The Nanosized Dye Adsorbents for Water Treatment
Total Page：16
File Type：pdf, Size：1020Kb
nanomaterials Review The Nanosized Dye Adsorbents for Water Treatment Shahin Homaeigohar y Nanochemistry and Nanoengineering, Department of Chemistry and Materials Science, School of Chemical Engineering, Aalto University, Kemistintie 1, 00076 Aalto, Finland; [email protected]; Tel.: +49-152-025-79933 The author’s current address is “Institute of Biomaterials, Department of Materials Science and Engineering, y University of Erlangen-Nuremberg, Erlangen 91058, Germany”. Received: 23 December 2019; Accepted: 4 February 2020; Published: 10 February 2020 Abstract: Clean water is a vital element for survival of any living creature and, thus, crucially important to achieve largely and economically for any nation worldwide. However, the astonishingly fast trend of industrialization and population growth and the arisen extensive water pollutions have challenged access to clean water across the world. In this regard, 1.6 million tons of dyes are annually consumed. Thereof, 10%–15% are wasted during use. To decolorize water streams, there is an urgent need for the advanced remediation approaches involving utilization of novel materials and technologies, which are cost and energy efficient. Nanomaterials, with their outstanding physicochemical properties, can potentially resolve the challenge of need to water treatment in a less energy demanding manner. In this review, a variety of the most recent (from 2015 onwards) opportunities arisen from nanomaterials in different dimensionalities, performances, and compositions for water decolorization is introduced and discussed. The state-of-the-art research studies are presented in a classified manner, particularly based on structural dimensionality, to better illustrate the current status of adsorption-based water decolorization using nanomaterials. Considering the introduction of many newly developed nano-adsorbents and their classification based on the dimensionality factor, which has never been employed for this sake in the related literature, a comprehensive review will be presented. Keywords: dye pollution; nanomaterials; adsorption; water treatment; decolorization 1. Introduction For many centuries, the human being had access to water as a plentiful, free resource across the world. This situation has drastically changed over recent decades and, currently, water scarcity has become a threat for sustainable development of the human community [1,2]. This challenge is going to exponentially expand and is, thus, considered a global systemic risk. Mekonen and Hoekstra [1] determined month-by-month blue water shortage statistics worldwide at a high spatial resolution. According to this assessment, they claimed that 4 billion people, i.e., two-thirds of the world’s population, with half living in India and China, suffer from intense water scarcity at least one month per year. Additionally, they stated that 0.5 billion people in the world are struggling with such a problem all year round (Figure1). Nanomaterials 2020, 10, 295; doi:10.3390/nano10020295 www.mdpi.com/journal/nanomaterials Nanomaterials 2020, 10, 295 2 of 43 Nanomaterials 2020, 10, x FOR PEER REVIEW 2 of 42 Figure 1. Water scarcity recorded for the world betweenbetween 1996 andand 2005.2005. Reproduced with permission [[1].1]. Copyright 2016, The The American American Association Association for for the the Advancement Advancement of of Science Science (AAAS). (AAAS). The main causescauses ofof waterwater scarcity areare thethe urban,urban, agricultural,agricultural, andand industrialindustrial pollutions.pollutions. In thesethese sectors,sectors, waterwater consumption has raised as much as 70 (agriculture), 22 (industry), and 8% (domestic) of thethe availableavailable fresh waterwater and,and, proportionally,proportionally, aa hugehuge amountamount ofof wastewaterwastewater containingcontaining a varietyvariety of pollutantspollutants has beenbeen generatedgenerated [[3].3]. Undoubtedly,Undoubtedly, the releaserelease ofof wastewaterwastewater fromfrom commercialcommercial andand industrialindustrial sectorssectors alongsidealongside thethe untreateduntreated domesticdomestic sewage,sewage, and chemicalchemical pollutantspollutants into thethe freshfresh waterwater resourcesresources is is disastrous disastrous not not only only to to the the human human community community but but also also to animals to animals and plantsand plants as well as aswell to as the to ecosystem. the ecosystem. Heavy Heavy metal metal ions, organicsions, organics (e.g., dyes),(e.g., dyes), and oils and whose oils whose presence presence in any in water any streamwater stream disqualifies disqualifies it for drinking it for drinking are part ar ofe part the majorof the watermajor contaminantswater contaminants [4]. [4]. Dyes have a history of thousands of years application for textile, paint, pigment, etc. Currently, Currently, almost 100,000100,000 types types of of dyes dyes are ar producede produced commercially. commercially. In terms In terms of consumption of consumption volume, volume, 1.6 million 1.6 tonsmillion of tons dyes of are dyes annually are annually consumed. consumed. Thereof, Thereo 10%–15%f, 10%–15% are are wasted wasted during during use use [5 ].