wastewater by sulforaphane crystallization 26 ; (6) use calcined eggshells to remove phosphate, phosphorus, cadmium, and dyes from aqueous solution 14 , 27 – 29 . Because of the limited amount of freshwater, the severe effects of industrial pollution, and the increasingly stringent regulations in various countries, water resource management and improvement have become vital to enterprises and scientists 5 , 21 , 30 .…”

Physicochemical Properties of Marl and Travertine and their Thermally Modified Forms in the Perspective of Phosphorus Removal from Wastewater

“…Other physicochemical properties should indicate the characteristics of the material in terms of its use as a filtering medium/aiding purification, which, apart from not interfering with the operation of the purification device, should not adversely affect the chemical parameters and physicochemical properties of the purified medium [Jucherski et al, 2017;Bus et al, 2022]. For newly identified phosphorus sorbents beyond the materials included in the review [Gubernat et al, 2020], consideration should be given to: biochars [Almanassra et al, 2021;Luo et al, 2022], silica nanoparticles prepared from rice husk ash [Nguyen 2022], cockle shell powder [Nayeem et al, 2023], eggshells and calcined eggshells [Park et al, 2022] agnetite/zirconium-comodified attapulgite (Fe/ZrATP) [Deng et al, 2023]. The basic properties of sorbents/filter materials include structural properties, i.e.…”

Adsorption Removal of Phosphate from Rural Domestic Sewage by Ca-Modified Biochar Derived from Waste Eggshell and Sawdust

“…For example, the carbon dioxide (CO 2 ) from the decomposition of CaCO 3 in eggshells can be used to activate substances and produce activated carbon [22]. Additionally, eggshells have the potential to be a source of calcium for the creation of Ca-modified biochar since they have the ability to absorb phosphorus and then be used as a phosphate fertilizer [23,24]. Sawdust is a by-product generated from wood processing.…”