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Effect of Substituents on the Homopolymerization Activity of Methyl Alkyl Diallyl Ammonium Chloride. Molecules 2022; 27:molecules27154677. [PMID: 35897851 PMCID: PMC9330561 DOI: 10.3390/molecules27154677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 07/18/2022] [Accepted: 07/18/2022] [Indexed: 12/04/2022] Open
Abstract
Among nitrogen-containing cationic electrolytes, diallyl quaternary ammonium salt is a typical monomer with the highest positive charge density, which has attracted the most attention, especially in the research on homopolymers and copolymers of dimethyl diallyl ammonium chloride (DMDAAC), which occupy a very unique and important position. In order to improve the lipophilicity of substituted diallyl ammonium chloride monomers under the premise of high cationic charge density, the simplest, most direct, and most efficient structure design strategy was selected in this paper. Only one of the substituents on DMDAAC quaternary ammonium nitrogen was modified by alkyl; the substituents were propyl and amyl groups, and their corresponding monomers were methyl propyl diallyl ammonium chloride (MPDAAC) and methyl amyl diallyl ammonium chloride (MADAAC), respectively. The effect of substituent structure on the homopolymerization activity of methyl alkyl diallyl ammonium chloride was illustrated by quantum chemical calculation and homopolymerization rate determination experiments via ammonium persulfate (APS) as the initiator system. The results of quantum chemistry simulation showed that, with the finite increase in substituted alkyl chain length, the numerical values of the bond length and the charge distribution of methyl alkyl diallyl ammonium chloride monomer changed little, with the activation energy of the reactions in the following order: DMDAAC < MPDAAC < MADAAC. The polymerization activities measured by the dilatometer method were in the order DMDAAC > MPDAAC > MADAAC. The activation energies Ea of homopolymerization were 96.70 kJ/mol, 97.25 kJ/mol, and 100.23 kJ/mol, and the rate equation of homopolymerization of each monomer was obtained. After analyzing and comparing these results, it could be easily found that the electronic effect of substituent was not obvious, whereas the effect of the steric hindrance was dominant. The above studies have laid a good foundation for an understanding of the polymerization activity of methyl alkyl diallyl ammonium chloride monomers and the possibility of preparation and application of these polymers with high molecular weight.
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Hashemi T, Mehrnia MR, Ghezelgheshlaghi S. Influence of alumina nanoparticles on the performance of polyacrylonitrile membranes in MBR. JOURNAL OF ENVIRONMENTAL HEALTH SCIENCE & ENGINEERING 2022; 20:375-384. [PMID: 35669801 PMCID: PMC9163238 DOI: 10.1007/s40201-021-00784-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 12/28/2021] [Indexed: 06/15/2023]
Abstract
This study aims to investigate the effect of using Al2O3 nanoparticles (NPs) in membrane structure on the operation condition of the membrane bioreactor. To this end, alumina NPs as the high hydrophilic agents with an approximate size of 40 nm and a concentration of 0-3 wt.% were placed within the PAN polymeric membrane matrix structure with high hydrophilicity and high mechanical resistance over the others via the phase inversion method. Characterization of synthesized nanocomposite membranes was carried out by SEM analysis. In the presence of the alumina NPs, the porosity of the membranes improved. The water contact angle measurement confirmed the superior hydrophilicity of mixed PAN membranes compared to the pure polymeric membranes. The best nanocomposite membrane with better antifouling properties was selected to evaluate the MBR's performance in wastewater treatment and assessed in terms of the resistance, flux recovery, and COD removal rates. The result of a comparison with pure membrane showed that by increasing the Al2O3 amount up to 2wt.%, irreversible fouling resistance mitigated as much as 50%. Moreover, the flux recovery ratio was increased by 15%, and the COD removal rate was also raised as large as 16%. Our investigation illustrated that the presence of alumina NPs has improved the MBR performance and decreased the irreversible fouling resistance of the membrane.
