Abstracts of International Conferences & Meetings

Editorial information: Selected Abstracts of the International Congress on Membranes & Membrane Processes (ICMMAP 2021), Kottayam, Kerala, India

2021-12-07T07:01:37-05:00

Prof. Dr. Sabu Thomas (Chairman)

Vice- Chancellor of Mahatma Gandhi University, Professor of Polymer Science and Engineering at the School of Chemical Sciences/ School of Energy Materials (SEM) and Founder Director of the International and Inter University Centre for Nanoscience and Nanotechnology at Mahatma Gandhi University, Kottayam-686560, Kerala, India.

Dr. Hanna J Maria (Convener)

School of Energy Materials (SEM),

Mahatma Gandhi University, Kottayam-686 560, Kerala, India.

Dr. Maciej Jaroszewski

Wroclaw University of Technology, Faculty of Electrical Engineering

27 Wybrzeze Wyspianskiego St.

50-370 Wroclaw, Poland.

Dr. Kaushik Pal

(M.Sc.; PhD; Marie-Curie & CAS Fellow)

Research Professor & Founding Director of Research Excellence,

Department of Nanotechnology, Bharath University, Chennai, India.

Dr. Robin Augustine

Editor, AICM

College of Engineering, Qatar University, Doha, Qatar.

Ms. Jominy Joseph

Managing editor, AICM.

Amadou Belal Gueye (Special issue technical editor)

School of Chemical Sciences,

Mahatma Gandhi University, Kottayam-686 560, Kerala, India.

Application of polymeric membranes and membrane processes in energy, environment, and medicine

2021-12-07T07:08:09-05:00

Over the past century, there have been some very useful applications in the field of science and technology with polymeric membranes (1). This issue of AICM covers the selected abstracts of papers presented at International Congress on Membranes & Membrane Processes (ICMMAP 2021) held during 12– 14, February 2021 at Mahatma Gandhi University, Kerala, India. ICMMAP 2021 brought together innovative academics and industrial experts in the field of polymer science & technology, materials science, environmental science, chemical engineering, biological sciences, and applied physics to a common forum. The primary goal of the conference was to promote research and developmental activities in membrane science and technology. This also aimed to promote scientific information interchange between scientists, researchers, students, and leaders from various fields such as materials science, chemistry, physics, biomedical engineering, polymer technology, electronics, automobile engineering, biotechnology, and other fields.

The congress was listened to by hundreds of researchers, doctors, and engineers, making it a grand success. Some of the selected abstracts of this issue cover a brief discussion on the application of porous silicon carbide ceramic membranes for the treatment of oily wastewater. Some other experts discussed the application of membrane processing technologies as a viable alternative to many traditional dairy processes like distillation, evaporation or extraction. One such presentation demonstrated the suitability of membrane technology in shrikhand (a popular Indian dessert from milk) preparation. One of the studies discussed the impact of ultra-confinement on the dilation of polymer films under supercritical carbon dioxide. Moly et al. presented the applicability of nanocomposite anion-exchange membranes in redox flow batteries. Lakra et al. presented their important findings on the use of integrated membrane processes the recovery of protein and carbohydrate from whey water. An interesting study investigated the separation potential of a bulk liquid membrane comprising of chemical species to recover organic acids from their dilute solutions. Nath and Reang showcased interesting research focused on an integrated ultrafiltration approach for the recovery of surfactant and potable water from domestic washing machine discharge. Some studies reported the use of anaerobic membrane bioreactor for zero-liquid discharge (ZLD) industrial processes. Yet, some others stressed the importance investigating the elementary transfers of electrons and/or protons using the principles of quantum-classical mechanics in the membranes of living cells.

Such deliberations emphasized the importance of developing novel membranes and appropriate membrane processes for a multitude of applications in energy, engineering and medicine. It is anticipated that the articles published in this issue of AICM will help to bring a meaningful change in scientific and technological research using membrane science and technology to fulfill the needs of society.

Keywords: Membranes, membrane process, polymers, composites, blends

References

Yusuf, A., Sodiq, A., Giwa, A., Eke, J., Pikuda, O., De Luca, G., ... & Chakraborty, S. (2020). A review of emerging trends in membrane science and technology for sustainable water treatment. Journal of Cleaner Production, 266, 121867.

Processing of oxide bonded porous silicon carbide ceramic membrane for the treatment of oily wastewater

2021-09-12T21:26:14-04:00

Introduction: The demand for ceramic membrane from its various end-user industries is continuously showing an upward trend mainly due to the increasing demand for high purity filtration components in various applications. Among applications, the water & wastewater treatment, pharmaceuticals, chemical processing, etc. segment is expected to grow significantly. Today our water resources are threatened worldwide more than ever due to rapid population growth and industrialization and water-borne diseases kill nearly 12 million people every year. Modern human activities have however disrupted the balance between the usage and natural purification processes leading to a shortage of potable water. To meet the increasing demand for water wastewater needs to be purified and recycled. Ceramic membranes are considered a suitable filter for water filtration and purification due to their advantageous properties compared to polymeric membranes. Compared with other ceramic membranes such as titania, zirconia, etc., silicon carbide (SiC) is a promising material due to its higher hydrophilicity, lower fouling tendency, better resistance to chemicals, higher permeate fluxes in wastewater treatment. However, due to the covalent nature of the Si–C bonds, high sintering temperatures (~2000°C) are required for the production of SiC ceramics. The Oxide-bonding technique is considered a simple technique for the fabrication of porous SiC membranes [1] at a lower temperature. Oxidized SiC surface could lower water contact angle, improve the hydrophilic property and offer better water permeability.

