1
|
Zhou W, Liu X, Long Y, Xie G, Chen Y. Monitoring effects of hydrodynamic cavitation pretreatment of sodium oleate on the aggregation of fine diaspore particles through small-angle laser scattering. ULTRASONICS SONOCHEMISTRY 2023; 100:106574. [PMID: 37734167 PMCID: PMC10514452 DOI: 10.1016/j.ultsonch.2023.106574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 08/11/2023] [Accepted: 08/29/2023] [Indexed: 09/23/2023]
Abstract
Hydrodynamic cavitation (HC) enhanced fine particle aggregation could be largely due to the generation of tiny bubbles and their role in bridging particles. However, the lack of adequate characterizations of aggregates severally limits our further understanding of the associated aggregation behaviors. In this study, the aggregation of fine diaspore particles was comparatively investigated in sodium oleate (NaOl) solutions with and without HC pretreatment through the small-angle laser scattering (SALS) technique in a shear-induced aggregation (SIA) system. Results showed that HC pretreatment caused the formation of bulk nanobubbles (BNBs), which significantly modified the particle interactions and thereby modified the size and mass fractal dimension (Df) of aggregates under different SIA conditions. Although HC pretreatment did not noticeably alter the gradual change trend of aggregate size and structure characteristics under specific variables, BNBs bridging facilitated the aggregation process towards the diffusion-limited cluster aggregation model, resulting in the formation of larger but looser aggregates. This effect was more pronounced under relatively high NaOl concentrations. Apart from BNBs, the aggregation was also affected by cavitation bubbles formed during shear cavitation, which was more significant under high stirring intensity conditions (i.e., 1800 rpm) than the low stirring intensity conditions (i.e., 600 rpm).
Collapse
Affiliation(s)
- Weiguang Zhou
- Key Laboratory of Coal Processing and Efficient Utilization of Ministry of Education, School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116, PR China; Yunnan Key Laboratory of Green Separation and Enrichment of Strategic Metal Mineral Resources, Kunming University of Science and Technology, Kunming 650093, PR China
| | - Xinran Liu
- Key Laboratory of Coal Processing and Efficient Utilization of Ministry of Education, School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116, PR China
| | - Yufeng Long
- Key Laboratory of Coal Processing and Efficient Utilization of Ministry of Education, School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116, PR China
| | - Guangyuan Xie
- Key Laboratory of Coal Processing and Efficient Utilization of Ministry of Education, School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116, PR China.
| | - Yanfei Chen
- School of Metallurgy and Environment, Central South University, Changsha 410083, PR China.
| |
Collapse
|
2
|
Rao NRH, Granville AM, Henderson RK. Understanding variability in algal solid-liquid separation process outcomes by manipulating extracellular protein-carbohydrate interactions. WATER RESEARCH 2021; 190:116747. [PMID: 33385876 DOI: 10.1016/j.watres.2020.116747] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 12/09/2020] [Accepted: 12/12/2020] [Indexed: 06/12/2023]
Abstract
Coagulation-flocculation followed by sedimentation or dissolved air flotation (DAF) are processes routinely used for separating microalgae from water; however, during algae separation then can exhibit inconsistent separation, high coagulant demand, and high operating cost. To circumvent these problems, previous studies reported the development of a novel DAF process in which bubbles were modified instead of particles. While this process was shown to be sustainable and inexpensive, the problem of inconsistent algal separation across species remained. Recent research has suggested that this could be due to the varying concentration and character of algal-derived proteins and carbohydrates within the extracellular organic matter (EOM) and their associated interactions. This hypothesis is tested in the current study using the novel modified-bubble DAF process, which has been highly susceptible to EOM protein and carbohydrate concentrations and character. Biomolecular additives (commercially available proteins and carbohydrates, and algal-extracted proteins) of widely differing molecular weight (MW) and charge were dosed in varying proportions into samples containing either Chlorella vulgaris CS-42/7, Microcystis aeruginosa CS-564/01, or Microcystis aeruginosa CS-555/1 after removing the intrinsic EOM. These cell-rich suspensions were then subject to flotation using cationic bubbles modified with poly(diallyldimethylammonium chloride) (PDADMAC). When additives were dosed independently, separation increased from <5% to up to 62%. The maximum separation was obtained when the dose was double the respective biopolymer concentration measured in the intrinsic EOM for the equivalent species, and, in the case of protein additives, when MW and charge were >50 kDa, and >0.5 meq·g-1, respectively, irrespective of the species tested. When evaluating steric- and charge-based protein-carbohydrate interactions on cell separation by simultaneously dosing high MW and high charge protein- and carbohydrate-additives, enhanced separation of up to 79% was achieved. It is suggested that enhanced cell separation is achieved due to proteins and carbohydrates bridging with cells and forming protein-carbohydrate-cell suprastructures in the presence of a flocculant, e.g. PDADMAC, and this only occurs when the intrinsic EOM comprises proteins and carbohydrates that have high MW (>25 kDa) and charge (>0.2 meq·g-1), and interactions with each other and with the cell surface.