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Affiliation(s)
- Targol Hashemi
- School of Chemical Engineering, University College of Engineering, University of Tehran, P.O. Box 11155-45, Tehran, Iran
| | - Mohammad Reza Mehrnia
- School of Chemical Engineering, University College of Engineering, University of Tehran, P.O. Box 11155-45, Tehran, Iran
| | - Saeid Ghezelgheshlaghi
- School of Chemical Engineering, University College of Engineering, University of Tehran, P.O. Box 11155-45, Tehran, Iran
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Odriozola M, van Lier JB, Spanjers H. Optimising the Flux Enhancer Dosing Strategy in a Pilot-Scale Anaerobic Membrane Bioreactor by Mathematical Modelling. MEMBRANES 2022; 12:membranes12020151. [PMID: 35207073 PMCID: PMC8877340 DOI: 10.3390/membranes12020151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 01/20/2022] [Accepted: 01/22/2022] [Indexed: 11/30/2022]
Abstract
Flux enhancers (FEs) have been successfully applied for fouling mitigation in membrane bioreactors. However, more research is needed to compare and optimise different dosing strategies to improve the filtration performance, while minimising the use of FEs and preventing overdosing. Therefore, the goal of this research is to develop an optimised control strategy for FE dosing into an AnMBR by developing a comprehensive integrated mathematical model. The integrated model includes filtration, flocculation, and biochemical processes to predict the effect of FE dosing on sludge filterability and membrane fouling rate in an AnMBR. The biochemical model was based on an ADM1, modified to include FEs and colloidal material. We developed an empirical model for the FE-induced flocculation of colloidal material. Various alternate filtration models from the literature and our own empirical models were implemented, calibrated, and validated; the best alternatives were selected based on model accuracy and capacity of the model to predict the effect of varying sludge characteristics on the corresponding output, that is fouling rate or sludge filterability. The results showed that fouling rate and sludge filterability were satisfactorily predicted by the selected filtration models. The best integrated model was successfully applied in the simulation environment to compare three feedback and two feedforward control tools to manipulate FE dosing to an AnMBR. The modelling results revealed that the most appropriate control tool was a feedback sludge filterability controller that dosed FEs continuously, referred to as ∆R20_10. Compared to the other control tools, application of the ∆R20_10 controller resulted in a more stable sludge filterability and steady fouling rate, when the AnMBR was subject to specific disturbances. The simulation environment developed in this research was shown to be a useful tool to test strategies for dosing flux enhancer into AnMBRs.
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Noormohamadi A, Homayoonfal M, Mehrnia MR, Davar F. Employing magnetism of Fe 3O 4 and hydrophilicity of ZrO 2 to mitigate biofouling in magnetic MBR by Fe 3O 4-coated ZrO 2/PAN nanocomposite membrane. ENVIRONMENTAL TECHNOLOGY 2020; 41:2683-2704. [PMID: 30741624 DOI: 10.1080/09593330.2019.1579870] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2018] [Accepted: 01/26/2019] [Indexed: 06/09/2023]
Abstract
The aim of this research is benefiting from the synergistic effect of the simultaneous presence of Fe3O4 and ZrO2 in the form of Fe3O4-coated ZrO2 (Fe3O4@ZrO2) nanoparticles within the structure of PAN membrane to reduce membrane fouling. The role of Fe3O4 nanoparticles in increasing the pore size and magnetic saturation as well as the role of ZrO2 in decreasing surface roughness and hydrophobicity can mitigate membrane fouling in magnetic-assisted membrane bioreactors. For this purpose, Fe3O4, ZrO2, and Fe3O4@ZrO2 nanoparticles were embedded into PAN membrane structure and magnetic (M nM), hydrophilic (H nM), and magnetic-hydrophilic (HM nM) membranes were synthesized. H 1M (1ZrO2/PAN) membrane with a contact angle of 31 degrees, M 1N (1Fe3O4/PAN) with a pore size of 90 nm, and H 3M (3ZrO2/PAN) membrane with an RMS roughness of 13.5 nm were the most hydrophilic, porous, and smoothest membranes, respectively. High sensitivity to magnetic field along with high porosity, high hydrophilicity and low surface roughness simultaneously exist within the structure of MHMs membranes, such that MH 1M (1Fe3O4@ZrO2/PAN) indicated 116% greater flux, 121% greater flux recovery, and 85% less total filtration resistance in comparison with the blank membrane in magnetic membrane bioreactor, at a magnetic field intensity of 120 mT and MLSS = 10,000 mg/l. As an overall conclusion, the output of this research was compared with other research in term of normalized flux. Results reveal that at MLSS = 10,000 mg/l, HRT = 8 h and TMP = 0.3 bar, MH 1M membrane has normalized flux equal to 1.56 g/m2 h bar which is an acceptable value compared to normalized flux reported by other researchers.
