Are adsorption systems superior to membrane filtration systems for purifying drinking water, especially in removing emerging contaminants? If yes, why?
Dear Gabriel O. Ogbeh ,
Adsorption would not be superior to NF or RO but it could complement it to remove soluble recalcitrant organic compounds at ppb levels (micropollutants) such as residual pharmaceuticals, pesticides, ...
That's why we apply enhanced biosorption with continuous regeneration in our upstream AS+(tm) biotreatment resulting in very clean drinking water after NF or RO as proven over 15 years. Because our AS+(tm) outlet water is so clean, the NF/RO membranes last 3 to 5 times longer as compared to outlet water from classic activated sludge (AS) systems including MBR.
Good day!
These are different systems. They can work together. In other cases, they can replace each other.
When comparing these systems, take into account:
- a specific water quality parameter or a group of parameters, for example, oil products, chlorine,
- a capacity of water supply system,
- adsorber loading type,
- technological scheme of water treatment,
etc.
Best regards,
Dear Gabriel O. Ogbeh
Although membrane filtration systems are favored for their purity and resistance to fouling, it would be premature to assert that adsorption systems are inherently inferior to membrane filtration systems. The choice of water treatment methods is contingent upon several factors, including but not limited to the nature and concentration of pollutants, adherence to water quality regulations, economic feasibility, and system design parameters. The combination of adsorption and membrane filtration can yield hybrid systems that exhibit superior purification efficacy in specific contexts.
Use of activated carbon adsorption in combination with ultrafiltration membranes, for example.The activated carbon adsorption step may remove biodegradable organic pollutants, and the ultrafiltration membrane can efficiently remove suspended solids, germs, and viruses. When these two processes are combined, they can produce high-quality effluent that fulfills severe water quality criteria. Furthermore, using activated carbon in the system can aid to prevent membrane fouling, improving membrane lifespan and lowering operating expenses.
superiority between adsorption and membrane filtration systems depends on the specific water quality parameters, type and concentration of contaminants, and the desired water treatment objective. In many cases, a combination of both technologies may be employed in water treatment processes to achieve comprehensive purification.
no.membrane technologies are better than adsorbtion, although adsorbtion have many porous inside, because impurities just needed separate by phisically proccess no more action
Hello,
you are talking about drinking water purification. Hence, removing of ions will not be the topic.
I assume, that removal of organic substances is the target.
We have to consider two things: size and polarity/charge of the molecules.
For membrane systems the size is decisive and the higher the better the retention. The retention for small molecules is even rather poor.
For adsorbents (and we firstly take into account unfunctionalised adsorbents) the adsorption enthalpy increases with size and the uptake behaviour is following a similar rule like with membranes. The difference is the pore size of the adsorbent, which defines a maximum molecule size which is adsorbed. Larger molecules are size excluded.
Hier a complementary way of functioning is obvious, which means that both technologies can help each other.
If ionic functionalities are existing on the molecules (e.g. organic acids, polyamides, amines), ion exchange proved to be the best solution and often is superior to adsorption and membranes due to the extremely high purity which is possible. Well known examples are PFA. The molecular size is decisive too as with adsorbents. It is not as critical, since IEX resins mostly have bigger pore sizes (100…200 nm for macroporous types) compared to adsorbents (1…40 nm).
If bigger molecular weights than 5000 g/mol is interesting, the membranes might be very interesting, but consider the fouling topic!
With best regards Dieter Mauer
The choice between adsorption systems and membrane filtration systems for purifying drinking water depends on several factors, including the specific water quality issues, treatment objectives, cost considerations, and system maintenance requirements. Both adsorption and membrane filtration are effective methods for removing contaminants from drinking water, but their superiority can vary based on the application and water source. Let's explore the advantages and considerations for each system:
Adsorption Systems: Advantages:
Considerations:
Membrane Filtration Systems: Advantages:
Considerations:
Ultimately, the best choice between adsorption systems and membrane filtration systems depends on the specific water quality concerns, treatment goals, available budget, and infrastructure. In some cases, a combination of both technologies might be used to address multiple contaminants effectively. Water treatment professionals and engineers carefully consider these factors to design the most suitable and efficient treatment system for a particular drinking water source.
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