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1.
Environ Sci Technol ; 57(22): 8256-8268, 2023 06 06.
Artigo em Inglês | MEDLINE | ID: mdl-37212265

RESUMO

Due to the dispersed distribution of e-waste and crude disassembly in traditional recycling, valuable metals are not traceable during their life cycle. Meanwhile, incomplete separation between metals and nonmetals reduces the economic value of disassembled parts, which leads to higher environmental costs for metal refining. Therefore, this study proposes a precise disassembly of e-waste to finely classify and recover metals in an environmentally friendly way. First, the macroscopic material flow of e-waste in China (source, flow, scrap, and recycling gap) was measured based on data collected by the government and 109 formal recycling enterprises. The sustainable recycling balance time points for e-waste recycling and scrap volumes were forecast by introducing an additional recycling efficiency. By 2030, the total scrap volume of e-waste is predicted to reach 133.06 million units. For precise disassembly, the main metals and their percentages from these typical e-wastes were measured based on material flow analysis combined with experimental methods. After precise disassembly, the proportion of reusable metals increases significantly. The CO2 emission of precise disassembly with the smelting process was the lowest compared with crude disassembly with smelting and ore metallurgy. The greenhouse gas for secondary metals Fe, Cu, and Al was 830.32, 1151.62, and 716.6 kg CO2/t metal, respectively. The precise disassembly of e-waste is meaningful for building a future resource sustainable society and for carbon emission reduction.


Assuntos
Resíduo Eletrônico , Resíduo Eletrônico/análise , Dióxido de Carbono , Metais , Meio Ambiente , China , Reciclagem/métodos
2.
Dalton Trans ; 50(22): 7768-7775, 2021 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-33998639

RESUMO

Strontium titanate (SrTiO3) is considered to be a promising photocatalyst. However, the rapid recombination of photo-generated charge carriers limits the practical applications of SrTiO3-based photocatalysts. In this work, we prepared hydrogenated SrTiO3 using NaBH4 as a reducing reagent. The optimized photocatalyst shows a H2-evolution rate up to 409.5 µmol g-1 h-1 with a CuS co-catalyst, which is 152, 14 and 1.8 times higher than those of pure SrTiO3, hydrogenated SrTiO3, and CuS/SrTiO3, respectively. The enhanced photocatalytic H2-evolution activity can be attributed to the synergistic effect of the CuS co-catalyst and the appropriate oxygen vacancies produced by hydrogenation, which are beneficial for lowering the separation of photo-generated charge carriers. The present finding could shed light on the design of efficient SrTiO3-based photocatalysts.

3.
Nanomaterials (Basel) ; 11(1)2020 Dec 25.
Artigo em Inglês | MEDLINE | ID: mdl-33375731

RESUMO

As promising heterojunction photocatalysts, the binary CdS-based heterojunctions were investigated extensively. In most of the reported CdS-based heterojunctions, however, electrons come from the semiconductor with wide band gap (e.g., TiO2) would limit the visible-light absorption of CdS and hence lower the performance. In this work, we introduced 1T-MoS2 to form a novel ternary heterojunction, namely CdS/1T-MoS2/TiO2, in which 1T-MoS2 has more positive conduction band than CdS and TiO2. The hydrogen evolution rate of CdS/1T-MoS2/TiO2 reaches 3.15 mmol g-1 h-1, which is approximately 12 and 35 times higher than that of pure CdS and CdS/TiO2 binary heterojunction under the same conditions, respectively. This performance enhancement could be attributed to the presence of 1T-MoS2 and a plausible mechanism is proposed based on photoelectrochemical characterizations. Our results illustrate that the performance of CdS-based heterojunctions for solar hydrogen evolution can be greatly improved by appropriate materials selection.

4.
Onco Targets Ther ; 11: 5195-5201, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30214225

RESUMO

INTRODUCTION: This meta-analysis was conducted to evaluate efficacy and safety in patients treated with sorafenib vs other tyrosine-kinase inhibitors (TKIs) or selective internal radiotherapy (SIRT) for advanced hepatocellular carcinoma (HCC). METHODS: Electronic databases were systematically reviewed for randomized Phase III trials comparing sorafenib with other TKIs or SIRT in advanced HCC. Sorafenib was defined as the control arm. Other TKIs or SIRT was defined as the experimental arm. Overall survival (OS), time to progression (TTP), objective response rate (ORR), disease-control rate (DCR), and adverse events (AEs) were reviewed. Four trials in the other-TKI group (n=4,218) and two in the SIRT group (n=819) were eligible. RESULTS: Compared with sorafenib, other TKIs showed similar benefit on OS (HR 1.08, 95% CI 0.93-1.24; P=0.31) and TTP (HR 0.86, 95% CI 0.66-1.12; P=0.26) for advanced HCC. A significant increase in ORR (RR 1.67, 95% CI 1.15-2.43; P=0.008) was found with other TKIs, but no increase in DCR (RR 1.11, 95% CI 0.98-1.26; P=0.11) was observed. Other TKIs were associated with more frequent grade 3/4 AEs than sorafenib, including hypertension (P<0.00001), thrombocytopenia (P=0.002), fatigue (P<0.00001), decreased appetite (P<0.00001), and vomiting (P<0.0001). For locally advanced HCC, neither OS (HR 1.14, 95% CI 0.98-1.32; P=0.09) nor TTP (HR 0.87, 95% CI 0.74-1.02; P=0.10) differed significantly in SIRT and sorafenib. There was an increase in ORR (RR 2.60, 95% CI 1.69-4.00; P<0.0001), but no improvement in DCR (RR 0.91, 95% CI 0.81-1.02; P=0.11) in the SIRT group. Fewer patients treated with SIRT had grade 3/4 AEs than those treated with sorafenib, including diarrhea (P<0.0001), fatigue (P=0.0006), and hand-foot syndrome (P=0.0002). Other TKIs were noninferior to sorafenib in OS and TTP in advanced HCC, but with increased risk of toxicities. CONCLUSION: Patients with locally advanced HCC treated with SIRT got similar efficacy with less toxicity to those treated with sorafenib.

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