Collapse
Affiliation(s)
- N R H Rao
- Algae and Organic Matter Laboratory (AOM Lab), School of Chemical Engineering, The University of New South Wales, Sydney, Australia; Centre for Advanced Macromolecular Design (CAMD), School of Chemical Engineering, The University of New South Wales, Sydney, Australia
| | - A M Granville
- Centre for Advanced Macromolecular Design (CAMD), School of Chemical Engineering, The University of New South Wales, Sydney, Australia
| | - R K Henderson
- Algae and Organic Matter Laboratory (AOM Lab), School of Chemical Engineering, The University of New South Wales, Sydney, Australia.
| |
Collapse
|
3
|
Hanumanth Rao NR, Yap R, Whittaker M, Stuetz RM, Jefferson B, Peirson WL, Granville AM, Henderson RK. The role of algal organic matter in the separation of algae and cyanobacteria using the novel "Posi" - Dissolved air flotation process. WATER RESEARCH 2018; 130:20-30. [PMID: 29190513 DOI: 10.1016/j.watres.2017.11.049] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 11/19/2017] [Accepted: 11/23/2017] [Indexed: 06/07/2023]
Abstract
Algae and cyanobacteria frequently require separation from liquid media in both water treatment and algae culturing for biotechnology applications. The effectiveness of cell separation using a novel dissolved air flotation process that incorporates positively charged bubbles (PosiDAF) has recently been of interest but has been shown to be dependent on the algae or cyanobacteria species tested. Previously, it was hypothesised that algal organic matter (AOM) could be impacting the separation efficiency. Hence, this study investigates the influence of AOM on cell separation using PosiDAF, in which bubbles are modified using a commercially available cationic polyelectrolyte poly(N, N-diallyl-N,N-dimethylammonium chloride) (PDADMAC). The separation of Chlorella vulgaris CS-42/7, Mychonastes homosphaera CS-556/01 and two strains of Microcystis aeruginosa (CS-564/01 and CS-555/1), all of which have similar cell morphology but different AOM character, was investigated. By testing the cell separation in the presence and absence of AOM, it was determined that AOM enhanced cell separation for all the strains but to different extents depending on the quantity and composition of carbohydrates and proteins in the AOM. By extracting AOM from the strain for which optimal separation was observed and adding it to the others, cell separation improved from <55% to >90%. This was attributed to elevated levels of acidic carbohydrates as well as glycoprotein-carbohydrate conjugations, which in turn were related to the nature and quantity of proteins and carbohydrates present in the AOM. Therefore, it was concluded that process optimisation requires an in-depth understanding of the AOM and its components. If culturing algae for biotechnology applications, this indicates that strain selection is not only important with respect to high value product content, but also for cell separation.
