scholarly journals Mathematical modelling of flux recovery during chemical cleaning of tubular membrane fouled with whey proteins

2009 ◽  
pp. 135-144 ◽  
Author(s):  
Natasa Lukic ◽  
Svetlana Popovic ◽  
Jelena Markovic
Keyword(s):  
Mathematical Modelling ◽  
Pore Diameter ◽  
Whey Proteins ◽  
Process Efficiency ◽  
Chemical Cleaning ◽  
Tubular Membrane ◽  
Cleaning Agents ◽  
Naoh Solution ◽  
Cleaning Procedures ◽  
Insight Into

Membrane process efficiency in the dairy industry is impaired by the formation of deposits during filtration processes. This work describes cleaning procedures for ceramic tubular membrane (50 nm) fouled with whey proteins. Also, mathematical modelling was performed to obtain models which allow deeper insight into the mechanisms involved during cleaning procedures. The caustic solutions (0.2%w/w, 0.4%w/w and 1.0%w/w NaOH) and the mixture of two commercial detergents (0.8%w/w P3-ultrasil 69+0.5% w/w P3-ultrasil 67 and 1.2% P3-ultrasil 69+0.75 P3-ultrasil 67) were used as chemical cleaning agents. The results showed that the best flux recovery was achieved with 0.4%w/w NaOH solution. After analyzing the experimental data, five parameter and six parameter kinetic models were suggested for alkali and detergent cleaning, respectively. The changes of total and specific resistances, as well as the change of the effective pore diameter and deposit thickness during cleaning are estimated by applying these models.

Strategies for chemical cleaning in large scale membrane bioreactors

2008 ◽  
Vol 57 (3) ◽  
pp. 457-463 ◽  
Author(s):  
C. Brepols ◽  
K. Drensla ◽  
A. Janot ◽  
M. Trimborn ◽  
N. Engelhardt
Keyword(s):  
Large Scale ◽  
Membrane Bioreactor ◽  
Effective Means ◽  
Membrane Bioreactors ◽  
Ex Situ ◽  
Chemical Cleaning ◽  
Membrane Cleaning ◽  
Cleaning Agents ◽  
Cleaning Procedures ◽  
Alkaline Cleaning

Systematically testing alternative cleaning agents and cleaning procedures on a large scale municipal membrane bioreactor, the Erftverband optimized the cleaning strategies and refined the original cleaning procedures for the hollow fiber membranes in use. A time-consuming, intensive ex-situ membrane cleaning twice a year was initially the regular routine. By introducing the effective means of cleaning in place in use today, which employs several acidic and oxidative/alkaline cleaning steps, intensive membrane cleaning could be delayed for years. An overview and an assessment of various cleaning strategies for large scale plants are given.

Application of an ultrasound field in chemical cleaning of ceramic tubular membrane fouled with whey proteins

2010 ◽  
Vol 101 (3) ◽  
pp. 296-302 ◽  
Author(s):  
Svetlana Popović ◽  
Mirjana Djurić ◽  
Spasenija Milanović ◽  
Miodrag N. Tekić ◽  
Nataša Lukić
Keyword(s):  
Whey Proteins ◽  
Chemical Cleaning ◽  
Tubular Membrane ◽  
Ultrasound Field

scholarly journals The Mathematical Proficiency Promoted by Mathematical Modelling

2021 ◽  
Vol 4 (2) ◽  
pp. 107-131
Author(s):  
Priscila Dias Corrêa ◽  
Keyword(s):  
High School Students ◽  
Mathematical Modelling ◽  
Mathematics Teaching ◽  
Research Study ◽  
Mathematical Work ◽  
School Students ◽  
Design Based Research ◽  
Video Recordings ◽  
Mathematical Proficiency ◽  
Insight Into

This study aims to investigate the mathematical proficiency promoted by mathematical modelling tasks that require students to get involved in the processes of developing mathematical models, instead of just using known or given models. The research methodology is grounded on design-based research, and the classroom design framework is supported by complexity science underpinnings. The research intervention consists of high-school students, from a grade 11 mathematics course, aiming to solve four different modelling tasks in four distinct moments. Data was collected during the intervention from students’ written mathematical work and audio and video recordings, and from recall interviews after the intervention. Data analysis was conducted based on a model of mathematical proficiency and assisted by interpretive diagrams created for this research purpose. This research study offers insight into mathematics teaching by portraying how mathematical modelling tasks can be integrated into mathematics classes to promote students’ mathematical proficiency. The study discusses observed expressions and behaviours in students’ development of mathematical proficiency and suggests a relationship between mathematical modelling processes and the promotion of mathematical proficiency. The study also reveals that students develop mathematical proficiency, even when they do not come to full resolutions of modelling tasks, which emphasizes the relevance of learning processes, and not only of the products of these processes.

