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Wang Y, Zhang J, Liu J, Fan D, Qu H, Zhou L, Zheng S. Effects of Different Calcium Sources on Mechanical Properties of Metakaolin Geopolymers. MATERIALS (BASEL, SWITZERLAND) 2024; 17:2087. [PMID: 38730893 PMCID: PMC11084789 DOI: 10.3390/ma17092087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2024] [Revised: 04/20/2024] [Accepted: 04/25/2024] [Indexed: 05/13/2024]
Abstract
Metakaolin-based geopolymers have substantial potential as replacements for cement, but their relatively inferior mechanical properties restrict their application. This paper aims to enhance the mechanical properties of metakaolin-based geopolymers by incorporating appropriate amounts of calcium sources. CaCO3, Ca(OH)2, and CaSO4 are three types of calcium sources commonly found in nature and are widely present in various industrial wastes. Thus, the effects of these three calcium sources on the performance of metakaolin-based geopolymers were studied. Through the analysis of the mechanical properties, heat-release behavior during hydration, hydration products, and microstructure of geopolymers, the effectiveness of the aforementioned calcium sources in improving the performance of metakaolin-based geopolymer was evaluated, and the mechanisms of action were elucidated. The results indicate that the pozzolanic reaction between CH and MK could promote MK hydration and increase the proportion of CASH gel in the hydration products, thereby facilitating the setting of the geopolymer and enhancing its strength. CS could react with the active aluminates in MK to form ettringite, thus forming a higher early strength. CC had a lower reactivity with MK and does not improve the performance of MK-based geopolymers.
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Affiliation(s)
- Yiren Wang
- School of Environment and Civil Engineering, Dongguan University of Technology & Guangdong Provincial Key Laboratory of Intelligent Disaster Prevention and Emergency Technologies for Urban Lifeline Engineering, Dongguan 523808, China; (Y.W.); (L.Z.)
| | - Jiangtao Zhang
- China Building Materials Academy, CNBM Zhongyan Technology Co., Ltd., Beijing 100024, China; (D.F.); (H.Q.)
| | - Jie Liu
- School of Civil Engineering, Sun Yat-sen University, Zhuhai 519082, China;
| | - Deke Fan
- China Building Materials Academy, CNBM Zhongyan Technology Co., Ltd., Beijing 100024, China; (D.F.); (H.Q.)
| | - Haiyang Qu
- China Building Materials Academy, CNBM Zhongyan Technology Co., Ltd., Beijing 100024, China; (D.F.); (H.Q.)
| | - Lingzhu Zhou
- School of Environment and Civil Engineering, Dongguan University of Technology & Guangdong Provincial Key Laboratory of Intelligent Disaster Prevention and Emergency Technologies for Urban Lifeline Engineering, Dongguan 523808, China; (Y.W.); (L.Z.)
| | - Sen Zheng
- ENAC/IIC/LHE, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland;
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Kuttiyathil MS, Ali L, Hajamohideen AR, Altarawneh M. Debromination of novel brominated flame retardants using Zn-based additives: A viable thermochemical approach in the mitigation of toxic effects during e-waste recycling. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 346:123645. [PMID: 38402939 DOI: 10.1016/j.envpol.2024.123645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Revised: 02/16/2024] [Accepted: 02/22/2024] [Indexed: 02/27/2024]
Abstract
Brominated flame retardants (BFRs) are bromine-bearing additives added to the polymeric fraction in various applications to impede fire ignition. The Stockholm Convention and various other legislations abolished legacy BFRs usage and hence, the so-called novel BFRs (NBFRs) were introduced into the market. Recent studies spotlighted their existence in household dust, aquifers and aquatic/aerial species. Co-pyrolysis of BFRs with metal oxides has emerged as a potent chemical recycling approach that produces a bromine-free stream of hydrocarbon. Herein, we investigate the debromination of two prominent two NBFRs; namely tetrabromobisphenol A 2,3-dibromopropyl ether (TD) and tetrabromobisphenol A diallyl ether (TAE) through their co-pyrolysis with zinc oxide (ZnO) and franklinite (ZnFe2O4). Most of the zinc content in electrical arc furnace dust (EAFD) exists in the form of these two metal oxides. Conversion of these metal oxides into their respective bromides could also assist in the selective extraction of the valuable zinc content in EAFD. The debromination potential of both oxides was unveiled via a multitude of characterization studies to analyze products (char, gas and condensates). The thermogravimetric analysis suggested a pyrolytic run up to 500 °C and the TAE treatment with ZnO produced only a trivial amount of brominated compounds (relative area, 0.83%). Phenol was the sole common compound in condensable products; potentially formed by the β-scission debromination reaction from the parental molecular skeleton. Inorganic compounds and methane were the major constituents in the gaseous products. The pyrochar analyses confirmed the presence of metal bromides retained in the residue, averting the bromine release into the atmosphere. The ion chromatography analysis portrayed <8% of HBr gas release into the atmosphere upon pyrolysis with ZnO. The ZnO dominance herein envisaged further probes into other spinel ferrites in combating brominated polymers.