Methods: Different amounts of SiC powders, bond phase additives (such as alumina, clay, silica, Y₂O_3, etc.), and pore formers were mixed homogeneously and then pressed into the disc and bar-shaped samples. After that, the green SiC samples were sintered at (1000-1400°C) via oxide bonding technique. The sintered membranes were characterized by Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), Pore size distribution (PSD) analysis; density and porosity were measured by Archimedes method. Oily wastewater was collected, and the filtration studies were carried out in a laboratory-made test setup.

Results & Discussions: Oxide bonded porous SiC ceramic membranes were fabricated at a comparatively lower sintering temperature (1000-1400°C) via oxide bonding technique using different bond phase additives. Moreover, industrial waste fly ash was recycled and used as a source of bonding phase additives. The porosity of the membranes was increased with the addition of pore formers to the final ceramics. XRD study showed that there is a formation of mullite phases for the composition. SEM analysis indicated the formation of porous microstructure with interconnected pores. The SiC particles were bonded through rod-type mullite and fish scale type cristobalite phases at neck regions. Depending on the processing parameters, the membrane showed an average pore diameter, porosity, pure water permeability, and strength in the range of ~1.3-6.5 µm, 31-58 vol%, 1532-13298 Lm^-2h^-1bar^-1, and 12.47-38.40 MPa respectively. The results showed that depending on the porosity of the membrane ~77-93% oil, 89-94% turbidity, and 82-93% COD were removed from grey wastewater.

Conclusions: This study may provide a suitable method to produce high-valued SiC-based porous ceramic membranes at a comparatively lower temperature for potential oily wastewater separation.

Keywords: SiC membrane, Reaction Bonding, Fly ash, Oil-water filtration

Acknowledgment: The authors would like to thank SERB, the Department of Science and Technology, Government of India (GAP-0261) for their financial support

References

Das D, Kayal N, Marsola GA,. Damasceno LA, Innocentini MDM. Permeability behavior of silicon carbide-based membrane and performance study for oily waste water treatment. Int. J. Appl. Ceram. Techol.2020;17(3);893-903.

Ultrafiltration process in the mechanized production of Shrikhand, a fermented dairy product

2021-09-12T04:14:29-04:00

Introduction: Membrane processing is a green technology serving as a viable alternative to many traditional dairy processes like distillation, evaporation or extraction (1). Shrikhand is a popular Indian dessert from milk popular in western Indian states of Gujarat and Maharashtra. Traditionally it is prepared from cow or buffalo milk curd or dahi. The curd is hung to get a semi-solid mass called chakka, which is blended with required amount of sugar, colour and flavorings to a smooth and homogenous consistency (2). The process is tedious consuming about 22 hours, giving a lower yield and involving less mechanization. The present study is proposed to utilize ultrafiltered and diafiltered whole milk retentate to make shrikhand. The membrane module used was spiral wound type made of polyethersulphone having a molecular weight cut-off (MWCO) of 10,000 Daltons and surface area of 5.57m²procured from PMI process systems, Bangalore. Operation was in batch mode.

Methods: Ultrafiltration of standardized whole milk was done at different temperature-transmembrane pressure combinations of 45/50/55^oC and 0.3/0.4/0.5 MPa for optimization with respect to the membrane used by measuring the permeate flux. Concentration of milk was done at 3,4 and 5 levels of concentration factors. The retentate and permeate were analyzed for the rejection factors of the major components for optimization of the concentration factor. The retentate was used to make shrikhand. The physico-chemical and sensory properties of the product were compared with the control sample prepared by traditional method.

Results & Discussions: The processing parameters of the membrane were optimized at 50^oC, 0.4 MPa transmembrane pressure and a concentration factor of 3. Ultrafiltered whole milk shrikhand was on par with the control in sensory attributes as evaluated by a panel of trained judges based on 9-point hedonic scale. Diafiltered shrikhand had low acidity and dull colour due to the removal of most of the lactose in the permeate. There was no significant difference between the control and ultrafiltered sample though the control was adjudged the best. The treatments had higher yield (25% more than the control) due to the incorporation of highly nutritive whey proteins, which are otherwise lost in whey. The production time was reduced to 8 hours. The microbiological quality of the mechanized product was also high. Results were analyzed using Completely Randomized Design (CRD) using three replications.

Conclusions: The study demonstrates the suitability of membrane technology in shrikhand preparation. The distinct advantages include improved yield, enhanced nutritive value and uniform product without sacrificing the sensory qualities of the final product.

