Recycling of dredged sediment (DS), derived from the routine dredging operation of rivers, lakes and seas, into construction materials represents an eco-friendly way to alleviate the burden on the environment. At higher incorporation dosages, however, DS causes a dramatic reduction in the mechanical properties of the host materials, which greatly stymies a broader application. In this study, DS from Taihu Lake, combined with ground granulated blast-furnace slag (GGBS) and calcium carbide slag (CCS), was used to produce low-strength foamed concrete (FC). Moreover, visible-light active Bi 4 Ti 3 O 12 photocatalyst was added to the developed FC to obtain photocatalytic-functional and sound-proof products, which can be used as highway barrier walls. The results showed that within a dry density range of 500–1000 kg/m 3 , the compressive strength of the FC decreased greatly with an increase in the porosity. However, above 1000 kg/m 3 , the porosity exerted a much dwindled impact on the compressive strength . The pore structure of the sediment-based FC played a decisive role in influencing the basic properties and functional performance, which might follow the fractal characteristics. At a fixed dosage of foaming agent (hydrogen peroxide (HP)), the specimens prepared with 60% cement and 40% DS (DS-40) had the best sound insulation effect (1767 m/s, 9% HP), the lowest thermal conductivity (0.2831 W/m·k, 6% HP) and an excellent photocatalytic NO removal (14.1%, Bi 4 Ti 3 O 12 ), which was the optimal mixture for manufacturing sound barrier walls. A broader application of photocatalytic-functional sediment-based FC offers a sustainable way in recycling DS, reducing air pollution and creating pleasant living environments.
Zhiqi Yao,Kejie Li,Jiaqi Zhao,Haicheng Xia,Zuoling Fu,Sung Heum Park
A RE-doped Bi 4 Ti 3 O 12 perovskite-based luminescence material is developed. • Dual NIR-II emissions of Ho 3+ /Er 3+ are achieved under 980 nm excitation. • High performance (Sr=1.3% K-1) phonon-assisted ratiometric thermometer is constructed. High-performance optical thermometers operating in the second near-infrared (NIR-II) window hold great promise for biomedical applications due to their tissue penetration depth and minimal autofluorescence. However, developing reliable NIR-II thermometers with high sensitivity and robust performance across a wide temperature range remains a challenge. Herein, the luminescence properties and NIR-II ratiometric thermometric performance of Er 3+ , Ho 3+ , Yb 3+ co-doped Bi 4 Ti 3 O 12 (BTO) perovskite oxide were investigated. Upon 980 nm excitation, NIR-II emission from Er 3+ at 1560 nm ( 4 I 13/2 → 4 I 15/2 ) and Ho 3+ at 1200 nm ( 5 I 6 → 5 I 8 ) was achieved. A ratiometric thermometer was constructed using the temperature-dependent intensity ratio, I Er /I Ho . Relying on the thermal dependence of this ratio, the BTO system exhibits a relative sensitivity (S r ) of 1.3% at 333 K. Furthermore, the results suggest that phonon characteristics of the BTO host influence energy-transfer processes and NIR-II thermometric performance, highlighting importance of host properties in designing rare-earth-doped NIR-II thermometric materials. Download: Download high-res image (154KB) Download: Download full-size image A high-sensitivity NIR-II ratiometric thermometer is achieved in Bi 4 Ti 3 O 12 : Yb 3+ , Ho 3+ , Er 3+ Perovskites via a unique phonon-assisted energy transfer pathway.
Hongyang Wang,Chengqi Lu,Pengchang Sun,Zilin Cao,Zhongkang Han,Qianhong Shen,Zhongyuan Hu,Xudan Cao,Hui Yang
A Bi₄Ti₃O₁₂/BiOCl heterojunction with a coherent interface was constructed via a room-temperature ion-exchange process. • A Bi₄Ti₃O₁₂/BiOCl heterojunction with a coherent interface was constructed via a room-temperature ion-exchange process. • The photocatalyst exhibits excellent performance for the degradation of high-concentration, recalcitrant antibiotics. A strategy is reported for the in-situ fabrication of a Bi₄Ti₃O₁₂/BiOCl heterojunction with shared atomic layer through simple room-temperature ion-exchange on pure Bi₄Ti₃O₁₂. This strategic interfacial engineering, combined with a Type-II band alignment, the Aurivillius-type Bi₄Ti₃O₁₂ and BiOCl share the Bi₂O₂ 2+ layers at the interface, thereby dramatically accelerating the separation and migration of photo-generated carriers and ultimately significantly increasing the yield of photocatalytic reactive species. Consequently, the optimized composite photocatalyst exhibits exceptional performance in the degradation of high-concentration antibiotics. It achieves remarkable degradation efficiencies of 90.8% for sulfamethoxazole (20 ppm) within 120 min, 92% for tetracycline hydrochloride (40 ppm) and 78.6% ciprofloxacin (15 ppm) within just 30 min. Demonstrating superior photocatalytic performance compared to the previously reported analogous photocatalysts in recent years with respect to antibiotic degradation. Furthermore, the degradation efficiency of the as-prepared photocatalyst also demonstrates outstanding cycling stability, with a reduction of only 3.4% after 4 cycles. Therefore, this coherent Bi₄Ti₃O₁₂/BiOCl heterojunction photocatalyst exhibits immense potential for practical applications in environmental remediation.
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