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Affiliation(s)
- Mohamed Shafi Kuttiyathil
- United Arab Emirates University, Department of Chemical and Petroleum Engineering, Sheikh Khalifa bin Zayed Street, Al-Ain, 15551, United Arab Emirates
| | - Labeeb Ali
- United Arab Emirates University, Department of Chemical and Petroleum Engineering, Sheikh Khalifa bin Zayed Street, Al-Ain, 15551, United Arab Emirates
| | - Abdul Razack Hajamohideen
- United Arab Emirates University, Department of Physics, Sheikh Khalifa bin Zayed Street, Al-Ain, 15551, United Arab Emirates
| | - Mohammednoor Altarawneh
- United Arab Emirates University, Department of Chemical and Petroleum Engineering, Sheikh Khalifa bin Zayed Street, Al-Ain, 15551, United Arab Emirates.
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Wu Y, Tao R, Li B, Hu C, Zhang W, Yuan H, Gu J, Chen Y. New insights into brominated epoxy resin type WPCBs pyrolysis mechanisms: Integrated experimental and DFT simulation studies. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 912:169610. [PMID: 38157909 DOI: 10.1016/j.scitotenv.2023.169610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 12/06/2023] [Accepted: 12/20/2023] [Indexed: 01/03/2024]
Abstract
Pyrolysis is a recycling technology for waste circuit boards (WPCBs) with a wide range of applications. In this research, the brominated epoxy resin (BER) type WPCBs were taken as the research object, and the optimal pyrolysis process parameters were determined. Combined with experiments and density functional theory (DFT) calculations, the pyrolysis gaseous generation pattern and product distribution of BER type WPCBs were analyzed, and the generation mechanism of phenol, bromide and other pyrolysis products was investigated in depth. The results of the study showed that the pyrolysis rate of WPCBs exceeded 95 % under optimal reaction conditions. In the initial phase of the pyrolysis of WPCBs, the BER's CO bonds and a portion of Ph-Br bonds will be broken, leading to the production of intermediates such propylene oxide, bisphenol A, isopropyl alcohol, tetrabromobisphenol A and HBr. Among them, propylene oxide can generate ethylene oxide through free radical reaction. In the second stage, intermediates such as bisphenol A undergo homolytic cleavage and radical addition to form phenols, bromides, alcohols, ketones and other pyrolysis products.
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Affiliation(s)
- Yufeng Wu
- Institute of Circular Economy, Beijing University of Technology, Beijing 100124, PR China; Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, PR China
| | - Ran Tao
- Institute of Circular Economy, Beijing University of Technology, Beijing 100124, PR China; Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, PR China
| | - Bin Li
- Institute of Circular Economy, Beijing University of Technology, Beijing 100124, PR China; Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, PR China.
| | - Chenwei Hu
- Institute of Circular Economy, Beijing University of Technology, Beijing 100124, PR China; Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, PR China
| | - Wei Zhang
- Institute of Circular Economy, Beijing University of Technology, Beijing 100124, PR China; Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, PR China
| | - Haoran Yuan
- Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, PR China
| | - Jing Gu
- Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, PR China
| | - Yong Chen
- Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, PR China
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Liu J, Jia H, Xu Z, Wang T, Mei M, Chen S, Li J, Zhang W. An impressive pristine biochar from food waste digestate for arsenic(V) removal from water: Performance, optimization, and mechanism. BIORESOURCE TECHNOLOGY 2023; 387:129586. [PMID: 37516138 DOI: 10.1016/j.biortech.2023.129586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 07/25/2023] [Accepted: 07/26/2023] [Indexed: 07/31/2023]
Abstract
Anaerobic digestion has become a global practice for valorizing food waste, but the recycling of the digestate (FWD) remains challenging. This study aimed to address this issue by utilizing FWD as a low-cost feedstock for Ca-rich biochar production. The results demonstrated that biochar pyrolyzed at 900 °C exhibited impressive As(V) adsorption performance without any modifications. Kinetic analysis suggested As(V) was chemisorbed onto CDBC9, while isotherm data conformed well to Langmuir model, indicating monolayer adsorption with a maximum capacity of 76.764 mg/g. Further analysis using response surface methodology revealed that pH value and adsorbent dosage were significant influencing factors, and density functional theory (DFT) calculation visualized the formation of ionic bonds between HAsO42- and CaO(110) and Ca(OH)2(101) surfaces. This work demonstrated the potential of using FWD for producing Ca-rich biochar, providing an effective solution for As(V) removal and highlighting the importance of waste material utilization in sustainable environmental remediation.