3. Do you believe in models? Simplicity and complexity

2018 ◽  
pp. 34-47
Author(s):  
Alain Goriely
Keyword(s):  
Mathematical Modelling ◽  
Mathematical Models ◽  
Applied Mathematics ◽  
Abstract Representation ◽  
The World ◽  
Insight Into

Models are central to the world of applied mathematics. In its simplest sense, a model is an abstract representation of a system developed in order to answer specific questions or gain insight into a phenomenon. In general, we expect a model to be based on sound principles, to be mathematically consistent, and to have some predictive or insight value. Models are the ultimate form of quantification since all variables and parameters that appear must be properly defined and quantified for the equations to make sense. ‘Do you believe in models? Simplicity and complexity’ discusses the complexity of models; the steps involved in developing mathematical models—the physics paradigm; and collaborative mathematical modelling.

scholarly journals Chemical Cleaning of Ultrafiltration Membrane Fouled by Humic Substances: Comparison between Hydrogen Peroxide and Sodium Hypochlorite

2019 ◽  
Vol 16 (14) ◽  
pp. 2568 ◽  
Author(s):  
Kai Li ◽  
Shu Li ◽  
Tinglin Huang ◽  
Chongzhe Dong ◽  
Jiawei Li ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Humic Substances ◽  
Sodium Hypochlorite ◽  
Alkaline Condition ◽  
Chemical Cleaning ◽  
H2o2 Treatment ◽  
Cleaning Agent ◽  
Cleaning Agents ◽  
Cleaning Efficacy ◽  
By Products

Chemical cleaning is indispensable for the sustainable operation of ultrafiltration (UF) system in water and wastewater treatment. Sodium hypochlorite (NaClO) is an established cleaning agent for membranes subject to organic and microbial fouling, but concerns have been raised about the generation of toxic halogenated by-products during NaClO cleaning. Hydrogen peroxide (H2O2) is a potential “green” cleaning agent that can avoid the formation of halogenated by-products. In this work, cleaning efficacy of H2O2 and NaClO for UF membrane fouled by humic substances (HS) was evaluated under a wide pH range, and change of HS’s properties due to reaction with cleaning agents was examined. The cleaning efficacy of H2O2 was lower than that of NaClO at pH 3–9, but it increased to a level (91.4%) comparable with that of NaClO at pH 11. The extents of changes in properties and fouling potential of HS due to reacting with cleaning agents were consistent with their cleaning efficacy. H2O2 treatment at pH 11 significantly increased negative charge of HS molecules, decomposed high-MW molecules, and reduced its fouling potential. Therefore, considering treatment/disposal of cleaning waste and cleaning efficacy, H2O2 cleaning under strong alkaline condition can be a good choice for HS-fouled membrane.

scholarly journals Study on Chemical Cleaning Agent in Treatment of Abandoned Oil Pipeline

2019 ◽  
Vol 118 ◽  
pp. 01031
Author(s):  
Fajie Yang ◽  
Chunman Li ◽  
Jing Li ◽  
Hongtao Wang ◽  
Siyu Wu ◽  
...  
Keyword(s):  
Developed Countries ◽  
Environment Protection ◽  
Chemical Cleaning ◽  
The Public ◽  
Oil Pipeline ◽  
Cleaning Agent ◽  
Cleaning Agents ◽  
Standards And Guidelines ◽  
Safety And Environment ◽  
Very High

After pipeline construction burst china energy pipeline industry commonly faced with aging and abandonment problem. The study on pipeline abandonment was still in preliminary state, because there is nearly no pipeline abandonment standards and guidelines. Pipeline cleaning is the first step to dispose the abandoned pipeline to eliminate the risk of environment and safety. In foreign developed countries there are many chemical cleaning agents. But this chemical cleaning agent is not suitable for residual of chines pipeline because of oil difference between china and foreign country. The most of residual in china have a very high paraffin and resin-asphaltenes content. So preparation of chemical cleaning suitable for china residual is a challenge on the technology of abandonment pipeline. In this paper two kinds of chemical cleaning agent were prepared to clean the different type of residual. They are hydrophilic chemical cleaning agent and oil soluble chemical cleaning agent. The result of cleaning project shows that the both kind of chemical cleaning have good performance for the abandoned pipeline. The chemical cleaning agents will assist pipeline company to totally clean the abandoned pipeline to ensure the public safety and environment protection.