[5]. AA varietyvariety of industries including including those those producing producing textile, textile, leather, leather, paper, paper, cosmetics, cosmetics, plastics, plastics, food, food, etc. deal etc. with deal witha dyeing a dyeing process process involving involving organic organic dyes dyes and and water. water. Such Such processes processes create create dye containingcontaining wastewaters,wastewaters, i.e., i.e., water water streams streams co contaminatedntaminated with with dye dye molecules molecules that that are colored are colored organics organics with withpoor poorbiodegradability biodegradability [6–9]. [Dyes,6–9]. particularly Dyes, particularly azo dyes azo, are dyes, recalcitrant are recalcitrant and endure and endureagainst againstthe aerobic the aerobicdigestion digestion and oxidizing and oxidizing agents [10]. agents This [10 significan]. This significantt resistance resistance arises from arises azo from dyes’ azo several dyes’ benzene several benzenerings. Statistically rings. Statistically 1%–20% 1%–20%of the entire of the producti entire productionon of dyes ofworldwide dyes worldwide are wasted are wastedin the textile in the textileeffluents effl uents[7,11] [and7,11 ]adversely and adversely influence influence the theme metabolismtabolism of ofthe the human, human, ecosystem, ecosystem, and and natural processesprocesses likelike eutrophication.eutrophication. The release of colored eeffluentsffluents intointo thethe aquaticaquatic mediamedia blocksblocks sunlightsunlight and, thus,thus, impedesimpedes the photosynthesisphotosynthesis process of thethe algal and aquaticaquatic plantsplants [[12].12]. Moreover, it hashas been provenproven thatthat azoazo dyesdyes andand theirtheir metabolitesmetabolites adversely aaffectffect humanshumans and animals due to theirtheir toxicity,toxicity, carcinogenicity,carcinogenicity, and and mutagenicity mutagenicity [ 13[13].]. Dyes couldcould be be classified classified based based on their on functionaltheir func groups,tional groups, color, and color, ionic and charges ionic upon charges dissolution upon indissolution aqueous solutionsin aqueous [14 solutions]. The latter [14]. mode The latter of classification mode of classification based on the based ionization on the ofionization dye molecules, of dye whichmolecules, intensively which aintensivelyffects the effiaffectsciency the of efficiency dye adsorption, of dye isadsorption, of higher importance.is of higher Accordingly,importance. dyesAccordingly, can be classified dyes can tobe theclassified ionic and to the non-ionic ionic and ones. non-ionic The non-ionic ones. The dyes non-ionic are divided dyes are to vatdivided and disperseto vat and dyes, disperse while thedyes, ionic while ones the are ionic divided ones to ar cationice divided (basic) to cationic and anionic (basic) dyes and (reactive, anionic direct, dyes and(reactive, acidic) direct, [5]. Table and 1acidic) tabulates [5]. theTable specific 1 tabulates properties, the specific application, properties, and toxicity application, of each and type toxicity of dye. of Aseach seen type in of the dye. table, As the seen listed in the dyes table, are mostlythe listed carcinogenic dyes are mostly and must carcinogenic be treated eandffectively must inbe thetreated dye manufacturingeffectively in the factories dye manufacturing to prevent their factories release to into prevent the environment. their release into the environment. Nanomaterials 2020, 10, 295 3 of 43 Table 1. Classification of dyes and their corresponding properties, applications, and toxicities (Reproduced with permission [5]. Copyright 2015, Elsevier). Dyes Properties Applications Toxicity Examples Acid red 183, acid orange 10, acid orange 12, acid orange 8, acid red 73, acid Nylon, wool, silk, paper, Acidic Soluble in water, anionic Carcinogenic red 18, sunset yellow, acid leather, ink-jet printing green 27, methyl orange, amido black 10B, indigo carmine Paper, PAN, treated MB, janus green, basic Soluble in water, and liberates nylons, treated polyesters, Cationic Carcinogenic green 5, basic violet 10, colored cations as antiseptic for rhodamine 6G biomedicine Insoluble in water, non-ionic, for Polyester, nylon, cellulose, Disperse orange 3, Allergenic (skin), Disperse the aqueous/hydrophobic cellulose acetate, disperse red, disperse red carcinogenic