Collapse
Affiliation(s)
- Narasinga Rao Hanumanth Rao
- bioMASS Lab, School of Chemical Engineering, The University of New South Wales, Sydney, NSW, 2052, Australia; Centre for Advanced Macromolecular Design, School of Chemical Engineering, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - Russell Yap
- bioMASS Lab, School of Chemical Engineering, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - Michael Whittaker
- Centre for Advanced Macromolecular Design, School of Chemical Engineering, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - Richard M Stuetz
- bioMASS Lab, School of Chemical Engineering, The University of New South Wales, Sydney, NSW, 2052, Australia; UNSW Water Research Centre, School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - Bruce Jefferson
- Cranfield Water Science Institute, School of Applied Sciences, Cranfield University, Bedfordshire, MK43 0AL, UK
| | - William L Peirson
- Water Research Laboratory, School of Civil and Environmental Engineering, The University of New South Wales, Manly Vale, NSW, 2093, Australia
| | - Anthony M Granville
- Centre for Advanced Macromolecular Design, School of Chemical Engineering, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - Rita K Henderson
- bioMASS Lab, School of Chemical Engineering, The University of New South Wales, Sydney, NSW, 2052, Australia.
| |
Collapse
|
4
|
Yap RKL, Whittaker M, Diao M, Stuetz RM, Jefferson B, Bulmus V, Peirson WL, Nguyen AV, Henderson RK. Hydrophobically-associating cationic polymers as micro-bubble surface modifiers in dissolved air flotation for cyanobacteria cell separation. WATER RESEARCH 2014; 61:253-262. [PMID: 24934266 DOI: 10.1016/j.watres.2014.05.032] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 05/15/2014] [Accepted: 05/18/2014] [Indexed: 06/03/2023]
Abstract
Dissolved air flotation (DAF), an effective treatment method for clarifying algae/cyanobacteria-laden water, is highly dependent on coagulation-flocculation. Treatment of algae can be problematic due to unpredictable coagulant demand during blooms. To eliminate the need for coagulation-flocculation, the use of commercial polymers or surfactants to alter bubble charge in DAF has shown potential, termed the PosiDAF process. When using surfactants, poor removal was obtained but good bubble adherence was observed. Conversely, when using polymers, effective cell removal was obtained, attributed to polymer bridging, but polymers did not adhere well to the bubble surface, resulting in a cationic clarified effluent that was indicative of high polymer concentrations. In order to combine the attributes of both polymers (bridging ability) and surfactants (hydrophobicity), in this study, a commercially-available cationic polymer, poly(dimethylaminoethyl methacrylate) (polyDMAEMA), was functionalised with hydrophobic pendant groups of various carbon chain lengths to improve adherence of polymer to a bubble surface. Its performance in PosiDAF was contrasted against commercially-available poly(diallyl dimethyl ammonium chloride) (polyDADMAC). All synthesised polymers used for bubble surface modification were found to produce positively charged bubbles. When applying these cationic micro-bubbles in PosiDAF, in the absence of coagulation-flocculation, cell removals in excess of 90% were obtained, reaching a maximum of 99% cell removal and thus demonstrating process viability. Of the synthesised polymers, the polymer containing the largest hydrophobic functionality resulted in highly anionic treated effluent, suggesting stronger adherence of polymers to bubble surfaces and reduced residual polymer concentrations.
Collapse
Affiliation(s)
- R K L Yap
- UNSW Water Research Centre, School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW 2052, Australia; Centre for Advanced Macromolecular Design, School of Chemical Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
| | - M Whittaker
- Monash Institute of Pharmaceutical Sciences (MIPS), Monash University, IVC 3052, Australia
| | - M Diao
- School of Chemical Engineering, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - R M Stuetz
- UNSW Water Research Centre, School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
| | - B Jefferson
- Cranfield Water Science Institute, School of Applied Sciences, Cranfield University, Bedfordshire MK43 0AL, UK
| | - V Bulmus
- Department of Chemical Engineering, Izmir Institute of Technology, Urla, 35430 Izmir, Turkey
| | - W L Peirson
- Water Research Laboratory, School of Civil and Environmental Engineering, The University of New South Wales, Manly Vale, NSW 2093, Australia
| | - A V Nguyen
- School of Chemical Engineering, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - R K Henderson
- UNSW Water Research Centre, School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW 2052, Australia.
| |
Collapse
|