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Tan H, Othman MHD, Chong WT, Kek HY, Wong SL, Nyakuma BB, Mong GR, Wahab RA, Wong KY. Turning plastics/microplastics into valuable resources? Current and potential research for future applications. J Environ Manage 2024; 356:120644. [PMID: 38522274 DOI: 10.1016/j.jenvman.2024.120644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 01/26/2024] [Accepted: 03/10/2024] [Indexed: 03/26/2024]
Abstract
Plastics are a wide range of synthetic or semi-synthetic materials, mainly consisting of polymers. The use of plastics has increased to over 300 million metric tonnes in recent years, and by 2050, it is expected to grow to 800 million. Presently, a mere 10% of plastic waste is recycled, with approximately 75% ended up in landfills. Inappropriate disposal of plastic waste into the environment poses a threat to human lives and marine species. Therefore, this review article highlights potential routes for converting plastic/microplastic waste into valuable resources to promote a greener and more sustainable environment. The literature review revealed that plastics/microplastics (P/MP) could be recycled or upcycled into various products or materials via several innovative processes. For example, P/MP are recycled and utilized as anodes in lithium-ion (Li-ion) and sodium-ion (Na-ion) batteries. The anode in Na-ion batteries comprising PP carbon powder exhibits a high reversible capacity of ∼340 mAh/g at 0.01 A/g current state. In contrast, integrating Fe3O4 and PE into a Li-ion battery yielded an excellent capacity of 1123 mAh/g at 0.5 A/g current state. Additionally, recycled Nylon displayed high physical and mechanical properties necessary for excellent application as 3D printing material. Induction heating is considered a revolutionary pyrolysis technique with improved yield, efficiency, and lower energy utilization. Overall, P/MPs are highlighted as abundant resources for the sustainable production of valuable products and materials such as batteries, nanomaterials, graphene, and membranes for future applications.
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Affiliation(s)
- Huiyi Tan
- Faculty of Chemical and Energy Engineering, University Teknologi Malaysia, 81310, Skudai, Johor, Malaysia
| | - Mohd Hafiz Dzarfan Othman
- Advanced Membrane Technology Research Centre (AMTEC), Universiti Teknlogi Malaysia, 81310, Skudai, Johor, Malaysia
| | - Wen Tong Chong
- Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Hong Yee Kek
- Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310, Skudai, Johor, Malaysia
| | - Syie Luing Wong
- Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Eindhoven, the Netherlands
| | - Bemgba Bevan Nyakuma
- Department of Chemical Sciences, Faculty of Science and Computing, Pen Resource University, P. M. B. 08, Gombe, Gombe State, Nigeria
| | - Guo Ren Mong
- School of Energy and Chemical Engineering, Xiamen University Malaysia, 43900, Sepang, Selangor, Malaysia
| | | | - Keng Yinn Wong
- Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310, Skudai, Johor, Malaysia; Process Systems Engineering Centre (PROSPECT), Universiti Teknologi Malaysia, 81310, Skudai, Johor, Malaysia.
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Tan H, Wong KY, Othman MHD, Kek HY, Wahab RA, Ern GKP, Chong WT, Lee KQ. Current and potential approaches on assessing airflow and particle dispersion in healthcare facilities: a systematic review. Environ Sci Pollut Res Int 2022; 29:80137-80160. [PMID: 36194323 PMCID: PMC9531230 DOI: 10.1007/s11356-022-23407-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 09/27/2022] [Indexed: 06/04/2023]
Abstract
An indoor environment in a hospital building requires a high indoor air quality (IAQ) to overcome patients' risks of getting wound infections without interrupting the recovery process. However, several problems arose in obtaining a satisfactory IAQ, such as poor ventilation design strategies, insufficient air exchange, improper medical equipment placement and high door opening frequency. This paper presents an overview of various methods used for assessing the IAQ in hospital facilities, especially in an operating room, isolation room, anteroom, postoperative room, inpatient room and dentistry room. This review shows that both experimental and numerical methods demonstrated their advantages in the IAQ assessment. It was revealed that both airflow and particle tracking models could result in different particle dispersion predictions. The model selection should depend on the compatibility of the simulated result with the experimental measurement data. The primary and secondary forces affecting the characteristics of particle dispersion were also discussed in detail. The main contributing forces to the trajectory characteristics of a particle could be attributed to the gravitational force and drag force regardless of particle size. Meanwhile, the additional forces could be considered when there involves temperature gradient, intense light source, submicron particle, etc. The particle size concerned in a healthcare facility should be less than 20 μm as this particle size range showed a closer relationship with the virus load and a higher tendency to remain airborne. Also, further research opportunities that reflect a more realistic approach and improvement in the current assessment approach were proposed.
