scholarly journals Chemical Cleaning of Fouled Polyethersulphone Nanofiltration Membranes with Ethylenediaminetetraacetic Acid

2018 ◽  
Vol 23 (1) ◽  
Author(s):  
V. Y. F. Chong ◽  
C. H. Koo ◽  
H. S. Thiam ◽  
S. O. Lai
Keyword(s):  
Recovery Rate ◽  
Ethylenediaminetetraacetic Acid ◽  
Applied Pressure ◽  
Permeate Flux ◽  
Nanofiltration Membranes ◽  
Cleaning Efficiency ◽  
Chemical Cleaning ◽  
Maximum Flux ◽  
Edta Concentration ◽  
Potential Use

This study mainly investigated the potential use of ethylenediaminetetraacetic acid (EDTA) as the chemical cleaning agent to restore the permeate flux of organically fouled polyethersulfone (PES) nanofiltration (NF) membranes under varying applied pressures. The cleaning efficiency was quantified based on flux recovery rate. The results showed that the optimum EDTA concentration is 1.0 wt%, within the range investigated, which proved that higher concentration does not necessary enhance the cleaning efficiency. The results also demonstrated that the highest flux recovery was achieved at the applied pressure of 14 bar regardless of EDTA concentration. Overall, the maximum flux recovery that could be achieved is only 35.03%, implying EDTA is not very effective in removing foulants from the PES NF membranes.

scholarly journals Development of Red Clay Ultrafiltration Membranes for Oil-Water Separation

Crystals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 248
Author(s):  
Saad A. Aljlil
Keyword(s):  
Ceramic Membrane ◽  
Applied Pressure ◽  
Operating Pressure ◽  
Permeate Flux ◽  
Carbon Membrane ◽  
Red Clay ◽  
Water Separation ◽  
Water Emulsion ◽  
Cross Flow Filtration ◽  
Oil Water

In this study, a red clay/nano-activated carbon membrane was investigated for the removal of oil from industrial wastewater. The sintering temperature was minimized using CaF2 powder as a binder. The fabricated membrane was characterized by its mechanical properties, average pore size, and hydrophilicity. A contact angle of 67.3° and membrane spore size of 95.46 nm were obtained. The prepared membrane was tested by a cross-flow filtration process using an oil-water emulsion, and showed a promising permeate flux and oil rejection results. During the separation of oil from water, the flux increased from 191.38 to 284.99 L/m2 on increasing the applied pressure from 3 to 6 bar. In addition, high water permeability was obtained for the fabricated membrane at low operating pressure. However, the membrane flux decreased from 490.28 to 367.32 L/m2·h due to oil deposition on the membrane surface; regardless, the maximum oil rejection was 99.96% at an oil concentration of 80 NTU and a pressure of 5 bar. The fabricated membrane was negatively charged, as were the oil droplets, thereby facilitating membrane purification through backwashing. The obtained ceramic membrane functioned well as a hydrophilic membrane and showed potential for use in oil wastewater treatment.

Characterization of the biofouling and cleaning efficiency of nanofiltration membranes

Biofouling ◽  
2010 ◽  
Vol 26 (1) ◽  
pp. 15-21 ◽  
Author(s):  
A. Houari ◽  
D. Seyer ◽  
F. Couquard ◽  
K. Kecili ◽  
C. Démocrate ◽  
...  
Keyword(s):  
Nanofiltration Membranes ◽  
Cleaning Efficiency

scholarly journals Stimulatory effects on bacteria induced by chemical cleaning cause severe biofouling of membranes

2020 ◽  
Vol 10 (1) ◽  
pp. 82-94
Author(s):  
Xueye Wang ◽  
Jinxing Ma ◽  
Zhichao Wu ◽  
Zhiwei Wang
Keyword(s):  
Membrane Surface ◽  
Oxygen Species ◽  
Cleaning Efficiency ◽  
Chemical Cleaning ◽  
Physiological Mechanisms ◽  
Homoserine Lactones ◽  
Membrane Surfaces ◽  
Enhanced Production ◽  
Membrane Biofouling ◽  
Microbial Regrowth

