Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / O presente estudo teve o objetivo de avaliar a remoÃÃo de metais pesados em efluentes industriais pelo uso de sulfeto quÃmico e biogÃnico. Inicialmente, foi operado, sob condiÃÃes mesofÃlicas (27  2 ÂC), um reator anaerÃbio de manta de lodo e fluxo ascendente (VÃtil = 2,7 L; TDH = 24 h) suplementado com sulfato (em relaÃÃes DQO/SO42- de aproximadamente 10 e 5) para a produÃÃo de sulfeto biogÃnico. Posteriormente, o efluente das indÃstrias de folheaÃÃo de joias da cidade de Juazeiro do Norte, CearÃ, foi caracterizado para verificar os principais metais contidos e suas faixas de concentraÃÃes, alÃm de outros constituintes. Em seguida, analisou-se a aplicaÃÃo de planejamento experimental multivariado cujos fatores estudados foram concentraÃÃo de metal (20, 80 e 140 mg/L), concentraÃÃo de sulfeto (20, 40 e 60 mg/L) e tempo de reaÃÃo (1, 5 e 9 min), no processo de remoÃÃo dos metais cobre, zinco e nÃquel, tanto na presenÃa quanto na ausÃncia de macro e micronutrientes. Finalmente, foi verificada em experimentos univariacionais a influÃncia das condiÃÃes operacionais tempo de reaÃÃo (15 e 30 min), razÃo molar metal/sulfeto (0,5; 0,7; 1; 1,6; 1,75 e 2) e fonte de sulfeto (quÃmico e biogÃnico) na eficiÃncia de remoÃÃo dos metais pesados analisados. ApÃs a caracterizaÃÃo do efluente das indÃstrias de folheaÃÃo de joias constatou-se que os metais majoritÃrios foram cobre, nÃquel e zinco. O reator sulfetogÃnico apresentou operaÃÃo estÃvel para as relaÃÃes DQO/SO42- estudadas, com remoÃÃo de DQO superior a 70% e reduÃÃo de sulfato acima de 90%. A partir do planejamento experimental multivariado, observou-se que o fator mais significativo foi a concentraÃÃo de metal para todos os casos, sendo que, para o cobre, a concentraÃÃo de sulfeto nÃo teve efeito significativo na presenÃa de macro e micronutrientes. Por sua vez, para o nÃquel, constatou-se que todos os fatores exercem influÃncia sobre a eficiÃncia de remoÃÃo. Jà para o zinco, o tempo nÃo teve influÃncia significativa na ausÃncia de macro e micronutrientes, enquanto que na presenÃa dos mesmos tal variÃvel apresentou significÃncia. Em seguida, nos experimentos univariacionais verificou-se que o tempo de reaÃÃo nÃo influenciou a remoÃÃo de metais estudados. A fonte de sulfeto apresentou efeitos diversos assim como a relaÃÃo molar metal/sulfeto. Por exemplo, com o cobre, em razÃes molares metal/sulfeto menores que 1,6, foram obtidas as maiores diferenÃas na eficiÃncia de remoÃÃo chegando atà 70%. Jà para o zinco, sà foram observadas algumas diferenÃas para razÃes molares acima de 1,6. Finalmente, para o nÃquel, alguma diferenÃa sà foi verificada para razÃes de atà 1. / The present study aimed to assess heavy metals removal from industrial effluents by using chemical and biogenic sulfide. Initially, an upflow anaerobic sludge blanket reactor (working volume = 2.7 L, HRT = 24 h), supplemented with sulfate (COD/SO42- ratio of approximately 10 and 5), was operated under mesophilic conditions (27  2 ÂC) for biogenic sulfide production. Subsequently, the effluent of jewelry plating industries from the city of Juazeiro do Norte, CearÃ, was characterized in order to verify the major metals and their concentration ranges, as well as other constituents. Then, the application of a multivariate experimental design, whose factors were metal concentration (20, 80 and 140 mg/L), sulfide concentration (20, 40 and 60 mg/L) and reaction time (1, 5 and 9 min), in the process of copper, zinc and nickel removal, both in the presence and absence of macro and micronutrients, was analyzed. Finally, in univariate experiments, the influence of the operating conditions, such as reaction time (15 and 30 min), metal/sulfide molar ratio (0.5, 0.7, 1, 1.6, 1.75 and 2) and sulfide source (chemical and biogenic), on the removal efficiency of the tested heavy metals was verified. After the characterization of the jewelry plating industries effluent, it was found that the majority metals were copper, nickel and zinc. The sulfidogenic reactor showed stable operation for the COD/SO42- ratios studied, with COD removal higher than 70% and sulfate reduction above 90%. From the multivariate experimental design, the most significant factor was metal concentration in all cases. For copper, sulfide concentration had no significant effect in the presence of macro and micronutrients. However, for nickel, all the factors have an influence on removal efficiency. And, for zinc, the time had no significant influence in the absence of macro and micronutrients, whereas, in their presence, that variable was significant. From the response surface contour plot, the optimum point, in terms of removal efficiency, obtained for nickel in the presence and absence of macro and micronutrients was [Ni2+] = 140 mg/L, [S2-] = 60 mg/L and t = 1 min. Subsequently, in the univariate experiments, it was found that the reaction time did not affect the removal of metals studied. The sulfide source had different effects as well as the metal/sulfide molar ratio. For example, for copper, at metal/sulfide molar ratios lower than 1.6, the greatest differences in removal efficiency were obtained, which reached up to 70%. However, for zinc, some differences were only observed at molar ratios above 1.6. Finally, for nickel, differences were observed for molar ratios below 1.

