This study presents a sustainable and cost-effective approach to fabricating silicon carbide (SiC) membrane supports via low-temperature sintering (800 °C) using recycled SiC derived from photovoltaic wafer cutting waste. The recycling process combines flotation-sedimentation, acid leaching, and alkali dissolution, yielding high-qualitySiC and enabling the simultaneous recovery of sodium metasilicate (Na2SiO3) as a valuable byproduct. Recovered SiC powders were processed into membrane supports through liquid-phase sintering using boric acid (H3BO3), sodium dodecylbenzenesulfonate (SDBS), and Na2SiO3 as sintering additives. The influence of boric acid content (0–5 wt%) on the microstructure, crystallinity, density, porosity, and chemical durability was systematically investigated. The membrane support with 4 wt% boric acid exhibited optimal performance, with an enhanced crystallinity, an open porosity of 32.85 <InlineEquation ID="IEq1"> <EquationSource Format="TEX">$\pm$</EquationSource> <EquationSource Format="MATHML"><math> <mo>±</mo> </math></EquationSource> </InlineEquation> 0.15%, a bulk density of 1.75 <InlineEquation ID="IEq2"> <EquationSource Format="TEX">$\pm$</EquationSource> <EquationSource Format="MATHML"><math> <mo>±</mo> </math></EquationSource> </InlineEquation> 0.01 g·cm−3 and a bending strength of 26.64 <InlineEquation ID="IEq3"> <EquationSource Format="TEX">$\pm$</EquationSource> <EquationSource Format="MATHML"><math> <mo>±</mo> </math></EquationSource> </InlineEquation> 0.59 MPa. The sintered material also demonstrated high chemical resistance, showing only 1.03% weight loss after 20 days in pH1 solution, confirming its long-term stability under acidic conditions. In addition to these promising functional properties, a detailed cost analysis revealed a remarkably low fabrication cost of 14.73 $.m−2, significantly lower than that of conventional ceramic membranes, typically ranging from 500 to 3000 $.m−2. This cost advantage, rarely addressed in previous ceramic membrane supports studies, underscores the strong potential of this sustainable process for industrial-scale applications. Graphical Abstract This study presents a sustainable approach for fabricating porous SiC membrane supports from recycled photovoltaic silicon carbide waste. The process involves flotation-sedimentation for particle size homogenization, followed by leaching and alkali treatment to recover high-quality SiC and sodium metasilicate. Using boric acid-assisted liquid-phase sintering at 800 °C in air, the optimized support (SiC-4%BA) exhibited 32.85 0.15 % porosity, 1.75 0.01 g.cm-3 bulk density, 26.64 0.59 MPa bending strength, and an excellent chemical resistance (1.03% weight loss in pH 1 solution). A detailed cost evaluation revealed a remarkably low production cost of 14.73 $.m-2, highlighting the material’s potential for scalable and affordable membrane applications.

Recycling of Photovoltaic Silicon Carbide Waste into Green Porous Ceramic Supports via Low-Temperature Sintering

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发表日期：

2025年12月12日

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Nabila Saighi,
Mouna Hecini,
Yacine Kerchich,
Hayet Lallali,
Nadjib Meribai,
Khaled Kouaci,
Meftah Tablaoui,
Seif-Eddine Friha,
Nadjib Drouiche

摘要

This study presents a sustainable and cost-effective approach to fabricating silicon carbide (SiC) membrane supports via low-temperature sintering (800 °C) using recycled SiC derived from photovoltaic wafer cutting waste. The recycling process combines flotation-sedimentation, acid leaching, and alkali dissolution, yielding high-qualitySiC and enabling the simultaneous recovery of sodium metasilicate (Na₂SiO₃) as a valuable byproduct. Recovered SiC powders were processed into membrane supports through liquid-phase sintering using boric acid (H₃BO₃), sodium dodecylbenzenesulfonate (SDBS), and Na₂SiO₃ as sintering additives. The influence of boric acid content (0–5 wt%) on the microstructure, crystallinity, density, porosity, and chemical durability was systematically investigated. The membrane support with 4 wt% boric acid exhibited optimal performance, with an enhanced crystallinity, an open porosity of 32.85 $\pm$ $\pm$ 0.15%, a bulk density of 1.75 $\pm$ $\pm$ 0.01 g·cm⁻³ and a bending strength of 26.64 $\pm$ $\pm$ 0.59 MPa. The sintered material also demonstrated high chemical resistance, showing only 1.03% weight loss after 20 days in pH1 solution, confirming its long-term stability under acidic conditions. In addition to these promising functional properties, a detailed cost analysis revealed a remarkably low fabrication cost of 14.73 $.m⁻², significantly lower than that of conventional ceramic membranes, typically ranging from 500 to 3000 $.m⁻². This cost advantage, rarely addressed in previous ceramic membrane supports studies, underscores the strong potential of this sustainable process for industrial-scale applications.

Graphical Abstract

This study presents a sustainable approach for fabricating porous SiC membrane supports from recycled photovoltaic silicon carbide waste. The process involves flotation-sedimentation for particle size homogenization, followed by leaching and alkali treatment to recover high-quality SiC and sodium metasilicate. Using boric acid-assisted liquid-phase sintering at 800 °C in air, the optimized support (SiC-4%BA) exhibited 32.85 0.15 % porosity, 1.75 0.01 g.cm^-3 bulk density, 26.64 0.59 MPa bending strength, and an excellent chemical resistance (1.03% weight loss in pH 1 solution). A detailed cost evaluation revealed a remarkably low production cost of 14.73 $.m^-2, highlighting the material’s potential for scalable and affordable membrane applications.