Mini Review - Journal of Nanotechnology and Nanomaterials (2021) Volume 2, Issue 1
Nanotechnology in Water Treatment: An Optimistic Perspective for the Near Future
Bruna Maria Praun Pereira, Bianca Pizzorno Backx*
Universidade Federal do Rio de Janeiro, Campus Duque de Caxias, Brazil
- *Corresponding Author:
- Bianca Pizzorno Backx
Received date: April 15, 2021; Accepted date: June 01, 2021
Citation: Praun Pereira BM, Backx BP. Nanotechnology in Water Treatment: An Optimistic Perspective for the Near Future. J
Nanotechnol Nanomaterials. 2021; 2(1): 51-56.
Copyright: © 2021 Praun Pereira BM, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Due to water scarcity and the growing disputes over this vital supply, alternatives for the decontamination and reuse of water are
among the most requested technologies to solve those problems. Nanotechnology can significantly contribute to the evolution of
these devices since nanoscale materials have mechanical, catalytic, even antimicrobial properties that increase the effectiveness of
decontamination, filtration and desalination processes, which will be addressed in this article.
Nanomaterials, Decontamination of effluents, Water treatment, Antimicrobial effect, Adsorption
Unequal access to drinking water and basic sanitation are old issues in Brazil and worldwide [1,2]. Besides, this situation foments the proliferation of infectious parasitic diseases. Moreover, mainly in underdeveloped countries, it victimizes socioeconomically vulnerable people [3,4]. The degree of water contamination analysis, usually by fecal matter, is made by the number of microorganisms present in the sample, including Escherichia coli or thermotolerant coliforms . In addition, several other bacteria, protozoa, viruses from water contaminated by fecal waste causes serious diseases that lead to infant mortality rates in Africa and Southeast Asia [6,7].
The bacterium Escherichia Coli is mainly associated with untreated domestic sewage and the carrying of animal feces. This pathogen lodges in the intestinal tract, promoting hemorrhagic colitis that can be lethal . On the other hand, the bacteria Staphylococcus aureus settles on the skin and nasal fossae, causing simple skin infections to severe ones such as pneumonia, meningitis, endocarditis, etc. . The protozoa, often present in water contaminated by fecal waste, are Giardia intestinalis and Cryptosporidium. The first has part of its life cycle in the host’s intestine, which contains two phases of trophozoites and viable cysts, contaminating the water. The infection ranges from asymptomatic, moderate to severe. The second protozoan, also from an aquatic life cycle, is transmitted by its oocysts, which have high resistance to adverse conditions of the environment . Inside the host’s
body, it attaches to epithelial cells of the gastrointestinal
tract, compromising the intestinal mucosa, consequently
inducing malabsorption and diarrhea .
Moreover, some viruses are spread by contaminated water, such as adenovirus, hepatitis-type A, E - , and viruses from the family Caliciviridae. Adenoviruses can selectively infect a predetermined number of cells (viral histotropism). Although it can be asymptomatic, it can provoke intestinal, urinary, and respiratory infections .
Hepatitis A and E are transmitted mainly via the fecaloral route from contaminated water. The hepatitis A virus’s replication occurs in the liver. After being released by the gallbladder, it infects the digestive system, bringing fever, abdominal pain, vomiting, and diarrhea . The hepatitis E virus of the Hepeviridae family causes light and limited hepatitis. However, it can be aggravated to a severe clinical condition when contracted by pregnant women or immunodeficient people [15,16]. The most common viruses of the Caliciviridae family are Norovirus and Sapovirus, which infect humans. Both replicate in the intestinal tract and induce symptoms discussed above .
Those severe and neglected diseases must be considered when it comes to the mismanagement of water resources and its consequences. Given the above, practical and economically viable alternatives are increasingly needed to provide treated water.