Unravelling Nature's networks

2003 ◽  
Vol 31 (6) ◽  
pp. 1457-1461 ◽  
Author(s):  
N.A.M. Monk
Keyword(s):  
Dynamical System ◽  
Mathematical Modelling ◽  
Computational Analysis ◽  
Spatiotemporal Dynamics ◽  
Interaction Networks ◽  
Living Systems ◽  
Cellular Interaction ◽  
Cellular Mechanisms ◽  
Complex Dynamical System ◽  
Insight Into

Dramatic progress has been made recently in determining the genetic and molecular composition of cells. This has prompted the development of new approaches to the challenge of understanding how basic cellular mechanisms are coordinated to produce the dazzling complexity of living systems. To face this challenge fully, it is critical not only to know what genes and proteins are expressed in cells, but also to understand the spatiotemporal dynamics of their networks of interactions. The sheer scale and complexity of cellular interaction networks necessitates a multi-disciplinary effort in which sophisticated experimental techniques are employed in combination with computational analysis and mathematical modelling. Such approaches are beginning to provide insight into basic structures and mechanisms, and promise to become critical to the post-genomic mission of understanding the cell as a complex dynamical system.

Fabrication of Low Cost Anodic Aluminum Oxide (AAO) Tubular Membrane and their Application for Hemodialysis

2012 ◽  
Vol 550-553 ◽  
pp. 2040-2045 ◽  
Author(s):  
Ajab Khan Kasi ◽  
Jafar Khan Kasi ◽  
Mahadi Hasan ◽  
Nitin Afzulpurkar ◽  
Sirapat Pratontep ◽  
...  
Keyword(s):  
Anodic Aluminum Oxide ◽  
Pore Diameter ◽  
Low Cost ◽  
Membrane Thickness ◽  
Low Grade ◽  
Fluid Filtration ◽  
Tubular Membrane ◽  
Anodic Aluminum ◽  
Self Organized ◽  
Impurity Defects

This paper reports the fabrication of AAO tubular membrane using 99.35% and 99.56% pure Al and their potential application for hemodialysis. Here we discussed the effect of impurity on membrane structure. We found that the self organized structure of AAO nanochannels minimizes impurity defects in membrane. If micro size impurity blocks the generation of nanochannels then the neighboring nanochannels bend and make branches to fulfill that gap. We observed that if impurity size is less than the AAO membrane thickness then it does not produce any micro size hole. In low grade Al the periodic hexagonal order was disturbed however there was no big difference in pore diameter. It was observed that such type of membrane do not have any leakage and it can be used for fluid filtration. The fabricated tubular membrane was used for hemodialysis successfully. The hemodialysis results show that AAO tubular membrane can be used for both diffusive and convective filtration

scholarly journals Synthesis of Silica Powder from Sugar Cane Bagasse Ash and Its Application as Adsorbent in Adsorptive-distillation of Ethanol-water Solution

2018 ◽  
Vol 237 ◽  
pp. 02002 ◽  
Author(s):  
Megawati ◽  
Dewi Selvia Fardhyanti ◽  
Radenrara Dewi Artanti Putri ◽  
Oki Fianti ◽  
Agustin Fitrianingsi Simalango ◽  
...  
Keyword(s):  
Pore Diameter ◽  
Ethanol Concentration ◽  
Water Solution ◽  
Silica Powder ◽  
Azeotropic Point ◽  
Naoh Solution ◽  
Sugarcane Bagasse Ash ◽  
Paper Filter ◽  
Sugar Cane Bagasse Ash ◽  
Hcl Solution

In this study, sugarcane bagasse ash (SCBA) as waste from sugarcane factory was extracted into silica powder. This powder was then used as adsorbent for ethanol purification. Prior to used, the SCBA was washed using HCl solution. The silica extraction was conducted using various NaOH concentrations (0.5; 1; 1.5 and 2 mol/L) as well as extraction times (30, 60 and 90 minutes). After that the mixture was precipitated using HCl solution. The solution was filtrated through a paper filter and its solid particle was dried until its weight was constant. The particle was grounded and sieved using 18 mesh sieves. The silica powder obtained was analysed using FTIR and its result showed that the powder has silica functional groups. The silica yield increases with increasing of concentration of NaOH solution as well as extraction time. The highest silica yield (45.5% w/w) was achieved at 2 mol/L NaOH solution at 90 min. The surface area, pore diameter, and pore volume of silica powder were measured to be 407 m2/g, 3.81Å, and 2.76 dm3/g, respectively. From application of silica powder as adsorbent in adsorptive-distillation, ethanol concentration can reach 99.3% w/w which indicates azeotropic point can be passed.

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