New Techniques & Trends in Industrial Uses of Filtration Systems

Pure water and clean air are the basic necessities of every part of the world, but obtaining this is difficult at times. Filtration is so important that it is found almost everywhere. Use of nonwoven filtration media provides us an opportunity to solve purification challenges and help us to create a healthier, safer and cleaner environment. Nonwoven materials in the global filtration market continue to enjoy steady growth and are expected to reach 747,000 million tons by the end of 2020, according to India’s Worldwide Outlook for the Nonwovens Industry report. With the expansion of human settlement and more pollutants reaching the environment there is a higher need for clean air and water. This need is felt not only in developed countries, but also in developing countries worldwide. This is leading to new innovation and interesting solutions being developed for filtration.

Environmental concerns all around the world are leading us towards more stringent regulations for clean air and water. This is creating a major need for innovation and improvement in filtration technologies around the world. Air quality is an issue of social concern worldwide in the backdrop of rising industrial and vehicular air pollution. In Global Burden of Disease 2010 (GBD), Outdoor Air pollution is among top 10 risks worldwide and among the top five risks in the developing countries of Asia. The alarming high levels of air pollutant emissions from automotive emissions has contributed to the development of the filtration sector as more stringent regulations are being implemented globally to reduce the discharge of carbon dioxide (CO2), sulphur oxide (SOx), nitrogen oxides (NOx) and particulate matter into the environment. With new government regulations and public pressure many companies are responding with their efforts to either remove CO2 from the air or reduce their CO2 output to achieve carbon neutrality. There is an ever greater need to develop new and improved filters for vehicles. These filters help in removing contaminants from engine, hydraulic, transmission and lubricating fluids. Better filtration systems can also improve the air-fuel mixture, helping the engine to function more efficiently, minimizing ignition problems, lowering fuel consumption, and reducing emissions. Air Intake filters absorb dust, debris, and other solid particulates that pose a threat to auto cylinders and pistons, also better air filters for cabin can highly improve the air quality inside vehicles.Nonwoven filters plays a very important role for filtration in automobiles including motorcycle engines that create enormous pollution, but their cost is still a factor.

Global power generation and regulations by governments of various countries are fuelling growth in filtration for industrial and manufacturing applications. As manufacturers look to streamline their processes, higher levels of filtration is increasingly seen as a way to boost efficiency and reduce carbon footprints. Coal-burning electric power plants are major sources of the greenhouse gas, and control measures are required to keep them under check. To remove carbon dioxide from smokestack gases a Carbon Filter Process is designed to meet this need. It uses a simple, low-cost filter filled with porous carbonaceous sorbent that works at low pressures. Modelling data and laboratory tests suggest that the device removes 90 percent of carbon dioxide from smokestack gases.

The use of electrostatic charge can provide a higher efficiency on filtration products. Electrostatic charge is being embraced in Asia and other parts of the world because of the performance it provides. Electrostatic air filters work similarly to a magnet. Formulated fibres generate strong static charges when air passes through them they attract airborne particles and hold them until the filter is cleaned.

The indoor air filtration systems are one of the fastest growing sectors in air filtrations especially in Asia. There is an increasing desire to improve health by reducing the dangers from dust, mould, bacteria, pollen and allergens resulting in development and creation of high-performance filters that can capture submicron particles and improve the quality of air in homes, offices, buildings and public spaces. This result may be achieved by the use of membrane filter systems. Membrane filters are microporous plastic films with specific pore size ratings. Also known as screen, sieve or microporous filters, these membranes retain particles or microorganisms larger than their pore size primarily by surface capture. Some particles that are smaller than the stated pore size may be retained by other mechanisms.

Filtration systems play a critical role in public health and safety in hospital and operating room environments, medical applications such as dialysis and in the pharmaceutical industry. In blood filtration, Berry’s Meltex polyester meltblown media is capable of removing white blood cells to decrease leukocytes that cause infection. The media performs based on size exclusion to remove white blood cells so the red blood cells can be used in transfusions. Today’s biopharmaceutical process has six to eight stages of high-level filtration to remove viruses and certain proteins, requiring very absorbent and selective filtration. The industry is looking at creating single-use nonwovens membranes that can capture a significant amount of proteins through surface modification of the filter, which would reduce costs and liabilities.

The global demand for laboratory filtration is growing significantly over the decades and is one of the most important techniques used in laboratories for deriving precise results. Many new filtrations have been introduced as a result of research and fundamental pathogenesis of diseases. Microfiltration is expected to hold the largest share of this global laboratory filtration market. Microfiltration is widely used for cold sterilization of API and enzymes and also for the separation of solid-liquid phases in the various industries. Chemical resistance and high thermal stability are the main factors for increased adoption of microfiltration in this market.

. Nanotechnology is the biggest emerging technology that will continue to impact the filtration industry that will drive future industry growth. Nanofibers can be used to drive down scale and to enhance filtration selectivity. The study and use of nanofibers in filters is on a rise, this will bring many commercial products in market in the near future. Solid-Phase Extraction (SPE) is an extractive technique by which compounds that are dissolved or suspended in a liquid mixture are separated from other compounds in the mixture according to their physical and chemical properties. Solid phase extraction can be used to isolate analytes of interest from a wide variety of matrices, including urine, blood, water, beverages, soil, and animal tissue. New trapping medias are being developed and tested like nanostructured materials, including carbon nanomaterials, electrospun nanofibers, magnetic nanoparticles and many others. These new materials and technologies are propelling us to a brighter future for the improvements of SPE for the extraction of different kind of materials; such as biological, environmental, pharmaceutical and food samples.