Abstract Chemical cleaning with hypochlorite is routinely used in membrane-based processes. However, a high-transient cleaning efficiency does not guarantee a low biofouling rate when filtration is restarted, with the physiological mechanisms largely remaining unknown. Herein, we investigated the microbial regrowth and surface colonization on membrane surfaces after NaOCl cleaning had been completed. Results of this study showed that the regrowth of model bacteria, Pseudomonas aeruginosa, was initially subject to inhibition due to the damage of key enzymes' activity and the accumulation of intracellular reactive oxygen species although the oxidative stress induced by NaOCl had been removed. However, with the resuscitation ongoing, the stimulatory effects became obvious, which was associated with the enhanced production of N-acyl homoserine lactones and the secretion of eDNA that ultimately led to more severe biofouling on the membrane surface. This study elucidates the inhibition–stimulation mechanisms involved in biofilm reformation (membrane biofouling) after membrane chemical cleaning, which is of particular significance to the improvement of cleaning efficiency and application of membrane technologies.

scholarly journals Phytoextraction of lead by Helianthus annuus: effect of mobilising agent application time

2008 ◽  
Vol 54 (No. 10) ◽  
pp. 434-440 ◽  
Author(s):  
A.A. Safari Sinegani ◽  
F. Khalilikhah
Keyword(s):  
Helianthus Annuus ◽  
Ethylenediaminetetraacetic Acid ◽  
Seedling Emergence ◽  
Dry Weight ◽  
Application Time ◽  
Growth Depression ◽  
Sheep Manure ◽  
Edta Concentration ◽  
Sunflower Seedling ◽  
Severe Growth

Pot experiments were conducted to determine the best time for application of (ethylenediaminetetraacetic acid) EDTA and sheep manure extract (SME) in phytoremediation of a contaminated soil by <I>Helianthus annuus</I>. The plant was grown in a mine calcareous soil treated with increasing concentrations of EDTA or SME in 30 and 10 days before sowing (T1 and T2) and 10 and 30 days after sowing (T3 and T4). The best time for EDTA application was T4. The EDTA application before seed germination significantly reduced sunflower seedling emergence and dry weight. Soil available Pb and lead concentrations in plant organs increased with EDTA concentration but the actual amount of phytoextracted Pb decreased at high EDTA concentrations significantly, due to severe growth depression. SME application after sowing can increase plant dry weight and Pb concentration in the soil solution, enhancing the accumulated metal concentrations in shoots and roots. However the results showed that the most efficient treatments for Pb phytoextraction by sunflower are applications of 0.5 and 2 g EDTA/kg soil at T3 and T4, respectively.

scholarly journals The impact of anionic polyacrylamide (APAM) on ultrafiltration efficiency in flocculation-ultrafiltration process

2017 ◽  
Vol 75 (8) ◽  
pp. 1982-1989 ◽  
Author(s):  
Ruijun Zhang ◽  
Shengnan Yuan ◽  
Wenxin Shi ◽  
Cong Ma ◽  
Zhiqiang Zhang ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Aluminium Chloride ◽  
Optimal Dosage ◽  
Cleaning Efficiency ◽  
Chemical Cleaning ◽  
Membrane Cleaning ◽  
Effluent Quality ◽  
Adsorption Sites ◽  
The Impact ◽  
Anionic Polyacrylamide

With the purpose of improving the ultrafiltration (UF) efficiency, anionic polyacrylamide (APAM) has been used as a coagulant aid in the flocculation-UF process. In this study, the impact of APAM on UF efficiency has been investigated with regard to membrane fouling, membrane cleaning and effluent quality. The results indicated that the optimal dosage of APAM had positive impacts on membrane fouling control, membrane cleaning and effluent quality. According to the flux decline curve, scanning electron microscopy and contact angle characterization, the optimal dosage of APAM was determined to be 0.1 mg/L coupled with 2 mg/L (as Al3+) poly-aluminium chloride. Under this optimal condition, membrane fouling can be mitigated because of the formation of a porous and hydrophilic fouling layer. APAM in the fouling layer can improve the chemical cleaning efficiency of 0.5% NaOH due to the disintegration of the fouling layer when APAM is dissolved under strong alkaline conditions. Furthermore, with the addition of APAM in the flocculation-UF process, more active adsorption sites can be formed in the flocs as well as the membrane fouling layer, thus more antipyrine molecules in the raw water can be adsorbed and removed in the flocculation-UF process.