Keywords: Membrane process, dairy, ultrafiltration, diafiltration, shrikhand, mechanization

References

Kumar P, Sharma N, Ranjan R, Kumar S, Bhat ZF, and Jeong DK. Perspective of membrane technology in dairy industry: A review, Asian-Australasian Journal of Animal Sciences. 2013; 26(9): 1347.
Narayanan R, and Lingam J. Sensory analysis of banana blended shrikhand, African Journal of Agricultural Research. 2013; 8(44): 5518-5521.

Impact of ultra-confinement on dilation of polymer films under supercritical carbon dioxide

2021-09-12T03:20:30-04:00

Introduction: Since last two decades the use of supercritical ﬂuids such as supercritical carbon dioxide (scCO₂) has emerged as a leading alternative to toxic organic solvents in polymer processing and synthesis, reactor clean up and preparation of pharmaceutical products. While the effect of CO₂ has been studied extensively in thick polymer films (thickness d > 100 nm) since long back and more recently in thin films (20 nm < d < 100 nm), to the best of our knowledge there is a lack of report on the dilation behaviour of ultra-confined polymer films under scCO₂ in the thickness regime below 20 nm, especially down to 3 nm [1]. Here, we report the dilation process of various types of confined polymers (PS-PEB-PS, PS and PBMA) ultrathin films (d ranges from 3 to 110 nm) under scCO₂. The swelling is found to be dependent on the confinement of polymer films.

Methods: Polymer ultrathin films of different thicknesses (d » 3 nm to 110 nm) were prepared by adjusting the concentration of polymer-solvent (e.g. toluene) solutions. Films were deposited by spin-coating (Apex Instruments) these solutions at 2000 rpm for 1 min onto cleaned Si(100) substrates. The Si surfaces (of size ≈ 20×20 mm²) were made hydrophilic by immersing them in a mixed solution of ammonium hydroxide (NH₄OH, Sigma-Aldrich, 25%), hydrogen peroxide (H₂O₂, Acros Organics, 35%), and Milli-Q water (H₂O:NH₄OH:H₂O₂= 2:1:1, by volume) for 10 min at 100 °C. XRR measurements were carried to investigate the structure of polymer ultrathin films before and after CO₂exposition followed by their relaxation.

Results & Discussions: Relatively thinner films (d » 3 nm) exhibit higher swelling (> 100%) compared to the thicker ones (< 20%) [1,2]. Rapid release of CO₂during depressurization in the process of scCO₂exposition leads to swollen structures [2], resulting in low-density polymer ultrathin films where free volume is enlarged and/or nanometer-scale sized porosity is significantly (13 – 25 %) introduced. These effects alter polymer to polymer which having large difference in T_g and chemical groups [2]. In addition, relaxation process is found to be extremely slow until the temperature reaches to glass transition temperature (T_g) [1]. Hence this swollen structure could easily be preserved. Such porous polymers are ideal to develop novel highly gas permeable membranes for gas filtration that selectively allow specific gas molecules. Furthermore, scCO₂ acts as a plasticiser that increases the mobility of polymer chains by reducing the cumulative intermolecular forces among the polymer chain segments.

Conclusions: We have carried out XRR measurements to investigate the dilation and relaxation characteristics of homo (PS and PBMA) and triblock copolymer (PS-PEB-PS) films having different thicknesses exposed to scCO₂and compared with each other. In all these cases, thinner films exhibit a large swellability in opposition to thicker films due to densification of the former. A general relation between density, thickness and swellability of polymer thin film is established. A significant difference in swellability and absolute swelling, which are dominant in PBMA, is encountered. The presence of specific interaction of CO₂ with the carbonyl groups of PBMA, unlike PS and PS-PEB-PS, allows large mobility of polymer chains in scCO₂ solvent which results in highly swollen films.

Keywords: Supercritical Carbon Dioxide, Dilation, Confinement, X-ray reflectivity.

Acknowledgment: J.K.B. gratefully acknowledges Department of Science and Technology (DST), Government of India, for providing the research grant through SERB (CRG/2018/002290) and INSPIRE Faculty Award (IFA13-PH-79).

References

Bal JK, Beuvier T, Chebil MS, Vignaud G, Grohens Y, Sanyal MK and Gibaud A. Relaxation of Ultrathin Polystyrene Films Hyperswollen in Supercritical Carbon Dioxide. Macromolecules 2014;47: 8738–8747.

Bal JK, Beuvier T, Chebil MS, Vignaud G, Ben-Jabrallah S, Ahmed I, Grohens Y and Gibaud, A. Swelling of poly(n-butyl methacrylate) Films Exposed to Supercritical Carbon Dioxide: A Comparative Study with Polystyrene. Langmuir 2016;32: 1716–1722.

Nanocomposite anion-exchange membranes for redox flow batteries

2021-09-11T13:40:38-04:00

Introduction: The ion-exchange membrane is a vital part of fuel cells, rechargeable batteries, and other electrochemical devices because it determines their efficiency (1). Anion exchange membranes are currently a hot topic of research because they are more efficient and cost-effective in practical applications (2). Organic–inorganic hybrid membranes found to be excellent materials for practical applications due to their improved electrochemical properties, mechanical strength, chemical and thermal stability.