Two-thirds of the world's population may be facing water shortages. The inadequate water filtration system is a problem for 2.4 billion people. This can lead to deadly diarrheal diseases, including cholera and typhoid fever, and other water-borne illnesses. For cleaning water, reverse osmosis is the key filtration process used for desalination, industrial process waters, municipal and industrial wastewater reuse.

However Graphene-based water filters have proven to be one of the effective ways for:

1. Separation of Oil from water

2. Domestic water filtration

3. Wastewater treatment

4. Desalination

. 1. During the exploration and production of crude oil and gas, there is a lot of water that is brought to the surface. The water contains chemicals and additives used during drilling and production. The water can constitute up to 10 times the volume of oil. Graphene based filters have proven to show a quick, easy and cost-effective method of separation.

Water can be treated, decontaminated and discharged as harmless surface water. Here both properties of graphene are used hydrophilicity and hydrophobicity. The added benefit of graphene is that fewer chemicals and synthetics are needed for cleaning purpose. So it makes easier to dispose of this water as safe surface water or to be recycled within the oil & gas sector.

. 2. Over 2 billion people have poor or no access to safe drinking water and half of the world’s population will be living in water-stressed areas by 2025 (WHO report, Nov 2016). Poor water quality is a serious public health issue with 80% of diseases in the developing world being water-borne which leads to 1 in 5 deaths under the age of 5. Even in the developed world, exposure to pesticides, antibiotics & pharmaceuticals, and heavy metals (e.g. arsenic, lead) remains a significant concern. Graphene-based technology has proven to show better rejection ratios increasing the water flux and increased durability for long term usage/performance and thus show improved fouling resistance.

3. Wastewater treatment has 3 major subdivision:

a. Removal of contaminants from water.

b. Management of industrial water to ensure legal compliance.

c. Ability to filter clean drinking (portable) water effectively and cost-efficiently where water is needed.

. Conventional Solutions Limitations:

a.) Short lifetime

b.) High energy consumption

c.) Quick fouling

d.) Poor selectivity and specificity

Conventional treatment industries primarily use the membrane bioreactor process to filter water and face a challenge with membrane contamination which causes frequent downtime.

Graphene-based membrane structure with nanosheets creates several layers along with microscopic channels through which only water molecules can pass. These structures repel more contaminants and operate four times longer than a traditional membrane before it needs cleaning.

This Graphene-based membrane with increased efficiency means the water treatment plant’s footprint is also reduced.

4. Roughly 300 million people consume more than 86 million m^3 of desalination water daily. As water scarcity grows, the prospect for the desalination industry is coming up with the increasing need for clean and safe water.

Graphene membrane has proven that it takes less energy than other membranes to produce the same amount of water. The preferential transportation of water between the graphene sheets results in high salt rejection.

With graphene, a single atomic layer of carbon, a clean water solution has emerged. Cutting edge water filtration systems are being developed using graphene to remove highly hazardous contaminants that are otherwise not efficiently removed by previous technologies. The properties that make graphene unique to water treatments are large surface area, little or no cytotoxicity, large delocalized ∏-electrons and tuneable chemical properties. Importantly, graphene can easily be reused with minimal chemical alterations.

Graphene-based materials comprise graphene, grapheme oxide and reduced graphene oxide - all of which constitute the graphene family, is similar in structure, but different in sp2 region predominantly and the surface groups. The adsorption capacity of these materials is higher than traditional materials such as activated carbon and resins and also carbon nanotubes. Graphene possesses “ultrathin thickness for maintaining high flux efficiency, high mechanical strength to withstand high pressures, high chemical and thermal stability, allowing for membrane design and fabrication” – these are the potential factors in the water treatment process.

Graphene is the promising material for use in water treatments across the world to meet the water demands. A bottleneck challenge is in the perfection of fabricating large graphene sheets for large scale production considering the cost-efficiency and the need for environmental-friendly procedures.

Most of the technologies available today for treating drinking water are physical and/or chemical processes. In fact, the water treatment industry depends solely on physical and/or chemical processes to meet water quality goals. Utilization of biological processes in water treatment was frowned on by the industry because of concern about the introduction of microorganisms to water. However, this barrier has been broken by the introduction of biological filtration as the most effective process for the production of biologically stable water. Many water treatment plants today use biological filtration after ozonation to remove biodegradable organic matter. The use of biofiltration in drinking water treatment opens the door to new and innovative applications of this process. Biofiltration can be used for the biological reduction of various inorganic contaminants such as nitrate, bromate, perchlorate, chlorate, and selenate.

In recent times there has been a rapid entry of new technologies that continue to be developed, tested, demonstrated and introduced into the filtration market. Some of these technologies used for water treatment industries are membrane filtration, UV irradiation, advanced oxidation, ion exchange, reverse osmosis and biological filtration. These are certainly not the only technologies being considered by the water treatment industry and new ones are tested regularly. However, they have come a long way towards demonstrating their reliability and applicability to large-scale water treatment plants. As the cost of these technologies continues to decrease, their applicability is steadily increasing. Today, there is almost no contaminant that cannot be removed from water. The question becomes that of cost. As alternative water resources become increasingly less available, the need for innovative and cost-effective treatment technologies will rise steadily.

New Techniques & Trends in Industrial Uses of Filtration Systems

Dhananjay Sharma

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