The Reuse of Rainwater
Although it must follow rigorous criteria that ensure portability, its sanitary safety rules are more flexible, water is used for cleaning or irrigation when intended for consumption. In this case, catchment and reuse of rainwater is a viable alternative . A practical example, applied in Brazil, of the direct capture of rain, not contaminated from surface runoff, is the national program to support the rainwater collection and other social technologies (called cistern program) created by the Brazilian Ministry of Citizenship .
Traditional Treatment of Domestic and Industrial Effluents
Urban effluents must go through the decontamination process, carried out by sewage treatment systems before being disposed of since organic matter and pollutants can cause lots of environmental damage . This process consists of the retention of macroscopic dimensioned solids, followed by sand removal through sedimentation. After that, pH neutralization, flocculation, and decantation phases coagulate and sediment the pollutants. Then, the liquid phase of the surface goes to the next stage. Finally, occurs the disinfection of the effluent, promoting the decomposition of organic matter and oxygenation through sanitizing chemicals and biological treatment . Subsequently, others processes allow the reuse of nonpotable effluent, which involves filtration, chlorination, etc. [22,23]. Therefore, it is necessary to optimize and increase technology’s efficiency to promote water reuse and intelligent management in this perspective. Thus, nanotechnological materials come as an answer to this demand regarding their properties .
Use of Nanotechnological Tools in Water Treatment
Antimicrobial effect of nanoparticles
The antimicrobial effect of many nanostructures is, above all, due to the highly reactive character. The nanometric scale dimensions suggest an excellent ratio between surface and volume, hence more significant interaction with bacterial and fungal cells . Silver nanoparticles (AgNPs), in gram-negative bacteria, Ag+ ions interrupt and compromise the respiratory chain [26,27]. In this context,
the method and the synthesis conditions are essential for modulating their size and, consequently, their properties
[28,29]. Besides, alternative routes are already known
are sustainable and low cost, oxidizing silver ions in plant
Other nanoparticles in this bias are also evaluated, such as copper and zinc oxide, for delaying the development or elimination of microorganisms . According to recent researches, this property can be applied to filtering technology, incorporating these particles in different substrates [30,31]. The results indicate that there is a promising future in the development of products based on this technology. However, it demands a better understanding of the mechanism in which inhibition occurs and against which types of microorganisms this is more efficacious .
TiO2-mediated photocatalysis consists of the generation of oxidation sites on their surface from radiation incidence and, consequently, inhibits microorganisms [33,34]. This technology can also oxidize organic compounds, such as industrial contaminants, being recognized for their low cost and non-toxicity. Furthermore, studies indicate that the use of this technique corroborated, under the conditions tested, the inactivation capacity of approximately 99% of the total coliforms in the residual water sample . In another perspective, the use of TiO2is being evaluated for decontamination of industrial wastewater with some phenol concentrations .
The Use of Nanobiotechnological Membranes
The separation of contaminants by membranes has been widely used due to its optimized system, continuous operation, high selectivity, and its economic viability on a large scale [36,37]. Membranes can be distinguished by their symmetry, morphology, density, and porosity (Figure 1). Moreover, the separation process is classified by the direction of the filtration flow, as perpendicular or tangential. . Initially, membrane use was aimed at desalination processes. Over time, those membranes were visible to be applied at the decontamination of effluents by pesticides. Further, some research groups are currently studying its potential to remove waste from industrial sectors .
Nanofiltration is an example of this membrane separation technology which separates organic substances from immiscible solids in water using pressure or concentration gradient. The differential of this process is linked to the pore’s size, the retention capacity at the molecular level [37,39]. Therefore, nanofiber filters are also studied for this purpose. Usually, a second layer is deposited on a
microfiber substrate such as glass fibers or cellulose .
Indeed, another application of nanobiotechnology would be the dynamic membranes associated with bioreactors, which effectively retain inorganic particles and organic matter, and their use is increasingly present in sewage treatment. The advantages of this system consist in the reduction of steps when compared to the traditional process. In addition, it has a better capacity to retain biomass and by helping in disinfection. There is a deposition of sludge layer and microorganisms in this type of membrane, constituting a biofilm (the membrane itself) on support, promoting the containment of particles and organic material .