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2015-10-27T14:26:57Z No. of bitstreams: 2 Dissertação - Delcir Magalhães Cardoso Filho - 2015.pdf: 1361711 bytes, checksum: efc64fdbb620dc4c287b17ce56d2aaed (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2015-10-27T14:28:50Z (GMT) No. of bitstreams: 2 Dissertação - Delcir Magalhães Cardoso Filho - 2015.pdf: 1361711 bytes, checksum: efc64fdbb620dc4c287b17ce56d2aaed (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2015-10-27T14:28:50Z (GMT). No. of bitstreams: 2 Dissertação - Delcir Magalhães Cardoso Filho - 2015.pdf: 1361711 bytes, checksum: efc64fdbb620dc4c287b17ce56d2aaed (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2015-06-17 / The pits and septic tanks wastes have high organic load, pathogens, metals and other elements, requiring appropriate treatment for not pollute the environment. Among the alternatives for their treatment, it has recently been proposed to use constructed wetlands. However, information on such use is scarce. Therefore, this study aimed to evaluate the performance of a constructed wetlands system using the Vetiver grass plant species (Chrysopogon zizanioides), on removing metals, P, S and Se from cesspools residues. Two tanks were constructed, dug into the ground (planted tank and control) and filled with a substrate consisting of gravel # 0, gravel # 1 and medium sand. The system built has operated under batch, with Hydraulic Retention Time of six days and subsurface vertical downward flow. Through obtained concentrations of different inorganic elements on: the applied cesspools residues; the treated effluent; the sludge accumulated at tanks surface and; the vegetal tissues, they were calculated: the total loads influent to the system; the output loads; the efficiency in removing attributes; the load accumulated at tanks surface; the load absorbed by macrophytes and; the loads retained in the roots and by the substrate. The attributes removal efficiency was calculated considering the evapotranspiration that showed an average rate of 40.27% in the Vetiver tank. The applied cesspools residues showed considerable variability in their concentrations. The concentrations of the treated effluent were subjected to Tukey test (α = 0.05). The effluents concentrations from Vetiver and control tanks statistically differed only for antimony, sulfur and iron, but the Vetiver grass showed removal efficiency greater than 20% to 30 of the 33 analyzed parameters. / Os resíduos de fossas e tanques sépticos possuem elevada carga orgânica, microrganismos patogênicos, metais e outros elementos, necessitando de tratamento adequado para não poluir o ambiente. Dentre as alternativas para seu tratamento, recentemente tem sido proposta a utilização de alagados construídos. Todavia, as informações sobre tal uso são ainda escassas. Assim, este trabalho teve como objetivo avaliar o desempenho de um sistema de alagado construído, utilizando a espécie vegetal capim Vetiver (Chrysopogon zizanioides), na remoção de metais, P, S e Se do resíduo de fossa. Foram escavados dois tanques idênticos (tanque plantado e controle) sendo preenchidos com meio suporte formado por brita # 0, brita # 1 e areia média. O sistema construído operou em regime de batelada, com Tempo de Detenção Hidráulica de seis dias e fluxo subsuperficial vertical descendente. Por meio das concentrações obtidas para diferentes elementos inorgânicos: no resíduo de fossa aplicado; no efluente tratado; no lodo superficial acumulado e; nos tecidos das macrófitas, foram calculadas: as cargas totais afluentes do sistema; as cargas de saída; a eficiência na remoção inorgânica; as cargas acumuladas no lodo superficial; as cargas absorvidas pelas macrófitas e; as cargas retidas nas raízes e no meio suporte. A eficiência na remoção inorgânica foi calculada considerando a evapotranspiração, que apresentou taxa média de 40,27% no tanque Vetiver. Os resíduos de fossa aplicados apresentaram grande variabilidade em suas concentrações. As concentrações do efluente tratado foram submetidas ao teste de Tukey (α = 0,05). As concentrações de saída dos tanques Vetiver e Controle diferiram estatisticamente apenas para Antimônio, Enxofre e Ferro, contudo o capim Vetiver apresentou eficiência de remoção superior a 20% para 30 dos 33 atributos analisados. Palavras-chave: capim Vetiver, remoção de metais, zona de raízes.