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Affiliation(s)
- Huiyi Tan
- School of Chemical and Energy Engineering, Faculty of Engineering, Universiti Teknologi Malaysia, Johor, Malaysia
| | - Keng Yinn Wong
- School of Mechanical Engineering, Faculty of Engineering, Universiti Teknologi Malaysia, Johor, Malaysia.
| | - Mohd Hafiz Dzarfan Othman
- Advanced Membrane Technology Research Centre (AMTEC), Universiti Teknologi Malaysia, Johor, Malaysia
| | - Hong Yee Kek
- School of Mechanical Engineering, Faculty of Engineering, Universiti Teknologi Malaysia, Johor, Malaysia
| | - Roswanira Abdul Wahab
- Advanced Membrane Technology Research Centre (AMTEC), Universiti Teknologi Malaysia, Johor, Malaysia
- Department of Chemistry, Faculty of Sciences, Universiti Teknologi Malaysia, Johor, Malaysia
| | - Garry Kuan Pei Ern
- School of Health Science, Universiti Sains Malaysia, Kelantan, Malaysia
- Department of Life Sciences, Brunel University, Uxbridge, London, UK
| | - Wen Tong Chong
- Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur, Malaysia
| | - Kee Quen Lee
- Malaysia-Japan International Institute of Technology, Universiti Teknologi Malaysia Kuala Lumpur, 54100, Kuala Lumpur, Malaysia
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Tan H, Wong KY, Nyakuma BB, Kamar HM, Chong WT, Wong SL, Kang HS. Systematic study on the relationship between particulate matter and microbial counts in hospital operating rooms. Environ Sci Pollut Res Int 2022; 29:6710-6721. [PMID: 34458973 PMCID: PMC8403507 DOI: 10.1007/s11356-021-16171-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 08/22/2021] [Indexed: 06/04/2023]
Abstract
In this study, a systematic procedure for establishing the relationship between particulate matter (PM) and microbial counts in four operating rooms (ORs) was developed. The ORs are located in a private hospital on the western coast of Peninsular Malaysia. The objective of developing the systematic procedure is to ensure that the correlation between the PMs and microbial counts are valid. Each of the procedures is conducted based on the ISO, IEST, and NEBB standards. The procedures involved verifying the operating parameters are air change rate, room differential pressure, relative humidity, and air temperature. Upon verifying that the OR parameters are in the recommended operating range, the measurements of the PMs and sampling of the microbes were conducted. The TSI 9510-02 particle counter was used to measure three different sizes of PMs: PM 0.5, PM 5, and PM 10. The MAS-100ECO air sampler was used to quantify the microbial counts. The present study confirms that PM 0.5 does not have an apparent positive correlation with the microbial count. However, the evident correlation of 7% and 15% were identified for both PM 5 and PM 10, respectively. Therefore, it is suggested that frequent monitoring of both PM 5 and PM 10 should be practised in an OR before each surgical procedure. This correlation approach could provide an instantaneous estimation of the microbial counts present in the OR.
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Affiliation(s)
- Huiyi Tan
- School of Chemical and Energy Engineering, Faculty of Engineering, Universiti Teknologi Malaysia, 81310, Skudai, Johor, Malaysia
| | - Keng Yinn Wong
- School of Mechanical Engineering, Faculty of Engineering, Universiti Teknologi Malaysia, 81310, Skudai, Johor, Malaysia.
