To me the two main problem is related to the fine powder form most materials have. A material might have a very high activity to sorbe or degrade pollutants but to achieve a reasonable treatment time excess of the material powder needs to be added to the water flow being treated.

This excess and residuals of the spend material remaining in suspension causes (1) that some potential activity is not used and (2) there is a huge concern for the use of the water afterwards about the possible toxicity of the remaining nanomaterial in the water.

We can separate powder materials from the water treatment using e.g. membranes but this add to the cost and the recovered nanomaterial is rarely reusable as it tend to lose activity with contact time in water (fouling, side reactions, aggregation etc. ).

Dear Sir. Concerning your issue about the disadvantages of using nanotechnology in water and wastewater treatment. Supply of clean, safe and potable water to meet human needs is great challenge in this era. To achieve this objective wastewater needs be treated and reused. Nanotechnology has emerged as one of the leading new innovative technologies with a great potential for treating wastewater in a more effective and efficient manner than methods that have been previously used. Now a day mainly the nanoscale filtration techniques, the adsorption of pollutants on nanoparticles, the breakdown of contaminants by nanoparticles catalysts are generally used. In this current review the application of nanotechnology in waste water treatment, the different nonmaterial, properties, advantages and limitations over existing processes has been discussed. The literature survey shows that this method still require lots of research before successful industrial application and commercialization. There is the huge hope that nano technological applications and products will lead to a cleaner and healthier environment. Besides its use in water treatment, nanotechnology mayhave effects on human health and the environment. With more than 1100 nanotechnology products already

available to consumers worldwide, nanoparticles may eventually interact with humans and the environment at different stages of the products’ life cycles. There are concerns that the same properties (size, shape, reactivity,conductivity) that make nanoparticles so useful to mankind can also make them potentially harmful to the environment and toxic to humans, especially if they enter and build up in drinking water supplies and the food chain. How this will effect their toxicity in the long term is unclear. For example, silver nanoparticles used in socks to reduce foot odor are being released during washing with possible negative consequences. The silver nanoparticles may then destroy beneficial bacteria which are important for breaking down organic matter in wastewater treatment plants. Extreme care needs to be taken with the use of nanotechnology in water treatment. The catalytic activity of a nanoparticle can be advantageous when used for the degradation of pollutants, but can induce a toxic response

when taken up by a cell. The high sorption capacity of certain nanoparticles is exploited for the removal of organic and inorganic pollutants while this property may also mobilize

sequestered pollutants in the environment. The detection of nanomaterial release is a major technical hurdle for risk assessment and remain challenging. So fast, sensitive and

selective nanomaterial analytical techniques are in great need. I think the following below links may help you in your analysis:

http://nanogloss.com/nanotechnology/advantages-and-disadvantages-of-nanotechnology/

https://www.ncbi.nlm.nih.gov/pubmed/23571110

https://pdfs.semanticscholar.org/67a1/cf97bba4977ac6c1736a6fd34d746495d8f5.pdf

Thanks

So far overall the nanotechnologies have not offered any water treatment possibilities that are significantly better than that is possible with existing methods. Meanwhile most are inherently expensive and energy demanding compared to the methods that achieve the same by other means.

They are good for scientific funding but not very promising for actual use.

Dr. Rasmus

I agree with you but what disadvantages that you faced to be avoided from other researchers in that feild according to your nanoparticles that you dealt with.

To me the two main problem is related to the fine powder form most materials have. A material might have a very high activity to sorbe or degrade pollutants but to achieve a reasonable treatment time excess of the material powder needs to be added to the water flow being treated.

This excess and residuals of the spend material remaining in suspension causes (1) that some potential activity is not used and (2) there is a huge concern for the use of the water afterwards about the possible toxicity of the remaining nanomaterial in the water.

We can separate powder materials from the water treatment using e.g. membranes but this add to the cost and the recovered nanomaterial is rarely reusable as it tend to lose activity with contact time in water (fouling, side reactions, aggregation etc. ).

Another disadvantage is synthesis of nano material which involves complex mechanisms in accordance with other commonly used materials preferred in other conventional methods.

The application of nanotechnologies in water treatment for drinking purposes - have some disadvantages. I agree with the points, mentioned by Dr.Henrik and Mr.Adrij.

Thanks and regards

Hi dear,

Yes, i agree with Dr. Asit, Dr. Henrik and Dr. Adrij.

With my best regards!

Adel

As above shared agreed & exisitin methods are suffice the requirments.

Hi all,

I agree that for wastewater treatment the nanoparticles are not so interesting regarding the potential toxicity versus efficiency and cost but for sure they are very useful for groundwater remediation.