In this project the adsorption ability of mesoporous magnesium carbonate (MMC) for copper (Cu), cobalt (Co), chromium (Cr) and arsenic (As) was evaluated. This was done by mixing MMC and dissolved metal (of different concentrations) and measuring the concentration of the solution before and after addition of MMC with Inductively coupled plasma optical emission spectroscopy. Besides MMC, “ordinary” magnesium carbonate (MgCO_3) was evaluated for comparison. Furthermore, the MMC was characterised with various instruments before and after adsorption of the metals. The adsorption experiments established that MMC was able to adsorb large amounts of Cu, Co and As while MgCO_3 was not. Moreover, it was discovered that both materials adsorbed equally large amounts of Cr. At higher concentrations of Cu and Co the uptake capacity of MMC suddenly dropped. However, for As, it was determined that MMC reached saturation at a concentration of ~22 mg/L. An adsorption experiment of a mixture of metals of 20 mg/L of each metal could not conclude anything about the selectivity of MMC, but the experiment revealed that MMC was able to adsorb all of Cu, Co and As rapidly at this concentration. The characterisation of MMC before adsorption revealed an amorphous structure and a high porosity. The structure of MMC after adsorption of Cu went from amorphous to crystalline and after adsorption of Co and As the structure also became crystalline, but of a lower degree than after adsorption of Cu. Furthermore, it was discovered that ion exchange also occurred along with adsorption.

Batch equilibrium and dynamic column studies were undertaken to compare the metal-removal capabilities of two natural, low-cost materials (dried, crushed brown seaweed and shrimp shells) with a commercially available strong acid cation exchange resin (CER). All media maintained structural and hydraulic integrity over the duration of the column experiments. The batch tests showed that the low-cost materials demonstrated high adsorption capacities and affinities to Pb, Cu, Cd and Zn, but were slightly outperformed by the CER. Metal removal by each media was far superior to that reported for other types of low cost materials. Fixed beds of each media reduced concentrations of the target metals in a synthetic drainage water solution to levels below reference values measured at a case study site. This result suggests that any of the materials tested have the potential to completely remove impacts of a point source of metal contamination on the local water regime at the site. The CER column sustained the longest service time without large-scale breakthrough of any metal.

Stormwater runoff may contain high levels of pollutants and is regulated by the Federal National Pollution Discharge Elimination System (NPDES). Stormwater bioretention (BR) systems are often used to satisfy these regulations. BR systems collect accumulated runoff that leaches into groundwater. A greenhouse study evaluated nutrient and metal removal among plant species that are typically found growing in BR systems. A field demonstration study assessed citric acid enhanced metal bioaccumulation potential under typical BR system conditions. The greenhouse experiment examined pollutant retention, and bioaccumulation potential for six plant species undergoing three hydraulic and pollutant loads. Results verified there was 98% recovery of total phosphorous over the study period. Biomass increased with higher hydraulic and pollutant loads for all species. Phragmites australis, Carex praegracilis, and Carex microptera took up significantly more total phosphorous and nitrogen mass into shoots than Typha latifolia, Scirpus valid us, and Scirpus acutus. This study also found that 89% of applied metals were removed within the top 27 em of soil in all treatments. Similar results were found regarding copper, lead, and zinc concentrations and bioaccumulation. Carex praegracilis, and Carex microptera exhibited higher metal distribution in plant tissue and exfiltrate, and lower distribution in the soil media than the other species. This indicated species differences in biological and chemical processes taking place within the simulated BRsystems. The field experiment investigated citric acid enhanced metal bioaccumulation potential among three different plant species under representative BR conditions. Citric acid significantly increased metal concentrations in the soil pore water for the planted treatments, but this did not result in increased metal uptake into plant tissue. However, notable differences were found among species, where Carex microptera accumulated more AI, Cr, Cu, and Fe in the above ground tissue than Helianthus maximiliani and Typha /atifolia (except for Cu in Helianthus). These results provide greater insight into the biological and chemical process that affect transport, uptake and translocation of nutrients and metals, and confirm the importance of species selection in BR systems to optimize nutrient and metal retention and recovery from stormwater runoff to minimize subsequent groundwater pollutant loading.

