Strontium Ion Removal From Artificial Seawater Using a Combination of Adsorption With Biochar and Precipitation by Blowing CO2 Nanobubble With Neutralization

Abstract

While enjoying the convenience of nuclear energy development, the environmental contamination by radionuclide leakage is of significant concern. Because of its cost-effectiveness and environmental friendliness, biochar has attracted a lot of attention in the field of radioactive water treatment. Herein, a novel teak peel modified biochar (labeled as PMBN3) was prepared and applied to remove strontium from artificial seawater. The characterisation of the prepared PMBN3 showed it contains numerous oxygen-containing functional groups (i.e. carboxyl and hydroxyl groups), laminar morphology, mesoporous structure, large specific surface area. PMBN3 exhibited great advantages in Sr(II) adsorption, such as rapid adsorption kinetics (<1 h for equilibrium) and superior reusability. The adsorption of strontium by biochar is consistent with pseudo-second order and internal diffusion kinetic models. Among the four types of adsorption isotherms, the Freundlich isotherm showed the best fit with R2 > 0.98. The calculated thermodynamic parameters indicate that strontium adsorption on biochar occurs exothermically and spontaneously. Furthermore, for efficient removal of Sr(II), CO2 nanobubbles were blown into artificial seawater to precipitate the interfering metal ions, and followed by the adsorption of PMBN3 towards residual metal ions with the removal rate of Sr(II) over 99.7%. Finally, mechanistic studies have shown that the strontium adsorption process by PMBN3 is a multiple adsorption mechanism consisting of ion exchange between H+ (from -OH and -COOH) and Sr(II), and weak intermolecular forces between Sr(II) and the PMBN3 adsorbent. This study creatively combines chemisorption and nanobubble precipitation for strontium removal, which provides great reference value and guidance for environmental remediation.

Chestnut Shell-Activated Carbon Mixed with Pyrolytic Snail Shells for Methylene Blue Adsorption

“…The presence of both graphite carbon peaks indicates that the material was partially graphitized during pyrolysis, but the main structure remained amorphous carbon. There was no significant difference in the peak positions compared to other carbon materials pretreated with different chemical reagents [35][36][37]. This indicated that phosphoric acid mainly affected the organic composition and pore structure of the material surface but not the crystalline structure.…”

Separation, purification, and crystallization of 1,5-pentanediamine hydrochloride from fermentation broth by cation resin

“…16 , the linear fitting is shown in Figure 3B , and the fitting correlation coefficient was R 2 = 0.965. Finally, the enthalpy change was calculated as = −1.412 kJ mol −1 , indicating an exothermic reaction; G = −10.474 kJ mol −1 , indicating that the adsorption reaction described as spontaneous; ΔS = 29.89 J·(mol⋅K) −1 , indicating that the disorder degree of solid-liquid interface increased ( Chen and Zhang, 2014 ; Guo et al, 2014 ), and the arrangement of PDA adsorbed on the resin surface was more disordered after adsorption.…”

Highly efficient removal of Sr2+ from aqueous solutions using a polyacrylic acid/crown-ether/graphene oxide hydrogel composite

“…Many methods have been attempted to remove strontium ions from solution, such as chemical precipitation, 8 solvent extraction, 9,10 membrane separation 11,12 and adsorption. 13,14 Compared to other methods, adsorption method has a number of advantages, such as simple operation, high removal efficiency and large treatment capacity.…”