scholarly journals Advantages of TiO2/carbon nanotube modified photocatalytic membranes in the purification of oil-in-water emulsions

2018 ◽  
Vol 19 (4) ◽  
pp. 1167-1174 ◽  
Author(s):  
Gábor Veréb ◽  
Viktória Kálmán ◽  
Tamás Gyulavári ◽  
Szabolcs Kertész ◽  
Sándor Beszédes ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Membrane Separation ◽  
Advanced Treatment ◽  
Filtration Resistance ◽  
Beneficial Effects ◽  
Oil In Water ◽  
Photocatalytic Activities ◽  
Total Filtration ◽  
First Time

Abstract For the effective purification of emulsified oil contaminated waters advanced treatment methods have to be applied, such as membrane filtration, which is able to eliminate macro-, and even nanoscale oil droplets, however, membrane fouling is still a major problem, which prevents economic utilization. Therefore, fouling mitigation is one of the most important aspects in the field of membrane separation developments. In the present study, solely TiO2 and TiO2/carbon nanotubes (CNT) composite modified PVDF membranes were prepared and used to purify oil-in-water emulsions. Achievable fluxes, reversible and irreversible filtration resistances, fouling models, filtration efficiencies and photocatalytic activities were compared in case of different nanomaterial covered and unmodified PVDF membranes. Applying either solely TiO2 or solely CNT coating resulted in the significant reduction of total filtration resistance in both cases, but the combination of the two components (TiO2 with 1 wt% CNT) resulted in by far the highest flux and lowest resistance, meanwhile, the enhanced photocatalytic efficiency of the composite was also achieved. To the best of our knowledge, this study demonstrates the beneficial effects of the combination of TiO2 and CNT nanomaterials for the first time in the field of membrane separation of oil-in-water emulsions.

scholarly journals Effect of vibration on the efficiency of ultrafiltration

2021 ◽  
Vol 15 (1) ◽  
pp. 37-44
Author(s):  
Szabolcs Gyula Szerencsés ◽  
Sándor Beszédes ◽  
Zsuzsanna László ◽  
Gábor Veréb ◽  
Balázs Szegedi ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Membrane Fouling ◽  
Energy Demand ◽  
Membrane Filtration ◽  
The European Union ◽  
Treatment Technology ◽  
Filtration Resistance ◽  
Filtration System ◽  
Total Filtration ◽  
Sustainable Wastewater Treatment

Nowadays, several environmental challenges are present to cope with. One with outstanding importance is the protection of our water supplies, therefore examination of wastewater treatment technology is a priority, especially in the European Union. In this work, the effect of membrane module vibration amplitude on the efficiency of ultrafiltration (UF) was investigated in a vibratory shear enhanced membrane filtration system. Based on the results of model dairy effluent UF and statistical analysis, the maximum vibration level available resulted in the most efficient filtration process, due to the most significant reduction of membrane fouling. From our results it was observed that the permeate fluxes more than doubled, specific energy demand was roughly halved, with almost identical retentions for organic matter, and total filtration resistance was reduced to less than half. Results also showed that setting the optimal operating parameters, an advantageous, efficiency focused, and sustainable wastewater treatment technology can be established.

scholarly journals Effect of Pre-Oxidation on Coagulation/Ceramic Membrane Treatment of Yangtze River Water

Membranes ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 369
Author(s):  
Shengji Xia ◽  
Xinran Zhang ◽  
Yuanchen Zhao ◽  
Fibor J. Tan ◽  
Pan Li ◽  
...  
Keyword(s):  
Water Treatment ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Ceramic Membrane ◽  
Membrane Separation ◽  
Membrane System ◽  
Coagulation System ◽  
Fouling Control ◽  
Filtration System ◽  
Membrane Treatment