<p> Heavy metals, especially arsenic, have become a hot research topic due to their high toxicity and low removal efficiency in drinking water. Biofouling is one of the main factors affecting the removal efficiency of point-of-use (POU) water filtration systems. However, limited information is available on the effect of biofouling on heavy metal removal by POU systems. The aim of this study was to investigate how biofouling affects the removal efficiency of heavy metals,  especially arsenic, by different POU systems. Daily water use patterns in the U. S. households were simulated under laboratory conditions for the operation of POU systems. Sodium acetate was added to tap water to simulate an assimilable organic carbon source that contributes to biofouling formation and the concentration of sodium acetate gradually increased from 100 μg/L to 400 μg/L.  Sodium meta-arsenate (100 μg/L) was added to tap water to test its removal efficiency by POU  systems. Biofouling development and metal removal efficiency were monitored and correlated.  The results showed that arsenic removal efficiency and biofouling were positively correlated in both the activated carbon (AC) and reverse osmosis (RO) POU systems. Other conditions, such as temperature and flow rate, were negatively correlated with metal removal efficiencies in both systems. Overall, biofouling has been shown to contribute to improved removal efficiency of arsenic by POU, and the promotion effect was more significant in AC systems than in RO systems.  The results may contribute to an improved understanding of the maintenance of POU systems for heavy  metal removal </p>

Highway runoff and its pollutants are of growing concern. These pollutants require treatment as their concentration often are increased. A common removal method is the use of sedimentation ponds that removes particulates through gravity. However, sedimentation does not remove the pollutants inside very fine particulate material or the dissolved pollutants. An additional treatment step is required to remove these pollutants and necessary to reach more stringent discharge demands. In this report, the removal of metals was studied on stormwater after sedimentation in a dam in the existing treatment facility at Lilla Essingen. The runoff reaching the facility largely comes from the highway Essingeleden, which has an annual average daily traffic of 140 000 vehicles. The commercial filter material D-Rainclean was used in this study, which started in late August 2021 and ended in November 2021. The filter material was filled equally into two separate filter wells. After sedimentation, the runoff was pumped to each filter well with a constant flow of around 600 L/h. This load caused a hydraulic retention time of about 41 minutes. The stormwater flowed through the filter material from the bottom towards its surface, i.e. upward flow, creating saturated conditions. The removal of dissolved zinc (Zn) was just above 90% while dissolved copper (Cu) was in average removed by 50 %. The effluent concentrations of Cu were generally above the regulation limits set by Järfälla municipality and Gothenburg city. Dissolved calcium (Ca) and potassium (K) was released by the filter material itself through the entire trial and dissolved vanadium (V) was released initially but decreased continuously and reached close to zero at the end of the trial. Influent stormwater concentrations of sodium (Na), magnesium (Mg), chromium (Cr) and molybdenum (Mo) was unaffected by the filter as was the dissolved fraction of nickel (Ni), iron (Fe) and aluminium (Al). Particulate material was removed by the filters. However, at the end of the trial a release of particulate material was observed. This is likely caused by filter erosion that occurred through the combination of clogging and the high surface load. Surface loading and retention time was elevated during the trials. The sharp increase of suspended solids loads in November followed by increased filter pressure drop shows the importance of having a functional sedimentation to prevent physical clogging of the filter media. / Dagvatten från vägar och föreningarna inuti detta vatten är ett ökande problem. Avskiljningen av dessa föroreningar är en utmaning, en konventionell reningsmetod är användandet av sedimenteringsdammar för att avskilja de partikulära föroreningarna. Med hårdare krav på utsläpp av metaller krävs ytterligare reningsmetoder för att hantera de lösta metallföreningarna i dagvatten, vilka ej kan avskiljas med sedimentering. Av speciellt intresse är de lösta fraktionerna av zink (Zn) och koppar (Cu). Zink (Zn) och koppar (Cu) är av