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Patel S, Hedayati Marzbali M, Hakeem IG, Veluswamy G, Rathnayake N, Nahar K, Agnihotri S, Bergmann D, Surapaneni A, Gupta R, Sharma A, Shah K. Production of H 2 and CNM from biogas decomposition using biosolids-derived biochar and the application of the CNM-coated biochar for PFAS adsorption. WASTE MANAGEMENT (NEW YORK, N.Y.) 2023; 159:146-153. [PMID: 36764239 DOI: 10.1016/j.wasman.2023.01.037] [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: 09/29/2022] [Revised: 01/26/2023] [Accepted: 01/31/2023] [Indexed: 06/18/2023]
Abstract
Anaerobic digestion is a popular unit operation in wastewater treatment to degrade organic contaminants, thereby generating biogas (methane-rich gas stream). Catalytic decomposition of the biogas could be a promising upcycling approach to produce renewable hydrogen and sequester carbon in the form of carbon nanomaterials (CNMs). Biosolids are solid waste generated during the wastewater treatment process, which can be valorised to biochar via pyrolysis. This work demonstrates the use of biosolids-derived biochar compared with ilmenite as catalysts for biogas decomposition to hydrogen and CNMs. Depending on the reaction time, biosolids-derived biochar achieved a CH4 and CO2 conversion of 50-70 % and 70-90 % at 900 °C with a weight hourly space velocity (WHSV) of 1.2 Lg-1h-1. The high conversion rate was attributed to the formation of amorphous carbon on the biochar surface, where the carbon deposits acted as catalysts and substrates for the further decomposition of CH4 and CO2. Morphological characterisation of biochar after biogas decomposition revealed the formation of high-quality carbon nanospheres (200-500 nm) and carbon nanofibres (10-100 nm) on its surface. XRD pattern and Raman spectroscopy also signified the presence of graphitic structures with ID/IG ratio of 1.19, a reduction from 1.33 in the pristine biochar. Finally, the produced CNM-loaded biochar was tested for PFAS adsorption from contaminated wastewater. A removal efficiency of 79 % was observed for CNM-coated biochar which was 10-60 % higher than using biochar and ilmenite alone. This work demonstrated an integrated approach for upcycling waste streams generated in wastewater treatment facilities.
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Affiliation(s)
- Savankumar Patel
- Chemical and Environmental Engineering, School of Engineering, RMIT University, Melbourne, VIC 3000, Australia; ARC Training Centre for the Transformation of Australia's Biosolids Resources, RMIT University, Bundoora, VIC 3083, Australia
| | - Mojtaba Hedayati Marzbali
- Chemical and Environmental Engineering, School of Engineering, RMIT University, Melbourne, VIC 3000, Australia; ARC Training Centre for the Transformation of Australia's Biosolids Resources, RMIT University, Bundoora, VIC 3083, Australia
| | - Ibrahim Gbolahan Hakeem
- Chemical and Environmental Engineering, School of Engineering, RMIT University, Melbourne, VIC 3000, Australia; ARC Training Centre for the Transformation of Australia's Biosolids Resources, RMIT University, Bundoora, VIC 3083, Australia
| | - Ganesh Veluswamy
- Chemical and Environmental Engineering, School of Engineering, RMIT University, Melbourne, VIC 3000, Australia; ARC Training Centre for the Transformation of Australia's Biosolids Resources, RMIT University, Bundoora, VIC 3083, Australia
| | - Nimesha Rathnayake
- Chemical and Environmental Engineering, School of Engineering, RMIT University, Melbourne, VIC 3000, Australia; ARC Training Centre for the Transformation of Australia's Biosolids Resources, RMIT University, Bundoora, VIC 3083, Australia
| | - Kamrun Nahar
- Chemical and Environmental Engineering, School of Engineering, RMIT University, Melbourne, VIC 3000, Australia; ARC Training Centre for the Transformation of Australia's Biosolids Resources, RMIT University, Bundoora, VIC 3083, Australia
| | - Shivani Agnihotri
- Chemical and Environmental Engineering, School of Engineering, RMIT University, Melbourne, VIC 3000, Australia; ARC Training Centre for the Transformation of Australia's Biosolids Resources, RMIT University, Bundoora, VIC 3083, Australia
| | - David Bergmann
- South East Water Corporation, Frankston, VIC 3199, Australia
| | - Aravind Surapaneni
- ARC Training Centre for the Transformation of Australia's Biosolids Resources, RMIT University, Bundoora, VIC 3083, Australia; South East Water Corporation, Frankston, VIC 3199, Australia
| | - Rajender Gupta
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB T6G 2G6, Canada
| | - Abhishek Sharma
- ARC Training Centre for the Transformation of Australia's Biosolids Resources, RMIT University, Bundoora, VIC 3083, Australia; Department of Chemical Engineering, Manipal University Jaipur, Jaipur, Rajasthan 303007, India
| | - Kalpit Shah
- Chemical and Environmental Engineering, School of Engineering, RMIT University, Melbourne, VIC 3000, Australia; ARC Training Centre for the Transformation of Australia's Biosolids Resources, RMIT University, Bundoora, VIC 3083, Australia.
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Magnetic Hydrogel Composite for Wastewater Treatment. Polymers (Basel) 2022; 14:polym14235074. [PMID: 36501469 PMCID: PMC9741452 DOI: 10.3390/polym14235074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 11/16/2022] [Accepted: 11/19/2022] [Indexed: 11/24/2022] Open
Abstract
Nanocomposite hydrogels are highly porous colloidal structures with a high adsorption capacity, making them promising materials for wastewater treatment. In particular, magnetic nanoparticle (MNP) incorporated hydrogels are an excellent adsorbent for aquatic pollutants. An added advantage is that, with the application of an external magnetic field, magnetic hydrogels can be collected back from the wastewater system. However, magnetic hydrogels are quite brittle and structurally unstable under compact conditions such as in fixed-bed adsorption columns. To address this issue, this study demonstrates a unique hydrogel composite bead structure, providing a good adsorption capacity and superior compressive stress tolerance due to the presence of hollow cores within the beads. The gel beads contain alginate polymer as the matrix and MNP-decorated cellulose nanofibres (CNF) as the reinforcing agent. The MNPs within the gel provide active adsorption functionality, while CNF provide a good stress transfer phenomenon when the beads are under compressive stress. Their adsorption performance is evaluated in a red mud solution for pollutant adsorption. Composite gel beads have shown high performance in adsorbing metal (aluminium, potassium, selenium, sodium, and vanadium) and non-metal (sulphur) contaminations. This novel hybrid hydrogel could be a promising alternative to the conventionally used toxic adsorbent, providing environmentally friendly operational benefits.
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