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Hegyi A, Petcu C, Ciobanu AA, Calatan G, Bradu A. Development of Clay-Composite Plasters Integrating Industrial Waste. MATERIALS (BASEL, SWITZERLAND) 2023; 16:4903. [PMID: 37512178 PMCID: PMC10381511 DOI: 10.3390/ma16144903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 07/03/2023] [Accepted: 07/06/2023] [Indexed: 07/30/2023]
Abstract
This research investigates the feasibility of developing clay composites using natural materials and incorporating waste by-products suitable for plastering diverse support structures. The study identified a versatile composition suitable for a wide range of support materials and explored the potential of revaluing industrial waste and by-products by reintegrating them into the Circular Economy. The experimental investigation outlines the process of evaluating the influence of different raw materials on the performance of the clay composite. The findings confirm that using limestone sludge and fly ash as additives to clay contributes to reducing axial shrinkage and increasing mechanical strengths, respectively. The optimal percentage of additives for the clay used are identified and provided. Using hydraulic lime as a partial substitute for clay reduces the apparent density of dried clay composites, axial shrinkage, and fissures formation while improving adhesion to the substrate. Introducing dextrin into this mix increases the apparent density of the hardened plaster while keeping axial shrinkage below the maximum threshold indicated by the literature. Mechanical strengths improved, and better compatibility in terms of adhesion to the support was achieved, with composition S3 presenting the best results and a smooth, fissure-free plastered surface after drying.
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Affiliation(s)
- Andreea Hegyi
- NIRD URBAN-INCERC Cluj-Napoca Branch, 117 Calea Florești, 400524 Cluj-Napoca, Romania
- Faculty of Materials and Environmental Engineering, Technical University of Cluj-Napoca, 103-105 Muncii Boulevard, 400641 Cluj-Napoca, Romania
| | - Cristian Petcu
- NIRD URBAN-INCERC Bucharest, 266 Șoseaua Pantelimon, 021652 Bucharest, Romania
| | | | - Gabriela Calatan
- Office for Pedological and Agrochemical Studies Cluj-Napoca, 1 Fagului Str., 400483 Cluj-Napoca, Romania
| | - Aurelia Bradu
- NIRD URBAN-INCERC Iaşi Branch, 6 Anton Şesan Street, 700048 Iaşi, Romania
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Nazaroff WW, Weschler CJ. Indoor ozone: Concentrations and influencing factors. INDOOR AIR 2022; 32:e12942. [PMID: 34609012 DOI: 10.1111/ina.12942] [Citation(s) in RCA: 42] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 09/21/2021] [Accepted: 09/24/2021] [Indexed: 05/03/2023]
Abstract
Because people spend most of their time indoors, much of their exposure to ozone occurs in buildings, which are partially protective against outdoor ozone. Measurements in approximately 2000 indoor environments (residences, schools, and offices) show a central tendency for average indoor ozone concentration of 4-6 ppb and an indoor to outdoor concentration ratio of about 25%. Considerable variability in this ratio exists among buildings, as influenced by seven building-associated factors: ozone removal in mechanical ventilation systems, ozone penetration through the building envelope, air-change rates, ozone loss rate on fixed indoor surfaces, ozone loss rate on human occupants, ozone loss by homogeneous reaction with nitrogen oxides, and ozone loss by reaction with gas-phase organics. Among these, the most important are air-change rates, ozone loss rate on fixed indoor surfaces, and, in densely occupied spaces, ozone loss rate on human occupants. Although most indoor ozone originates outdoors and enters with ventilation air, indoor emission sources can materially increase indoor ozone concentrations. Mitigation technologies to reduce indoor ozone concentrations are available or are being investigated. The most mature of these technologies, activated carbon filtration of mechanical ventilation supply air, shows a high modeled health-benefit to cost ratio when applied in densely occupied spaces.