störst intresse när de förekommer till stor del i löst form, varvid de ej tas bort i sedimenteringsdammar. Försöket i den här rapporten testar avskiljningsförmågan hos det reaktiva filtermaterialet D-Rainclean under hög ytbelastning, 0,35 m/h och kort uppehållstid, 41 min. Dagvattnet kommer från ett område på 1,76 ha där majoriteten av ytan består av hårt trafikerad väg. Dagvattnet når två separata reaktiva filter efter försedimentering. Filtermaterialet ligger fördelat i två filterbrunnar, F1 och F2, med samma mängd D-Rainclean.Totalt passerade ungefär 3000 provolymer genom filtren. Den totala mängden suspenderat material som belastade filtren var 35 kg. Efter 600 porvolymer uppstod ett tryckfall på 40 cm för både F1 och F2. En 60 cm tryckpelare nåddes i båda filtren efter ungefär 1000 till 1200 porvolymer. Under flöden med hög turbiditet mot slutet av försöket nådde tryckfallet 110 cm för F1 och över 80 cm för F2.Avskiljningen av löst Zn var över 90%. Avskiljning av löst Cu var runt 50 %. Koncentration av Cu efter de reaktiva filtren översteg de riktvärden som satts av Järfälla kommun samt Göteborg stad. Löst kalcium (Ca) och kalium (K) släpptes av filtren under hela försöket. Löst vanadin (V) släpptes också av filtret men halten V minskade kontinuerligt och nådde till slut en koncentration nära detektionsgränsen. Inkommande koncentrationer av natrium (Na), magnesium (Mg), krom (Cr) och molybden (Mo) var opåverkade av filtret, likaså den lösta fraktionen av nickel (Ni), järn (Fe) och aluminium (Al). Majoriteten av metallernas partikelfraktioner avskildes av filtren men mot slutet började filtren släppa partikulärt bundna metaller.Uppehållstiden för vattnet i filtret var antagligen för kort för att få hög avskiljning av Cu varför den föreslås att den förlängs om det är praktiskt möjligt.

Heavy metal contamination in water is a serious environmental and human health issue. Lead (Pb2+) and cadmium (Cd2+) are strictly regulated in wastewater effluent due to their high toxicity at low concentrations. Heavy metals are difficult to remove in conventional biological wastewater treatment because they are water soluble and non-biodegradable. Advanced treatment, such as tight membrane filtration and ion exchange, can be applied but they often require a high electrical energy input and a large amount of chemicals for pre- or post-treatment. Microbial electrolysis cells (MECs) can be used to treat wastewater while simultaneously recovering energy in the form of hydrogen gas. Additionally, MECs were proven to be effective for heavy metal removal. The commonly investigated removal mechanism for heavy metals in MECs is reduction at the cathode where heavy metal ions are reduced to metallic solids. The research presented in this thesis examined the effectiveness of cathodic reduction and other heavy metal removal mechanisms in MECs over a wide range of metal concentrations (10 μg/L-12 mg/L). Lab-scale MEC operation demonstrated successful removal of both Pb2+ and Cd2+ under different electric conditions, operation times, and initial metal concentrations. In addition to cathodic reduction, heavy metal removal in MECs was demonstrated through chemical precipitation at the cathode and electrochemical reduction and biosorption at the bioanode. The results of this research also confirmed the importance of microbial activity at the bioanode to efficiently drive the removal mechanisms in MECs. / Thesis / Master of Applied Science (MASc)

Roads, buildings, vehicles, and human activities cause spreading of pollutants, which partly end up in stormwater. The pollutant load contains solid particles of various size, hydrocarbons, organics, metals, nutrients, and microorganisms, which can have negative effects on water quality of surface-, coastal- and ground waters. Furthermore, urban development causes hardening of ground and reduced soil permeability that promotes rapid runoff during precipitation. The conversion from permeable to impermeable surfaces therefore lead to increased volumes stormwater but also decrease in stormwater water quality.  Stormwater runoff metals are bound to various particles or occur in the dissolved fraction which is more toxic to aquatic life. Infiltration to soil, sand or other media is common practice to reduce runoff and filtrate metals and many treatment facilities and filter media have therefore been assessed for their metal removal efficiencies. High metal removal is often achieved for total metals, but removal of dissolved fraction remains elusive in many studies. Hence the importance of evaluate removal of dissolved metals before application to stormwater treatment facilities.  