Nanoarquitecture of nanomaterials/molecules for the elimination of arsenic in drinking water.

Arsenic ranks the 20th most abundant element in nature. It can have a valency of −3, 0, +3, or +5, depending on water chemistry. In natural waters, it exists as arsenate (AsO4)-3 and/or arsenite (AsO3)-3, also referred to as arsenic(V) and arsenic(III). The toxicity and mobility of arsenic are affected by its oxidation states. Arsenite is more toxic and mobile than arsenate in the aqueous environment. Arsenate primary exists in surface water, whereas arsenite dominates in ground water. The presence of arsenic in water is a serious threat to more than 100 million people in the world. There have been many documented incidents of arsenic contamination in ground water around the world, most notably in countries such as Taiwan, Chile, Argentina, Hungary, Bangladesh, India, Pakistan, Thailand, Vietnam, China, México (Zacatecas, San Luis Potosi, Chihuahua, Torreón, Durango) and the United States. In Mexico alone, it is estimated that 13 of the 31 states in Mexico suffer of arsenic contamination. It is known that Arsenic ingestion can lead to many adverse health effects, including skin lesions, diabetes mellitus, chronic bronchitis, cardiovascular disease, peripheral neuropathy, adverse reproductive outcomes, and hematological effects. Prolonged exposure to arsenic damages the central nervous system and results in diverse types of cancer in liver, lungs, bladder and skin. Arsenic poisoning has a great social cost since it affects children and adults alike. Due to these reasons is of great importance to provide cost-effective technologies capable of eliminating or reduce the levels of concentration of arsenic in drinking water, especially in rural and poor communities where access to costly or complex filtering systems is limited.

Arsenic removal from water is possible through different physicochemical processes which include coagulation, precipitation, ion exchange, membrane filtration, and sorption. Among them, sorption can have a good performance, ease in operation, and lower cost, which makes it attractive for its utilization.

Adsorption is limited by the surface area, active sites and lack of selectivity of the material used, however the arrival of nanomaterials has opened the opportunity to considerably increase the absorption capacity of materials. Furthermore, the possibility to carry out multiscale modeling of chemical systems (topic of research of this year Nobel laureates in Chemistry) can also be used to design molecules or materials with specific properties, for example the selectivity towards a specific chemical molecule or element.

At the CenERgy group in CINVESTAV-SALTILLO (Mexico), in collaboration with Dr. Joaquín Barroso Flores from the National Autonomous University of Mexico, we are combining computer modeling and experimentation to design and synthesize molecules and nanomaterials capable of eliminating arsenic more efficiently. For example, Figure 1 shows some computer models where the interaction between arsenic oxide and calix[n]arenos is being studied.

calix[n]arenos and arsenic modeling top and side view

Figure 1. Top and side view of different calix[n]arenos obtained by computer modelling showing their interaction with arsenic (purple).

María Monserrat Enriquez González, PhD student working on this topic.

María Monserrat Enriquez González, PhD student working on this topic.

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4 responses to “Nanoarquitecture of nanomaterials/molecules for the elimination of arsenic in drinking water.

  1. anup basnet chetry

    thanks for the research development about the removal of arsenic. i have also done my phD on solvent extraction for the removal of precious and rare earth metal. it seems to be new about the extraction of arsenic and also interested to do research in this field.

  2. Hello Anup,

    I´m glad the little article was of interest to you. I am also moving from another area towards the problem of arsenic. It is really fascinating and needless to say quite challenging. I will be happy to help if you have any question regarding working with arsenic or even collaborate. Regards,

    Eddie

    • anup basnet chetry

      Hello Eddy,
      Thanks for reply.Arsenic contamination is the major problem in my country.And I am also trying to do research for the complete removal of arsenic from drinking water.Now I am focused to remove arsenic by using biomass,if you have any idea to share I am very helpful to complete my research. If you have time can u share your research activity so that we can share our research field.I feel glad if we collaborate to do some research work on arsenic removal.
      Regards,
      Anoop

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