The membrane separation process is being widely used in water treatment. It is very important to control membrane fouling in the process of water treatment. This study was conducted to evaluate the efficiency of a pre-oxidation-coagulation flat ceramic membrane filtration process using different oxidant types and dosages in water treatment and membrane fouling control. The results showed that under suitable concentration conditions, the effect on membrane fouling control of a NaClO pre-oxidation combined with a coagulation/ceramic membrane system was better than that of an O3 system. The oxidation process changed the structure of pollutants, reduced the pollution load and enhanced the coagulation process in a pre-oxidation-coagulation system as well. The influence of the oxidant on the filtration system was related to its oxidizability and other characteristics. NaClO and O3 performed more efficiently than KMnO4. NaClO was more conducive to the removal of DOC, and O3 was more conducive to the removal of UV254.

Flow Dynamic Effect in Cake Shape and Resistance in Membrane Filtration

2011 ◽  
Author(s):  
Aklilu T. G. Giorges ◽  
John A. Pierson
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Film Growth ◽  
Dynamic Effect ◽  
Extended Period ◽  
Flow Dynamics ◽  
Flux Rate ◽  
Filtration Resistance ◽  
Filter Surface ◽  
Filtration System

Membrane filtration is one of the methods for separating targeted material from a fluid stream. Membrane based filtration is applied in many areas of processing to separate and concentrate fluids. However, fouling and film growth at the filter surface is a major problem that causes loss in efficiency. The cake buildup during the filtration process is investigated experimentally to understand the affect of flow dynamics on the cake characteristics, shape and associated resistance. The experiments were conducted without and with shear generated using an impeller operated at various rotational speeds. The results illustrate that indeed the cake shape and character are affected by the flow dynamics that eventually influence filtration resistance. Likewise the filtrate rate and the cake shape significantly affect the flow dynamics. Furthermore, the filtration resistance is not only affected by the thickness of the cake, but also by how the cake is formed. After similar volumes of filtrate, the flux rate of 120 Lm−2hr−1 for 4.4 mm thick and 1.8 g cake is observed for dead-end filtration, while the flux rate of 600 Lm−2hr−1 for 1.1 mm thick and 0.35 g cake where observed with a shearing rate of 630 s−1. Understanding the size and characters of cake buildup is very important to designing a system to overcome the drawbacks associated with membrane fouling. Moreover, developing a technology with the cleaning process that removes or eliminates cake and maintains a reasonable flux for an extended period requires a thorough understanding of the filtration system geometry and flow dynamics.

scholarly journals In-Situ Ultrasound-Assisted Control of Polymeric Membrane Fouling

2021 ◽  
Author(s):  
Westphalen Dornelas Camara Heloisa
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Membrane Separation ◽  
Feed Solution ◽  
Solution Concentration ◽  
Polymeric Membrane ◽  
Permeate Flux ◽  
Latex Paint ◽  
Water And Wastewater Treatment ◽  
Maximum Increase

Membrane separation processes have been more widely applied to industrial activities, especially in water and wastewater treatment. However, there are still challenges associated to the use of membranes. Concentration polarization and fouling can cause significant permeate flux decay during the filtration process, hindering its efficiency and increasing cost. Among many strategies, the combination of membrane filtration with ultrasound (US) application has shown promising results in reducing membrane fouling. The main goal of this research was to identify the effect of US frequency, US power intensity and feed solution concentration on permeate flux during ultrafiltration of simulated latex paint effluent. Maximum increase in permeate flux of 19.7% was obtained by applying 20 kHz and 0.29 W.cm-2 to feed solution with 0.075 wt.% of solid concentration. The effect of feed flow rate was analyzed showing that an increase in feed flowrate is not beneficial to the fouling minimization process. Overall, the application of US improves permeate flux by reducing fouling of ultrafiltration polymeric membrane.

scholarly journals Assessing Enzyme Immobilization on Reverse Asymmetric Membranes and Biocatalytic Reactor Performance

