Selective Removal of Boron from Aqueous Solutions Using ECH@NGM Aerogels with Excellent Hydrophilic and Mechanical Properties: Performance and Response Surface Methodology Analysis

Abstract

The remediation of environmental boron contamination has received extensive research attention. The adsorbent ECH@NGM aerogel with high hydrophilic and mechanical properties was synthesized to remove boron. The ECH@NGM aerogel had a high adsorption capacity of 81.11 mg/g, which was 14.50% higher than that of commercial boron-selective resin Amberlite IRA743. The Freundlich model and pseudo-second-order model described the adsorption behavior well. In addition, the response surface methodology (RSM) could predict the experimental outcomes and optimize the reaction conditions, and X-ray photoelectron spectroscopy (XPS) and control tests were utilized to investigate probable adsorption mechanisms. These data showed that the B ← N coordination bond was the primary adsorption force. The adsorbent had good resistance to interference from coexisting salts, high reusability, good adsorption performance even after five reuse cycles, and a high desorption rate in a relatively short time. The adsorption performance in real brines could be maintained at 80%. Therefore, this work not only provided ECH@NGM aerogels for the removal of boron from brine but also elucidated the main adsorption processes between N-containing adsorbents and boron, facilitating the design of future adsorbents for boron removal.

Quantitative Evaluation of the Effects of Salt Concentration and pH on the Self-Assembly of Kaolin Nanoplatelets

“…7,15 The selfassembly behavior is influenced by the ion concentration and pH of the solution. 1,8 Salt ions play a significant role in affecting the aggregation behavior of clay minerals. The electrical double layer (EDL) 9,15 around clay platelets determines their electrostatic attraction or repulsion with each other.…”

“…A constant threat of diffusion of pollutants in strata hangs over both the environment and human health. When pollutants are released into the environment, they can penetrate the ground and become trapped in the pore spaces of soil and rock strata . These contaminants will be transported through the strata, potentially polluting groundwater, surface water, and deep soil layers. , The microstructure of clay particles impacts the reactivity, adsorption capacity, and transport properties of the soil, which in turn affect the migration and diffusion of pollutants in the natural environment .…”

“…When pollutants are released into the environment, they can penetrate the ground and become trapped in the pore spaces of soil and rock strata . These contaminants will be transported through the strata, potentially polluting groundwater, surface water, and deep soil layers. , The microstructure of clay particles impacts the reactivity, adsorption capacity, and transport properties of the soil, which in turn affect the migration and diffusion of pollutants in the natural environment . Furthermore, pollutants will cause changes in the chemical properties of the pore water, and for clay soil, which is extremely sensitive to the hydration environment, the impact on the microstructure of clay is undoubtedly tremendous. − …”

“…In various water chemistry conditions, clay layers exhibit self-assembly behavior, leading to different microstructures of clay minerals such as the “house-of-card” structure formed by edge-to-edge and edge-to-face contacts, i.e., face-to-face (FF), edge-to-face (EF), and edge-to-edge (EE) arrangement. , The self-assembly behavior is influenced by the ion concentration and pH of the solution. , …”