- Process Systems Engineering Centre (PROSPECT), Faculty of Engineering, Universiti Teknologi Malaysia, 81310, Skudai, Johor, Malaysia.
| | - Bemgba Bevan Nyakuma
- Department of Chemistry, Faculty of Sciences, Benue State University, Makurdi, Benue State, P. M. B 102119, Nigeria
| | - Haslinda Mohamed Kamar
- School of Mechanical Engineering, Faculty of Engineering, Universiti Teknologi Malaysia, 81310, Skudai, Johor, Malaysia
| | - Wen Tong Chong
- Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Syie Luing Wong
- Dpto. Matemática Aplicada, Ciencia e Ingeniería de Materiales y Tecnología Electrónica, Universidad Rey Juan Carlos, C/ Tulipán s/n, Móstoles, Madrid, Spain
| | - Hooi Siang Kang
- School of Mechanical Engineering, Faculty of Engineering, Universiti Teknologi Malaysia, 81310, Skudai, Johor, Malaysia
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Chang L, Chong WT, Wang X, Pei F, Zhang X, Wang T, Wang C, Pan S. Recent progress in research on PM 2.5 in subways. Environ Sci Process Impacts 2021; 23:642-663. [PMID: 33889885 DOI: 10.1039/d1em00002k] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Nowadays, PM2.5 concentrations greatly influence indoor air quality in subways and threaten passenger and staff health because PM2.5 not only contains heavy metal elements, but can also carry toxic and harmful substances due to its small size and large specific surface area. Exploring the physicochemical and distribution characteristics of PM2.5 in subways is necessary to limit its concentration and remove it. At present, there are numerous studies on PM2.5 in subways around the world, yet, there is no comprehensive and well-organized review available on this topic. This paper reviews the nearly twenty years of research and over 130 published studies on PM2.5 in subway stations, including aspects such as concentration levels and their influencing factors, physicochemical properties, sources, impacts on health, and mitigation measures. Although many determinants of station PM2.5 concentration have been reported in current studies, e.g., the season, outdoor environment, and station depth, their relative influence is uncertain. The sources of subway PM2.5 include those from the exterior (e.g., road traffic and fuel oil) and the interior (e.g., steel wheels and rails and metallic brake pads), but the proportion of these sources is also unknown. Control strategies of PM mainly include adequate ventilation and filtration, but these measures are often inefficient in removing PM2.5. The impacts of PM2.5 from subways on human health are still poorly understood. Further research should focus on long-term data collection, influencing factors, the mechanism of health impacts, and PM2.5 standards or regulations.
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Affiliation(s)
- Li Chang
- Department of Mechanical Engineering, Faculty of Engineering, Universiti Malaya, Kuala Lumpur, 50603, Malaysia.
| | - Wen Tong Chong
- Department of Mechanical Engineering, Faculty of Engineering, Universiti Malaya, Kuala Lumpur, 50603, Malaysia.
| | - Xinru Wang
- College of Emergency Technology and Management, North China Institute of Science and Technology, Hebei 065201, China
| | - Fei Pei
- Beijing Key Laboratory of Green Built Environment and Energy Efficient Technology, Beijing University of Technology, Beijing, 100124, China
| | - Xingxing Zhang
- Department of Energy, Forest and Built Environment, Dalarna University, Falun, 79188, Sweden
| | - Tongzhao Wang
- Rizhao Fire and Rescue Station, Rizhao, 276800, China
| | - Chunqing Wang
- School of Municipal and Environmental Engineering, Jilin Jianzhu University, Jilin, 130118, China
| | - Song Pan
- Beijing Key Laboratory of Green Built Environment and Energy Efficient Technology, Beijing University of Technology, Beijing, 100124, China
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Pang YL, Lim S, Ong HC, Chong WT. Synthesis, characteristics and sonocatalytic activities of calcined γ-Fe2O3 and TiO2 nanotubes/γ-Fe2O3 magnetic catalysts in the degradation of Orange G. Ultrason Sonochem 2016; 29:317-327. [PMID: 26585012 DOI: 10.1016/j.ultsonch.2015.10.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 10/04/2015] [Accepted: 10/04/2015] [Indexed: 06/05/2023]
Abstract
In this work, γ-Fe2O3 and TiO2 NTs/γ-Fe2O3 composites with good magnetism and sonocatalytic activity were prepared by a facile polyol method and utilize the principle of isoelectric point method, respectively. The structural and magnetic features of the prepared calcined γ-Fe2O3 and composite catalysts were investigated by transmission electron microscopy (TEM), powder X-ray diffraction (XRD), surface analysis, UV-Vis diffuse reflectance spectra (UV-Vis DRS), vibrating sample magnetometry (VSM) and zeta potential analysis. The effects of calcination temperature on γ-Fe2O3 phase variation, physical properties and sonocatalytic properties were investigated. The porosity, specific surface area, band gap energy and sonocatalytic activity of γ-Fe2O3 were gradually decreased with calcination temperature increased. TiO2 NTs/γ-Fe2O3 with appropriate composition and specific structural features possess synergetic effects such as efficient separation of charge carriers and hydroxyl radicals produced by heterogeneous fenton and fenton-like reactions. This enhanced the sonocatalytic activity for the degradation of Orange G under ultrasonic irradiation. The sonocatalytic reactions obeyed pseudo first-order kinetics. All these information provide insight into the design and development of high-efficiency catalyst for wastewater treatment.