Nanomaterials and Their Applications as Adsorbents
One of the most used properties of nanomaterials is adsorption, which consists of the ability of certain solids to concentrate liquid or gaseous substances on their surfaces to the point of separating them from other substances in the environment in which they are found . Nanomaterials have been standing out at the water treatment based on the adsorption process due to their potential for cleaning water contaminated by industrial products. In addition, they are reusable and economically viable since there is a large surface area nanoscale in a small volume (Figure 2). This feature promotes the removal of the contaminant with a smaller amount of adsorbent. Thus, among its
applications, nanomaterials turn out to be a worthwhile
alternative for both wastewater treatment and the
mitigation of environmental damage .
Functionalized carbon nanotubes have also been developed as adsorbents to heavy metals removal . Another feature already researched of carbon nanotubes was is its potential use for the desalination process. A membrane was developed with a nanotube network in a porous matrix that performed sodium and chlorine ions’ retention in the study. [45,46]
The use of zeolites, better known in catalytic applications, also stands out because of their crystalline and porous structure. A significant surface area is applied as adsorbents of metallic particles and suitable for nanofiltration [47,48]. Research whose results point to removing 99% of aluminum and iron from a sample of water contaminated with residues from the mining activity indicates that zeolites are likely beneficial to treat effluents from some industrial sectors .
Other studies also point to the potential of other nanostructures with this property, such as graphene oxide. Through the oxygenated radicals present in its structure, it can interact with organic compounds and metal ions. Therefore, graphene oxide magnetic composites are also being researched to promote the recovery and reuse of this adsorbent [29,50].
Overall, it is clear that there are several nanotechnology’s contributions to water treatment, aiming at sustainability and low cost. Although there are still obstacles to their widespread use, such as the difficulty of scheduling and the investment required, alternatives showed in this article are continuously being improved. Thus, it is important to highlight their possible contribution in the long term to the spread of access to basic sanitation, reducing the proliferation of diseases related to drinking contaminated water, and improving water resource management.
- Pesquisa nacional de saneamento básico 2017,
abastecimento de água e esgoto sanitário, instituto
brasileiro de geografia e estatística.
- Carlão LF. A escassez de água no mundo não é mais
uma hipótese ou teoria: é o alerta para a mudança do
modelo de desenvolvimento humano. LEOPOLDIANUM.
2018 Aug 29;44(123):11.
- World Health Organization, Guidelines for drinkingwater
quality, 4th edition, incorporating the 1st addendum
- Omarova A, Tussupova K, Berndtsson R, Kalishev M,
Sharapatova K. Protozoan parasites in drinking water:
A system approach for improved water, sanitation and hygiene in developing countries. International journal
of environmental research and public health. 2018
- de Souza MF. Associação entre condições
socioeconômicas, sanitárias e de atenção básica e a
morbidade hospitalar por doenças de veiculação hídrica
no Brasil. cad. Saúde Pública. 2018;34(1):e00017316.
- World Health Organization. Progress on household
drinking water, sanitation and hygiene 2000-2017: special
focus on inequalities. World Health Organization; 2019.
- Gómez-Doñate M, Casanovas-Massana A, Muniesa M,
Blanch AR. Development of new host-specific Bacteroides
qPCR s for the identification of fecal contamination sources
in water. MicrobiologyOpen. 2016 Feb;5(1):83-94.
- Drumond SN, Santiago AD, Moreira M, Lanna MC,
Roeser HM. Identificação molecular de Escherichia coli
diarreiogênica na Bacia Hidrográfica do Rio Xopotó na
região do Alto Rio Doce. Engenharia Sanitária e Ambiental.