Knowledge-based system for automatic MBR control

2010 ◽  
Vol 62 (12) ◽  
pp. 2829-2836 ◽  
Author(s):  
J. Comas ◽  
E. Meabe ◽  
L. Sancho ◽  
G. Ferrero ◽  
J. Sipma ◽  
...  
Keyword(s):  
Automatic Control ◽  
Flow Rate ◽  
Membrane Fouling ◽  
Deterministic Model ◽  
Permeate Flux ◽  
Chemical Cleaning ◽  
Control Module ◽  
Flow Rates ◽  
Knowledge Based ◽  
Operational Variables

MBR technology is currently challenging traditional wastewater treatment systems and is increasingly selected for WWTP upgrading. MBR systems typically are constructed on a smaller footprint, and provide superior treated water quality. However, the main drawback of MBR technology is that the permeability of membranes declines during filtration due to membrane fouling, which for a large part causes the high aeration requirements of an MBR to counteract this fouling phenomenon. Due to the complex and still unknown mechanisms of membrane fouling it is neither possible to describe clearly its development by means of a deterministic model, nor to control it with a purely mathematical law. Consequently the majority of MBR applications are controlled in an “open-loop” way i.e. with predefined and fixed air scour and filtration/relaxation or backwashing cycles, and scheduled inline or offline chemical cleaning as a preventive measure, without taking into account the real needs of membrane cleaning based on its filtration performance. However, existing theoretical and empirical knowledge about potential cause-effect relations between a number of factors (influent characteristics, biomass characteristics and operational conditions) and MBR operation can be used to build a knowledge-based decision support system (KB-DSS) for the automatic control of MBRs. This KB-DSS contains a knowledge-based control module, which, based on real time comparison of the current permeability trend with “reference trends”, aims at optimizing the operation and energy costs and decreasing fouling rates. In practice the automatic control system proposed regulates the set points of the key operational variables controlled in MBR systems (permeate flux, relaxation and backwash times, backwash flows and times, aeration flow rates, chemical cleaning frequency, waste sludge flow rate and recycle flow rates) and identifies its optimal value. This paper describes the concepts and the 3-level architecture of the knowledge-based DSS and details the knowledge-based control module. Preliminary results of the application of the control module to regulate the air flow rate of an MBR working with variable flux demonstrates the usefulness of this approach.

scholarly journals Application of a triblock copolymer additive modified polyvinylidene fluoride membrane for effective oil/water separation

2018 ◽  
Vol 5 (5) ◽  
pp. 171979 ◽  
Author(s):  
S. S. Shen ◽  
K. P. Liu ◽  
J. J. Yang ◽  
Y. Li ◽  
R. B. Bai ◽  
...  
Keyword(s):  
Polyvinylidene Fluoride ◽  
Triblock Copolymer ◽  
Oily Wastewater ◽  
The Novel ◽  
Permeate Flux ◽  
Cleaning Efficiency ◽  
Water Separation ◽  
Water Emulsion ◽  
Oil Water Separation ◽  
Oil Water

