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Ghibaudo N, Ferretti M, Al-Hetlani E, Madkour M, Amin MO, Alberti S. Synthesis and characterization of TiO 2-based supported materials for industrial application and recovery in a pilot photocatalytic plant using chemometric approach. Environ Sci Pollut Res Int 2024; 31:20556-20567. [PMID: 38376776 DOI: 10.1007/s11356-024-32467-y] [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: 11/22/2023] [Accepted: 02/09/2024] [Indexed: 02/21/2024]
Abstract
In this contribution, the performance of powdered titanium dioxide (TiO2)-based photocatalysts was evaluated in a pilot photocatalytic plant for the degradation of different dyes, with an investigated volume of 1 L and solar simulated light as irradiation source. Five different samples, synthesized in our laboratories, were tested in the pilot plant, each consisting of TiO2 nanoparticles (NPs) coupled with a different material (persistent luminescent material and semiconductor material) and treated in different thermal conditions. All synthesized samples have been subjected to X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller analysis (BET), and transmission electron microscopy (TEM) characterization, to shed light on the influence of introducing other materials on titania characteristics. To study and evaluate the significance of the parameters affecting the process in the pilot plant, a chemometric approach was applied, by selecting a mathematical model (D-Optimal) to simultaneously monitor a large number of variables (i.e., 7), both qualitative and quantitative, over a wide range of levels. At the same time, the recovery of the synthesized photocatalysts was studied following a novel promising recuperation method, i.e., annulling the surface charge of the suspended samples by reaching the isoelectric point (pHPZC) of each sample, for the quantitative precipitation of TiO2 nanoparticles.
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Affiliation(s)
- Nicolò Ghibaudo
- Chemistry and Industrial Chemistry Department, University of Genoa, Via Dodecaneso 31, 16146, Genoa (Ge), Italy
| | - Maurizio Ferretti
- Chemistry and Industrial Chemistry Department, University of Genoa, Via Dodecaneso 31, 16146, Genoa (Ge), Italy
| | - Entesar Al-Hetlani
- Chemistry Department, Faculty of Science, Kuwait University, P.O. Box 5969, 13060, Safat, Kuwait
| | - Metwally Madkour
- Chemistry Department, Faculty of Science, Arish University, Al-Arish, 45511, Egypt
| | - Mohamed O Amin
- Chemistry Department, Faculty of Science, Kuwait University, P.O. Box 5969, 13060, Safat, Kuwait
| | - Stefano Alberti
- Chemistry and Industrial Chemistry Department, University of Genoa, Via Dodecaneso 31, 16146, Genoa (Ge), Italy.
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He C, Scott E, Rochfort Q. Enhancing sedimentation by improving flow conditions using parallel retrofit baffles. J Environ Manage 2015; 160:1-6. [PMID: 26081303 DOI: 10.1016/j.jenvman.2015.06.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [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: 12/15/2014] [Revised: 05/07/2015] [Accepted: 06/05/2015] [Indexed: 06/04/2023]
Abstract
In this study, placing parallel-connected baffles in the vicinity of the inlet was proposed to improve hydraulic conditions for enhancing TSS (total suspended solids) removal. The purpose of the retrofit baffle design is to divide the large and fast inflow into smaller and slower flows to increase flow uniformity. This avoids short-circuiting and increases residence time in the sedimentation basin. The newly proposed parallel-connected baffle configuration was assessed in the laboratory by comparing its TSS removal performance and the optimal flow residence time with those from the widely used series-connected baffles. The experimental results showed that the parallel-connected baffles outperformed the series-connected baffles because it could disperse flow faster and in less space by splitting the large inflow into many small branches instead of solely depending on flow internal friction over a longer flow path, as was the case under the series-connected baffles. Being able to dampen faster flow before entering the sedimentation basin is critical to reducing the possibility of disturbing any settled particles, especially under high inflow conditions. Also, for a large sedimentation basin, it may be more economically feasible to deploy the proposed parallel retrofit baffle in the vicinity of the inlet than series-connected baffles throughout the entire settling basin.
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Affiliation(s)
- Cheng He
- National Water Research Institute, Environment Canada, 867 Lakeshore Road, Burlington, Ontario L7R 4A6, Canada.
| | - Eric Scott
- Department of Mechanical Engineering, McMaster University, Hamilton, Canada.
| | - Quintin Rochfort
- National Water Research Institute, Environment Canada, 867 Lakeshore Road, Burlington, Ontario L7R 4A6, Canada.