- Prado RR, Freitas EA, Júnior EC, Costa PC, Siqueira
MC, Rossi DA. Staphylococcus spp.: importantes riscos à
saúde pública. PUBVET. 2015 Jul 31;9:348-99.
- Santana LA, Vitorino RR, Antonio VE, Moreira TR,
Gomes AP. Atualidades sobre giardíase. Jornal Brasileiro
de Medicina. 2014 Jan;102(1):7-10.
- Lima LM, SANTOS JD, FRANZ H. Atlas de
parasitologia clínica e doenças infecciosas associadas ao
sistema digestivo. Santa Catarina: UFSC/Departamento
de Análises Clínicas,[2014. 2005.
- Gall AM, Mariñas BJ, Lu Y, Shisler JL. Waterborne
viruses: a barrier to safe drinking water. PLoS Pathog.
2015 Jun 25;11(6):e1004867.
- Detecção e caracterização de adenovírus humano
proveniente de casos de paralisia flácida aguda, na
região norte do Brasil, Ver Pan-Amaz Saúde v.5 n.3
Ananindeua, set. 2014 http://dx.doi.org/10.5123/S2176-
- Departamento de condições crônicas e infecções
sexualmente transmissíveis/ hepatite A / governo
- Departamento de condições crônicas e infecções
sexualmente transmissíveis/ hepatite E / governo
- Centro de informação em saúde para viajantes (Cives),
UFRJ / Hepatite E
- Anjos KD. Calicivírus humanos: pesquisa em amostra
de esgoto, construção de clone e modelagem estrutural.
- Norma ABNT NBR 13969:1997
- Programa Cisternas, secretaria especial do
desenvolvimento social, ministério da cidadania brasileiro.
- Companhia de águas e esgotos de Brasília, Caesb,
legislações e resoluções sistema de esgoto.
- Grupo interação, quatro etapas do tratamento de
efluentes industriais, grupo-interacao.com.
- EOS consultores, como funciona o tratamneto de
efluentes no Brasil, 2017.
- Tratamento de esgoto: conheça quais são as etapas.
SAMAE Caxias, Serviço autônomo municipal de água e
esgoto, Caxias do sul–RS.
- Martins MA, Trindade T. Os nanomateriais e a
descoberta de novos mundos na bancada do químico.
Química nova. 2012;35(7):1434-46.
- Mukherji S, Ruparelia J, Agnihotri S. Antimicrobial
activity of silver and copper nanoparticles: variation in
sensitivity across various strains of bacteria and fungi. In:
Nano-antimicrobials. Berlin, Heidelberg: Springer. 2012;
- DESENVOLVIMENTO DE FILTRO A BASE DE CELULOSE MICROCRISTALINA FUNCIONALIZADA
COM NANOPARTÍCULAS DE PRATA PARA
DESINFECÇÃO DA ÁGUA, I-238, congresso ABES
FENASAN , 2017
- Castro L, Blázquez ML, González F, Muñoz JÁ, Ballester
A. Biosynthesis of silver and platinum nanoparticles using
orange peel extract: characterisation and applications. IET
Nanobiotechnology. 2015 Oct 1;9(5):252-8.
- Gontijo LA, Raphael E, Ferrari DP, Ferrari JL, Lyon
JP, Schiavon MA. Efeito do pH na síntese de diferentes
tamanhos de nanopartículas de prata avaliados por EDL
e sua atividade antimicrobiana dependente do tamanho.
Matéria (Rio de Janeiro). 2020;25(4).
- Cheminski T. Preparação de nanomateriais derivados
do óxido de grafeno, caracterização e sua aplicação na
purificação de águas: Preparation of nanomaterials derived
from graphene oxide, characterization and its application
in water purification.