A hollow fibre membrane was fabricated by blending polyvinylidene fluoride (PVDF) with a triblock copolymer additive polymer that has both hydrophilic and oleophobic surface properties. The novel membrane was characterized and examined for oil/water separation under various system conditions, including different cross-flow rate, feed temperature, trans-membrane pressure, and its rejection and cleaning efficiency, etc. By applying the membrane into the filtration of synthesized oil/water emulsion, the membrane constantly achieved an oil rejection rate of above 99%, with a relatively constant permeate flux varied in the range of 68.9–59.0 l m −2  h −1 . More importantly, the fouling of the used membrane can be easily removed by simple water flushing. The membrane also demonstrated a wide adaptability for different types of real oily wastewater, even at very high feed oil concentration (approx. 115 000 mg l −1 in terms of chemical oxygen demand (COM)). Hence, the novel triblock copolymer additive-modified PVDF membrane can have a great prospect in the continuing effort to expand the engineering application of polymeric membranes for oily wastewater treatment.

scholarly journals Investigation of ciprofloxacin removal from aqueous solution by nanofiltration process

2016 ◽  
Vol 18 (2) ◽  
pp. 291-308 ◽  
Keyword(s):  
Ph Value ◽  
Applied Pressure ◽  
Reduction Factor ◽  
Operating Conditions ◽  
Transmembrane Pressure ◽  
Permeate Flux ◽  
Dead End ◽  
Filtration System ◽  
Membrane Type ◽  
Stirred Cell

<div> <p>10 mg l<sup>-1</sup> and the permeate flux behavior during dead-end stirred-cell filtration system using six type of commercially available loose and tight NF membranes (NP010, NP030, NF90, NF270, CK3001 and DS-5DK). The rejection of CIPRO and permeate flux value were evaluated according to the effects of different parameters such as volume reduction factor (VRF), membrane type, transmembrane pressure (TMP) and pH. Contact angle and SEM measurements were also performed for the analysis of the pollution occurring in the pores and on the surfaces of the membranes. Filtration experiments for all membranes used indicated that the flux reached the steady state at VRF 3. CIPRO rejection was found to vary especially with both pH and membrane tightness. Despite the fact that, the loose NF membranes showed poor and variable CIPRO removal, the highest rejection was obtained with NF90 tight membrane at the original pH value (pH 5.65) and 10 bar of applied pressure. NF90 membrane achieved 98.3% TOC, 98.9% COD, 96.9% TDS and 95.7% <em>E</em><sub>c </sub>rejections at 24.39 L m<sup>-2</sup> h<sup>-1</sup> permeate flux at the predefined operating conditions.&nbsp;</p> </div> <p>&nbsp;</p>

scholarly journals Enhanced Removal of Organic Pollutants and Reactive Dye in Polyethersulfone Submerged Membrane Bioreactor (PES-SMBR) for Textile Wastewater

2021 ◽  
Vol 16 (1) ◽  
pp. 329-341
Author(s):  
Tukaram P. Chavan ◽  
Ganpat B. More ◽  
Sanjaykumar R. Thorat
Keyword(s):  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Textile Wastewater ◽  
Pilot Scale ◽  
Reactive Dye ◽  
Hollow Fibre ◽  
Flow Mode ◽  
Permeate Flux ◽  
Chemical Cleaning ◽  
Submerged Membrane Bioreactor

The present investigation was carried out to assess the operation of a pilot-scale submerged membrane bioreactor (SMBR) for the treatment of reactive dye and textile wastewater. The operation of SMBR model was conducted by using a polyethersulfone (PES) hollow fibre membrane with continuous flow mode at different HRTs at 8, 6 and 4 h, for 90 days. During the entire operation, the average permeate flux, TMP, F/M ratio and OLR was found to be 19 (L/m²/h), 2.6 (psi), 0.10 (g BOD/(g MLSS•d) and 0.89 (kg BOD/m³.d), respectively. The variations in the permeate flux, TMP, F/M ratio and OLR have not adversely effects on the operation of the SMBR model. Throughout the entire operation, despite the TP, TDS and conductivity, the high amount of COD (82%), BOD (86%), NO3-N (79%), TSS (98%), turbidity (97%) and colour (79%), removal was achieved. The permeate flux was declined by membrane fouling and it was recovered by chemical cleaning as well as regular backwashing during the entire operation. The results obtained from the study concluded that the hollow fibre ultrafiltration polyethersulfone (PES) membrane shows good performance while treating textile wastewater along with reactive dye solution.

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