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Alcántara C, Domínguez JM, García D, Blanco S, Pérez R, García-Encina PA, Muñoz R. Evaluation of wastewater treatment in a novel anoxic-aerobic algal-bacterial photobioreactor with biomass recycling through carbon and nitrogen mass balances. Bioresour Technol 2015; 191:173-186. [PMID: 25989093 DOI: 10.1016/j.biortech.2015.04.125] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [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: 03/13/2015] [Revised: 04/29/2015] [Accepted: 04/30/2015] [Indexed: 06/04/2023]
Abstract
Algal-bacterial symbiosis, implemented in an innovative anoxic-aerobic photobioreactor configuration with biomass recycling, supported an efficient removal of total organic carbon (86-90%), inorganic carbon (57-98%) and total nitrogen (68-79%) during synthetic wastewater treatment at a hydraulic and sludge retention times of 2 days and 20 days, respectively. The availability of inorganic carbon in the photobioreactor, determined by its supply in the wastewater and microalgae activity, governed the extent of nitrogen removal by assimilation or nitrification-denitrification. Unexpectedly, nitrate production was negligible despite the high dissolved oxygen concentrations, denitrification being only based on nitrite reduction. Biomass recycling resulted in the enrichment of rapidly settling algal flocs, which supported effluent total suspended solid concentrations below the European Union maximum discharge limits. Finally, the maximum nitrous oxide emissions recorded were far below the emission factors reported for wastewater treatment plants, confirming the environmental sustainability of this innovative photobioreactor in terms of global warming impact.
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Affiliation(s)
- Cynthia Alcántara
- Department of Chemical Engineering and Environmental Technology, Valladolid University, Dr. Mergelina, s/n, 47011 Valladolid, Spain
| | - Jesús M Domínguez
- Department of Chemical Engineering and Environmental Technology, Valladolid University, Dr. Mergelina, s/n, 47011 Valladolid, Spain
| | - Dimas García
- Department of Chemical Engineering and Environmental Technology, Valladolid University, Dr. Mergelina, s/n, 47011 Valladolid, Spain
| | - Saúl Blanco
- Department of Biodiversity and Environmental Management, University of León, 24071 León, Spain
| | - Rebeca Pérez
- Department of Chemical Engineering and Environmental Technology, Valladolid University, Dr. Mergelina, s/n, 47011 Valladolid, Spain
| | - Pedro A García-Encina
- Department of Chemical Engineering and Environmental Technology, Valladolid University, Dr. Mergelina, s/n, 47011 Valladolid, Spain
| | - Raúl Muñoz
- Department of Chemical Engineering and Environmental Technology, Valladolid University, Dr. Mergelina, s/n, 47011 Valladolid, Spain.
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de Godos I, Vargas VA, Guzmán HO, Soto R, García B, García PA, Muñoz R. Assessing carbon and nitrogen removal in a novel anoxic-aerobic cyanobacterial-bacterial photobioreactor configuration with enhanced biomass sedimentation. Water Res 2014; 61:77-85. [PMID: 24880959 DOI: 10.1016/j.watres.2014.04.050] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [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: 12/17/2013] [Revised: 04/22/2014] [Accepted: 04/29/2014] [Indexed: 05/24/2023]
Abstract
The carbon and nitrogen removal potential of an innovative anoxic-aerobic photobioreactor configuration operated with both internal and external recyclings was evaluated under different cyanobacterial-bacterial sludge residence times (9-31 days) during the treatment of wastewaters with low C/N ratios. Under optimal operating conditions, the two-stage photobioreactor was capable of providing organic carbon and nitrogen removals over 95% and 90%, respectively. The continuous biomass recycling from the settler resulted in the enrichment and predominance of rapidly-settling cyanobacterial-bacterial flocs and effluent suspended solid concentrations lower than 35 mg VSS L(-1). These flocs exhibited sedimentation rates of 0.28-0.42 m h(-1) but sludge volumetric indexes of 333-430 ml/g. The decoupling between the hydraulic retention time and sludge retention time mediated by the external recycling also avoided the washout of nitrifying bacteria and supported process operation at biomass concentrations of 1000-1500 mg VSS L(-1). The addition of additional NaHCO3 to the process overcame the CO2 limitation resulting from the intense competition for inorganic carbon between cyanobacteria and nitrifying bacteria in the photobioreactor, which supported the successful implementation of a nitrification-denitrification process. Unexpectedly, this nitrification-denitrification process occurred both simultaneously in the photobioreactor alone (as a result of the negligible dissolved oxygen concentrations) and sequentially in the two-stage anoxic-aerobic configuration with internal NO3(-)/NO2(-) recycling.
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Affiliation(s)
- I de Godos
- Department of Chemical Engineering and Environmental Technology, University of Valladolid, C/Dr. Mergelina s/n, 47005 Valladolid, Spain; Aqualia Gestión Integral del Agua S.A., Avenida Camino de Santiago, 40, Madrid, Spain
| | - V A Vargas
- Center of Biotechnology, University of San Simon, Campus Universitario, s/n Cochabamba, Bolivia
| | - H O Guzmán
- Center of Biotechnology, University of San Simon, Campus Universitario, s/n Cochabamba, Bolivia
| | - R Soto
- Center of Biotechnology, University of San Simon, Campus Universitario, s/n Cochabamba, Bolivia
| | - B García
- Department of Chemical Engineering and Environmental Technology, University of Valladolid, C/Dr. Mergelina s/n, 47005 Valladolid, Spain
| | - P A García
- Department of Chemical Engineering and Environmental Technology, University of Valladolid, C/Dr. Mergelina s/n, 47005 Valladolid, Spain
| | - R Muñoz
- Department of Chemical Engineering and Environmental Technology, University of Valladolid, C/Dr. Mergelina s/n, 47005 Valladolid, Spain.
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