Methods: Layered double hydroxides (LDHs) of Magnesium with Aluminium ([Mg-Al] LDH) were prepared by precipitation at low saturation. 5 wt% PVA solution was prepared. Then a calculated amount of double hydroxide was stirred with PVA solution for 8 hrs and crosslinked using glutaraldehyde. The membranes were characterized by XRD, AC impedance analysis and conducted charge –discharge experiment in redox-flow battery (3).

Results & Discussions: Figure 1 shows the XRD pattern of Mg-Al LDHs. The diffraction pattern of the sample is well correlated with the standard diffraction pattern (ICSD PDF# 54-1030). A Galvanostatic charge–discharge experiment was carried out in a redox-flow battery using the prepared membrane as a separator. Over multiple cycles, the results showed above 70% efficiency. This indicates a low level of cross mixing of ions (4).

Conclusions: We used a co-precipitation method to make nanoparticles of ([Mg-Al] LDH. Its phase purity was revealed by the XRD pattern. The newly fabricated nanocomposite membrane was put to the test as a separator in a redox flow battery. The results of a Galvanostatic charge-discharge test revealed that coulombic efficiency was greater than 70 %.

Keywords: Ion-exchange membrane, Redox-flow battery, Charge–discharge experiment, Hybrid membranes

References

Wang X, Sheng W, Shen Y, Liu L, Dai S, Li N. N-cyclic quaternary ammonium-functionalized anion exchange membrane with improved alkaline stability enabled by aryl-ether free polymer backbones for alkaline fuel cells. J Memb Sci [Internet]. Elsevier B.V.; 2019;587(May):117135. Available from: https://doi.org/10.1016/j.memsci.2019.05.059
Yang Q, Li L, Gao XL, Wu HY, Liu FH, Zhang QG, et al. Crown ether bridged anion exchange membranes with robust alkaline durability. J Memb Sci [Internet]. Elsevier B.V.; 2019;578(November 2018):230–8. Available from: https://doi.org/10.1016/j.memsci.2019.02.038
Suc M, Yeop H, Young H, Hyun S, Kim T, Oh S, et al. Crosslinked anion exchange membranes with primary diamine-based crosslinkers for vanadium redox fl ow battery application. J Power Sources [Internet]. Elsevier B.V; 2017;363:78–86. Available from: http://dx.doi.org/10.1016/j.jpowsour.2017.07.068
Prifti H, Parasuraman A, Winardi S, Lim TM, Skyllas-Kazacos M. Membranes for redox flow battery applications. Membranes (Basel). 2012;2(2):275–306.

Recovery of protein and carbohydrate from whey water using integrated membrane processes

2021-09-11T06:03:09-04:00

Introduction: Whey is a by-product of cheese production. It contains water (93-94%), lactose (45-50 g/L), proteins (7-9 g/L), minerals (6-8 g/L), vitamins, and milk fat (1-2 g/L) (1). Whey protein is used as food supplements for muscle growth, and as animal fodder. Membrane technology is popular for the recovery of whey protein and carbohydrate. Commercial membranes available for whey water recovery includes, Nadir GmbH (UF-PES), Zoltecc Rt MAVIBRAN (UF-PVDF), Centramate, Pall Germany (UF-PES), Koch Membrane System (UF-PES), RA55 Millipore NF-400 Da, Dow Chemical USA NF-200, Koch membrane TFC-SR3, TIA Bollene France UF NF-NTR7450 (2). This study involves fractionation of whey water, recovery of protein and carbohydrate using an integrated UF-NF system, and effect of hydraulic cleaning of membrane.

Methods: Whey water was filtered through UF membranes (UF-20 kDa and UF-50 kDa) purchased from Tech Inc. Ltd., in a dead-end filtration cell (Tech Inc. Ltd.) at 2 bar (N₂). The UF permeate was passed through NF 200 Da (KOCH membrane MPF-34) at 20 bar NF-cell (Tech Inc. Ltd.). The water flux was determined by measuring permeate volume at different time intervals, protein and carbohydrate concentration in feed and permeate (UF and NF) was analyzed by spectrophotometer (UV-Vis Systronics 119, Kolkata).

Results & Discussions: The UF membrane shows that increased feed pressure (0.5 to 2.5 bar) improves membrane flux. UF-20 resulted increased flux from 17 LMH to 23 LMH, and for UF-50 it increased from 15 LMH to 20 LMH. Similarly at fixed pressure (2 bar) and at different time intervals, the water flux decreased with time. It indicates membrane fouling and cake layer formation at the boundary. A steady flux of 2-2.5 LMH was obtained after 1h of filtration. The permeate flux shows decreased water flux after hydraulic cleaning at different mass concentration factor (MCF). Thus, hydraulic cleaning did not improve the water flux at different MCF (1-5).

Conclusions: Complete recovery of protein and carbohydrate from whey water was obtained in UF-NF process. The UF- NF showed higher water flux (2.5 LMH), compared to NF-RO reported (1-1.5 LMH). The recovered protein and carbohydrate may be used to make different products (e.g confectionery, dietetic food, infant formula, pharmaceuticals).