2021 ◽  
Author(s):  
Amirah Syakirah Zahirulain ◽  
Fauziah Marpani ◽  
Syazana Mohamad Pauzi ◽  
'Azzah Nazihah Che Abd Rahim ◽  
Hang Thi Thuy Cao ◽  
...  
Keyword(s):  
Enzyme Immobilization ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Membrane Separation ◽  
Permeate Flux ◽  
Reactor Performance ◽  
Membrane Performance ◽  
Reverse Mode ◽  
Substrate Conversion ◽  
Product Separation

Abstract Integration of membrane filtration and biocatalysis has appealing benefits in terms of simultaneous substrate conversion and product separation in one reactor. Nevertheless, the interaction between enzymes and membrane is complex and the mechanism of enzyme docking on membrane is similar to membrane fouling. In this study, focus is given on the assessment of enzyme immobilization mechanism on reverse asymmetric polymer membrane based on the permeate flux data during the procedure. Evaluation of membrane performance in terms of its permeability, fouling mechanisms, enzyme loading, enzyme reusability and biocatalytic productivity were also conducted. Alcohol Dehydrogenase (EC 1.1.1.1), able to catalyze formaldehyde to methanol with subsequent oxidation of NADH to NAD was selected as the model enzyme. Two commercial, asymmetric, flat sheet polymer membranes (PES and PVDF) were immobilized with the enzyme in the reverse mode. Combination of concentration polarization phenomenon and pressure driven filtration successfully immobilized almost 100% of the enzymes in the feed solutions. The biocatalytic membrane reactor recorded more than 90% conversion, stable permeate flux with no enzyme leaching even after 5 cycles. The technique showing promising results to be expanded to continuous membrane separation setup for repeated use of enzymes.

Treatment of waste thermal waters by ozonation and nanofiltraton

2013 ◽  
Vol 67 (6) ◽  
pp. 1272-1279 ◽  
Author(s):  
Z. L. Kiss ◽  
A. Szép ◽  
S. Kertész ◽  
C. Hodúr ◽  
Z. László
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Membrane Separation ◽  
Oxygen Demand ◽  
Organic Content ◽  
Ozone Treatment ◽  
Thermal Waters ◽  
Toxic Compounds ◽  
Ozone Pretreatment ◽  
High Organic Content

After their use for heating, e.g. in greenhouses, waste thermal waters may cause environmental problems due to their high contents of ions, and in some cases organic matter (associated with an oxygen demand) or toxic compounds. The aims of this work were to decrease the high organic content of waste thermal water by a combination of ozone treatment and membrane separation, and to investigate the accompanying membrane fouling. The results demonstrated that the chemical oxygen demand and the total organic content can be effectively decreased by a combination of ozone pretreatment and membrane filtration. Ozone treatment is more effective for phenol elimination than nanofiltration alone: with a combination of the two processes, 100% elimination efficiency can be achieved. The fouling index b proved to correlate well with the fouling and polarization layer resistances.

scholarly journals In-Situ Ultrasound-Assisted Control of Polymeric Membrane Fouling

2021 ◽  
Author(s):  
Westphalen Dornelas Camara Heloisa
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Membrane Separation ◽  
Feed Solution ◽  
Solution Concentration ◽  
Polymeric Membrane ◽  
Permeate Flux ◽  
Latex Paint ◽  
Water And Wastewater Treatment ◽  
Maximum Increase

Membrane separation processes have been more widely applied to industrial activities, especially in water and wastewater treatment. However, there are still challenges associated to the use of membranes. Concentration polarization and fouling can cause significant permeate flux decay during the filtration process, hindering its efficiency and increasing cost. Among many strategies, the combination of membrane filtration with ultrasound (US) application has shown promising results in reducing membrane fouling. The main goal of this research was to identify the effect of US frequency, US power intensity and feed solution concentration on permeate flux during ultrafiltration of simulated latex paint effluent. Maximum increase in permeate flux of 19.7% was obtained by applying 20 kHz and 0.29 W.cm-2 to feed solution with 0.075 wt.% of solid concentration. The effect of feed flow rate was analyzed showing that an increase in feed flowrate is not beneficial to the fouling minimization process. Overall, the application of US improves permeate flux by reducing fouling of ultrafiltration polymeric membrane.

