Direct Quantification of Ion Partitioning and Diffusion Resistances in Reverse Osmosis Membranes via Electrochemical Impedance Spectroscopy DOI

Xueye Wang,

Wei Kong, Xiaohu Zhai

и другие.

Environmental Science & Technology, Год журнала: 2025, Номер unknown

Опубликована: Май 28, 2025

Polyamide (PA) reverse osmosis (RO) membranes are crucial for water desalination and purification, where salt ion transport is governed by partitioning diffusion through the PA film. Despite extensive research, decoupling these two steps quantifying their relative contributions remain challenging due to lack of reliable characterization methods. Here, we develop a rapid, reproducible electrochemical impedance spectroscopy (EIS) protocol incorporating advanced electrical equivalent circuits directly quantify resistance. Its validity verified membrane filtration experiments activation energy analysis. Our findings reveal that dominates resistance, with values 4.5 6.0 times higher than resistance across diverse monovalent cations. However, discovered critical concentration-dependent behavior becomes increasingly significant at lower electrolyte concentrations, eventually equaling near 0.1 mM. We also uncovered anomalously low rejection NH4+ RO stemmed from significantly reduced likely moderate hydrogen-bonding interactions pores or its tetrahedral geometry. This quantitative insight into mechanisms establishes new design principles next-generation membranes, enabling tailored strategies applications ranging high-salinity removal low-concentration micropollutants.

Язык: Английский

Sustainable Phosphate Remediation via Hierarchical Mg-Fe Layered Double Hydroxides on Magnetic Biochar from Agricultural Waste DOI Creative Commons
Xiuling Li, Lei Xin,

Yuhan Peng

и другие.

Magnetochemistry, Год журнала: 2025, Номер 11(4), С. 27 - 27

Опубликована: Апрель 1, 2025

Addressing aquatic phosphate pollution requires advanced materials that combine high selectivity with recyclability. Here, we present a hierarchically structured composite integrating Mg-Fe layered double hydroxides (LDHs) magnetic biochar derived from mulberry branches—an abundant agricultural byproduct. Through hydrothermal synthesis, the achieves unique architecture combining Fe3O4-enabled recovery (2.63 emu·g−1 saturation) LDHs’ anion exchange capacity and biochar’s porous network. Systematic characterization reveals capture mechanisms dominated by hydrogen bonding through deprotonated carboxyl groups, inner-sphere complexation metal oxides, interlayer exchange, enabling 99.22% removal at optimal conditions (pH 6, 25 °C). Crucially, material demonstrates exceptional over competing Cl− NO3− ions while maintaining 87.83% efficiency after three regeneration cycles via alkaline treatment. Kinetic thermodynamic analyses confirm chemisorption-driven uptake aligned pseudo-second-order kinetics (R2 > 0.9998) Langmuir monolayer adsorption (7.72 mg·g−1 capacity). This waste-derived establishes sustainable paradigm for eutrophication control, merging selective sequestration energy-efficient circular water treatment applications.

Язык: Английский

Процитировано

0
Direct Quantification of Ion Partitioning and Diffusion Resistances in Reverse Osmosis Membranes via Electrochemical Impedance Spectroscopy DOI

Xueye Wang,

Wei Kong, Xiaohu Zhai

и другие.

Environmental Science & Technology, Год журнала: 2025, Номер unknown

Опубликована: Май 28, 2025

Polyamide (PA) reverse osmosis (RO) membranes are crucial for water desalination and purification, where salt ion transport is governed by partitioning diffusion through the PA film. Despite extensive research, decoupling these two steps quantifying their relative contributions remain challenging due to lack of reliable characterization methods. Here, we develop a rapid, reproducible electrochemical impedance spectroscopy (EIS) protocol incorporating advanced electrical equivalent circuits directly quantify resistance. Its validity verified membrane filtration experiments activation energy analysis. Our findings reveal that dominates resistance, with values 4.5 6.0 times higher than resistance across diverse monovalent cations. However, discovered critical concentration-dependent behavior becomes increasingly significant at lower electrolyte concentrations, eventually equaling near 0.1 mM. We also uncovered anomalously low rejection NH4+ RO stemmed from significantly reduced likely moderate hydrogen-bonding interactions pores or its tetrahedral geometry. This quantitative insight into mechanisms establishes new design principles next-generation membranes, enabling tailored strategies applications ranging high-salinity removal low-concentration micropollutants.

Язык: Английский

Процитировано

0