The experimental column study of metal removal using commercially available reactive filter media showed that all filter media removal efficiencies in the order of zinc &gt; copper &gt; nickel. Removal efficiencies of chromium and lead were not considerably higher in tested filter media compared to the reference filter sand. Two filter media also leached chromium during the initial part of the experiment. / Vägar, byggnader, fordon och mänskliga aktiviteter orsakar spridning av föroreningar av vilka en del förekommer i dagvatten. Urban bebyggelse orsakar också hårdgörande av ytor och reducerar jordens permeabilitet vilket skapar snabb avrinning vid nederbörd. Avrinningen innehåller bland annat partiklar, kolväten och andra organiska ämnen, metaller, näringsämnen och mikroorganismer vilka kan ha negativa effekter på yt-, kust- och grundvatten. Omvandlingen till hårdgjorda ytor orsakar därför både ökade volymer avrinning och sämre vattenkvalité.  Metaller i dagvatten är ofta bundna till olika partiklar eller förekommer i löst form där den lösta formen anses vara mest miljöfarlig. Infiltration i jord, sand eller annan media är vanliga sätt att reducera avrinning och filtrera metaller. Hög förmåga att avskilja metaller kan ofta hittas för totala koncentrationen av metall men avskiljning av den lösta formen är ofta oklar. Utvärdering av olika filtermaterials förmåga att reducera lösta metaller är därför av särskilt intresse.  Kolonnförsöken gjorda för att utvärdera metallavskiljningskapacitet med kommersiellt tillgängliga reaktiva filtermaterial har i denna uppsats visat att filtermaterialen har högst procentuell avskiljning för zink följt av koppar och därefter nickel. Krom och bly avskiljs inte mer i dessa filtermaterial än vad de gör i sandfilter. Två av filtermaterial läckte dessutom initialt höga koncentrationer krom.

Maintaining a constant supply of clean drinking water is among the most pressing global challenges in our time. About one-third of the population is affected by the water scarcity and it can only get worse with climate change, rapid industrialization, and the population growth. Even though nearly 70 percent of the planet is covered by water, the consumable freshwater content is only 2.5 percent of it. Unfortunately, the accessible portion of it is only 1 percent. Even so, most of the freshwater bodies are choked with pollution. Considering the vast availability of saline water on the planet and the increasing wastewater generation, seawater desalination, and wastewater treatment and recycling seem to have the potential to address current water-related issues. Therefore, it is necessary to find efficient techniques for seawater desalination and wastewater treatment. The use of nanostructured materials for these applications is becoming a popular approach due to the unique chemical and physical properties they possess compared to bulk materials Solar energy is the cleanest and most abundant renewable natural resource available. Materials for solar photothermal energy conversion are highly sought after for their cost savings, clean environment, and broad utility in providing water heating and/or steam for many applications including domestic water heating and solar-driven desalination. Extensive research efforts have been made to develop efficient solar absorbers with characteristics such as low weight, low thermal conductivity, broad solar absorption and porosity to be able to float on water to provide more efficient and cost-effective solar steam generation systems. Metal NPs have been proposed to take advantage of the high efficiency of the photothermal energy conversion associated with surface plasmon resonance absorption. Nanostructured carbon-based materials such as graphene oxide, carbon nanotubes, carbonized biomass are also in use due to their excellent photothermal energy conversion ability over the range of the visible and near infra-red region of the electromagnetic spectrum. In this dissertation, five projects based on the utility of nanostructured materials for desalination, photocatalysis and water treatment will be discussed. The first three projects involve the fabrication and design of plasmonic and carbon-based photothermal materials for applications in solar steam generation, water desalination, and wastewater treatment. In the fourth project, a unique shape of ZnO nanostructure was synthesized for photodegradation of organic dyes in industrial wastewater. The final project demonstrates the shape-controlled synthesis of iron carbide nanostructures and composite materials of aminated graphene oxide for the removal of Cr(VI) from wastewater.