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Affiliation(s)
- William W Nazaroff
- Department of Civil and Environmental Engineering, University of California, Berkeley, CA, USA
| | - Charles J Weschler
- Environmental and Occupational Health Sciences Institute, Rutgers University, Piscataway, NJ, USA
- International Centre for Indoor Environment and Energy, Technical University of Denmark, Lyngby, Denmark
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Collins DB, Farmer DK. Unintended Consequences of Air Cleaning Chemistry. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:12172-12179. [PMID: 34464124 DOI: 10.1021/acs.est.1c02582] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Amplified interest in maintaining clean indoor air associated with the airborne transmission risks of SARS-CoV-2 have led to an expansion in the market for commercially available air cleaning systems. While the optimal way to mitigate indoor air pollutants or contaminants is to control (remove) the source, air cleaners are a tool for use when absolute source control is not possible. Interventions for indoor air quality management include physical removal of pollutants through ventilation or collection on filters and sorbent materials, along with chemically reactive processes that transform pollutants or seek to deactivate biological entities. This perspective intends to highlight the perhaps unintended consequences of various air cleaning approaches via indoor air chemistry. Introduction of new chemical agents or reactive processes can initiate complex chemistry that results in the release of reactive intermediates and/or byproducts into the indoor environment. Since air cleaning systems are often continuously running to maximize their effectiveness and most people spend a vast majority of their time indoors, human exposure to both primary and secondary products from air cleaners may represent significant exposure risk. This Perspective highlights the need for further study of chemically reactive air cleaning and disinfection methods before broader adoption.
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Affiliation(s)
- Douglas B Collins
- Department of Chemistry, Bucknell University, Lewisburg, Pennsylvania 17837, United States
| | - Delphine K Farmer
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
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Ault AP, Grassian VH, Carslaw N, Collins DB, Destaillats H, Donaldson DJ, Farmer DK, Jimenez JL, McNeill VF, Morrison GC, O'Brien RE, Shiraiwa M, Vance ME, Wells JR, Xiong W. Indoor Surface Chemistry: Developing a Molecular Picture of Reactions on Indoor Interfaces. Chem 2020; 6:3203-3218. [PMID: 32984643 PMCID: PMC7501779 DOI: 10.1016/j.chempr.2020.08.023] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Chemical reactions on indoor surfaces play an important role in air quality in indoor environments, where humans spend 90% of their time. We focus on the challenges of understanding the complex chemistry that takes place on indoor surfaces and identify crucial steps necessary to gain a molecular-level understanding of environmental indoor surface chemistry: (1) elucidate key surface reaction mechanisms and kinetics important to indoor air chemistry, (2) define a range of relevant and representative surfaces to probe, and (3) define the drivers of surface reactivity, particularly with respect to the surface composition, light, and temperature. Within the drivers of surface composition are the roles of adsorbed/absorbed water associated with indoor surfaces and the prevalence, inhomogeneity, and properties of secondary organic films that can impact surface reactivity. By combining laboratory studies, field measurements, and modeling we can gain insights into the molecular processes necessary to further our understanding of the indoor environment.
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Affiliation(s)
- Andrew P Ault
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Vicki H Grassian
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA.,Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92037, USA.,Department of Nanoengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Nicola Carslaw
- Department of Environment and Geography, University of York, York, North Yorkshire YO10 5NG, UK
| | - Douglas B Collins
- Department of Chemistry, University of Toronto, Toronto, ON M5S 3H6, Canada.,Department of Chemistry, Bucknell University, Lewisburg, PA 17837, USA
| | - Hugo Destaillats
- Indoor Environment Group, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - D James Donaldson
- Department of Chemistry, University of Toronto, Toronto, ON M5S 3H6, Canada.,Department of Physical and Environmental Sciences, University of Toronto, Toronto, ON M1C 1A4, Canada
| | - Delphine K Farmer
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523, USA
| | - Jose L Jimenez
- Department of Chemistry and Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado Boulder, Boulder, CO 80309, USA
| | - V Faye McNeill
- Department of Chemical Engineering, Columbia University, New York, NY 10027, USA
| | - Glenn C Morrison
- Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Rachel E O'Brien
- Department of Chemistry, College of William and Mary, Williamsburg, VA 23185, USA
| | - Manabu Shiraiwa
- Department of Chemistry, University of California Irvine, Irvine, CA 92697, USA
| | - Marina E Vance
- Department of Mechanical Engineering, University of Colorado Boulder, Boulder, CO 80309, USA
| | - J R Wells
- National Institute for Occupational Safety and Health, Morgantown, WV 26505, USA
| | - Wei Xiong
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA.,Materials Science and Engineering Program, University of California, San Diego, La Jolla, CA 92093, USA
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