Enhanced extracellular polymeric substances production and aggravated membrane fouling potential caused by different disinfection treatment
TL;DR: In this paper, three commonly-used disinfection methods (free chlorine, chloramine and ozone disinfection) were used to investigate their effects on microbial EPS production and the further effects on membrane fouling.
About: This article is published in Journal of Membrane Science.The article was published on 2022-02-15. It has received 5 citations till now. The article focuses on the topics: Chemistry & Biofouling.
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TL;DR: In this article , the authors examined how colloidal, biological, organic, and inorganic fouling varied in 4-year-old reverse osmosis (RO) membranes taken from lead and lag ends of pressure vessels of each of the three stages from the world's largest potable reuse facility.
Abstract: We examined how colloidal, biological, organic, and inorganic fouling varied in 4-year-old reverse osmosis (RO) membranes taken from lead and lag ends of pressure vessels of each of the three stages from the world’s largest potable reuse facility. Colorimetry, microscopy, spectroscopy, and microbial analysis revealed varying combined fouling extents in all cases. Bioorganics dominated all but the last element. In the first and second stages, non-siliceous multivalent inorganics accumulated more on lead elements, whereas silicon-based foulants prevailed in lag elements. The third-stage lag element suffered the heaviest inorganic and the lowest bioorganic fouling. Cleaning small swatches cut from each element with a mixture of sodium tripolyphosphate and sodium dodecylbenzenesulfonic acid fully recovered the permeability of only the lag element of the first stage, which had endured the lowest inorganic fouling. Partial permeability recovery of all of the other elements suggested that cleaning was only effective against bioorganics, and harsher cleaners and/or interstage treatment were needed to combat silicon fouling. Cleaning agents did not appear to penetrate and remove entrapped foulants, resulting in faster performance deterioration when the membranes resumed service post-cleaning. Results emphasize the importance of systematically autopsying elements from each stage and evaluating their post-cleaning characteristics to optimize RO pretreatment and cleaning protocols.
3 citations
TL;DR: In this paper , a series of membranes made from in-situ ozone oxidized intrinsic mciroporous polymer membranes (O 3 -PIMs) were used to obtain high performance hydrogen separation membranes.
1 citations
TL;DR: In this article , a combination of potassium ferrate (K2FeO4) preoxidation with magnetic ion exchange resin (MIEX) adsorption was used to reduce membrane fouling caused by the treatment of natural surface water pollutants before ultrafiltration (UF).
1 citations
TL;DR: In this article , the authors performed a 32-day experiment to parallelly compare the biofouling characteristics of RO membranes of DRB after five mature water disinfection methods (NaClO, NH 2 Cl, ClO 2 , UV, and O 3 ) and two recently developed water disinfections methods (K 2 FeO 4 and flow-through electrode system).
Abstract: Abstract Reverse osmosis (RO) is widely used in wastewater reclamation to alleviate the increasingly global water shortage. However, it has an inconvenient defect of biofouling. Some disinfection processes have been reported to select certain undesirable disinfection-residual bacteria (DRB), leading to severe long-term biofouling potential. To provide constructive guidance on biofouling prevention in RO systems, this study performed a 32-day experiment to parallelly compared the biofouling characteristics of RO membranes of DRB after five mature water disinfection methods (NaClO, NH 2 Cl, ClO 2 , UV, and O 3 ) and two recently developed water disinfection methods (K 2 FeO 4 and flow-through electrode system). As a result, the DRB biofilm of K 2 FeO 4 and O 3 caused a slight normalised flux drop (22.4 ± 2.4% and 23.9 ± 1.7%) of RO membrane compared to the control group (non-disinfected, ~27% normalised flux drop). FES, UV, NaClO and ClO 2 caused aggravated membrane flux drop (29.1 ± 0.3%, 33.3 ± 7.8%, 34.6 ± 6.4%, and 35.5 ± 4.0%, respectively). The biofouling behaviour showed no relationship with bacterial concentration or metabolic activity ( p > 0.05). The thickness and compactness of the biofilms and the organics/bacterial number ratio in the biofilm, helped explain the difference in the fouling degree between each group. Moreover, microbial community analysis showed that the relative abundance of typical highly EPS-secretory and biofouling-related genera, such as Pseudomonas , Sphingomonas , Acinetobacter , Methylobacterium , Sphingobium , and Ralstonia , were the main reasons for the high EPS secreting ability of the total bacteria, resulting in aggravation of biofouling degree ( p < 0.05). All types of disinfection except for NaClO and ClO 2 effectively prevented pathogen reproduction in the DRB biofilm.
TL;DR: In this article , a review summarizes recent developments and uses of Cellulose Nanocrystals (CNCs) in water treatment membranes and discusses the challenges and development prospects of CNCs materials from the perspectives of ecological safety and human health by comparing them with traditional one-dimensional nanomaterials.
References
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TL;DR: The principles that underlie the determination of protein secondary structure by FTIR spectroscopy are detailed, as well as the basic steps involved in protein sample preparation, instrument operation,FTIR spectra collection and spectra analysis in order to estimate protein secondary-structural components in aqueous solution.
Abstract: Fourier transform IR (FTIR) spectroscopy is a nondestructive technique for structural characterization of proteins and polypeptides. The IR spectral data of polymers are usually interpreted in terms of the vibrations of a structural repeat. The repeat units in proteins give rise to nine characteristic IR absorption bands (amides A, B and I-VII). Amide I bands (1,700-1,600 cm(-1)) are the most prominent and sensitive vibrational bands of the protein backbone, and they relate to protein secondary structural components. In this protocol, we have detailed the principles that underlie the determination of protein secondary structure by FTIR spectroscopy, as well as the basic steps involved in protein sample preparation, instrument operation, FTIR spectra collection and spectra analysis in order to estimate protein secondary-structural components in aqueous (both H2O and deuterium oxide (D2O)) solution using algorithms, such as second-derivative, deconvolution and curve fitting. Small amounts of high-purity (>95%) proteins at high concentrations (>3 mg ml(-1)) are needed in this protocol; typically, the procedure can be completed in 1-2 d.
757 citations
TL;DR: An overview on the potential treatments to overcome the environmental problems associated to the direct discharge of RO concentrates is given and recent studies that are mainly focused on reducing the organic pollutant load through the application of innovative advanced oxidation technologies are addressed.
647 citations
TL;DR: “biofilm-enhanced osmotic pressure” plays a dominant role in RO biofouling, with scanning electron microscope images of dead cells and biofilm supporting these proposed mechanisms.
586 citations
TL;DR: This paper reviews membrane fouling types and fouling control strategies, with a focus on the latest developments, including biofouling, organic fouling, inorganic scaling and colloidal fouling.
567 citations
TL;DR: The fundamentals of EPSs including definitions, compositions and properties, and factors affecting EPSs production and characteristics are summarized and based on which, EPSs control towards membrane fouling mitigation in MBRs are comprehensively discussed.
564 citations