- Shimabuku QL, Arakawa FS, Camacho FP, Moreti
LD, de Lima Bazana S, Silveira C, et al. Estudo dos
parâmetros físico-químicos em filtros de carvão ativado
granular modificados com nanopartículas de prata e cobre
para aplicação no tratamento de água. e-xacta. 2015 Nov
- Rosa PD, Aguiar ML, Bernardo A. Avaliação da
eliminação de bioaerossóis em filtros de malha modificados
com nanopartículas de prata. Engenharia Sanitaria e
Ambiental. 2016 Dec;21(4):747-52.
- Freire NB, Pires LC, Oliveira HP, Costa MM.
Atividade antimicrobiana e antibiofilme de nanopartículas
de prata sobre isolados de Aeromonas spp. obtidos de
organismos aquáticos. Pesquisa Veterinária Brasileira.
- Teodoro A, Boncz MÁ, Paulo PL, Machulek Junior A.
Desinfecção de água cinza por fotocatálise heterogênea.
Engenharia Sanitaria e Ambiental. 2017 Oct;22(5):1017-
- Fotocatálise heterogênea aplicada no tratamento de
águas contaminadas por arsênio, Julio Anchieto Scherer
Filho, Universidade Federal de Santa Catarina, 2019.
- Fotocatálise heterogênea com luz UV para tratamento
de água. In: Rios Urbanos Limpos: Possibilidades e
desafios. 2017; pp.914-923.
- Avaliação dos processos de filtração por membranas e
de adsorção na purificação de biodisel, Magno José Alves,
Universidade Federal de Uberlândia, 2015
- Bueno MZ, Coral LA, Sens ML, Lapolli FR. Avaliação
da nanofiltração e da osmose inversa na remoção de
carbofurano em águas de abastecimento. Engenharia
Sanitaria e Ambiental. 2016 Sep;21(3):447-58.
- Avaliação do efeito antimicrobiano de nanopartículas
de óxidos metálicos, Embrapa instrumentação, 2017.
- Nóbrega R. Eficiência de membranas filtrantes de
nanofiltração e osmose inversa no pós-tratamento de
esgoto doméstico (Bachelor’s thesis, Universidade Federal
do Rio Grande do Norte).
- Pianowski Salussoglia AI, Guerra Béttega V, Tronville
PM, Lopes Aguiar M. Caracterização e desempenho de
filtros com nanofibras e HEPA utilizando nanopartículas.
MEIO FILTRANTE. 2016;14(78):16-22.
- Aplicação de um biorreator de membrana dinâmica
para tratamento de águas residuárias, Alvânia Barros de
Queiroz, UEPB, 2019
- Adsorção: aspectos teóricos e aplicações ambientais,
UFC, 2014, primeira edição
- Avaliação toxicológica e remoção de mercúrio(ii) em
águas contaminadas e resídios de mineração da bacia do
rio doce usando nanoadsorventes de δ-FeOOH modificado
quimicamente , Luiz Fernando Oliveira Maia,UFVJM,
- Aplicação de nanotubos de titanato modificados como
adsorventes para remoção de cobre(ii) em solução, ISBN
978-85-85905-25-5, 59 Congresso brasileiro de química,
- Confecção e caracterização de membrana para
dessalinização de água a partir de rede de nanotubos de
carbono, Plínio Fernandes Borges Silva, 2017.
- Dessalinização por membranas: tecnologias
consagradas e emergentes, Carolina Barbosa, UFMG,
- Desenvolvimento de tecnologia para purificação de
água através do uso de nanomateriais, Mariana Cerdeira,
Universidade do Porto, 2017.
- Aplicação de nanomateriais no tratamento de águas
residuais, IX Congresso Brasileiro de Engenharia de
- Utilização de zeólita para tratamento de águas
naturais impactadas pela drenagem ácida da mineração
do carvão, Agleison Anacleto Balicki, UFSC,2018.
- Preparação de nanomateriais magnéticos baseados
óxido de grafeno/quitosana, caracterização e sua aplicação
na remoção de poluentes em águas, 30 congresso ABES