Keywords: Whey water, Recovery, Protein & Carbohydrate, Membrane Processes

Acknowledgment: Financial Support from SERB-DST, GoI (CRG/2018/003463).

References

Khaire R. A., Gogate P.R. Optimization of ultrafiltration of whey using Taguchi method for maximizing recovery of latose, Sep. Purif. Technol. 2020; 248: 117063.
Hikova A., Zidova P., et al. Potential of membrane separation processes in cheese whey fraction and separation. Procedia Engineering, 2012; 42: 1425-36.

Membrane processes – contemporary relevance & prospects

2021-09-11T05:49:14-04:00

Introduction: Membrane mediated separation is a versatile unit operation that can be used at various stages of product recovery for separation, concentration or purification of products. Membrane science is a highly interdisciplinary field, comprising of engineering, material science as well as chemistry. Over the last few decades, membranes have grown from a basic laboratory tool to a large scale industrial tool. Applications include desalination of sea water, removal of cells or cell debris, protein concentration, removal of virus, purification of food and pharmaceutical products. Nevertheless, membranes are the cardinal components of artificial organs, drug delivery and energy conversion devices. In this study, separation aspects of membranes through bulk liquid membrane set up have been demonstrated. Furthermore, the recovery potential for organic acids recovery from dilute solutions in lab and from a fermentation medium has been reviewed.

Methods: Experiments were carried out in a customized glass vessel consisting of 2 concentric cylinders joined from base. Inner cylinder carried the strip phase and the outer cylinder carried the feed phase. Organic LM was poured over two aqueous phases. The experiments were performed under stirring conditions. A range of feed and strip phase solutions along with different extractant concentrations have been used.

Results & Discussions: Separation potential of a bulk liquid membrane comprising of chemical species so as to recover organic acids from their dilute solutions was investigated. The BLM was made up of 2 aqueous phases and one organic phase comprised of an extractant. Recovery of acids upto 40% could be achieved for organic acids such as propionic acid, acetic acid and fumaric acid. It is speculated that these recoveries were based on reactive extraction process.

Conclusions: Successful energy efficient separations were achieved using the concept of BLM and the reactive extraction mechanism. Best separations were accomplished with enhanced carrier and strip phase concentrations. Further, careful selection of extractant chemistry with optimization of other parameters shall prove to be helpful for achieving substantial separations of given species.

Keywords: Liquid membranes, Reactive extraction, Separation, membrane assisted process

References

Guoping Li; Juanqin Xue; Nina Liu; Lihua Yu, Treatment of cyanide wastewater by bulk liquid membrane using tricaprylamine as a carrier. Water Sci Technol (2016) 73 (12): 2888–2895.
Ramkumar, J., & Chandramouleeswaran, S. (2015). A Perceptive on Bulk Liquid Membrane: A Brief Review.
K. Pourkhanali, M. Saleh, and G. Khayati, Performance Evaluation of Bulk Liquid Membrane Technique on p-Nitrophenol Removal from Aqueous Solution, Chem. Biochem. Eng. Q., 32 (1) 83–90 (2018).

An integrated environment friendly approach for recovery of surfactant and potable water from domestic washing machine discharge

2021-09-11T05:08:04-04:00

Introduction: It is a well-known fact that the demand of water increases with population increase. W.H.O. reported that by 2025, half of the population will be not able to have a clean source of water (1). Thus, water has to be used judiciously and should not be wasted. Estimates vary, but a typical household use about 80-100 gallons of water per day. The largest use of water in every house is for washing clothes, bathing, toilet flush, washing dishes. Urban waste water which includes water from bath, shower, hand basins, washing machine, dishwashers and kitchen sinks, but excludes streams from toilets is called grey water (2). Grey water which is also primarily discharged from washed laundry contains high in surfactants and is also very high in suspended solids, turbidity and oxygen demand. When the grey water is released without treatment it can cause environmental pollution and serious threat to living being. Currently treatment of laundry water is a challenge because of rapid population growth and also it is not accompanied by infrastructure improvements, especially in the field of sanitation. It is important that wastewater should be treated in order to save water as a future source and protect the environment from pollution. Previously grey water treatment was done physically where pollutants from grey water were removed by coarse sand and soil filtration (3). Now with the advancement of membrane-based water treatment technologies, such treatment methods have come into focus (4). The main object of this study to recover the valuable surfactant solution and generate potable water both of which could be reused again thereby leading to a cost effective, sustainable and environment friendly process.

Methods: An experimental setup has been developed which uses a spiral wound UF membrane that essentially removes the suspended matter from the grey water that was taken as the feed solution. The reject from this membrane is recycled back to the feed tank whereas the permeate enters a spiral wound RO membrane where the surfactant is removed from the solution thereby allowing potable water pass as a permeate. Both the membrane modules were optimized for its operating pressure and flowrates.