Adriana

Of course Dr. Adriana,

Czech Republic from the earlier countries in groundwater remediation using nano slurry But i think the nanoparticles effective in the removal of pesticides from agriculture waste and colour and heavy metal from industrial waste and have perfect antimicrobial effect, so what is the disadvantages of using some of nanomaterial in the treatment process and what is the best method (in your opinion) to overcome for that?

regards

To me magnetic nanosorbent is the most preferred because its magnetic properties that can support collecting from solution and does't lose there reactivity when entrapping into different polymer

Regarding magnetic nanosorbents,

Mr. Mahmoud did you find any applications there this is convincingly more effective and/or efficient than e.g. a traditional sorbent formulated as a reaction column?

Dr. Rasmus

NZVI have many advantages in the removal of different contaminants using chemisorption and physical adsorption such as phosphate removal using chemical adsorption and the removal percentages about 98 at 15 min from contact time and easy to recover at alkaline solution while traditional sorbent such as activated carbon, sewage sludge Ash, agricultural waste didn't reach this percent

Also, bimetallic iron have the same character but I found it more efficient to degrading pesticides especially organochlorine

Mr. Mahmoud,

One can also remove phosphate with 98% effective using iron and aluminium ions to precipate phosphates or sorbe it on a sorbent in a column with 15 min contact time. This is the most common methods used in the water industry. Where do you see nZVI out-competing these commonly used methods?

Is nZVI ever able to treat phosphate with less resources cost or more effective?

Dr. Rasmus

I agree with you but you can't reuse other sorbent again after the treatment process

The contact time effect using nZVI especially in phosphate removal effective after 5 min with the removal efficiency more than 85% which make it sutable to treat large number of contaminated solution per day

The nZVI treatment system doesn't need a huge land area ( construction area) about 200 meter mainly enough to do that leading to overcome the construction cost

I am wondering why all dear researchers are talking about nanoparticles!! We all know that using different kinds of porous materials including granular activated carbon and zeolite are also considred as using nanomaterial for water treatment as they have porosity.

In addition, I think we cant generally talk about the advantages and disadvantages of using nanomaterial for this purpose since sometimes there is not another option for an effective removal of pollutants. Therefore, if we want to talk about the advantages and disadvantages of using nanomaterials for removal of pollutants we need to concentrate on a certain pollutant or a certain family of pollutants and then compare the results.

Dear Dr. Saeide

Nanoparticles not only have large poure size but also have free electrons effect that can be used for the degrading organic contaminants and used as anti microbial.

Nanotechnology especially effective nanoparticles have different advantages and disadvantages in water and wastewater treatment So we can't use it in large scale for that.

We want to summarize different advantages and disadvantages according to different researcher applications to avoid these diffect in the future research.

Regards

Which reusable sorbents for phosphate can be used as nanoparticles or coating on magnetic particles but cannot be made and reused as a granular column material?

Nanotechnology in water and wastewater treatment

Two useful links on the topic:

Water and Wastewater Treatment using Nano-technology

https://link.springer.com/chapter/10.1007/978-3-642-23394-4_66

Nanotechnology and Water

https://www.npep.co.za/wp-content/uploads/2017/04/npep_fact_sheet_nanotechnology_water.pdf

Regards

for phosphate removal the most effective nanoparticles was nano zero valent iron with highest removal efficiency and higher recovery,

may be other nanoparticles have the same character in phosphate removal but may be under research study.

I tried different nanoparticles such as nZVA, and Bimetallic Cu/Fe in phosphate removal the removal was between 83 and 90% after 30 min with the same Iron Dose.

this link may be useful

Data Aqueous phosphate removal using nanoscale zero-valent iron

Mr. Ahmed - Good article. Thanks

Yes, it's a good work. Dr. Ahmed my congratulations.

my best regards!

Adel OUESLATI

I think this sites may be useful,

about the disadvantages of nanotechnology

http://www.thenewecologist.com/2015/11/disadvantages-nanotechnology/

http://nanogloss.com/nanotechnology/the-potential-disadvantages-of-nanotechnology/#axzz54TLLF8ww

https://www.google.com.eg/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&ved=0ahUKEwjPxuvy39_YAhWOL1AKHR-9AcoQFggtMAE&url=http%3A%2F%2Fec.europa.eu%2Fenvironment%2Fintegration%2Fresearch%2Fnewsalert%2Fpdf%2F75na3_en.pdf&usg=AOvVaw1Klja0K4vEC-0y0QfGh1kT

https://www.nanowerk.com/spotlight/spotid=25937.php

Yes, Ahmed the aforementioned sites give some information on the topic. Thanks

According to my knowledge and observation, nanotechnology in wastewater treatment possess following drawbacks:

1. Increase of agglomeration rate of nano sized catalysts or adsorbents, due to which blockage of reaction or adsorption sites occur reducing the overall efficiency of the process.

2. Difficulty in recovering the nano catalysts after the completion of wastewater treatment process.

Good luck!

Yes, these (drawbacks) are correct. Regards

They also do poses health risk also.

Dear Ahmed

I think there is some disadvantage like you must find a good adsorbent and if not, you may contour with a serious problem and another one is its procedure to make a composite nano structure.