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Affiliation(s)
- Jingxin Liu
- School of Environmental Engineering, Wuhan Textile University, Wuhan 430073, China; Engineering Research Centre for Clean Production of Textile Dyeing and Printing, Ministry of Education, Wuhan Textile University, Wuhan 430073, China
| | - Hang Jia
- Beijing Graphene Institute, Beijing 100095, China
| | - Zelin Xu
- School of Environmental Engineering, Wuhan Textile University, Wuhan 430073, China
| | - Teng Wang
- School of Environmental Engineering, Wuhan Textile University, Wuhan 430073, China; Engineering Research Centre for Clean Production of Textile Dyeing and Printing, Ministry of Education, Wuhan Textile University, Wuhan 430073, China
| | - Meng Mei
- School of Environmental Engineering, Wuhan Textile University, Wuhan 430073, China; Engineering Research Centre for Clean Production of Textile Dyeing and Printing, Ministry of Education, Wuhan Textile University, Wuhan 430073, China
| | - Si Chen
- School of Environmental Engineering, Wuhan Textile University, Wuhan 430073, China; Engineering Research Centre for Clean Production of Textile Dyeing and Printing, Ministry of Education, Wuhan Textile University, Wuhan 430073, China
| | - Jinping Li
- School of Environmental Engineering, Wuhan Textile University, Wuhan 430073, China; Engineering Research Centre for Clean Production of Textile Dyeing and Printing, Ministry of Education, Wuhan Textile University, Wuhan 430073, China
| | - Wenjuan Zhang
- School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China.
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Hu D, Zeng X, Lin Y, Chen Y, Chen W, Jia Z, Lin J. High Value-Added Reutilization of Waste-Printed Circuit Boards Non-Metallic Components in Sustainable Polymer Composites. Molecules 2023; 28:6199. [PMID: 37687027 PMCID: PMC10489137 DOI: 10.3390/molecules28176199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 08/16/2023] [Accepted: 08/21/2023] [Indexed: 09/10/2023] Open
Abstract
The reutilization non-metallic components from a waste-printed circuit board (WPCB) has become one of the most significant bottlenecks in the comprehensive reuse of electronic wastes due to its low value and complex compositions, and it has received great attention from scientific and industrial researchers. To effectively address the environmental pollution caused by inappropriate recycling methods, such as incineration and landfill, extensive efforts have been dedicated to achieving the high value-added reutilization of WPCB non-metals in sustainable polymer composites. In this review, recent progress in developing sustainable polymer composites based on WPCB non-metallic components was systematically summarized. It has been demonstrated that the WPCB non-metals can serve as a promising reinforcing and functional fillers to significantly ameliorate some of the physical and chemical properties of polymer composites, such as excellent mechanical properties, enhanced thermal stability, and flame retardancy. The recovery strategies and composition of WPCB non-metals were also briefly discussed. Finally, the future potentials and remaining challenges regarding the reutilization of WPCB non-metallic components are outlined. This work provides readers with a comprehensive understanding of the preparation, structure, and properties of the polymer composites based on WPCB non-metals, providing significant insights regarding the high value-added reutilization of WPCB non-metals of electronic wastes.
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Affiliation(s)
- Dechao Hu
- School of Materials Science and Hydrogen Energy, Foshan University, Foshan 528000, China; (D.H.)
| | - Xianghong Zeng
- School of Materials Science and Hydrogen Energy, Foshan University, Foshan 528000, China; (D.H.)
| | - Yinlei Lin
- School of Materials Science and Hydrogen Energy, Foshan University, Foshan 528000, China; (D.H.)
| | - Yongjun Chen
- Key Lab of Guangdong High Property and Functional Macromolecular Materials, School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, China
| | - Wanjuan Chen
- School of Materials Science and Hydrogen Energy, Foshan University, Foshan 528000, China; (D.H.)
| | - Zhixin Jia
- Key Lab of Guangdong High Property and Functional Macromolecular Materials, School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, China
| | - Jing Lin
- Research Center of Flexible Sensing Materials and Devices, School of Applied Physics and Materials, Wuyi University, Jiangmen 529020, China
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