Results & Discussions: The collected grey water used for the experiment was found to have TDS of 749 ppm, Turbidity of 106 NTU and BOD of 290 mg/l. On treating it using the UF membranes, the recovered surfactant was found to have a TDS of 830 ppm, turbidity of 12.6 NTU and BOD of 110 mg/l indicating the collection of concentrated surfactant solution. The potable water which was collected later as RO permeate tested to have a TDS of 25 ppm, turbidity of 0.41 NTU and BOD of just 20mg/l indicating that the RO permeate is now potable.

Conclusions: The process leads to an effective separation process where the grey water obtained from washing machine was first cleaned of dirt materials using UF membranes and further separating the surfactant solution from the mixture and yielding potable water. The recovered concentrated surfactant solution as well as potable water could be reused again for future washes. The process thus leads to conservation of water too in addition to being cost effective and environment friendly.

Keywords: Grey water treatment; surfactant recovery; potable water recovery; UF and RO membranes.

Acknowledgment: The authors would like to thank the Vice Chancellor, Tripura University for providing necessary research facility.

References

WHO. No Title [Internet]. W.H.O. 2019 [cited 2021 Sep 11]. Available from: https://www.who.int/news-room/fact-sheets/detail/drinking-water.
Reang S, Nath H. Grey water treatment with spiral wound UF and RO membranes. Mater Today Proc. 2021 Jan 1;46:6253–9.
A. Carmalin Sophia Harjeet Nath and N. V. S. Praneeth. Synthesis of nano-porous carbon from cellulosic waste and its application in water disinfection. Curr Sci (Research Commun. 2016;111(No. 8):1377.
Venkatesh T, Senthilmurugan S. Grey water treatment and simultaneous surfactant recovery using UF and RO process. Sep Sci Technol. 2017.

Anaerobic membrane bioreactor: A waste-to-energy solution in a zero liquid discharge system

2021-09-10T06:19:30-04:00

Introduction: The depletion of freshwater resources has spurred conscious awareness among citizens to conserve water and develop cost-effective strategies for water treatment and recycle. The zero-liquid discharge (ZLD) is a specially designed system for industries to restrict liquid waste discharge and maximise water-reusability. Conventional ZLD systems employ multiple sequential unit operations such as chemical precipitation, activated carbon adsorption, micro-filtration, reverse osmosis and multi-effect evaporators to achieve reusable-quality water (1). These energy-intensive processes contribute to high capital and operational costs. The anaerobic membrane bioreactor (AnMBR) combines anaerobic treatment with membrane technology to effectively remove organic pollutants while producing solids-free effluent (2). The objective of the present study was to demonstrate the capacity of AnMBR to effectuate wastewater treatment in a single stage with notable efficiency thereby eliminating multiple unit processes. The AnMBR was employed for the treatment of raw potato processing effluent.

Methods: The Chemical Oxygen Demand (COD) and 5-day Biological Oxygen Demand values in potato chips processing effluent ranged between 3 – 9 g/L and 0.9 – 5.4 g/L respectively. The average suspended solids concentration was 10 g/L and the feed pH was between 6 – 7. The reactor was operated at mesophilic conditions and the pH was maintained between 7 – 7.5. Tubular polyvinylidene fluoride membrane with polypropylene as support material was integrated to the bioreactor for solid-liquid separation. The feed, reactor and permeate samples were analysed daily for pH, COD, suspended and dissolved solids. The BOD₅, volatile fatty acid and alkalinity were estimated weekly. All the analytical methods were performed following the procedure described in standard methods for the examination of water and wastewater

Results & Discussions: The high solids handling capacity of AnMBR facilitated direct feeding of raw wastewater without prior treatment. The maximum degradation efficiency of 93% was achieved during the operation and the F/M ratio was recurrent at 0.48 during the process. The biogas production increased as COD removal efficiency improved in the system and a maximum biogas yield of 0.414 L/gCOD_addedwas obtained. Clear and non-turbid permeate was obtained and the suspended solids in permeate was consistently below 5 ppm despite an increase in mixed liquor suspended solids in the reactor.

Conclusions: The AnMBR was capable of handling untreated and raw wastewater because of its ability to withstand high solids and organic concentration. The reactor functioning was unaffected by changes in organic load as stable methanogenic population developed in the reactor and generated favourable biogas yield from high OLR. The membrane filtration yielded clear and solids-free permeate. The competency of AnMBR performance serves as a compendious solution to pollutant degradation and the consistent output in terms of suspended and dissolved solids makes this technology a cost-effective approach in ZLD operation.