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Affiliation(s)
- Yean Ling Pang
- Department of Chemical Engineering, Lee Kong Chian Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Sungai Long, Bandar Sungai Long, Cheras, 43000 Kajang, Selangor, Malaysia; Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia.
| | - Steven Lim
- Department of Chemical Engineering, Lee Kong Chian Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Sungai Long, Bandar Sungai Long, Cheras, 43000 Kajang, Selangor, Malaysia; Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Hwai Chyuan Ong
- Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Wen Tong Chong
- Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia
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Aditiya HB, Chong WT, Mahlia TMI, Sebayang AH, Berawi MA, Nur H. Second generation bioethanol potential from selected Malaysia's biodiversity biomasses: A review. Waste Manag 2016; 47:46-61. [PMID: 26253329 DOI: 10.1016/j.wasman.2015.07.031] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Revised: 06/22/2015] [Accepted: 07/19/2015] [Indexed: 06/04/2023]
Abstract
Rising global temperature, worsening air quality and drastic declining of fossil fuel reserve are the inevitable phenomena from the disorganized energy management. Bioethanol is believed to clear out the effects as being an energy-derivable product sourced from renewable organic sources. Second generation bioethanol interests many researches from its unique source of inedible biomass, and this paper presents the potential of several selected biomasses from Malaysia case. As one of countries with rich biodiversity, Malaysia holds enormous potential in second generation bioethanol production from its various agricultural and forestry biomasses, which are the source of lignocellulosic and starch compounds. This paper reviews potentials of biomasses and potential ethanol yield from oil palm, paddy (rice), pineapple, banana and durian, as the common agricultural waste in the country but uncommon to be served as bioethanol feedstock, by calculating the theoretical conversion of cellulose, hemicellulose and starch components of the biomasses into bioethanol. Moreover, the potential of the biomasses as feedstock are discussed based on several reported works.
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Affiliation(s)
- H B Aditiya
- Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia; Department of Mechanical Engineering, Universiti Tenaga Nasional, 43000 Kajang, Selangor, Malaysia.
| | - W T Chong
- Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia.
| | - T M I Mahlia
- Department of Mechanical Engineering, Universiti Tenaga Nasional, 43000 Kajang, Selangor, Malaysia.
| | - A H Sebayang
- Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - M A Berawi
- Department of Civil Engineering, Faculty of Engineering, Universitas Indonesia, Kampus UI, Depok, Indonesia
| | - Hadi Nur
- Centre for Sustainable Nanomaterials, Ibnu Sina Institute for Scientific and Industrial Research, Universiti Teknologi Malaysia, Johor Bahru, Malaysia
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Abdullah N, Abu Talib AR, Jaafar AA, Mohd Salleh MA, Chong WT. The basics and issues of Thermochromic Liquid Crystal Calibrations. Experimental Thermal and Fluid Science 2010; 34:1089-1121. [DOI: 10.1016/j.expthermflusci.2010.03.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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Abstract
For biomedical applications drug carrying polymers are coated around magnetic iron oxide particles to form microspheres. In the present study, the iron oxide powder was ball milled. Microspheres were then synthesized by solvent evaporation, resulting in iron oxide particles encapsulated in a polymer and drug coating. Various parameters, such as the duration of milling and agitation speed as well as the polymer concentration were varied. A milling time of 72 h was found to yield a small size and narrow size distribution of particles; the average particle size was about 600 nm. Measurements of the change in grain size and the magnetic properties of the powder with milling time were performed. It was determined that the size of the microspheres was not sensitive to the initial particle size, but it could be decreased by variation of agitation speed or polymer concentration. The agitation speed and polymer concentration of 400 rpm and 0.04 g poly(l-lactic acid) in 8 g dicholoromethane, respectively, was found to yield small, spherical microspheres with a narrow size distribution. The surface morphology and magnetic properties of the microspheres was also analyzed.
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Affiliation(s)
- R V Ramanujan
- School of Materials Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 63979.
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