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Affiliation(s)
- Amin Noormohamadi
- School of Chemical Engineering, College of Engineering, University of Tehran, Tehran, Iran
| | - Maryam Homayoonfal
- Department of Chemical Engineering, College of Engineering, University of Isfahan, Isfahan, Iran
| | - Mohammad Reza Mehrnia
- School of Chemical Engineering, College of Engineering, University of Tehran, Tehran, Iran
| | - Fatemeh Davar
- Department of Chemistry, Isfahan University of Technology, Isfahan, Iran
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Zhou JH, Jiang SF, Yu HC, Wu CH, Zeng T, Zhou YC, Hong QK, Wang HY. A comparative study on membrane fouling alleviation mechanisms by using nanoscale Fe 3O 4 and poly dimethyldiallylammonium chloride. ENVIRONMENTAL TECHNOLOGY 2020; 41:1477-1485. [PMID: 30339487 DOI: 10.1080/09593330.2018.1538260] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 10/13/2018] [Indexed: 06/08/2023]
Abstract
Membrane bioreactor (MBR) has become a promising technology for wastewater treatment. However, membrane fouling frequently occurred which greatly increased operational expense. Two different membrane fouling alleviation mechanisms were explored in this study. Addition of poly dimethyldiallylammonium chloride (PDMDAAC) facilitated formation of flocs-flocs aggregates, which were more adaptable to the changing environment, resulting in less soluble microbial products (SMP) secretion. However, PDMDAAC lose activity gradually, and had a less sustainable effect on membrane fouling alleviation. Nanoscale Fe3O4 was applied to alleviate membrane fouling, and membrane sustainable filtration cycle extended 2-fold compared to the control group. Results showed that dehydrogenase activity in the reactor with optimal addition of nanoscale Fe3O4 increased 2.86 ± 0.11 times compared to control group. SMP (especially tryptophan protein-like substances) decreased to 9.79 ± 1.34 mg L-1 with the addition of nanoscale Fe3O4, which was lower than that in the control group (15.31 ± 0.53 mg L-1). It's speculated that nanoscale Fe3O4 performed as conductive material, which intensified interspecies electron transfer. The sludge dehydrogenase activity was then enhanced, which facilitated the utilization and microbial degradation of SMP, suppressing membrane fouling consequently.
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Affiliation(s)
- Jia-Heng Zhou
- College of Civil Engineering and Architecture, Zhejiang University of Technology, Hangzhou, People's Republic of China
| | - Sheng-Feng Jiang
- College of Civil Engineering and Architecture, Zhejiang University of Technology, Hangzhou, People's Republic of China
| | - Hao-Cheng Yu
- College of Civil Engineering and Architecture, Zhejiang University of Technology, Hangzhou, People's Republic of China
| | - Chang-Hua Wu
- College of Civil Engineering and Architecture, Zhejiang University of Technology, Hangzhou, People's Republic of China
| | - Tao Zeng
- College of Environment, Zhejiang University of Technology, Hangzhou, People's Republic of China
| | - Yun-Cheng Zhou
- College of Civil Engineering and Architecture, Zhejiang University of Technology, Hangzhou, People's Republic of China
| | - Qian-Kun Hong
- College of Civil Engineering and Architecture, Zhejiang University of Technology, Hangzhou, People's Republic of China
| | - Hong-Yu Wang
- College of Civil Engineering and Architecture, Zhejiang University of Technology, Hangzhou, People's Republic of China
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Zheng T, Qiu Z, Dai Q, Chen J. Study of biogas slurry concentrated by reverse osmosis system: characteristics, optimization, and mechanism. WATER ENVIRONMENT RESEARCH : A RESEARCH PUBLICATION OF THE WATER ENVIRONMENT FEDERATION 2019; 91:1447-1454. [PMID: 31063631 DOI: 10.1002/wer.1137] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 04/14/2019] [Accepted: 04/30/2019] [Indexed: 06/09/2023]
Abstract
Biogas slurry, also called liquid digestate, refers to the liquid part of the anaerobic digestate produced from the anaerobic digestion process, which is an environmental pollution source if it is discharged without proper treatment. To recover the nutrients in the biogas slurry, a membrane system was designed to concentrate in the work. The effects of pretreatment technology including gravity settling and ultrafiltration process were studied via analyzing the chemical oxygen demand (COD), ammonia nitrogen (NH3 -N), total nitrogen (TN), and conductivity. Reverse osmosis was applied in the biogas slurry concentration. The performance of reverse osmosis membrane used in the concentration process was studied by analyzing the permeate and concentrate (retentate), the volume reduction factor, and the concentration factor. The suitable parameters were selected as 20.0-25.0°C for influent temperature, 0.8-1.0Mpa for operating pressure, and 6.0-8.0 for influent pH. Furthermore, the feasible concentration factor was evaluated as 4. The economic, environmental, and social benefits could be gained if (concentrated) biogas slurry was used as an alternative to chemical fertilizers. PRACTITIONER POINTS: Reverse osmosis system was established for biogas slurry concentrating. The operational factors were optimized on biogas slurry concentrating and separation. The biogas slurry separation mechanism was discussed.
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Affiliation(s)
- Tianxiang Zheng
- College of Environment, Zhejiang University of Technology, Hangzhou, China
| | - Zonglian Qiu
- College of Environment, Zhejiang University of Technology, Hangzhou, China
| | - Qizhou Dai
- College of Environment, Zhejiang University of Technology, Hangzhou, China
| | - Jianmeng Chen
- College of Environment, Zhejiang University of Technology, Hangzhou, China
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