Keywords: Anaerobic membrane bioreactor, energy-neutral process, reverse osmosis, zero liquid discharge

Acknowledgment: Snehal Menon would like to thank Thermax Limited and Confederation of Indian Industry for Prime Minister’s Fellowship Scheme for Doctoral Research and Dr Somnath Nandi, Savitribai Phule Pune University for his support and guidance

References

Tong, T., & Elimelech, M. The Global Rise of Zero Liquid Discharge for Wastewater Management: Drivers, Technologies, and Future Directions. Environmental Science and Technology, (2016). 50(13), 6846–6855. https://doi.org/10.1021/acs.est.6b01000

Sonde, R., Venkatraman, K., & Bornare, J. (2016). Patent No. WO 2016/027223 Al. India

Dynamic symmetry in quantum-classical mechanics: Simplicity in complexity

2021-09-09T12:40:29-04:00

Introduction: As is well known, elementary transfers of electrons and/or protons in the membranes of living cells are integral parts of their functioning. Therefore, fundamental theoretical knowledge about the elementary transfers of electrons and/or protons in condensed media is of great interest. The theory of elementary transfers of electrons and/or protons in condensed media is based on a new physical theory – quantum-classical mechanics (QCM; see (1–4) and references therein). As a new theory, QCM arises as a result of eliminating the singularity that occurs in quantum mechanics (QM) in the rates of elementary electron-charge transfers when going beyond the Born-Oppenheimer adiabatic approximation and the Franсk-Condon principle. This singularity can be easily demonstrated by the example of a one-dimensional potential box with a movable wall (1–4).

Methods: The singular dynamics of the joint motion of an electron and nuclei in the transient state of molecular “quantum” transitions is damping by introducing chaos into QM. This chaos arises only during molecular quantum transitions and is called dozy chaos. Dozy chaos is introduced by replacing the infinitesimal imaginary addition in the energy denominator of the full Green’s function of the electron-nuclear system with a finite value, which is called the dozy-chaos energy γ.

Results & Discussions: The result for the optical transition-rate constant does not change when the sign of γ is changed. Other dynamic symmetries appearing in theory are associated with the emergence of dynamic organization in electronic-vibrational transitions, in particular, with the emergence of an electron-nuclear-reorganization resonance (the so-called Egorov resonance) and its antisymmetric (chaotic) “twin”, with direct and reverse transitions, as well as with different values of the electron–phonon interaction in the initial and final states of the system. The efficacy of the damping for the singularity is shown by applications of the Egorov resonance to optical spectra in polymethine dyes and J-aggregates. Nonradiative transitions are considered within a simplified version of QCM (SVQCM), in which the electronic component of the complete electron-nuclear amplitude of transitions is fitted by the Gamow tunnel exponential, dependent on the transient phonon environment. Within SVQCM and the Einstein model of nuclear vibrations, the Brӧnsted coefficients α and β for proton-transfer reactions satisfy the well-known symmetric relation α + β = 1 (5). The linearity of the Brӧnsted relations is explained.

Conclusions: It is proposed to generalize QCM to the case of nonlinear optics (1), which, in particular, is rationalizing experimental studies in the field of bioimaging and photodynamic therapy. Prospects for further developments in QCM and their applications to problems of cancer and viral infections are discussed.

Keywords: Charge transfer, dozy-chaos mechanics, optical band shapes, Egorov resonance, Brӧnsted relations

Acknowledgment: This work was supported by the Ministry of Science and Higher Education within the State assignment Federal Scientific Research Center “Crystallography and Photonics” Russian Academy of Sciences.

References

Egorov VV, Thomas S. Quantum-classical mechanics: On the problem of a two-photon resonance band shape in polymethine dyes. Nano-Structures & Nano-Objects 2021;25:100650-1–10.
Egorov VV. Dynamic symmetry in dozy-chaos mechanics. Symmetry 2020;12:1856-1–19.
Egorov VV. Dozy-chaos mechanics for a broad audience. Challenges 2020;11:16-1–12.
Egorov VV. Quantum-classical mechanics as an alternative to quantum mechanics in molecular and chemical physics. Heliyon Physics 2019;5:e02579-1–27.
Brönsted JN. Acid and basic catalysis. Chemical Reviews 1928;5:231–338.

Lysosomal storage diseases: possible use of nanophosphor-nanogold coated immunoconjugates in affinity purification of lysosomal transport vesicles

2021-12-08T06:16:00-05:00

Introduction: Lysosomal Storage Diseases (LSDs), a group of 40 or more metabolic diseases result from functional defects of lysosomal membrane transporter proteins. In a directed approach to characterization of molecular defects, we describe a protocol for affinity isolation of lysosomal transport vesicles as well as explore the potential of nanophosphor-nanogold particle based dual conjugates in isolation of membrane transporter proteins.

Methods: We have employed a proteomics-data based approach using consensus amino acid sequence motifs Tyrosine (GYXXfin) or Leucine-Isoleucine (D/EEXXXLI/L) targeting cytosolic domains in lysosomal membrane proteins for designing antibodies against custom synthesized peptides with signature or consensus sequence. Recombinant Constructs with DKFZp564K2464 (Human Transmembrane protein TMEM22 (accession UGID: 692851, a Gift from Dr. S. Wiemann), coding for a probable lysosomal transport protein were made and specific Yolk antibodies (IgYs) were then raised (1). Nanogold particles per procedure of Gupta and Tartakoff (1989) (2) and nanogold-IgY conjugates were then prepared.