scholarly journals The Effect of Salinity on Membrane Fouling Characteristics in an Intermittently Aerated Membrane Bioreactor

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Kang Xie ◽  
Siqing Xia ◽  
Jing Song ◽  
Jixiang Li ◽  
Liping Qiu ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Membrane Bioreactor ◽  
Extracellular Polymeric Substances ◽  
Ammonia Nitrogen ◽  
Saline Wastewater ◽  
Sludge Characteristics ◽  
Filtration Resistance ◽  
Microbial Products ◽  
Fouling Characteristics

The effect of salinity on the membrane fouling characteristics was investigated in the intermittently aerated membrane bioreactor (IAMBR). Five different salinity loadings were set from 0 to 35 g·L−1(referring to NaCl), respectively. The removal of total organic carbon (TOC) and ammonia-nitrogen (NH4+-N) was gradually decreased with increasing salinity. The variation of membrane filtration resistance, particle size distribution (PSD), extracellular polymeric substances (EPS), soluble microbial products (SMP), and relative hydrophobicity (RH) analysis revealed that salinity has a significant effect on sludge characteristics in IAMBR. The results also indicated that the membrane fouling is often caused by the integration of sludge characteristics in saline wastewater.

Study on the Reuse of Production Wastewater with Submerged Ultrafiltration Membrane

2011 ◽  
Vol 213 ◽  
pp. 73-77
Author(s):  
Guo Wei Gao ◽  
Wen Jie He ◽  
Chen Li ◽  
Jian Kun Hu
Keyword(s):  
Water Quality ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Concentration Polarization ◽  
Removal Rate ◽  
Filtration Resistance ◽  
Water Treatment Plants ◽  
Filtration System ◽  
Cake Formation ◽  
Suitable Treatment

Production wastewater (PWW) produced at water treatment plants is an inescapable byproduct and most of it has long been treated as a waste. UF offers a suitable treatment for PWW in order to guarantee a water quality necessary for reuse. The aim of this study was to evaluate the performance of submerged membrane filtration for reducing NOM and the effects of backwash. Turbidity was almost removed to less than 0.11NTU and the removal rate of each series of particle size could be 99.99%. In a membrane-blocking formation comparable filtration system, the filtration resistance due to cake formation fouling was far more three-fold higher than that due to concentration polarization. The minimum TMP due to membrane fouling progressively increased from 0.052 MPa to 0.055 MPa during the operation. Backwash operation can effectively restrain particle fouling and therefore reduce filtration resistances, especially for the cake resistance. The TMP decreases from 0.065 MPa to 0.053MPa after backwash operation.

scholarly journals Purification of Dairy Wastewaters by Advanced Oxidation Processes and Membrane Filtration

2017 ◽  
Vol 11 (1) ◽  
pp. 32-38
Author(s):  
Mihály Zakar ◽  
Erika Lakatos ◽  
Gábor Keszthelyi-Szabó ◽  
Zsuzsanna László
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Membrane Separation ◽  
Separation Efficiency ◽  
Scale Up ◽  
Separation Processes ◽  
Physicochemical Changes ◽  
Current Trends ◽  
Pre Treatment ◽  
Cost Efficient

Membrane separation processes are space and cost-efficient, easy to scale-up operations, which have proved to treat food industrial wastewaters efficiently. Beside the advantages like high separation efficiency without any chemical changes and low energy-intensity, membrane filtration also has drawbacks, like decreased operational efficiency caused by flux decile resulting from fouling and concentration polarization. Combination of oxidation pre-treatment and membrane filtration is a promising method for decreasing fouling due to the physicochemical changes caused by pre-oxidation of the wastewater in structure of colloidal pollutants and in the interactions between the foulants and the membrane material. The aim of this work is to identify the parameters affecting the membrane fouling during treatment of dairy wastewaters, and present the current trends of research in this field.

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