Results & Discussions: Transfection experiments with HK 293 cells and cDNA reconstructs of fusion protein GFP- DKFZp564K2464 resulted in expression of a putative lysosomal transporter membrane protein with Mr 72000. In addition, we prepared a number of nanophosphors i.e., ZnS: Mn⁺² ((Histidine capped)), CdS Cd-Se, LaPO₄:Ce/Tb , Eu:Y₂O₃ ,Y₂O₃:Tb and also BSA-Tagged ZnS: Mn (Histidine capped) nanophosphors and characterized with regard to their Photoluminescence, UV absorption spectra, XRD studies, SEM, TEM and AFM characteristics of nanophosphors make them suitable for preparation of Double Tagged Nanogold-immuno-Nanophopshors conjugates. as a useful reagent.

Various polymers and solid metal-based nanoparticles investigated for drug delivery, especially in cancer therapeutics, do not preclude their potential toxicity to patients. The affinity retrieval of membrane transport vesicles using a double nanotag (nanophosphor and nanogold particle) will be a novel way of studying cell biologic issues concerned with protein transport.

Conclusions: Functionalized multifunctional and multiplex nanoparticles are going to be the next generation of nanoparticles, for personalized and tailored cancer treatment.

Keywords: Nanophosphors-Nanold Immunoconjugaates, Retrieval of Biomembranes

Acknowledgment: 1. Indo-German International Project DST-DAAD, DST Nanomission, DBT –BIF Grants to DKG. 2. Prof. Dr. S. Wiemann, German Cancer Research Center.

References

D. Gupta and A.M. Tartakoff, “Lectin-Colloidal Gold-Induced Density Perturbation of Membranes: Application to Affinity Elimination of the Plasma Membrane”. Methods in Cell Biol. Acad. Press, New York, 31: 247- 263, 1989. doi : 10.1016/s0091-679x(08)61614-3
.M.Romito, G. J.Viljoen, and D.H. Du Plessis “Eliciting Antigen-Specific Egg-Yolk IgY with Naked DNA” Biotechniques 31: 670-675, 2001.

Copolymeric membranes of heteropolyacid embedded poly (vinyl alcohol)-g-acrylamide and their evaluation for proton exchange membrane fuel cells

2021-09-10T12:49:38-04:00

Introduction: The development of purposeful fuel cells trace back in the early 1800’s by Sir William Grove and who become considered as discoverer of fuel cell in 1839. After attaining this great achievement scientists across the globe have been attempted to develop fuel cell technology by various electrolytes and fuels. In the early 20^th century first time fuel cell systems are used in Gemini and Apollo space flights. In the year 1959 first time the fully operated new generation fuel cell was demonstrated by Francis T. Bacon successfully. Later in the year 1960 proton exchange membrane fuel cell was developed and used by NASA as part of Gemini space program and the mission successfully continued for seven of its mission.

Methods: Synthesis of Copolymer: 5 g of PVA was dissolved in water at 60°C. Adequate amount of acrylamide (1 g) and initiator (0.4 wt.% to comonomer) were introduced to reaction vessel under continuous stirring. The temperature was maintained at 80°C for 6 Hrs. The obtained reaction mixture was precipitated in methanol and filtered under vacuum. The obtained product was dried in vacuum oven at 60°C for 12 Hrs.

Na-tungstate embedded copolymeric membrane fabrication and crosslinking: The synthesized PVA-g-AAm copolymer was dissolved in 100 mL of distilled water at 60°C. Once the viscous slurry was obtained different gravimetric ratio of Na-Tungstate (i.e. 1, 2.5 and 5 wt.% w.r.t total copolymeric weight) were added as filler under continuous stirring. The solution was cast on to doctor’s a neat and clean glass plate with the help of blade. The casted solution was allowed to dry under dust free atmosphere. Once the solution was dried membrane was peeled off from the glass plate and stored properly. Further the membranes were crosslinked with glutaraldehyde by soaking them in a crosslinking bath containing 5 mL of glutaraldehyde.

Results & Discussions: Ion exchange capacity test was performed for the crosslinked PVA-g-AAm copolymer and compared with uncrosslinked membrane. The uncrosslinked PVA-g-AAm showed 2.108 meq/g and the crosslinked PVA-g-AAm showed IEC of 0.593 meq/g. The IEC, which is equal to the total number of free hydroxyl and amide groups, has decreased after crosslinking reaction. The results shows that approximately 72% of the hydroxyl and amide groups from the uncrosslinked copolymeric membrane have involved in the croslinking reaction with glutaraldehyde. However, there are still some extra hydroxyl and amide groups are present and they allow the diffusion of molecules through crosslinked copolymeric membrane. The proton conductivity plots have been obtained shown in Figure 1. The obtained data shown that the modified membranes showed better performance as compared to its plain membrane. The plain membrane showed 3.492 x 10^-2S cm^-1for 75 % RH to 3.942 x 10^-2S cm^-1. Whereas 5 wt.% Na-Tungstate loaded Membranes showed 6.315 to 13.333 x 10^-2S cm^-1 for 75% to 100% RH.

Keywords: Fuel cell, copolymer, grafting reaction, proton exchange

Acknowledgment: Authors thank the Vision Group for Science and Technology (VGST), Bengaluru, India for a funding (GRD No: 951) (2020–2021) for establishing the laboratory at Basaveshwar Science College, Bagalkot, India.